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1
Hammerman, Mattias, and Robert Karlsson. "Analysis of undrained shear strength from drop-cone tests." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93142.
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The Swedish Geotechnical Institute, SGI, has been given the assignment of mapping the risk of landslides in the area by the river Göta älv. Tests were made to determine the shear strength of soil on land and in the river. It has been shown that shear strength values evaluated with drop cone tests from points under the river are higher compared to other test methods although experience shows that the shear strength values from fall cone tests usually is slightly lower compared with those from other test methods. The soil under the river is more over consolidated then the surrounding soil because of years of erosion from the river. When evaluating undrained shear strength from CPT- and field vane shear tests, consideration to over consolidation is taken. SGI is now interested to look into if this needs to be done when evaluating undrained shear strength from fall cone tests as well. This thesis compares values from fall cone tests without correction for the over consolidation with values which is corrected to see if a correction is necessary. All data concerning the soils effective stress is necessary for calculating the over consolidation ratio and is evaluated manually. There is no set method to correct fall cone tests for the over consolidation so the existing formula used in the correction of field vane shear tests in over consolidated soils were used, both in its original form and with the exponent -0,15 adjusted. Own evaluations were made on the CPT- and field vane shear tests for comparisons with the results from the fall con tests. All processed data comes from SGI's own measurements. Results show that shear strength values from fall cone test and CPT field tests match better after corrections due to the over consolidation with the presented formula.Statens Geotekniska institut, SGI har haft i uppdrag att skredkartera Göta älvdalen. Man har gjort provtagningar på land och i älven för att bestämma skjuvhållfastheten i jorden. Det har visat sig att skjuvhållfasthetsvärdena utvärderade med fallkonförsök på provpunkter i älven är högre än de från övriga provmetoder vilket de erfarenhetsmässigt inte brukar vara. I älven där leran under årens lopp avlastats genom erodering är leran mer överkonsoliderad jämfört med omkringliggande lera. Vid utvärdering av skjuvhållfasthet från CPT- och vingförsök tas numera hänsyn till jordens överkonsolidering. SGI är nu intresserade av att undersöka om detta även behöver göras vid bestämning av skjuvhållfasthet från fallkonförsök. I detta examensarbete jämförs skjuvhållfasthetsvärden från fallkonförsök utan korrigering för överkonsolidering med korrigerade värden för att se om en korrigering är nödvändig. Alla värden på jordens effektivspänning, som behövs för att beräkna överkonsolideringsgraden är beräknade manuellt. Det finns ingen vedertagen metod för att korrigera fallkonförsök för överkonsolidering, så den befintliga formeln som används vid korrigering av vingsonderingar i överkonsoliderade jordar har prövats, både i sin ursprungliga form och med justeringar av exponenten -0,15. Till jämförelsen har egna utvärderingar utöver de av fallkonförsöken gjorts på CPT- och vingsonderingar. Alla behandlade data kommer från SGI:s egna mätningar. Resultaten visar att skjuvhållfasthetsvärden från fallkonförsök och CPT-sondering stämmer bättre överens efter en korrigering för överkonsolidering med tidigare nämnd formel.
2
Hughes, Philip Daniel. "Development and clinical application of tests of respiratory muscle strength." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391625.
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3
Kyambadde, Benjamin Senyonga. "Soil Strength and Consistency Limits from Quasi-Static Cone Tests." Thesis, University of Brighton, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523435.
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4
Bonetti, Rodolfo Arturo. "Ultimate Strength of the Local Zone in Load Transfer Tests." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/31392.
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An improved equation is presented for the prediction of the ultimate strength of the local zone in Load Transfer Tests. The derivation of this new formulation is the result of the investigation of the ultimate bearing strength of plain and reinforced concrete blocks, concentrically loaded. A total of 199 bearing tests were performed on plain and reinforced concrete prisms to evaluate the variables involved in the bearing problem. A finite element analysis of a typical square block loaded with different bearing areas was performed. Two equations, one for plain concrete and the other for reinforced concrete were derived using the Mohr failure criterion.
The performance of the derived equations was evaluated against actual test data. The results of this evaluation showed very good agreement between the predicted ultimate strength and the actual test strength for both plain and reinforced concrete. For plain concrete specimens the ratio Ptest/Ppred was 1.05 with a coefficient of variation of 9 percent. In the case of reinforced concrete blocks the ratio Ptest/Ppred was 1.00 with a coefficient of variation of 14 percent.Master of Science
5
Greig, James William. "Estimating undrained shear strength of clay from cone penetration tests." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25076.
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This paper discusses several proposed methods for estimating undrained shear strength from cone penetration tests. This correlation has been studied in the past, however, most have focussed only on the cone bearing. In addition to discussing these traditional methods, this paper evaluates recently proposed methods of estimating Su from CPT pore pressure data.
The results of field vane and cone penetration tests from five lower mainland sites are presented in relation to the different proposed correlation techniques. The results show that there is no unique cone factor for estimating Su from CPT for all clays, however, a reasonable estimate of Su can be made by comparing the predictions from several of the proposed methods. With local correlations these techniques can be quite reliable. The results also show that the estimation of Su from CPT is influenced by various factors relating to: the choice of a reference Su, cone design, CPT test procedures and the soil characteristics. In particular, the estimation of Su from CPT is strongly influenced by such soil parameters as stress history, sensitivity and stiffness. Increases in OCR and sensitivity were reflected by increases in the traditional cone factors Nc and Nk.
The use of pore pressure data appears to be a promising means of estimating. Su from CPT. Expressions have been developed that predict excess pore pressures based on cavity expansion theory and attempt to include the effects of sensitivity, stress history and stiffness. In addition, comparisons between friction sleeve measurements and Su and a method for estimating sensitivity from friction ratios are presented. Lastly, recommended procedures for estimating Su from CPT are given.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
6
McElligott, Mark, and n/a. "The relationship between strength and endurance in female triathletes." University of Canberra. Human and Heritage Sciences, 1992. http://erl.canberra.edu.au./public/adt-AUC20060918.160011.
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Laham, Noor. "Episodic DSS tests to measure changing strength for whole-life geotechnical design." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Find full textAbstract:
Changes in seabed soil strength due to loading events during the life of a structure, affect the response of the structure to any future event. This change in soil strength due to loading events, in particular cyclic loads, was of great concern in the field of offshore geotechnics during the last decades. Allowing for these changes can have a beneficial outcome on the design. Studying the changes occurring in the soil can be mainly done using large scale centrifuge tests or Laboratory element testing, where the latter proved to be able to successfully illustrate soil strength changes during periods of cyclic loads and reconsolidation.
A new approach of life design known as “the whole life design” has been introduced lately to the industry “. Whole life design embraces the time-varying evolution of actions and resistances to create a continuous assessment of conditions of a structure.
This dissertation studies the possibility of one of the most famous element tests which is the “Direct simple shear testing” to capture the changing in strength under cyclic (i.e., episodic in this context) loads and the settlement of subsea layers for the whole life geotechnical design. The outcome of the DSS testing in addition to outcomes from other previous methods (eg T-bar penetrations and Triaxial testing) can form the basis for a new framework to be adopted in the future for demonstrating a whole life design for subsea structures.
In general, the project introduces the concept of whole-life geotechnical design through practical examples and shed lights on Direct simple shear testing ability to simulate specific cyclic loading scenarios. The topic closes with a discussion of next steps to enable whole-life geotechnical design to be more readily adopted in routine practice where appropriate.
8
Johnson, Jack Buckland Jr. "Evaluating the Importance of Strength, Power, and Performance Tests in an NCAA Division I Football Program." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/29933.
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Strength and conditioning professionals spend a great deal of time and effort trying to improve athletic performance. Even as coaches evaluate each athlete by using the results of a vast battery of tests, there has been considerable speculation and discussion about the physical attributes of Division I football players and their playing status. The purpose of this study was to determine what influence strength, power, and performance tests scores have on an individual's playing status.
The Skill group results indicate that power is the most important factor differentiating between starters and non-starters. Simultaneously, the Combo group results indicate that speed is the most important factor differentiating between starters and non-starters. Also, the L.O.S. group results indicate that bodyweight is the most important factor differentiating between starters and non-starters.Ph. D.
9
Zavoral, Dan. "Dynamic properties of an undisturbed clay from resonant column tests." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30144.
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The dynamic properties of clay deposits under seismic or wave loading conditions must be well understood to assure dynamic stability of structures founded on such soil. The dynamic shear modulus and damping appear to be a complex function of many variables, and a wide range of values have been reported in the literature. Consequently, considerable uncertainty exists in choosing the appropriate values of shear modulus and damping for a particular problem.
This thesis presents a study of the influence of various factors on the shear modulus and damping of a marine clay using a resonant column/torsional shear device. In particular, the influence of factors such as shear strain amplitude, effective confining stress, stress history, frequency (strain rate), and secondary time-dependent behaviour are examined. The pore pressure response is also studied.
The shear modulus was found to degrade for shear strains above 0.005%. The strain dependency was found to be well represented by a single normalized modulus reduction curve regardless of the confining pressure or overconsolidation ratio. Slower strain rates resulted in smaller values of shear modulus.
Of the variables studied, the duration of sample confinement was found to be the most imporant factor affecting the material damping. Above 0.005% strain, the damping of the marine clay increased with shearing strain amplitude. No significant effect of confining pressure and stress history on damping was observed at any strain level. As well, the material damping was found to be relatively independent of loading frequency.
Both the shear wave velocity and damping obtained in this study were found to be consistent with the in situ values determined using the seismic cone penetration test.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
10
Dirgėlienė, Neringa. "Research of soil shear strength in triaxial tests and probabilistic assessment of results." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20080207_161629-95063.
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Necessary information about soil properties, which is needed for designers and constructors, is obtained in each construction site while examining physical and mechanical properties of soils. Soil strength parameters and using them determined soil bearing resistance usually are defined with some errors. If we know the reasons of errors, disadvantages of testing equipment could be eliminated, methodology of data evaluation could be developed, soil parameters could be determined more precisely and foundation designed more economically.
At present triaxial and direct shear tests are the most common tests for determination of soil shear strength parameters in laboratories. Different values of soil shear strength parameters are determined using laboratory equipment of various types. Triaxial test is the most widely used method for determination of soil shear strength parameters. This is one of the most reliable methods to model stress-strain state of ground. It is assumed that soil sample deforms uniformly during the triaxial test. But it is not often the case that a sample in triaxial apparatus deforms uniformly. Questions arise, what is stress-strain distribution in soil sample, when a load is transmitted in a prescribed way? What influence does a non-uniformity have on the soil strength parameters and on foundation size calculated using determined soil strength parameters? Why sandy soil strength parameters obtained from triaxial test are bigger than the one’s, obtained... [to full text]Projektuojant ir statant įvairius pramoninius ir civilinius pastatus, visada reikalingi duomenys, kurie apibūdintų gruntų, sudarančių pastatų pagrindus, fizines ir mechanines savybes. Tokia projektuotojams ir statybos specialistams būtina informacija gaunama tiriant gruntų fizines, mechanines savybes kiekvienoje statybų aikštelėje. Šių savybių rodikliai ir pagal juos apskaičiuotas pagrindo stiprumas nustatomi su tam tikromis paklaidomis. Atskleidus tų paklaidų priežastis, šalinami tyrimo prietaisų trūkumai, tobulinami tyrimo duomenų apdorojimo metodai, tiksliau nustatomi grunto stiprumo rodikliai, ekonomiškiau projektuojami pamatai. Šiuo metu grunto kerpamojo stiprumo rodikliai dažniausiai nustatomi laboratorijose triašio slėgio ir tiesioginio kirpimo aparatais. Šių savybių rodikliai nustatyti įvairių konstrukcijų prietaisais gaunami skirtingi. Įtempimų ir deformacijų būvis grunto pagrinde geriau modeliuojamas triašio slėgio aparatu nei tiesioginio kirpimo aparatu, todėl triašio slėgio aparatas šiuo metu yra plačiai naudojamas pasaulyje nustatant grunto kerpamojo stiprumo savybių rodiklius. Daroma prielaida, kad bandinys bandymo metu deformuojasi vienodai. Šis teiginys yra pagrindinė triašio bandymo idėja. Tačiau dažniausiai bandinys deformuojasi nevienodai dėl grunto bandinio viršaus ir apačios horizontalių poslinkių suvaržymo, bandinio aukščio, nepakankamo drenavimo, guminės membranos poveikio, jo savojo svorio ir kt. Baigtinių elementų metodo analizė taip pat rodo, kad... [toliau žr. visą tekstą]
11
Honnette, Taylor R. "Measuring Liquefied Residual Strength Using Full-Scale Shake Table Cyclic Simple Shear Tests." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1998.
