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Park, Jin Young. "Pultruded composite materials under shear loading." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/32865.
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Suh, Jong Beom. "STRESS ANALYSIS OF RUBBER BLOCKS UNDER VERTICAL LOADING AND SHEAR LOADING." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1185822927.
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Corte, Marina Bellaver. "Desenvolvimento de equipamento para ensaios Simple Shear." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/139358.
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Em virtude da presença cada vez mais frequente de solicitações cíclicas nas estruturas de engenharia e do aprimoramento da análise de projetos, os ensaios em solos sob carregamentos cíclicos tiveram seu interesse renovado nos últimos anos. Os ensaios de laboratório são realizados de forma que simulem, da melhor maneira possível, as condições observadas em campo. Tais condições auxiliam na escolha dos ensaios a serem conduzidos para a determinação de parâmetros geotécnicos relevantes a cada situação observada em campo. Dentre os ensaios empregados na Engenharia Geotécnica, destaca-se o simple shear. Este ensaio é conhecido e utilizado para medir a resistência ao cisalhamento e a rigidez de solos. Este é o único ensaio de laboratório capaz de submeter uma amostra a condições de deformação plana sob volume constante e permitir a rotação das tensões principais. Tais condições são frequentemente representativas em diversas situações em campo como, por exemplo, o modo de cisalhamento adjacente ao fuste de uma estaca ou sob plataformas offshore com base gravitacional. Nesse contexto, um equipamento foi desenvolvido para a realização de ensaios do tipo simple shear. O aparato conta com uma câmara, na qual é aplicada pressão à amostra de solo. Diferenciando-se do equipamento comercial para tais ensaios, que emprega uma membrana com anéis metálicos, a amostra de solo neste equipamento é envolta por uma membrana de látex, o que possibilita a consolidação de forma isotrópica ou anisotrópica. Quanto ao carregamento, o equipamento desenvolvido permite que o carregamento seja realizado de forma monotônica ou clíclica. Quando do carregamento cíclico, este pode ainda ser realizado de forma a se manter a tensão controlada ou a deformação. Foram conduzidos ensaios de calibração e validação do equipamento empregando-se uma areia fina de granulometria uniforme cujas propriedades são amplamente conhecidas através de outros ensaios. Os resultados obtidos foram então comparados com estudos no mesmo material em equipamentos triaxiais, cisalhamento direto e outro simple shear. Os resultados mostraram-se satisfatórios, validando o equipamento desenvolvido.In view of the ever more frequent presence of the cyclic solicitations on Engineering structures and the enhancement of design analysis, the soil testing under cyclic loading conditions had its interest renewed in the last years. The laboratory tests are conduced in a way that simulates, in the best way possible, the observed field conditions. Said conditions aid on the choice of the tests to be conducted in order to determinate the relevant geomechanics parameters.to each situation observed on the field. Among the employed tests in Geotechnical Engineering, it is highlighted the simple shear. This test is known and used to measure the shear strength and soil righty. This is the only laboratory test capable of submitting the sample to plane strain conditions under constant volume and allows the main stress rotations. Said conditions are frequently representative in many field situations, such as, the adjacent shear mechanism to the shaft of a pile or, under offshore platforms with gravitational base. In this context, a equipment was developed to perform simple shear tests. The apparatus has a chamber, in which it is applied confining pressure to the soil sample. Contrasting from the commercial equipment for said tests, that uses a membrane with metallic rings, in this equipment the soil sample is involved by a latex membrane, allowing the consolidation being carried out isotropically or anisotropically. The loading on this equipment can be conduced on monotonic or cyclic conditions. The cyclic loading can even be conduced by controlling the deformation or the stress. Calibration and validation testes where conduced on the equipment using a fine sand of uniform granulometry which properties are largely known through other tests. The obtained results where then compared to other tests carried out on the same material in triaxial tests, direct shear and other simple shear, The results obtained were considered satisfactory, validating the developed equipment.
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Sanin, Maria Victoria. "Cyclic shear loading response of Fraser River delta silt." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/30064.
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The cyclic shear response of low-plastic Fraser River silt was investigated using constant-volume direct simple shear testing. Silt specimens, initially consolidated to stress levels at or above the preconsolidation stress, displayed cyclic mobility type strain development during cyclic loading. Liquefaction in the form of strain softening accompanied by loss of shear strength did not manifest regardless of the applied cyclic stress ratio (CSR), or the level of induced excess pore water pressure (Δu). Cyclic mobility type stress-strain behaviour was observed in spite of the initial static shear stress bias. The potential for excess pore water pressure generation and associated shear strain development during cyclic loading was observed to increase with increasing level of initial static shear. Tests on specimens of undisturbed field samples and specimens reconstituted using the same silt material showed that undisturbed silt, despite having a looser density under identical consolidation stress conditions, exhibited more dilative response and larger shear resistance compared to those displayed by reconstituted specimens. In addition to consolidation stress conditions and resulting void ratios, it appears that other naturally inherited parameters such as soil fabric and aging effects would influence the shear response of natural silt.
Studies were also conducted to examine the post-cyclic reconsolidation response of low-plastic silt using specimens of undisturbed and reconstituted Fraser River silt and reconstituted quartz powder initially subjected to constant volume cyclic loading at different CSR values and then reconsolidated to their initial effective stresses. The volumetric strains during post-cyclic reconsolidation (εv-ps) were noted to increase with the maximum Δu and maximum cyclic shear strain experienced during cyclic loading. The values of εv-ps and maximum excess cyclic pore water pressure ratio (ru max) were observed to form a coherent relationship regardless of overconsolidation effects, particle fabric, and initial void ratio of the soil. The specimens with high ru-max suffered significantly higher post-cyclic reconsolidation strains. The observed εv-ps versus ru-max relationship, when combined with the observed dependence of ru on CSR and number of load cycles, seems to provide a reasonable approach to estimate post-cyclic reconsolidation strains of low-plastic silt.
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Kaufmann, Alan. "Biomechanical Comparison of Meniscal Repair Systems in Shear Loading." Master's thesis, Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/216549.
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BioengineeringM.S.
A meniscal tear is an injury that often occurs as a result of a varus or valgus rotation of the femur on the tibia coupled with axial rotation while the knee is partially flexed, thus creating preferential loading of the posterior horn and shear forces on the meniscus. Such injuries can be repaired surgically, either with standard suturing techniques or with commercially available all-inside meniscal repair devices, which are designed to make the repair surgery faster, easier, and potentially safer. Many prior biomechanical studies have loaded an excised, repaired meniscus in tension and found that the repaired meniscus performs similarly to an uninjured sample. However, it is more appropriate to apply shear forces to the tissue in order to simulate the mechanism of injury. To date, three prior studies have investigated the biomechanical properties of meniscal repairs in shear, all of which used isolated meniscal tissue samples. The present study used an in situ bovine model to investigate the strength of commercially available meniscal repair systems under a shear loading regime. Medial menisci were torn and subsequently repaired using one of three techniques: standard inside-out vertical mattress sutures, Depuy Mitek Omnispan, or Smith & Nephew Fast-Fix. A control group was left unrepaired. Samples were subjected to a battery of cyclic side loading to create shear forces within the knee. Statistical analysis (ANOVA) demonstrated no significant difference in the stiffness, shear force, or subsidence between groups. The conclusion that the repair techniques perform similarly is consistent with tensile and in situ testing. Pathological observations showed no significant differences between repair devices, but all repaired samples demonstrated less wear than unrepaired samples, indicating that the experimental model is an effective method for creating wear within the knee. This result indicates that the flexible all-inside devices are mechanically comparable to the more commonly performed conventional suturing techniques. It is concluded that the mechanical performance may not be the best indicator of success of the surgical repair, as long as the device is able to anatomically reduce the tear.
Temple University--Theses
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Soysa, Achala Nishan. "Monotonic and cyclic shear loading response of natural silts." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52356.