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This research consists of full-scale cyclic shake table tests to investigate liquefied residual strength of #2/16 Monterey Sand. A simple shear testing apparatus was mounted to a full-scale one-dimensional shake table to mimic a confined layer of saturated sand subjected to strong ground motions. Testing was performed at the Parson’s Geotechnical and Earthquake Laboratory at California Polytechnic State University, San Luis Obispo. T-bar penetrometer pullout tests were used to measure residual strength of the liquefied soil during cyclic testing. Cone Penetration Testing (CPT) was performed on the soil specimen throughout testing to relate the laboratory specimen to field index test data and to compare CPT results of the #2/16 Monterey sand before and after liquefaction. The generation and dissipation of excess pore pressures during cyclic motion are measured and discussed. The effects of liquefied soil on seismic ground motion are investigated. Measured residual strengths are compared to previous correlations comparing liquefied residual strength ratios and CPT tip resistance.
12
Khudair, Mohammed. "The search for sport-specific tests in boxing: Strength, power and anaerobic measurements." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-33903.
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The sport of boxing is widely practiced around the world, and to compete internationally atthe World championships and the Olympic games, boxers need a high fitness level and one ofthe tools used to achieve a high fitness level is physical and physiological testing formethodological monitoring and planning of training. The aim of this thesis was to study therelationship between training time in boxers, as in the recalled number of weekly traininghours, and the results from four different tests, upper body Wingate anaerobic test (UWAnT),countermovement jump (CMJ), hand grip strength (HGS) and isometric mid-thigh pull(IMTP). The choice of each tests is discussed from a physiological perspective to show itsassociation to boxing performance. Testing consisted of one testing session, which was heldduring a competition period, and 16 male boxers (age=23±5 years) in the senior ranks wereincluded. The results showed that the number of weekly training hours had a weak correlationto HGS (r=0.236, r2=0.056), a strong correlation to CMJ(r=0.570. r2=0.325), a moderatecorrelation to peak isometric strength in IMTP (r=0.343, r2=0.118), a weak correlation torelative peak isometric strength in IMTP (r=0.189, r2=0.036) and a strong correlation to peakanaerobic power, relative peak anaerobic power and the fatigue index in UWAnT (r=0.574,r2=0.329; r=0.769, r2=0.591; r=0.641, r2=0.411 respectively). In the thesis, the appliedmethods and the group of participants included are also discussed to find a suitable way ofstudying the relationship between these and other tests that could be suitable to explaindifferent characteristics of boxing performance. Based on the findings in the thesis, it wasconcluded that HGS and IMTP do not explain strength in boxing performance and, therefore,should be studied further. Also, it was concluded that the different variables in UWAnT andCMJ do explain anaerobic power and capacity and lower body explosive strength in boxingperformance and could, therefore, be used as sport-specific test for boxing.
13
Taylor, Mark. "Characterisation of normal and high-strength plain and fibre-reinforced concretes by means of strength, fracture and combined fracture/relaxation tests." Thesis, Cardiff University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365107.
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The main objective of this study was the application of strength, fracture and creep/relaxation tests to plain and fibre-reinforced high-strength concretes. Initially, five grades of concrete were developed and evaluated. Target 28 day compressive strengths were 40,60,80 100 and 120 N/mm2, the latter three being high-strength concretes (HSCs) containing a süperplasticiser and 10% silica fume. The others were normal-strength mixes used for comparison purposes. Each grade was made with 10 mm maximum-sized crushed limestone and gravel coarse aggregates making ten mixes in total. All were required to have sufficiently high workability and stability to accept reasonable amounts of fibre reinforcement. The data reported allows estimates of mix proportions for a range of HSC mixes to be determined. Various amounts of steel and polypropylene fibres were then added to the ten mixes to determine their optimum and maximum practical concentrations. The traditional type of toughness test based on un-notched beams in four-point loading was not employed. Instead, notched beams in three-point loading (equivalent to the RILEM work-of-fracture arrangement) and compact compression specimens were used. Both were tested under closed-loop conditions using crack-mouth opening displacement (CMOD) control. Post-cracking toughness was determined by means of the 15a nd 110to ughness indices given in ASTM C 1018. It was found that though fracture-based tests under CMOD control were an improvement on more traditional techniques, 15 and 110 were too insensitive to allow fibre type and volume to be differentiated. Next, work-of-fracture tests to measure the fracture energy, GF, were carried out on the plain concretes, initially under quasi-static loading. Both load/deflection and load/CMOD curves were recorded. GF showed little change with strength for a given aggregate type. Even though similar grades of crushed limestone and gravel HSCs had different GF values, the measure was still considered unsuitable for characterising the fracture properties of concrete. Similar experiments were then carried out on all ten mixes at five orders of magnitude of test duration (30 seconds to 2 days). GF appeared to be independent of strain rate. Both types of test highlighted the greater suitability of load/CMOD rather than load/deflection curves when evaluating GF. Finally, combined fracture and relaxation tests were undertaken in an attempt to obtain medium term fracture parameters. Though the CMOD was locked at 90,70 and 50% of the peak load in the strain-softening region, the deflection, when measured, showed a noticeable reduction over the seven days of each experiment, suggesting that significant cracking and stress redistribution within the fracture process zone was taking place. This finding has opened up a major area of important future research by confirming that the use of quasi-static fracture parameters in finite element studies is suspect.
14
Gibbons, Craig. "The strength of biaxially loaded beam-columns in flexibly connected steel frames." Thesis, University of Sheffield, 1991. http://etheses.whiterose.ac.uk/14765/.
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This thesis describes the experimental appraisal of a series of 10 'non-sway' steel column subassemblages, each comprising a 6m long column with up to three 1.5m long beams, together with two full-scale 3 storey, 2 bay, single span, non-sway steel frames (typical overall dimensions 9m x 10m x 3.5m). The subassemblages tests were conducted in the Department of Civil and Structural Engineering at the University of Sheffield whilst the much larger frame tests were carried out at the Building Research Establishment. In all cases, the beam and column elements were connected using 'simple' bolted steelwork connections. The aim was to investigate the effect of the inherent rotational stiffness (semi-rigid characteristics) of such connections on the behaviour of steel frames in which the columns were loaded biaxially and were not restricted to in-plane deformation. The appraisal of the results from these experiments clearly shows that the stiffness of even the most modest connection can have a significant influence on the distribution of bending moments, the ultimate column capacity and deflection of frame members. The experimental data were subsequently used to validate the predictions of a sophisticated finite-element computer program which was developed specifically to analyse 3-dimensional column subassemblages employing semi-rigid connections. This thesis documents this validation and reports the findings of an extensive parametric study which was then conducted to investigate the influence of semi-rigid connection behaviour on a wide range of subassemblage configurations. Comparisons with the experimentally observed and analytically predicted ultimate capacities of the subassemblage and frame tests showed that 'commonly used' methods of frame design are unduly conservative. The author has therefore proposed a number of design approaches for both ultimate and serviceability limit state loading conditions which take into account the inherent benefits of semi-rigid joint action.
15
Mansour, Marwan. "Experimental tests on the effect of temperature on the short term behavior of FRC beams." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Find full textAbstract:
The effect of temperature under short term behavior on macro-synthetic polypropylene fibers reinforced concrete (MSFRC) was evaluated, to understand how this condition may affect the performance of this material. An experimental campaign of three-point bending, compressive tests and elastic modulus tests have been performed on prisms, cubes and cylinders cured at 6 temperatures, ranging from -30°C to +60°C. The results highlighted that, for the material tested, the increment of temperature causes a decrement of the peak and post-peak flexural strength. Further analysis have been done on the fibers number and failure type.
16
Erzin, Yusuf. "Strength Of Different Anatolian Sands In Wedge Shear, Triaxial Shear, And Shear Box Tests." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604689/index.pdf.
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Past studies on sands have shown that the shear strength measured in plane strain tests was higher than that measured in triaxial tests. It was observed that this difference changed with the friction angle φ
cv at constant volume related to the mineralogical composition. In order to investigate the difference in strength measured in the wedge shear test, which approaches the plane strain condition, in the triaxial test, and in the shear box test, Anatolian sands were obtained from different locations in Turkey. Mineralogical analyses, identification tests, wedge shear tests (cylindrical wedge shear tests (cylwests) and prismatic wedge shear tests (priswests)), triaxial tests, and shear box tests were performed on these samples. In all shear tests, the shear strength measured was found to increase with the inclination &
#948
of the shear plane to the bedding planes. Thus, cylwests (&
#948
= 60o) iii yielded higher values of internal friction &
#966
by about 3.6o than priswests (&
#948
= 30o) under normal stresses between 17 kPa and 59 kPa. Values of &
#966
measured in cylwests were about 1.08 times those measured in triaxial tests (&
#948
&
#8776
65o), a figure close to the corresponding ratio of 1.13 found by past researchers between actual plane strain and triaxial test results. There was some indication that the difference between cylwest and triaxial test results increased with the &
#966
cv value of the samples. With the smaller &
#948
values (30o and 40o), priswests yielded nearly the same &
#966
values as those obtained in triaxial tests under normal stresses between 20 kPa and 356 kPa. Shear box tests (&
#948
=0o) yielded lower values of &
#966
than cylwests (by about 7.9o), priswests (by about 4.4o), and triaxial tests (by about 4.2o) under normal stresses between 17 kPa and 48 kPa. It was shown that the shear strength measured in shear box tests showed an increase when &
#948
was increased from 30o to 60o
this increase (about 4.2o) was of the order of the difference (about 3.6o) between priswest (&
#948
= 30o) and cylwest (&
#948
= 60o) results mentioned earlier. Shear box specimens with &
#948
= 60o, prepared from the same batch of any sample as the corresponding cylwests, yielded &
#966
values very close to those obtained in cylwests.
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Faccioni, Adrian, and n/a. "Relationships between selected speed strength performance tests and temporal variables of maximal running velocity." University of Canberra. Human & Biomedical Sciences, 1995. http://erl.canberra.edu.au./public/adt-AUC20060707.160114.