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An experimental research program comprising constant-volume direct simple shear (DSS) tests was conducted to study the monotonic, cyclic shear and post cyclic consolidation response of natural silts. Relatively undisturbed samples of silt which were obtained from three different locations in the Lower Mainland area of British Columbia were used for this purpose. Plasticity indices of the natural silt samples which were considered for the study were 5, 7, and 34. Monotonic shear response of the natural silt was studied with the constant volume DSS test results that were conducted with different vertical effective stresses and different overconsolidation ratios (OCRs). Stress-strain response of normally consolidated silt at different consolidation stresses were found to be stress-history-normalizable where as higher OCR and higher plasticity resulted greater shear strength. Normally consolidated silt specimen, despite of their difference plasticity, exhibit gradual strain accumulation without abrupt loss of shear stiffness during cyclic loading with different cyclic stress ratios (CSRs) at different consolidation stress levels. The potential and rate of strain accumulation and development of excess pore-water pressure (Δu) were noted to be increased with higher CSRs at all tested consolidation stress levels. The cyclic shear resistances of silt, derived from cyclic direct simple shear (CDSS) tests, were not sensitive to the tested range of different consolidation stress levels, whereas higher plasticity resulted greater cyclic shear resistance. Relative undisturbed specimens exhibit comparatively higher cyclic shear resistance than the reconstituted specimens despite of comparatively denser particle arrangement in reconstituted specimens. However, during the constant-volume monotonic DSS tests, relative undisturbed specimens exhibit comparatively lesser shear resistance than the reconstituted specimens implying that soil fabric / microstructure plays a significant role in governing the shear loading response of silt. The examination of consolidation responses of silt specimens that were initially normally consolidated and subjected to constant-volume CDSS loading revealed that the post cyclic consolidation volumetric strain increases with the maximum cyclic pore-water pressure ratio developed during constant volume CDSS loading for all tested silt specimens with different plasticity.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Vaughan, Timothy Phillips. "Evaluation of masonry wall performance under cyclic loading." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/t_vaughan_042310.pdf.
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Thesis (M.S. in civil engineering)--Washington State University, May 2010.Title from PDF title page (viewed on July 14, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 72-73).
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Haider, Waheed, and haiderw@connellhatch com. "INPLANE RESPONSE OF WIDE SPACED REINFORCED MASONRY SHEAR WALLS." Central Queensland University. Centre for Railway Engineering, 2007. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20070421.130337.
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Wide spaced reinforced masonry (WSRM) walls that contain vertical reinforced cores at horizontal spacing up to 2000mm are commonly used in high wind zones of Australia although their inplane shear resistance is not well understood. This thesis aims at providing better insight into the behaviour of WSRM walls subjected to inplane lateral loading through experimental and numerical investigations.
The interactions between the unreinforced masonry (URM) panels and vertical reinforced cores are first determined using an elastic finite element analysis and the potential failure paths hypothesized. The hypotheses are then validated using a series of full-scale WSRM and Non-WSRM wall tests under monotonic and cyclic lateral loading by keeping the spacing between the vertical reinforced cores as the main design variable. Load-displacement response of these shear walls indicates that the current classification of the WSRM in AS3700 (2001) as those walls containing vertical reinforced grouted cores at 2000mm maximum spacing is appropriate.
A finite element model (FEM) based on an explicit solution algorithm is developed for predicting the response of the masonry shear walls tested under static loading. The FEM has adopted macroscopic masonry failure criteria and flow rules, damaged plasticity model for grout and tension-only model for reinforcing bars reported in the literature, and predicted crack opening and post-peak load behaviour of the shear walls. By minimising the kinetic energy using appropriate time scaling, the FEM has provided reasonable and efficient prediction of load flow, crack patterns and loaddisplacement curves of the shear walls. The FEM is further validated using full-scale tests on WSRM walls of aspect ratios and pre-compression different to that tested before.
The validated FEM is used to examine the appropriateness of the prescriptive design details for WSRM concrete masonry shear walls provided in AS3700 (2001) allowing for a large scatter in material properties. It is shown that the inplane shear capacity formula provided in AS3700 (2001) for squat WSRM shear walls is non-conservative.
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Palermo, Daniel. "Testing of a 3-D shear wall under cyclic loading." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/MQ34122.pdf.
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Harrison, Trevor. "Bearing strength of single shear CFRP joints under combined loading." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0006/MQ43342.pdf.
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Alkhtany, Moshabab Mobarek H. "MODELING STRUCTURAL POLYMERIC FOAMS UNDER COMBINED CYCLIC COMPRESSION-SHEAR LOADING." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1469532064.
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Hafez, Mhd Ammar. "THE BEHAVIOR OF SIMPLY SUPPORTED PLATES UNDER EXTREME SHEAR LOADING." Cleveland State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=csu1481821516088229.
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Salenikovich, Alexander J. "The Racking Performance of Light-Frame Shear Walls." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28963.
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The response of light-frame timber shear walls to lateral forces is the focus of the dissertation. The objective of this study was to obtain performance characteristics of shear walls with various aspect ratios and overturning restraint via experimental testing and analytical modeling. Presented are the test data of monotonic and cyclic tests on fifty-six light-frame timber shear walls with aspect ratios of 4:1, 2:1, 1:1, and 2:3. Overturning restraint conditions represent engineered construction and conventional construction practices. The walls representative of the engineered construction were attached to the base by means of tie-down anchors and shear bolts. As opposed to engineered construction, conventionally built walls were secured to the base by nails or shear bolts only. The specimens were tested in a horizontal position with oriented strandboard (OSB) sheathing on one side. To obtain conservative estimates, no dead load was applied in the wall plane during the tests. The nail-edge distance across the top and bottom plates varied from 10 mm (3/8 in.) to 19 mm (3/4 in.). Twelve walls were repaired after the initial tests and re-tested. A mechanics-based model was advanced to predict the racking resistance of conventional multi-panel shear walls using simple formulae. The deflections of engineered and conventional shear walls were predicted using the energy method combined with empirical formulae to account for load-deformation characteristics of sheathing-to-framing connections and overturning restraint. The proposed formulae were validated through comparison with test results obtained during this study. The results of the study serve to further development of a mechanics-based methodology for design of shear walls accounting for various wall configurations and boundary conditions.Ph. D.
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Seidalinova, Ainur. "Monotonic and cyclic shear loading response of fine-grained gold tailings." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46531.
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The monotonic, cyclic and post-cyclic shear response of gold tailings was investigated using constant-volume direct simple shear test device. The reconstituted gold tailings specimens normally consolidated to vertical effective stress levels ranging from 50 kPa to 400 kPa initially exhibited contractive behaviour followed by a dilative response under monotonic loading, with their shear stiffness and strength increasing with increasing initial effective confining stress. Overconsolidated specimens developed negative excess pore pressures during monotonic shear, with increasing dilative response, shear resistance, and stiffness displayed with increasing overconsolidation ratio (OCR). Overall, the monotonic behaviour of normally consolidated reconstituted gold tailings specimens is similar to the typical monotonic behaviour of normally consolidated clays and low-plastic silts; similarly, the behaviour of overconsolidated reconstituted gold tailings specimens is similar to the typical monotonic behaviour of overconsolidated clays. During cyclic loading, the tailings exhibited cumulative decrease in effective stress (or increase in equivalent excess pore-water pressure) with increasing number of loading cycles, resulting in progressive degradation of shear stiffness. The cyclic shear resistance increased with increasing OCR. The findings on the cyclic shear response of normally consolidated reconstituted gold tailings are in general agreement with those available published data on the cyclic response of different tailings, obtained from tests carried out on cyclic triaxial (TX) and DSS devices. The CRR of the gold tailings from this study, however, was found to be higher than that observed in Fraser river sand and Quartz rock powder, but in the same range as natural Fraser river silt. The post-cyclic monotonic shearing response, obtained from DSS tests, carried out on normally consolidated and overconsolidated reconstituted gold tailings specimens was also studied as a part of the current research work. The post-cyclic shear strength of normally and overconsolidated specimens, normalized to the initial effective confining stress, were observed to increase with increasing OCR. The post-cyclic consolidation volume changes experienced by the gold tailings specimens were in agreement with previously published results suggesting that post-cyclic volumetric strains would increase with increasing maximum excess pore water pressure ratio developed during cyclic loading.
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Gebretsadik, Alex Gezahegn. "Shear Resistance Degradation of Lime –Cement Stabilized Soil During Cyclic Loading." Thesis, KTH, Jord- och bergmekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141196.
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This thesis presents the results of a series of undrained cyclic triaxial tests carried out on four lime-cement stabilized specimens and clay specimen. The shear resistance degradation rate of lime-cement column subjected to cyclic loading simulated from heavy truck was investigated based on stress-controlled test. The influence of lime and cement on the degradation rate was investigated by comparing the behavior of stabilized kaolin and unstabilized kaolin with similar initial condition. The results indicate an increase in degree of degradation as the number of loading cycles and cyclic strain increase. It is observed that the degradation index has approximately a parabolic relationship with the number of cycles. Generally adding lime and cement to the clay will increase the degradation index which means lower degree of degradation. The degradation parameter, t has a hyperbolic relationship with shear strain, but it loses its hyperbolic shape as the soil getting stronger. On the other hand, for unstabilized clay an approximate linear relationship between degradation index and number of cycles was observed and the degradation parameter has a hyperbolic shape with the increase number of cycles. It was also observed that the stronger the material was, the lesser pore pressure developed in the lime-cement stabilized clay.