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The relationships between selected sprint specific bounding exercises and sprint
performance were analysed using fourteen sprint athletes (7 elite performers, 7 sub-elite
performers). Subjects were required to perform sprints over 60m, Counter Movement
Jumps with and without loading (20kg), High Speed Alternate Leg Bounding over 30m
and High Speed Single Leg Hopping over 20m. All athletes were subject to
anthropometric measurement (Height, Weight and Leg Length). Of all variables
measured, the Elite group were significantly better (p<0.001) in Counter Movement
Jump, Time to 60m, Time from 30m to 60m and in their Maximal Running Velocity.
Linear regressions were carried out on all variables that correlated with Time to 30m
(Acceleration Phase) and Maximal Running Velocity at both the pO.OOl and p<0.01
level of significance. This allowed several prediction tables to be compiled that had
performance measures (sprints and jumps) that could be used as testing measures for
sprint athletes to determine their Acceleration Phase and Maximal Running Velocity. A
stepwise multiple regression demonstrated that Time to 60m was the best predictor of
Maximal Running Velocity. Time to 60m, Leg length, High Speed Alternate Leg
Bounding and Sprint Stride Rate were the best predictors of the Acceleration Phase. A
Stepwise cross-validation linear discriminant function analysis was used to determine the
best predictors from both sprint and jump measures that would distinguish an athlete as
an elite or sub-elite performer. From sprint variables, Time to 60m and Time to 30m were
the two variables that best placed a sprint subject in either the Elite or Sub-elite group.
From the bounding variables, Counter Movement Jump and the Ground Contact Time of
the High Speed Alternate Leg Bounding were the two variables that best placed a sprint
subject in either the Elite or Sub-elite group. The present study suggests that Time to 60m
is the best predictor of Maximal Running Velocity and Acceleration Phase. Counter
Movement Jumping and High speed Alternate Leg Bounding are also useful tools in
developing and testing elite sprint athlete performance.
18
Miller, Bruno 1974. "Hybrid silicon/silicon carbide microstructures and silicon bond strength tests for the MIT Microengine." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9238.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000.Also available online at the MIT Theses Online homepage
Includes bibliographical references (leaves 109-113).
The Gas Turbine Laboratory (GTL) and the Microsystems Technology Laboratory (MTL) at the Massachusetts Institute of Technology initiated a joint effort to develop a series MEMS-based turbine engines and turbo generators in 1995. This thesis focuses on two independent research topics: first, the use of hybrid silicon/silicon carbide structures to extend the operating envelope of the first generation microengine, and second, a testing technique to measure the toughness of silicon to silicon fusion bonds. Due to the relatively low strength of Si at high temperatures, the all-silicon demonstration device does not yet meet the design specifications. The introduction of limited amounts of SiC in the turbine disc and turbine blades can increase the temperature tolerance of the rotating structure by 150-200K. A turbine disc with a 30% SiC core, and hollow turbine blades with a 300pim tall SiC core yield significant improvements in the microengine performance when compared to the all-silicon baseline design: 30% increase in compressor pressure ratio and fourfold increase in shaft power output. However, more aggressive cooling schemes or re-design of the rotating spool is needed for further improvements. Fabrication of the hybrid structures is compatible with the current microengine process flow, although some key SiC process steps must be developed further. A testing technique has been developed to measure the toughness of Si-Si fusion bonds using bi-layer interfacial notched specimens in a four point bend fixture. The test results confirm the trade-off between annealing time and temperature to achieve similar bond strengths. The experimental results agree with theory and published data. Subsequent experiments should further investigate the effect of different annealing time, surface preparation and contacting atmosphere on bond strength. The technique could also be applied to test bond strength between dissimilar materials, for instance silicon and silicon carbide.
by Bruno Miller.
S.M.
19
Brown, David Roger. "An assessment of the compaction behaviour of pharmaceutical compacts by means of complementary mechanical tests." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336444.
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Hassan, Husseen, and Abdifatah Sahal. "Experimental Tests of Pre - placed Aggregate Concrete for Concrete Repairs." Thesis, KTH, Betongbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278540.
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Since a large part of the hydropower structures in Sweden was built in the 1950s and 1960s, many of them are slowly but surely exhibiting deterioration. The hydropower companies are facing big challenges and are consequently investing in effective repairing methods since a hydropower structure failure could pose serious consequences and dangers to people, the environment, and the community. Many structures within hydropower are made of concrete and the demands on the new supplementing concrete are high. Concrete with the potential to meet these high demands is the pre-placed aggregate concrete, which has shown promising results regarding its mechanical properties in previous studies. For this reason, this type of concrete is of interest to investigate. The focus has not been on optimizing the pre-placed aggregate concrete for full-scale productions. Instead, the main objectives of this master thesis were to study and analyze the mechanical properties of this type of concrete, such as shrinkage, compressive strength, splitting tensile strength, freeze-thaw resistance and moreover investigate parameters of importance in the mix design to obtain a homogenous and easy flowing grout that successfully could fill the voids between the coarse aggregates. The investigations were carried out by laboratory experiments in the research and laboratory facilities of Vattenfall in Älvkarleby. The mix design of the grout was developed using the methods and requirements stated in the American Society for Testing and Materials, ASTM standards, and The Swedish Institute for Standards, SiS. A total of 15 grout-mixes were made. However, only the last five were used to cast specimens as the air content was insufficient in the first ten. The results indicated that it is necessary to replace the air-entraining admixture with microspheres in order for the pre-placed aggregate concrete to meet the requirements in exposure class XF3 and XC4. The scaling of the pre-placed aggregate concrete was less than 0.1 kg/m2 at 56 cycles, and thus, the freeze-thaw resistance was classed as very good. Moreover, the use of slag considerably reduced the bleeding of the grout and also improved the casting results. However, on the other hand, it increased the shrinkage of the pre-placed aggregate concrete. An efficiency factor of 0.6 proved to be too low since the compressive strength of the specimen with slag was approximately 50 % higher than the ones without. Furthermore, the shrinkage of the pre-placed aggregate concrete was after 63 days found to be lower than that of the conventional concrete. Also, the compressive strength of the pre-placed aggregate concrete without slag proved to be approximately 15 % lower than that of conventional concrete. Additionally, vibration during casting was found to increase the compressive strength of the pre-placed aggregate concrete and also improved the casting results. Low bleeding, combined with a high discharge time of approximately 45 seconds for 1.7 liters of grout, generated the best casting results. The results from the investigations have shown that this type of concrete has great potential. However, actions and further investigations should be made to see whether changing the fine aggregate size to a smaller one improves the ability of the grout to penetrate the voids between the coarse aggregates. Moreover, pump injection of the grout should be tested instead of pouring it over the coarse aggregates to see whether it improves the casting results and the mechanical properties.Då en stor del av vattenkraftsdammarna i Sverige byggdes på 1950 och 1960-talet börjar många av dessa sakta men säkert brytas ner. Vattenkraftföretagen står inför stora utmaningar och investerar följaktligen i effektiva reparationsmetoder då dammbrott skulle kunna få allvarliga konsekvenser för människor, den omgivande miljön och för samhället. Flertalet konstruktioner inom vattenkraften är gjorda av betong och kraven på den nya kompletterande betongen är höga. En betong med potentialen att möta och uppfylla dessa höga krav är injekteringsbetongen som i tidigare studier uppvisat lovande resultat beträffande dess mekaniska egenskaper. Med anledning av detta är injekteringsbetongen av intresse att undersöka. Fokus har inte varit på att optimera injekteringsbetongen i syfte att genomföra fullskaliga försök. Istället har huvudsyftet med detta examensarbete varit att studera och analysera injekteringsbetongens mekaniska egenskaper såsom krympning, tryckhållfasthet, spräckhållfasthet, frostbeständighet samt undersöka viktiga parametrar i skapandet av ett homogent och lättflytande cementbruk som med god framgång kunde fylla ut hålrummen mellan grova ballasten. Undersökningarna utfördes genom laboratorieförsök på Vattenfalls betonglaboratorium i Älvkarleby. Vidare har skapandet och utvecklandet av bruket utförts i enlighet med metoder och krav angivna i American Society for Testing and Materials, ASTM standards, samt i Svenska institutet för Standarder, SiS. Totalt gjordes 15 bruksblandningar, dock användes enbart de sista fem till gjutning av provkroppar då lufthalten visade sig vara för låg i dem första tio. Resultaten indikerade på att det är nödvändigt att ersätta luftporbildare med mikrosfärer för att erhålla en lufthalt som uppfyller kraven för betong i exponeringsklass XF3 samt XC4. Injekteringbetongens avflagning efter 56 dygn var mindre än 0.1 kg/m2 och frostbeständigheten kunde därmed klassas som mycket god. Användningen av slagg minskade cementbrukets vattenseparation avsevärt och bidrog även till förbättrade gjutresultat. Dock bidrog det å andra sidan till en ökad krympning hos injekteringsbetongen. En effektivitetsfaktor på 0.6 visade sig vara för låg då injekteringsbetongen med slagg hade en cirka 50 % högre tryckhållfasthet än dem utan. Dessutom visade sig injekteringsbetongens krympning vara mindre än den konventionella betongens efter 63 dagar. Tryckhållfastheten hos injekteringsbetongen utan slagg uppvisade även en cirka 15 % lägre tryckhållfasthet än den konventionella betongens. Vibrering under gjutning visade sig höja tryckhållfastheten hos injekteringsbetongen samt förbättra gjutresultaten. En låg vattenseparation i kombination med en flödestid på cirka 45 sekunder för 1.7 liter bruk visade sig ge bästa gjutresultaten. Resultaten från laboratorieförsöken har visat på att injekteringsbetongen besitter stor potential. Dock bör ytterligare undersökningar genomföras för att bedöma huruvida en mindre ballastfraktion för sanden påverkar brukets förmåga att penetrera den grova ballasten. Vidare bör bruket pumpas in istället för att hällas över den grova ballasten, detta för att se huruvida gjutresultaten samt de mekaniska egenskaperna hos injekteringsbetongen skulle förbättras.
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LECH, RONALD SCOTT. "DETERMINATION OF CONSOLIDATED-DRAINED SHEAR STRENGTH OF UNDISTURBED LAKEBED CLAYS FROM CONSOLIDATED-UNDRAINED TRIAXIAL TESTS." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin973284326.
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Lauer, Douglas F. "Ultimate strength analysis of partially composite and fully composite open-web steel joists." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06112009-063330/.
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Guirola, Marcela Renee. "Strength and Performance of Fiber-Reinforced Concrete Composite Slabs." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/35431.
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The purpose of this research is to evaluate and compare the influence of four types of secondary reinforcement on various component strengths related to composite slabs. These components include the composite slab strength under uniform load, the strength of two types of shear connectors used with composite beams and joists, composite slab strength due to a concentrated load, and the flexural toughness and first-crack strength of fiber-reinforced concrete using ASTM C1018 (1998) standard test. The performance of the specimens reinforced with fibers are compared with that of the specimens reinforced with welded-wire fabric (WWF), with the purpose of determining if fiber-reinforced concrete can be used as an alternative to WWF.Master of Science
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Castellanos, Bernardo Antonio. "Use and Measurement of Fully Softened Shear Strength." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/56631.
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The fully softened shear strength was defined by Skempton (1970) as the peak drained shear strength of a clay in a normally consolidated state. All the experience available on the applicability of the fully softened shear strength for slopes is based on back-analyses. Back-analyses of first-time failures in cuts in stiff-fissured clays and embankments constructed of fat clays have shown that, over a long period of time, the shear strength gets reduced from what is measured in the laboratory using undisturbed samples to the fully softened shear strength. These back-analyses require knowledge or assumption of pore pressures in the slope, which will have a significant influence on the shear strength obtained.
Karl Terzaghi, in 1936, was the first person that qualitatively explained the behavior of cut slopes in stiff-fissured clays. According to Terzaghi (1936), a softening process is initiated by the water percolating into the fissures causing swelling and decreasing the overall shear strength of the clay mass. Investigations presented later by Skempton and his colleagues showed that the controlling shear strength for cuts in stiff-fissured clays was equal to the fully softened shear strength and recommended this shear strength to be used for design (Skempton 1970; Chandler and Skempton 1974; Chandler 1974; Skempton 1977). Skempton (1977) concluded that displacements caused by progressive failure decrease the shear strength of stiff clays toward the fully softened shear strength.
At first, it was believed that only stiff-fissured clays were subjected to softening and that intact clays should be designed using the peak shear strength measured using undisturbed samples (Skempton and Brown 1961; Skempton 1964, 1970). Recent publications have showed that the likelihood of a clay experiencing softening is more dependent on the plasticity of the clay rather than the fissures (Bjerrum 1967; Chandler 1984a; Mesri and Abdel-Ghaffar 1993). Fat clays, when compared to lean clays, tend to be more brittle. This means that fat clays have a more pronounced decrease in shear strength after the peak shear strength is achieved and for this reason are more susceptible to progressive failure.
First-time failures in stiff clays usually occur a long period of time after construction. For this reason, steady state seepage was used in the back-analyses of the case histories presented by Skempton and his colleagues. They found that a pore pressure ratio of 0.3 was applicable to first-time failures in cuts in stiff-fissured clays (James 1970; Vaughan and Walbancke 1973; Chandler 1974; Skempton 1977).
Investigations presented by Professor Steve Wright and his colleagues of the University of Texas at Austin showed, based on back-analyses, that the fully softened shear strength is also the controlling shear strength of compacted embankments constructed of highly plastic clays (Green and Wright 1986; Kayyal and Wright 1991; Wright 2005; Wright et al. 2007). Steve Wright and his colleagues concluded that weathering, expressed in cycles of wetting and drying, was the main mechanism decreasing the shear strength of compacted clay embankments toward the fully softened shear strength. Failures in this type of projects were found to be shallow (less than 10 ft deep) and to occur numerous years after construction (USACE 1983; Stauffer and Wright 1984; Kayyal and Wright 1991; Wright et al. 2007). A pore pressure ratio ranging from 0.4 to 0.6 was found to be applicable for the case histories analyzed by Wright and his colleagues. Day and Axten (1989) recommended the use of the infinite slope method with seepage parallel to the slope face for slope stability analyses. This same recommendation was presented by Lade (2010). A seepage parallel to the slope face corresponds to a pore pressure ratio ranging from 0.4 to 0.5 for slopes with ratios of 2H:1V to 5H:1V. Failures on compacted clay embankments related to softening have been reported in Texas (Stauffer and Wright 1984; Kayyal and Wright 1991; Wright 2005; Wright et al. 2007), and Mississippi (USACE 1983). According to McCook (2012), softening of this type of structures also occur in Louisiana
To perform slope stability analyses using fully softened shear strength parameter, the type of soils, type of projects, and depths where this shear strength is applicable, and the pore pressures and factor of safety to be used in design should be determined. As stated above, the fully softened shear strength has been found to be the controlling shear strength of cuts in stiff clays and compacted embankments constructed of highly plastic clays. Steady state seepage conditions should be used to design cuts in stiff clays, and a pore pressure ratio ranging from 0.4 to 0.6 or a phreatic surface at the surface of the slope should be used to design compacted embankments made of fat clays.
In cuts in stiff clays, both shallow and deep failures related to fully softened shear strength have been observed. For this type of project, the recommended methodology for design is to assign a curved fully softened failure envelope to the whole slope, search for the critical failure surface, and obtain the factor of safety. This approach will provide the correct factor of safety but the critical surface obtained might not be what is expected to occur in situ. Pore pressures corresponding to steady state seepage should be used for design. It should be emphasized that the recommendation to use fully softened shear strength in first-time failures in stiff clays is based on the back-analyses of case histories. Research is required to better understand progressive failure and its influence on the shear strength mobilized in situ.
In compacted embankments constructed of fat clays, only shallow failures related to fully softened shear strength have been observed. For this type of projects, the recommended methodology for design is to assign a curved fully softened failure envelope to the whole embankment, search for the critical failure surface, and obtain the factor of safety. If for any reason deep failures are to be considered in designing compacted embankments constructed of fat clays, based on the fact that failures in this type of projects are usually shallow, the first 10 ft below the surface of the slope should be assumed to have a shear strength equal to the fully softened shear strength. Pore pressures should be calculated based on a water table coincident with the slope face.
The fully softened shear strength should not be used in the foundation soil. If any softening occurred in the foundation soil, this should be reflected in the shear strength measured using undisturbed samples. Softening of the foundation soil is not expected to occur after the embankment is constructed.
The consequences of shallow and a deep failures are usually not the same. For this reason, is reasonable that the same factor of safety should not be required for both cases. A shallow failure may be considered by some agencies solely as a maintenance issue. The factor of safety should be based on the uncertainties in the parameters being used for design and the consequences of failure of the structure (Duncan and Wright 2005). The parameters that have more impact on the factor of safety obtained for slope stability are shear strength and pore pressures. The fully softened shear strength is the lowest shear strength expected to be mobilized in first-time slides. This shear strength, coupled with a conservative assumption of pore pressure gives a low uncertainty in the parameters that have the most influence in the factor of safety.
For shallow failures, the consequences of failure are very low. For this reason, if the fully softened shear strength is used, coupled with a water table corresponding to the worst case scenario possible, a factor of safety as low as 1.25 can be used. For deep failures, the consequences of failure will vary depending on the structure. The pore pressure for this type of analyses should be based on the worst seepage condition expected throughout the life of the project. In this case, for structures with low to mid consequences of failure, a factor of safety of 1.35 can be used. For structures with a high consequence of failure, a factor of safety of 1.50 can be used. These factors of safety are based on the recommendations presented by Duncan and Wright (2005) for factors of safety based on uncertainties in the parameters and consequences of failures.
The fully softened shear strength should be measured using normally consolidated remolded specimens as recommended by Skempton (1977). Soil samples should be hydrated for two days using distilled or site-specific water. The soil sample should then be washed or pushed through a No. 40 (425 µm) sieve. To achieve the desired water content, the soil sample cab be air-dried or more water should be added. Water contents equal to or higher than the liquid limit should be used to prepare test specimens for fully softened shear strength measurements.
The direct shear device is recommended for fully softened shear strength measurements. The Bromhead ring shear device does not provide accurate values of fully softened shear strength. The triaxial device requires more time and effort to measure the fully softened shear strength and provides about the same fully softened shear strength as the direct shear device.
The fully softened shear strength failure envelope can be estimated using the correlation presented in Figure 6.59 for the parameters required for Equation 4.1. This correlation is only intended to be used in preliminary design or if better information is not available. Laboratory determination of fully softened shear strength is always recommended for final designs. If this is not possible, the confidence limits presented in Figure 6.59 should be used to determine the fully softened shear strength parameters.Ph. D.
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MOORE, AMY M. "EVALUATION OF THE CURRENT RESISTANCE FACTORS FOR HIGH-STRENGTH BOLTS." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1195432529.
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Bhanbhro, Riaz. "Mechanical Behavior of Tailings : Laboratory Tests from a Swedish Tailings Dam." Doctoral thesis, Luleå tekniska universitet, Geoteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62534.
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Tailings is leftover material from mining industry and is produced in huge quantities approximately 70-99% of the ore production. Tailings material is stored as impoundments by constructing tailings dams which are often constructed with tailings material itself. Tailings are artificial material and the mechanical behavior of tailings material upon loading is different as compared to natural soil materials. There are number of dam failures reported every year which has severe impact on inhabitants and environment nearby. Considering the failures of tailings dams and consequences there is a need to understand the tailings material in depth for safe existence of these dams. The confident dam design can assure the safe existence of tailings dams for long term as these dams are presumed to function for generations to come. The material properties in tailings dams can change during operation due to raising of new layer. Raised new layer can change stress level, which in turn may change the material properties in terms of strength, pore pressures, grain sizes etc. Today mostly tailings dam are designed by performing analysis for safety for existing and future rasings as well. These analyses are based upon a for certain factor of safety. Not very much can be done with design and analysis for tailings material if the material is not described very well. Understanding of tailings material in depth can provide help for detailed material parameters which later can be used in safety assessment for future raising and changed conditions in dam. This study presents the work carried out on tailings material from a Swedish tailings dam. The study is conducted on undisturbed and disturbed tailings material. The undisturbed tests are carried out to understand material properties as per in-situ conditions. Whereas disturbed materials are used to created different materials with different particles sizes. Initially in this study the basic properties of tailings materials are studied e.g. specific gravity, phase relationships, particle sizes, particle shapes and shear behavior on collected samples at various depths. During direct shear tests, the unexpected vertical height reductions were observed, these results are presented in this study. The comparison of strength parameters by direct shear and triaxial tests on material from various depths is also done and presented. Based on results from direct shear, triaxial and oedometer tests on uniform sized tailings material; the evaluation of primary and secondary deformations and particle breakage and effect of vertical loads is also carried out and presented. The study also includes the comparison of strength parameters for each particles size. The breakage of particles is analyzed by sieving the material after direct shear tests followed by a particle shape study. The effect of deposition on shear strength parameters is also studied by construction of samples with different angle of deposition of material. The strength parameters of uniform sized particles in triaxial tests are also evaluated and discussed.
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Cablayan, Ted. "Prediction of sprint times of male and female sprinters from selected leg power and isokinetic strength tests." Scholarly Commons, 1992. https://scholarlycommons.pacific.edu/uop_etds/2240.
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The problem of the study was to determine the better predictors of sprint performance for male and female sprinters from selected leg power and isokinetic strength tests. Ten male and five female sprinters volunteered to be measured for vertical jump performance, anaerobic power and capacity, peak isokinetic torque at the hip, knee, and ankle joint, and sprint performance. A forward stepwise multiple regression analysis was performed to allow selection from all strength and power variables regressed on the dependent variables of 30 meters, 60 meters, and flying 30 meter sprints. This procedure allowed one to examine the contribution of each predictor variable to the regression model. Only the independent variables that elicited a regression equation significant at the .05 level were used in final regression models. The regression models developed for the males were: 30 meters (crouch start) = 6.115 - .083(anaerobic power) - .055(vertical jump) - .044(plantarflex 120"/s) - .022(knee flex 60'/s); 60 meters (crouch start) = 11.111 - .145(vertical jump) - .086 (anaerobic power) - .172(hip flex 300'/s) - .098(knee flex 60'/s); and 30 meters (flying start) = 4.295- .055(anaerobic power) - .312(knee flex 180'/s) - .090(hip flex 300'/s). The regression models for the women were different than the males and were: 30 meters (crouch start) = 9.530 - .346(vertical jump); 60 meters (crouch start) = 18.083- .686(vertical jump); and 30 meters (flying start) = 8.733- .352(vertical jump) . By knowledge of the variance of the better strength and power measures, 83.2% to 98.0% of the variance of the respective sprint tests were explained. The regression models could allow for the identification of potential sprint performers and the development of optimal sprint training program.