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LaJeunesse, Jeff W. "Dynamic Behavior of Granular Earth Materials Subjected to Pressure-shear Loading." Thesis, Marquette University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10936006.
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The dynamic response of granular earth materials such as sand has been of interest for many years. Multiple previous works have explored the shock response of sand in various grain shapes, sizes, and moisture contents, but the response during rapid combined loading has been relatively unexplored. The current study contributes to that lack of data by performing pressure-shear experiments on Oklahoma #1 silica sand, with quasi-smooth grains of 63 - 120 micron diameter and 99.8 wt.% Si02 composition. In these experiments, an oblique flyer plate impacts an equally inclined target, imparting a longitudinal (pressure) and transverse (shear) wave into a material of interest. The final loading states within the sand were inferred by measuring the normal and transverse components of particle velocity from the rear surface of the target using Photon Doppler Velocimetry (PDV). Tests were performed over a range of impact velocities to vary the magnitude of combined loading on the sand. Uncertainty in the calculated transverse particle velocity was explored for a variety of normal and angled PDV collimator setups to minimize the measurement uncertainty in shear stress. Combined loading in the experiments reached 0.25 - 1.00 GPa and 0.02 - 0.10 GPa of normal and shear stress, respectively. Yield surface models originally derived for lower strain rate loading of granular materials were shown to fit the experimental data in normal-shear stress space. The failure surface had a slope, or shearing resistance, of μ = 0.130 and potential failure caps were presented. Scanning electron microscope images were taken of the recovered samples for 9 of 12 shots. Three-dimensional mesoscale simulations using an Eulerian hydrocode, CTH, were performed to better understand the experimental results and explore the boundaries of mesoscale formulations in Eulerian frameworks. Two different grain surface treatments were utilized, stiction and slide, to determine the influence of mixed cell treatments within CTH. Simulated normal stress - shear stress responses resulted in a shearing resistance of μ = 0.172 and μ = 0.176, for the sliding and stiction case, respectively, but failure caps were not observed for either mixed cell treatment.
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Conn, Gerald Michael. "The two-way repeated loading of a silty clay." Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/14564.
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The main aim of the research was to study the behaviour of a silty clay under two-way cyclic loading. Equipment was developed for the application of a sinusoidally varying deviator stress to a sample in the triaxial cell. The equipment was designed to apply deviator stresses in both compression and extension during each cycle. ii A programme of monotonic and two-way cyclic triaxial tests has been performed on samples of Keuper Marl, isotropically consolidated to a range of stress histories. The build-up of strain and pore pressure during repeated loading is discussed. A model is developed, within the framework of the critical state theory of soil mechanics, to predict the amount of pore pressure produced by a given number of loading cycles at a known stress level. An extension of the model is suggested whereby the varied loading, more appropriate to offshore foundation conditions, may be analysed. In addition, a programme of monotonic and cyclic simple shear tests has been performed. The equipment has been developed, during the course of the research, to enable the direct measurement of pore pressure during shear. At attempt has also been made to monitor the change in lateral stress during shear by means of an instrumented membrane. The results of the simple shear tests have been analysed and are presented in terms of horizontal shear stress and effective vertical stress. An attempt has been made. to deduce the principal stresses present in a sample subject to simple shear loading and a method of relating the results from monotonic tests using simple shear and triaxial devices is discussed.
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Hikita, Katherine. "Combined gravity and lateral loading of light gauge steel framewood panel shear walls." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99767.
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Methods for the design of steel frame/wood panel shear walls used as a seismic force resisting system have been developed. These methods, which can be used in conjunction with the 2005 NBCC, were based on the results of shear wall tests carried out using lateral loads alone. The research program was extended to determine the influence of gravity loads on the lateral performance of the shear wall. An initial series of stud column tests was completed to determine an appropriate predication method for the axial capacity of the principal vertical load carrying members. Recommendations for appropriate effective length factors and buckling lengths were derived from the results of 40 tests. A subsequent series of five single-storey shear wall configurations were designed using capacity based methods. These shear walls were tested under monotonic and cyclic lateral loading, where two of three shear walls were also subjected to a constant gravity load. In total, 32 steel frame/wood panel shear walls composed of 1.09--1.37 mm thick steel studs sheathed with DFP, CSP or OSB panels were tested and analyzed. The equivalent energy elastic-plastic analysis approach was used to determine design values for stiffness, strength, ductility and overstrength. The data from this most recent series of tests indicates that the additional gravity loads do not have a detrimental influence on the lateral behaviour of a steel frame/wood panel shear wall if the chord studs are designed to carry the combined lateral and gravity forces following a capacity based approach. A resistance factor of 0.7 was found to be in agreement with previous tests that did not include gravity loads. The calculated seismic force modification factors also agreed with the previous test results, which suggest that Rd = 2.5 and Ro = 1.7.
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Murray, Karl Anthony. "An investigation of the behaviour of reinforced concrete flat slabs in the vicinity of edge columns." Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343022.
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Yeo, In-Wook. "Anisotropic hydraulic properties of a rock fracture under normal and shear loading." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286893.
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Comlekoglu, Hakki Gurhan. "Effect Of Shear Walls On The Behavior Of Reinforced Concrete Buildings Under Earthquake Loading." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12611277/index.pdf.
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An analytical study was performed to evaluate the effect of shear wall ratio on the dynamic behavior of mid-rise reinforced concrete structures. The primary aim of this study is to examine the influence of shear wall area to floor area ratio on the dynamic performance of a building. Besides, the effect of shear wall configuration and area of existing columns on the seismic performance of the buildings were also investigated. For this purpose, twenty four mid-rise building models that have five and eight stories and shear wall ratios ranging between 0.51 and 2.17 percent in both directions were generated. These building models were examined by carrying out nonlinear time-history analyses using PERFORM 3D. The analytical model used in this study was verified by comparing the analytical results with the experimental results of a full-scale seven-story reinforced concrete shear wall building that was tested for U.S.-Japan Cooperative Research Program in 1981. In the analyses, seven different ground motion time histories were used and obtained data was averaged and utilized in the evaluation of the seismic performance. Main parameters affecting the overall performance were taken as roof and interstory drifts, their distribution throughout the
structure and the base shear characteristics. The analytical results indicated that at least 1.0 percent shear wall ratio should be provided in the design of mid-rise buildings, in order to control observed drift. In additionwhen the shear wall ratio increased beyond 1.5 percent, it was observed that the improvement of the seismic performance is not as significant.
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Dabbagh, Hooshang Civil & Environmental Engineering Faculty of Engineering UNSW. "Strength and ductility of high-strength concrete shear walls under reversed cyclic loading." Awarded by:University of New South Wales. School of Civil and Environmental Engineering, 2005. http://handle.unsw.edu.au/1959.4/27467.
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This study concerns the strength and behaviour of low-rise shear walls made from high-strength concrete under reversed cyclic loading. The response of such walls is often strongly governed by the shear effects leading to the shear induced or brittle failure. The brittle nature of high-strength concrete poses further difficulties in obtaining ductile response from shear walls. An experimental program consisting of six high-strength concrete shear walls was carried out. Specimens were tested under inplane axial load and reversed cyclic displacements with the test parameters investigated being longitudinal reinforcement ratio, transverse reinforcement ratio and axial load. Lateral loads, lateral displacements and the strains of reinforcement in edge elements and web wall were measured. The test results showed the presence of axial load has a significant effect on the strength and ductility of the shear walls. The axially loaded wall specimens exhibited a brittle behaviour regardless of reinforcement ratio whereas the specimen with no axial load had a lower strength but higher ductility. It was also found that an increase in the longitudinal reinforcement ratio gave an increase in the failure load while an increase in the transverse reinforcement ratio had no significant effect on the strength but influenced the failure mode. A non-linear finite element program based on the crack membrane model and using smeared-fixed crack approach was developed with a new aggregate interlock model incorporated into the finite element procedure. The finite element model was corroborated by experimental results of shear panels and walls. The finite element analysis of shear wall specimens indicated that while strengths can be predicted reasonably, the stiffness of edge elements has a significant effect on the deformational results for two-dimensional analyses. Therefore, to capture the deformation of walls accurately, three-dimensional finite element analyses are required. The shear wall design provisions given in the current Australian Standard and the Building Code of American Concrete Institute were compared with the experimental results. The comparison showed that the calculated strengths based on the codes are considerably conservative, specially when there exists the axial load.