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Porter, Jonathan R. "An Examination of the Validity of Steady State Shear Strength Determination Using Isotropically Consolidated Undrained Triaxial Tests." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/40529.
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The assessment of the shear strength of soil deposits after the occurrence of large strains is an important issue for geotechnical engineers. One method for doing so, the steady state approach, is based on the assumption that the steady state undrained shear strength is a unique function of the in situ void ratio and effective stress. This method, which has been applied to liquefaction and flow failures, has been criticized because it may overestimate the in situ shear strength. The key to the steady state approach is accurate determination of the relationship between void ratio and effective stress at steady state. This is typically accomplished using conventional isotropically consolidated undrained (ICU) triaxial tests. The triaxial test was developed for measuring peak strengths, which typically occur at small strains, but steady state conditions typically occur at much larger strains. At large strain levels, the suitability of conventional triaxial testing procedures and error corrections is uncertain. The measured response at large strains may be inaccurate due to the influence of various testing errors. Furthermore, the true material response in the test specimen at large strains may not accurately represent in situ material behavior at large strains.
This research effort consisted of an experimental and analytical study to examine the validity of steady state undrained shear strength determination using conventional ICU triaxial tests. The analytical study addressed triaxial testing errors and conventional corrections that are applied to test data and their influence on the measured steady state parameters. Finite element analyses were conducted to investigate the influence of variations in restraint at the end platens on stress distributions in the sample and measured stress-strain response. The finite element analyses incorporated axisymmetric interface elements to model the friction characteristics between the end platens and the specimen ends. The experimental study focused on several sands that are susceptible to liquefaction. An interface direct shear test program was conducted in order to evaluate various schemes for reducing end platen friction. ICU triaxial tests were conducted on each material using both conventional and lubricated end platens.Ph. D.
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Mukherjee, A. (Amit). "Methods for determining shear strength of soils and the limitations and/or advantages of the various tests." Kansas State University, 1987. http://hdl.handle.net/2097/18413.
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Palmieri, Giulia. "Diagonal compression tests on masonry panels reinforced with composite materials FRCM." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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In the last years, due to many severe seismic events, it becomes more and more important to understand the structural performance of masonry structures subjected to seismic actions and structural reinforce became an important task in civil engineering. The developments of innovative techniques for structural retrofitting represent a great change in order to reduce the seismic vulnerability of masonry buildings. Beside the traditional reinforce techniques, new reinforce born such as Fiber Reinforced Polymer (FRP) and Fiber Reinforced Cementitious Matrix (FRCM)
The aim of this thesis is to study the shear strength of masonry panels, subjected to in-plane actions, reinforced with FRCM.
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Moreira, Patrícia Sandei Galvão [UNESP]. "Comportamento da função cardiorrespiratória e muscular de pacientes com câncer submetidos à cirurgia abdominal oncológica." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153168.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Os pacientes com câncer podem apresentar sintomas pulmonares incapacitantes como dispneia, fadiga e intolerância ao exercício. Considerando que um dos principais tratamentos para essa patologia é a cirurgia, os profissionais devem atentar-se às complicações pós-operatórias (CPO) que estão presentes principalmente nas cirurgias abdominais e torácicas, já que interferem na função muscular e na mecânica respiratória. OBJETIVO: Analisar se a doença oncológica leva a alterações na função cardiorrespiratórias e musculares, avaliar o comportamento da função cardiorrespiratória e da força muscular de pacientes oncológicos submetidos à cirurgia abdominal aberta e identificar os fatores pré-operatórios que podem diferenciar as CPO em pacientes oncológicos submetidos a cirurgia abdominal aberta. METODOLOGIA: Os pacientes foram divididos em dois grupos: grupo experimental (GE) composto por pacientes com diagnóstico de câncer abdominal e grupo controle (GC) com pacientes saudáveis. Na avaliação passaram por anamnese, testes de esforço, teste da função e força pulmonar e teste de força de preensão manual. Considerou-se estatisticamente significante p<0,05. RESULTADOS: Foram avaliados 33 pacientes (19 mulheres) em cada grupo. Quando comparado os pacientes do GC e do GE, observou-se diferença estatística na PImax (%) e na distância percorrida no ISWT (%). Os pacientes que não complicaram no quinto dia de pós-operatório (PO5) ou no trigésimo dia de pós-operatório (PO30) tiveram as variáveis pré-operatórias (PRÉ) comparadas com PO5 ou PO30, respectivamente. Na primeira situação, observou-se que houve diferença estatística em CVF, VEF1, PEF, FEF25-75%, valores reais e (%), VEF1/CVF (%), PImax em valor real e PEmax e ISWT reais e em (%). Já os momentos PRÉ e PO30 sem CPO a diferença foi observada nas variáveis: distância do ISWT real e (%). Quando comparados todos os momentos de pacientes que não complicaram a diferença foi significante em CVF e VEF1 (%), PEF real e distância do ISWT real e (%). E por último foi comparado os momentos PRÉ dos pacientes que não tiveram CPO no PO5 com o PRÉ dos pacientes que tiveram CPO no PO5 e o momento PRÉ dos pacientes sem CPO no PO30 com o momento PRÉ dos pacientes com CPO no PO30. Na primeira situação observou-se diferença estatística em FEF25-75%, real e na distância do ISWT real e (%). Já na segunda situação foi observada diferença estatística em CVF, PFE e FEF25-75% reais e em VEF1 e ISWT reais e (%). CONCLUSÃO: Podemos concluir que a doença oncológica abdominal, assim como a cirurgia abdominal, levam a alterações funcionais cardiorrespiratórias e musculares. E que as variáveis espirométricas, o teste de esforço e a frequência cardíaca foram capazes de diferenciar pacientes que não complicam daqueles que complicam.
Cancer patients may present some disabling pulmonary symptoms such as dyspnea, fatigue and exercise intolerance. Considering that surgery is one of the main treatments for this pathology, professionals should pay attention to postoperative complications (POC) which are present mainly in abdominal and thoracic surgeries, since they interfere in muscle function and respiratory mechanics. OBJECTIVE: To analyze whether oncological disease leads to cardiorespiratory and muscular function disturbance, to evaluate the behavior of cardiorespiratory function and muscular strength in cancer patients submitted to open abdominal surgery and to identify preoperative factors that may differentiate PCO in oncological patients submitted open abdominal surgery. METHODOLOGY: Patients were divided into two groups: experimental group (EG) composed of patients with abdominal cancer and control group (CG) with healthy patients. The evaluation submitted both groups to anamnesis, stress tests, function test and pulmonary force and manual grip strength test. A value for p <0.05 was considered statistically significant. RESULTS: Thirty-three patients (19 women) were evaluated in each group. When comparing CG and EG patients, a statistical difference was observed in the MIP (%) and the distance covered in the ISWT (%). Patients who did not complicate on the fifth postoperative day (PO5) or on the 30th postoperative day (PO30) had the preoperative variables (PRÉ) compared to PO5 or PO30, respectively. In the first situation, it was observed that there was a statistical difference in FVC, FEV1, PEF, FEF(25-75%), real values and (%), FEV1/FVC (%), real MIP and real and (%) MEP, ISWT. In PRE and PO30 moments without PCO, the difference was observed in the variables: distance from the real ISWT and (%). When comparing all the moments of patients who did not complicate the difference was significant in FVC and FEV1 (%), real PEF and ISWT real and (%) distance. Finally, we compared the PRE moments of the patients who did not have POC in the PO5 with the PRE of the patients who had POC in the PO5 and the PRE moments of the patients without POC in the PO30 with the PRÉ moment of the patients with POC in the PO30. In the first situation, we observed a statistical difference in FEF(25-75%), real and in the distance of the real and (%) ISWT. In the second situation, a statistical difference was observed in real FVC, PEF and FEF(25-75%), and in FEV1 and ISWT real and (%). CONCLUSION: We can conclude that abdominal cancer, as well as abdominal surgery, lead to cardiorespiratory and muscular functional changes. And that the spirometric variables, the stress test and the heart rate were able to differentiate patients that do not complicate to those that complicate.
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Nygren, Björn. "Inner strength among the oldest old : a good aging /." Umeå : Umeå universitet, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-902.
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Olmez, Mehmet Salih. "Shear Strength Behaviour Of Sand-clay Mixtures." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609558/index.pdf.
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ABSTRACT
SHEAR STRENGTH BEHAVIOUR OF SAND - CLAY MIXTURES
ÖLMEZ, Mehmet Salih M.S., Department of Civil Engineering Supervisor: Prof. Dr. Mehmet Ufuk ERGUN May 2008, 106 pages A clean sand having about 5 % fines has been mixed with 5 to 40 % commercial kaolin to form different sand-clay soil mixtures. The purpose of making this study is to observe the effects of fraction of fine materials in the soil mixture on the behavior of shear strength. Three series of experiments have been performed throughout the study. Undrained triaxial compression tests (series 1) are performed on specimens taken out from homogeneously mixed soil mixtures at specified kaolin contents consolidated in a box without keeping the mixture under water. In series 2 experiments specimens are taken from a box where soil mixtures are consolidated under water and undrained triaxial compression tests are performed on the samples. Drained direct shear tests are performed on samples prepared without performing initial consolidation in large boxes but directly prepared in the direct shear boxes and consolidated prior to shear (series 3). It has been found that about 20 % kaolin - 80 % sand mixture seems to be a threshold composition and changes in both undrained and drained shear stress-strength behaviour occur afterwards with increasing fine material content.
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Boone, George L. (George Leeford). "Analysis and results of the Lazy-L tests for the strength and fracture behavior of welded T-joints." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38164.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1996, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996.Includes bibliographical references (leaves 75-76).
by George L. Boone, III.
M.S.
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Magnani, Marco. "Effect of fibre damage on compressive strength of CFRP laminates." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22322/.
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This work investigates the effects of fibre damage on compressive strength of CFRP laminates under compressive loading. To characterise the influence of fibre failure, parameters such as the length and depth of the damaged region are considered. 3D Finite Element models are created to reproduce the artificially damaged laminates and gain an initial understanding of how fibre damage may affect the specimens. Secondly, coupons are manufactured and tested in compression following ASTM D 7137. DIC equipment is employed to better visualise the behaviour of the loaded components and gain insight on the effects of the different damage configurations. The results show that although fibre damage reduces the compressive strength of the tested components, the configuration of such damage has little influence. Interestingly, damage configuration seems to play a pivotal role on the development of delamination and kinks at final failure.
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Beal, Philip Edward. "Estimation of the shear strengths of root reinforced soils." Connect to resource, 1987. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1117654465.
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Pool, Randal Gleason. "Rational framework for interpreting overconsolidation ratio, undrained strength ratio, and lateral stress coefficient from flat dilatometer tests in clay." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/32768.
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Stiles, Judith H. "The red imported fire ant, Solenopsis invicta, in early-successional coastal plain forests: tests of distribution and interaction strength." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/46488.
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The red imported fire ant, Solenopsis invicta, is an abundant and aggressive component of early-successional communities in the southeastern United States. After disturbance, it rapidly invades new habitats, and once there, it has strong competitive and predatory effects on the existing arthropod community. In upland coastal plain pine forests at the Savannah River Site in South Carolina, I conducted two studies of fire ant ecology. In my first study (chapter 1), I investigated the way in which fire ants colonize early-successional road and powerline cuts through forests, and I tested whether some of these linear habitats provided better fire ant habitat than others. I found that fire ant mound density (#/ha) was similar in narrow dirt roads and in wider roads with the same intermediate level of mowing disturbance, and that density was lower in wide powerline cuts where the vegetation is only removed every five years. Furthermore, mound density was greatest near the edges of cleared roads and powerline cuts and was also greater on the northern sides of roads and powerline cuts where there was less shading from the adjacent forest. Results from this study suggest that allowing increased shading from adjacent forest vegetation, especially along northern roadside edges, would limit the suitability of road and powerline cuts as fire ant habitat, thereby slowing invasion. In my second study (chapter 2), I examined the impact of fire ants on arthropod and plant species in early-successional forest gaps. In a tritrophic system, I tested whether the top-down effect of insect herbivore consumption by fire ants was strong enough to cascade through two trophic levels and improve plant growth and fitness. I compared this potential effect to that of other arthropod predators in the community. I found that fire ants controlled the level of tissue damage to plant leaves by herbivores, but that the damage was not severe enough to influence plant growth or fitness. Fire ants had stronger negative interactions with insect herbivores than other predators in the community, and for this reason, fire ants can be considered keystone predators. This project provides further evidence that fire ants successfully invade even small patches of early-successional habitat that exist within larger matrices of uninhabitable, late-successional forest, and that once there, they have a dramatic effect on the arthropod community. Restricting the amount of early-successional habitat within southeastern forests, either as permanent road and powerline cuts or as temporary gaps, would limit the potential for strong and detrimental effects by the invasive fire ant.Master of Science
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Saad, Suleiman S. E. "Mechanical behaviour of fibre reinforced unsaturated clay : this investigation is to determine the improvement in the mechanical behaviour of unsaturated clayey soil after inclusion of carpet fibre waste." Thesis, University of Bradford, 2016. http://hdl.handle.net/10454/14585.
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To acquire deeper understanding and insights into the mechanical behaviour of fibre reinforced saturated/unsaturated cohesive soils, a programme of work was designed and included. 1) Conducting standard Consolidation Undrained (CU) tests to investigate mechanical behaviour of non-reinforced fully saturated soil. 2) Studying the strength of fibre reinforced clay though unconfined compression tests. 3) Testing the behaviour of unsaturated reinforced soil in unsaturated triaxial tests. 4) Determining the soil-water characteristic curves (SWCC) on soil sample with different fibre content. The investigation was undertaken on a clay of low plasticity index. Samples tested with addition of 1, 3 and 5 % fibre content and different values of matric suction of 50, 100 and 200 kPa, one of the challenges that were encountered in this research are how to prepare homogenous samples. A method for prepared compacted fibre reinforced soils with improved fibre distribution and density profile has been proposed and examined. The test results indicated that waste carpet fibres increase the shear strength of unsaturated clay soils. It was also found that relative increase in strength is also a function of applied suction. An increase in waste carpet fibres was found to reduce the hysteresis of soil. A data analysis conducted on the results of unsaturated tests as a function of fibre content and matric suction. The behaviour modelled was shown to be a perfect fit with the experimental data.
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Ríos, Bayona Francisco. "Analytical and numerical approaches to estimate peak shear strength of rock joints." Licentiate thesis, KTH, Jord- och bergmekanik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-248019.
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In Sweden, there exists a large number of dams. Many of them are founded on rock masses normally affected by the presence of sub-horizontal rock fractures, which makes sliding along rock joints under the dam foundation one of the most critical failure mechanism. Various attempts have been made to relate the peak shear strength of rock joints to measurable parameters. However, the uncertainty in the determination of the shear strength of rock joints is nonetheless still significant.The main aim of this thesis is to investigate, develop and apply analytical and numerical techniques for estimation of peak shear strength of natural and unfilled rock joints. In a first step, the peak shear strength of several natural and unfilled rock joint was calculated by using surface aperture measurements from high-resolution optical scanning and a modified version of the analytical criterion previously developed by Johansson and Stille in 2014. In a second step, PFC2D was utilised to perform numerical shear tests on two-dimensional profiles selected from high-resolution optical scanning on unweathered and perfectly mated tensile induced rock joints.The results from the analytical approach show that the calculated peak shear strengths of the analysed samples are in good agreement compared with the laboratory investigations. Conversely, the obtained results from the numerical approach show lower peak shear strengths in the analysed two-dimensional profiles compared with the conducted laboratory shear tests.The analytical approach together with the advanced techniques to measure surface roughness available today, may be a possible way forward towards a methodology to determine peak shear strength of large-scale natural rock joints in-situ.Bergsprickors skjuvhållfasthet är en avgörande faktor för att kunna bestämma säkerheten mot gliding för dammar där sub-horisontella utbredda bergsprickor existerar. Samtidigt är parametern svår att bestämma då den påverkas av flera faktorer som sprickytans råhet, vittringsgrad, normalspänning, skala samt passning. Skjuvhållfasthet av bergsprickor kan bestämmas genom att använda empiriska och analytiska brottkriterier samt numeriska metoder. Problemet med de befintliga metodikerna är att de inte beaktar inverkan från sprickans passning. Detta innebär att hållfastheten riskerar att överskattas.Det övergripande syftet med denna licentiatuppsats är att studera, utveckla och tillämpa analytiska och numeriska metoder för uppskattning av skjuvhållfasthet för naturliga och ofyllda bergsprickor. I ett första steg beräknades skjuvhållfastheten för ett antal naturliga och ofyllda bergsprickor. Detta gjordes genom att mäta aperturen baserat på högupplöst skanning och en vidareutvecklad version av det analytiska kriteriet som föreslogs av Johansson och Stille 2014. I ett andra steg användes PFC2D för att genomföra numeriska skjuvtester på två-dimensionella sprickprofiler baserat på högupplöst skanning av perfekt passade och draginducerade bergsprickor.Resultaten från uppskattad skjuvhållfasthet med den analytiska metodiken visar på en bra överensstämmelse i jämförelse med de utförda skjuvförsöken. Resultaten från de utförda analyserna med PFC2D visar på en något lägre skjuvhållfasthet än vad som observeras i verkligheten.Den utvecklade analytiska metodiken, tillsammans med de avancerade tekniker som idag finns för att mäta sprickytornas råhet, bedöms kunna utgöra ett första steg mot att bättre kunna bestämma den storskaliga skjuvhållfastheten för bergsprickor i fält.
QC 20190402
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Ferreira, Palmira Gabriele. "Análise dos fatores limitantes do exercício físico em asmáticos obesos." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5160/tde-22082016-163024/.
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Introdução: Indivíduos obesos e pacientes asmáticos eutróficos apresentam, frequentemente, hiperinsuflação dinâmica (HD) e redução da capacidade de exercício. No entanto, não há estudos que tenham investigado a causa da redução da tolerância ao exercício em asmáticos obesos. Objetivo: Verificar os fatores limitantes do exercício físico em asmáticos obesos. Métodos: Esse estudo transversal incluiu mulheres asmáticas com obesidade grau II (G-Ob; IMC 35,0 - 39,9 kg/m2) e não obesas (G-NOb; IMC 18,5 - 29,9 kg/m2). Os pacientes realizaram um teste cardiopulmonar máximo para verificar a potência aeróbia (VO2 pico) e um teste submáximo para avaliar a HD. Medidas antropométricas, força e endurance muscular do quadríceps e função pulmonar também foram avaliadas. O teste qui-quadrado foi utilizado para comparar os dados categóricos e os teste-t e Mann-Whitney para comparar os dados numéricos. Uma regressão forward stepwise foi utilizada para avaliar a associação entre a tolerância ao exercício físico e os fatores limitantes do exercício. Resultados: Cinquenta e quatro pacientes completaram o estudo (G-Ob, n=36; G-NOb, n=18). A tolerância ao exercício apresentou correlação linear com endurance de quadríceps (r=0,65; p < 0, 001), pulso de oxigênio (r=0,52; p < 0,05) e HD (r=-0,46; p < 0,05). Embora o G-Ob (72,2%) tenha apresentado maior frequência de HD quando comparado ao G-NOb (38,9%; p < 0,05) e maior redução na capacidade inspiratória (respectivamente, -18,0% vs. -4,6%; p < 0,05), a regressão forward stepwise mostrou que o endurance muscular de quadríceps foi o único preditor da tolerância ao exercício nos pacientes do G-Ob (r=0,82; r2=0,67; p < 0,001). Conclusão: Apesar da hiperinsuflação dinâmica ser frequente nos asmáticos obesos, a limitação periférica foi o principal fator associado com a redução da tolerância ao exercício físico em asmáticos obesos. Uma possível implicação clínica destes achados é a necessidade de treinamento muscular de membros inferiores nos programas de reabilitação pulmonar em asmáticos obesosBackground: Obese individuals and patients with asthma can present dynamic hyperinflation (DH) and reduction of capacity exercise. However, no previous study has investigated the cause of intolerance exercise in obese asthmatics. Aim: To verify the limiting factors during exercise in obese asthmatics. Methods: This cross sectional study included asthmatic women with either obesity grade II (Ob-G; BMI 35.0 -39.9kg/m2; n=36) and non-obese (NOb-G; BMI 18.5 - 29.9kg/m2). Patients performed a cardiopulmonary test to quantify peak VO2 and a submaximal exercise test to assess DH. Anthropometric measurement, quadriceps muscle endurance and lung function were also evaluated. Chi-square test was used to compare categorical and t-test and Mann-Whitney test for numerical outcomes. A forward stepwise regression was used to evaluate the association between exercise tolerance and limiting exercise factors. Results: Fifty four patients completed the protocol (Ob-G; n=36; NOb-G; n=18). The exercise tolerance was associated with quadriceps endurance (r=0.65; p < 0.001), oxygen pulse (r=0.52; p < 0.05) and DH (r=-0.46; p < 0.05). Although Ob-G (72.2%) had showed a higher frequency of DH than NOb-G (38.9%; p < 0.05) and a greater reduction in the inspiratory capacity (-18.0% vs. -4.6%, respectively; p < 0.05), the forward stepwise regression showed that the exercise tolerance could be predicted from a linear association only for muscular endurance (r=0.82; r2=0.67; p < 0.001). Conclusion: In spite of DH to be a common condition in obese asthmatics, the peripheral limitation was the main factor associated with exercise intolerance in these patients. A possible clinical implication of these findings is the need for lower limb training in obese asthmatics
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Haff, G. Gregory, Michael H. Stone, and W. G. Hornsby. "The Comparison of Accelerometer Based Estimates of Maximal Bench Press Strength and Actual 1-Repetition Maximum Tests in Untrained College Students." Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etsu-works/4508.
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Borges, Cláudia dos Santos. "Avaliação da função e da força muscular respiratória em pacientes com artrite reumatóide." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/310631.
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Orientador: Manoel Barros BértoloDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
Made available in DSpace on 2018-08-16T21:47:52Z (GMT). No. of bitstreams: 1 Borges_ClaudiadosSantos_M.pdf: 1491680 bytes, checksum: c0fd7976233c88801d70d46b2fb9a774 (MD5) Previous issue date: 2010
Resumo: Objetivo: Avaliar a função pulmonar e a forca muscular respiratória em pacientes com artrite reumatóide (grupo AR) em comparação a grupo controle e avaliar a relação entre os resultados obtidos com atividade de doença, dor, comprometimento funcional e qualidade de vida. Pacientes e Métodos: Foram avaliadas a função pulmonar através da espirometria (volume expiratório forcado no primeiro secundo - VEF1, capacidade vital forcada - CVF, VEF1/CVF, fluxo expiratório forcado entre 25 e 75% da capacidade vital forcada-FEF25- 75% e o pico de fluxo expiratório - PFE), e as pressões inspiratória máxima (PImax) e a expiratória máxima (PEmax) através do manovacuometro de 50 pacientes reumatóides e 50 controles pareados por sexo e idade. Foi analisada a influencia da atividade da doença (DAS- 28), fator reumatóide (FR), dor (escala visual analógica - EVA), qualidade de vida (SF-36), incapacidade (HAQ) e dispnéia (escala Medical Research Council - MRC) nos resultados do grupo AR e a correlação entre a função e a forca muscular respiratória. Resultados: No grupo AR 28% dos pacientes apresentaram alteração da função pulmonar, sendo oito pacientes (16%) com padrão ventilatório restritivo e seis (12%) com padrão ventilatório obstrutivo (VEF1, CVF e FEF25-75% reduzidos). A PImax esteve reduzida de forma significativa e a PEmax apresentou uma tendência a redução. O DAS-28 esteve relacionado a menores valores do VEF1, VEF1/CVF, FEF25-75, Pimax e Pemax; o FR esteve associado a VEF1, CVF, FEF25-75; maior índice de dor foi associado a menores VEF1/CVF e FEF25-75%; maior HAQ com menores valores VEF1, FEF25-75% e PEmax; maior MRC com menores VEF1, CVF e FEF25-75. VEF1 e CVF reduzidos relacionaram-se aos componentes limitação de atividade, dor e vitalidade do SF-36. O FEF25-75 relacionou-se apenas ao componente de limitação de atividade. Na correlação entre forca e função no grupo AR a PEmax correlacionou-se com VEF1, CVF, VEF1/CVF, FEF25-75% e com PFE, a PImax também apresentou relação com todas as variáveis da função pulmonar exceto com VEF1/CVF apesar da tendência a redução. Conclusão: Pacientes com AR apresentaram pior função respiratória e forca muscular inspiratória em relação aos controles. A função pulmonar e a forca muscular respiratória podem ser associadas a maior atividade da doença. Os índices de função pulmonar podem também estar relacionados a maiores títulos de FR, incapacidade, pior qualidade de vida, dor e dispnéia. E importante que pacientes reumatóides com maior atividade inflamatória articular e comprometimento progressivo da função e qualidade de vida sejam adequadamente investigados e monitorizados quanto a parte respiratória
Abstract :Objective: To assess the pulmonary function and respiratory muscular strength, in rheumatoid arthritis (RA) patients and to evaluate its correlation with disease activity, pain, disability and quality of life. Patients and Methods: Pulmonary function using spirometry (forced expiratory volume in one second - FEV1, forced vital capacity - FVC, FEF1/FVC, forced expiratory flow from 25% and 75% of vital capacity - FEF 25-75% and the peak expiratory flow- PEF) and respiratory muscle strength (maximum inspiratory (MIP) and expiratory (MEP) pressures of 50 RA patients and 50 age and sex-matched healthy subjects were assessed. The influence of disease activity (Disease Activity Score, DAS-28), rheumatoid factor (RF), pain (visual analogue scale - VAS), quality of life (SF-36), disability (Health Assessment Questionnaire - HAQ-DI) and dyspnea (Scale of the British Research Council -MRC) in the RA group was evaluated and the correlation between function and respiratory muscle strength. Results: In RA group 28% of patients had pulmonary function changes, eight patients (16%) with restrictive ventilatory pattern and six (12%) with obstructive ventilatory pattern (FEV1, FVC, FEF25-75 reduced). The MIP was significantly reduced and MEP showed a trend. The DAS-28 was related to lower values of FEV1, FEV1/FVC, FEF25-75, MIP and MEP; RF was associated to FEV1, FVC , FEF 25-75; pain was related to FEV1/FVC and FEF25-75; HAQ was related to FEV1, FEF25-75 and MEP; MRC was combined with FEV1, FVC and FEF25-75. Lower FEV1 and FVC were related to SF-36 limitation of activities, pain and vitality components. Decreased FEF25-75 was related only to limitation of activities component. In the correlation between strength and function in the RA group MEP correlated with FEV1, FVC, FEV1/FVC, FEF25-75% and PEF, MIP also showed a correlation with all pulmonary function variables except FEV1/FVC despite trend. Conclusion: RA patients exhibited worse pulmonary function and inspiratory muscle strength compared to healthy subjects. Respiratory function and respiratory muscle strength may be related to disease activity. Pulmonary function indexes impairment may be also associated with higher RF titers, disability, worse quality of life, dyspnea and pain. Rheumatoid patients with respiratory symptoms, disease activity, progressive disability and worsening of quality of life should have respiratory function carefully investigated and monitored
Mestrado
Ciencias Basicas
Mestre em Clinica Medica
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Alwash, Maitham Fadhil Abbas. "Assessment of concrete strength in existing structures using nondestructive tests and cores : analysis of current methodology and recommendations for more reliable assessment." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0587/document.
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Pour évaluer la résistance mécanique du béton dans un ouvrage existant, la méthodologie courante combine des mesures non destructives (CND) comme le rebond ou/et la vitesse des ondes ultrasoniques avec la technique destructive (carottes) afin de produire une relation‘‘modèle de conversion” entre la résistance mécanique et les mesures CND. Le modèle de conversion est utilisé pour estimer la valeur locale de résistance mécanique à chaque emplacement de test en utilisant la valeur CND correspondante. Ensuite, on calcule les estimations de la résistance moyenne et/ou de l’écart-type de la résistance (variabilité de la résistance du béton). Cependant, la fiabilité d’estimation est toujours discutable en raison des incertitudes associées à l’évaluation de la résistance basée sur les mesures CND. Pour améliorer la fiabilité, les incertitudes doivent être réduites en spécifiant et en contrôlant leurs facteurs d’influence. Par conséquent, l’objectif de cette thèse est d’analyser la méthodologie d’évaluation courante afin de fournir des recommandations pratiques qui peuvent améliorer la fiabilité de l’évaluation de la résistance in-situ du béton dans les ouvrages existantes par des tests non destructifs et des carottes.Pour ce but, un simulateur a été construit afin d’analyser les effets des facteurs les plus influents en utilisant une vaste campagne de données provenant de sources différentes (études in situ ou en laboratoire et données synthétiques générées). La première contribution de ce travail est le développement d’une nouvelle approche d’identification du modèle ‘‘bi-objectif” qui peut efficacement capturer la variabilité de la résistance mécanique en plus de la moyenne. Après avoir étudié l’effet du mode de sélection des emplacements pour les carottes, une méthode a été proposée pour sélectionner ces emplacements en fonction des mesures CND ‘‘sélection conditionnelle” qui améliore la qualité de l’évaluation sans coût supplémentaire. Une dernière innovation est l’établissement de courbes de risque qui quantifient la relation entre le nombre de carottes et la précision de l’estimation. Enfin, des recommandations ont été formulées afin de fournir des estimations plus fiablesTo assess concrete strength in an existing structure, the current methodology combines nondestructive measurements (NDT) like rebound hammer or/and pulse velocity with destructive technique (cores) in order to implement a relationship ‘‘conversion model” between the compressive strength and NDT measurements. The conversion model is used to estimate the local strength value at each test location using the corresponding NDT value.Then the estimated mean strength and/or estimated strength standard deviation (concrete strength variability) values are calculated. However, the reliability of these estimated values isalways a questionable issue because of the uncertainties associated with the strength assessment based upon NDT measurements. To improve the reliability, the uncertainties must be reduced by specifying and controlling their influencing factors. Therefore, the objective of this thesis is to analyze the current assessment methodology in order to provide practical recommendations that can improve the reliability of assessing the in-situ strength in existing concrete structures by nondestructive tests and cores.To this end, a simulator was built in order to analyze the effects of the most influencing factors using a large campaign of datasets from different sources (in-situ or laboratory studies,and generated synthetic data).The first contribution of this work is the development of a new model identification approach“bi-objective” that can efficiently capture the strength variability in addition to the mean strength. After studying the effect of the way of selection the core locations, a method was proposed to select these locations depending on the NDT measurements “conditional selection” that improves the quality of assessment without additional cost. A third innovation was the development of a procedure to identify the relation between the number of cores and the accuracy of the estimation. Finally recommendations were derived in order to providemore reliable estimated values
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Babalola, Zainab. "Direct shear and direct simple shear tests: a comparative study of the strength parameters and their dependence on moisture and fines contents." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20922.
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Shear strength of soil is characterized by cohesion, angle of internal friction and dilatation. The first two parameters mentioned primarily define the soil's ability to resist shear stress underspecified load. These parameters can be determined by tests conducted either in the laboratory or the field for use in design of geotechnical structures. Some of the tests in the laboratory to determine the shear strength of soil, include triaxial, ring shear, torsional shear, direct shear and direct simple shear. Direct shear test is the most widely used geotechnical shear device due to its simplicity, however, the test suffers from stress inhomogeneity. Direct simple shear apparatus was developed because of the shortcomings in the direct shear test. In these two tests, different shearing conditions are applied to soil samples. For the direct shear test, shearing occurs at a predetermined center of the specimen which may not be the weakest plane of the soil while indirect simple shear, the entire specimen distorts without the formation of single shearing surface. The mode of shearing established in the direct simple shear device is similar to that which occurs around the shaft of a pile. In contrast to the extensive geotechnical application of direct shear test, limited information exists on direct simple shear test. This thesis endeavours to establish the relationship between the two tests by undertaking extensive testing to obtain a better understanding of direct simple shear test as used for testing local soils and to determine a correlation with the results from direct shear tests. A series of shear tests were undertaken on Klipheuwel sand, Kaolin clay and composite of the sand and clay using universal shear device. The soils were mixed with water in percentages of 5,10, 15, 20 and 25%, and the composite with clay percentages of 10, 25, 50 and 75%, to investigate the impact of water and clay on the shear parameters determined from the two tests. The results showed that direct shear test gives higher shear strength when compared to direct simple shear test under the same soil condition. The addition of water, and clay, generally reduced the internal friction angle of sand for both tests. Furthermore, increase in cohesion was observed with the addition of water to Kaolin clay for the direct simple shear test and the reverse was true in the direct shear test. The correlation factors developed in this study for the direct simple shear test could be used to refine the results from the direct shear test.
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Amin, Diyar. "Triaxial testing of lime/cement stabilized clay : A comparison with unconfined compression tests." Thesis, KTH, Jord- och bergmekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160626.
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Detta examensarbete presenterar resultat från en laboratoriestudie på en lera från Enköping stabiliserad med kalk och cement. I laboratoriet har isotropiskt konsoliderade odränerade aktiva triaxialförsök utförts på provkroppar och jämförts med enaxliga tryckförsök som utförts på provkroppar från samma inblandningstillfälle. De två metoderna har visat sig ge likvärdiga värden på utvärderad odränerad skjuvhållfasthet. Elasticitetsmodulen har däremot visat sig vara mycket högre för triaxialförsöken än enaxliga tryckförsök. För triaxialförsöken har förhållandet mellan sekantmodulen och den odränerade skjuvhållfastheten legat mellan 112-333. För de enaxliga tryckförsöken ligger förhållandet mellan sekantmodulen och den odränerade skjuvhållfastheten inom intervallet 44-146. Inget mönster har dock kunnat urskiljas då förhållandet mellan de två olika försöken har varierat mellan 1,0-3,5. Ett lägre och högre back pressure användes under triaxialförsöken. Till skillnad från tidigare studier har dock båda dessa back pressures vattenmättat provkroppen. Resultaten visar på att back pressure inte påverkar testresultaten, förutsatt att provet blivit fullt vattenmättat. Utöver denna jämförelse har ytterligare passiva triaxialförsök utförts. De passiva triaxialförsöken har utförts som isotropiskt konsoliderade odränerade försök.. Däremot har två olika metoder använts under skjuvningsfasen. I första typen av försök har den axiella spänningen minskats medan den radiella spänningen har hållits konstant. I den andra typen av försök har i stället den radiella spänningen ökats samtidigt som den axiella spänningen har hållits konstant. Skjuvhållfastheter har jämförts med resultat från kalkpelarsondering i fält och visar på att skjuvhållfastheten genomgående varit högre i fält än i laboratoriet. Dessutom har skjuvhållfastheter och elasticitetsmoduler testats efter olika lagringstider genom enaxliga tryckförsök.This master thesis presents results from a laboratory study on a clay from Enköping which was stabilized with lime and clay. Isotropic consolidated undrained compressive tests were performed on samples and compared to unconfined compressive testing. The two methods have shown no difference in the evaluation of undrained shear strength. However the modulus of elasticity was shown to be much higher for the triaxial tests. For the unconfined compressive tests the relation between the undrained shear strength and secant modulus was within the range of 44-146. The equivalent for the triaxial tests was in the interval of 112-333. However no pattern was extinguishable between the two tests as this relation has varied between 1,0 to 3,5. A lower and higher back pressure was used during the triaxial testing. However, both back pressures have succeeded in saturating the sample. Results show that the back pressure has little effect on the results, as long as the sample has been fully saturated. In addition to this extension tests were performed on samples as well. The tests performed were isotropic consolidated undrained. However two different shearing methods were used. The first test was strain rate dependant while the second test was stress rate dependant. In the first test the vertical stress decreased while the radial stresses were kept constant, while in the other test the radial stresses increased while the vertical stress were kept constant. The undrained shear strength was compared to lime/cement column penetration tests in field. Results showed that tests in field show a much higher undrained shear strength than laboratory testing.
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Queiroga, Marcos Vinícios Mendonça de. "Análise experimental de pilares de concreto de alto desempenho submetidos à compressão simples." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-13122017-164439/.
Full textAbstract:
O objetivo da pesquisa foi obter subsídios para o projeto de pilares de concreto de alta resistência, submetidos à compressão simples, com concreto de resistência média de 60 MPa. Este projeto faz parte de um plano mais amplo onde já se têm resultados experimentais que traduzem o comportamento de pilares moldados com concreto de resistência média à compressão de 80 MPa. Nestes constatou-se a participação isolada do núcleo de concreto definido pelo eixo da armadura transversal como seção resistente dos pilares. Na etapa experimental foram ensaiados pilares com seções transversais quadradas de 200 mm x 200 mm e retangulares de 150 mm x 300 mm. As alturas dos pilares correspondem a seis vezes a menor dimensão da seção transversal, portanto, 1200 mm e 900 mm, respectivamente. Nos modelos de seção quadrada, o valor médio das relações entre as forças últimas experimentais e as forças últimas teóricas, considerando a seção total de concreto, resultou igual a 0,82, indicando que a seção resistente não é a seção total. Por outro lado, a média das relações entre as forças últimas experimentais e as forças últimas teóricas, considerando apenas a área do núcleo limitada pelo eixo dos estribos, resultou igual a 1,21, o que mostra que a seção resistente pode ser considerada, no Estado Limite Último, como a seção do núcleo.This research\'s aim is to obtain information for design of high strength concrete columns under concentrically loads with medium cylinder compressive strength of 60 MPa. This project belongs to a more extensive plan which already has experimental results that represent the behavior of columns performed with concrete with medium cylinder compressive strength of 80 MPa. In these models has been verified the independent participation of concrete core defined by the transversal reinforcement axis as resistant section near the ultimate load. In the experimental stage it was tested twelve columns with square (200 mm x 200 mm) and rectangular (150 mm x 300 mm) cross sections. The height of the columns corresponds to six times the smallest dimension of the cross section, 1,200 mm and 900 mm, respectively. The medium value of the ratios between the ultimate experimental force and the ultimate theoretical force, regarding the full concrete section, was 0.82, indicating that the resistant section is not the full section. On the other hand, the medium of ratios between the ultimate experimental force and the ultimate theoretical force, considering only the core area limited by the axis of the lateral reinforcement bars, was 1.21, what shows that the resistant section can be considered as the core section in the Ultimate Limit State.
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Pimentel, Victor Eduardo. "Avaliação da resistência ao cisalhamento em GCLs - uma nova metodologia de ensaio." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-23042008-173842/.
Full textAbstract:
Os GCLs (Geosynthetic Clay Liners) são materiais geossintéticos destinados a compor sistemas de controle de fluxo em obras geotécnicas e ambientais. Suas propriedades vêm sendo cada vez mais estudadas visando a avaliação de seu comportamento de curto e longo prazo. Dentre as propriedades mais importantes de um GCL, está a sua resistência ao cisalhamento interno, tendo em vista que o seu principal componente, a bentonita, possui baixa resistência quando hidratada. Este trabalho apresenta o desenvolvimento de uma nova metodologia de ensaio-índice para estimativa da resistência ao cisalhamento em GCLs - o método CTM (cisalhamento por tração modificado). A principal inovação do método proposto é o formato \"U\" da garra para fixação dos corpos-de-prova. Foram executadas duas séries de ensaios, nas quais, realizou-se uma seleção criteriosa das amostras e um plano de preparação dos corpos-de-prova, de forma a evitar que a variabilidade inerente à fabricação dos GCLs, influenciasse nos resultados obtidos. A primeira fase de testes foi realizada com o objetivo de se correlacionar os resultados do método CTM com dois outros métodos de ensaios-índice existentes: ensaio de adesão (peeling-test) e ensaio de cisalhamento por tração (shear-tensile test). Os resultados obtidos apresentaram boa correlação e o método CTM se mostrou bastante prático. A segunda série de ensaios foi realizada visando aprimorar a montagem do ensaio CTM e comparar os seus resultados com ensaios de cisalhamento direto. Novamente as metodologias se correlacionaram bem, o que justifica o desenvolvimento do método CTM.GCLs (Geosynthetic Clay Liners) are geosynthetic products used to compose flux control barriers in geotechnical and environmental works. The mechanical properties of GCLs have to be investigated in short and long term. Among its mechanical parameters, GCL internal shear strength plays an important role in the stability of slopes of geotechnical works. The main component of a GCL, the bentonite, when hydrated, presents very low shear strength. This work presents the development of a new index test method that aims cheaply and quickly to estimate the shear strength of GCLs - the CTM method (modified shear-tensile test). The main innovation of the proposed method is the U-shape grip that imposes a state of deformation close to that observed in field works. Two series of tests were performed in which a careful selection of samples and specimens were done. This aimed to minimize variation effects, inherent to the GCL production, on the obtained results. The first series was carried out to correlate results from the CTM tests to other two index tests: peel test and shear-tensile test. The results showed a good correlation between CTM and the other test results. The second series of tests was planned to improve CTM test method in order to get even better results than peel or shear-tensile tests, apart from correlating its results to results of direct shear test. Comparisons of results show very good agreement what justifies the use of the cheaper and quicker CTM method.
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Moreillon, Lionel. "Shear strength of structural elements in high performance fibre reinforced concrete (HPFRC)." Phd thesis, Université Paris-Est, 2013. http://pastel.archives-ouvertes.fr/pastel-00861175.
Full textAbstract:
For members and flat slabs without shear reinforcement, the shear and punching shear strength are often the determining design criteria. These failure modes are characterized by a fragile behaviour implying possible partial or total collapse of the structure. Despite extensive research in this field, shear and punching shear in reinforced and prestressed concrete structures, remain complex phenomena so much that the current approach is often empirical or simplified. The ability of Steel Fibre Reinforced Concrete (SFRC) to reduce shear reinforcement in reinforced and prestressed concrete members and slabs,or even eliminate it, is supported by several experimental studies. However its practical application remains marginal mainly due to the lack of standard, procedures and rules adapted to its performance. The stationary processes in precast industry offer optimal possibilities for using high performance cementitious materials such as Self Compacting Concrete (SCC) and High Strength Concrete (HSC). For the author, the combination of High Performance Concrete and steel fibres is the following step in the development and the optimization of this industry. The High Performance Fibre Reinforced Concrete (HPFRC) stands between conventional SFRC and Ultra-High Performance Fibre Reinforced Concrete (UHPFRC). The HPFRC exhibiting a good strength/cost ratio is, thus, an alternative of UHPFRC for precast elements. The principal aim of this work was to analyse the shear and punching shear behaviour of HPFRC and UHPFRC structures without transversal reinforcement and to propose recommendations and design models adapted for practitioners. Several experimental studies on structural elements, i.e. beams and slabs, were undertaken for this purpose. Firstly, an original experimental campaign was performed on pre-tensioned members in HPFRC. A total number of six shear-critical beams of a 3.6 m span each, and two full scale beams of a 12 m span each, were tested in order to evaluate the shear and flexural strength. The principal parameter between the specimens was the fibres (...)
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Brink, André. "The relationship between three anxiety related clusters in projective drawings and anxiety and ego-strength scales of the Minnesota multiphasic personality inventory-2." Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1002451.
Full textAbstract:
Based on the shortcomings of past research, the need for understanding and investigation of the general relationship between self-report measures and human figure drawings required understanding and investigation (Riethmiller & Handler, 1997b; Waehler, 1997) while utilising a quantitative, configural scoring approach. Riethmiller and Handler (1997a; 1997b) hypothesised that subjects have one of two typical approach styles to anxiety/stress that influences their execution of the Human Figure Drawing (HFD) Test: “Avoidance” or “Coping” as measured by composite scoring index clusters. They argue that these two approach styles had to be taken into account when investigating anxiety on the HFD Test. According to Handler and Reyher (1965) those who experience more intense anxiety typically rely on an “Avoidant” approach, while those with lower anxiety typically rely on a “Coping” approach. The “Coping” response is hypothesised to suggest good ego-strength, and the “Avoidant” response poor ego-strength. Handler and Reyher (1964; 1965; 1966) also argued that there are two sources of anxiety on projective drawings: internal and external sources of anxiety. They hypothesised that the “External” anxiety cluster (measured by utilising the car drawing) and self-report measures both assess ‘external’ anxiety. Using Handler’s (1967) HFD index scoring manual, this research therefore inve stigated the level of correlation of the two MMPI-2 anxiety scale scores with (a) the hypothesised Stress Approach HFD cluster scores, as well as with (b) the “External” anxiety cluster score, while the hypothesised Stress Approach HFD cluster scores were compared with the (c) MMPI-2 ego strength scale score. The results of the investigated relationships yielded non-significant correlations overall. The differences in nature of the two measurement instruments, and the potential weaknesses of this study, as two likely explanations for these correlations, are discussed. In the consideration of the differences of the two measurement instruments, the weaknesses of SR measures and criterion-related validity are discussed while self- attributed and implicit motives are contrasted with each other. Potential extraneous variables and possible truncated range are discussed as potential weaknesses of this study.