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Martinez, Alejandro. "Multi-scale studies of particulate-continuum interface systems under axial and torsional loading conditions." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54423.
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The study of the shear behavior of particulate (soil) – continuum (man-made material) interfaces has received significant attention during the last three decades. The historical belief that the particulate – continuum interface represents the weak link in most geotechnical systems has been shown to be incorrect for many situations. Namely, prescribing properties of the continuum material, such as its surface roughness and hardness, can result in interface strengths that are equal to the contacting soil mass internal shear strength. This research expands the engineering implications of these findings by studying the response of interface systems in different loading conditions. Specifically, the axial and torsional shear modes are studied in detail. Throughout this thesis it is shown that taking an engineering approach to design the loading conditions induced to the interface system can result in interface strengths that exceed the previously considered limiting shear strength of the contacting soil.
Fundamental experimental and numerical studies on specimens of different types of sand subjected to torsional and axial interface shear highlighted the inherent differences of these processes. Specifically, micro-scale soil deformation measurements showed that torsional shear induces larger soil deformations as compared to axial shear, as well as complex volume-change tendencies consisting of dilation and contraction in the primary and secondary shear zones. Studies on the global response of torsional and axial shear tests showed that they are affected differently by soil properties such as particle angularity and roughness. This difference in global behavior highlights the benefits of making systems that transfer load to the contacting soil in different manners available for use in geotechnical engineering. Discrete Element Modeling (DEM) simulations allowed for internal information of the specimens to be studied, such as their fabric and shear-induced loading conditions. These findings allowed for the development of links between the measured micro-scale behavior and the observed global-scale response.
The understanding of the behavior of torsional and axial interfaces has allowed provides a framework for the development of enhanced geotechnical systems and applications. The global response of torsional shear found to induce larger cyclic contractive tendencies within the contacting soil mass. Therefore, this shear mode is more desirable than the conventional axial shear for the study of phenomena that depend on soil contractive behavior, such as liquefaction. A study on the influence of surface roughness form revealed that surfaces with periodic profiles of protruding elements that prevent clogging are capable of mobilizing interface friction angles that are 20 to 60% larger than the soil friction angle. These findings have direct implications in engineering design since their implementation can result in more resilient and sustainable geotechnical systems.
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Nedele, Martin Rolf. "Micromechanical modelling of unidirectional composites subjected to external and internal loadings." Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336828.
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Pilakoutas, Kypros. "Earthquake resistant design of reinforced concrete walls." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/7215.
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Dahlem, Emilie. "Characterisation of refractory failure under combined hydrostatic and shear loading at elevated temperatures." Limoges, 2011. https://aurore.unilim.fr/theses/nxfile/default/dfd9d04c-9d0f-4489-a364-f7ffe7a40e0c/blobholder:0/2011LIMO4051.pdf.
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In many industrial applications, combination of compressive and shear loads will act on refractory linings. Therefore the prediction of lining failure requires the knowledge of the multiaxial behaviour of the refractory materials under service conditions. In order to take into account those aspects in modelling, Drucker-Prager criterion is often used to describe the mechanical behaviour of granular materials. It applies a linear dependency of the shear strength on the hydrostatic pressure. Therefore the Drucker-Prager failure line requires the knowledge of two essential parameters which should be determined experimentally: the cohesion (d) representing the failure shear stress without any hydrostatic pressure, and the friction angle (β) defining the increase of the failure shear stress with hydrostatic pressure. For several materials experimental data are available in literature, especially in the field of geology or civil engineering. But, unfortunately characterization techniques applied so far are operating at ambient temperature only. For refractories, cohesion and friction angle have also to be determined at elevated temperature (up to e. G. 1500°C). A simple adaptation of available experimental devices, developed for room temperature measurements, to elevated temperatures is not possible. The present work proposes a new approach to carry out such measurements in the case of refractory materialsDans de nombreuses applications industrielles, les matériaux réfractaires subissent des contraintes combinées de compression et de cisaillement pouvant entrainer la rupture du matériau. La prédiction de la rupture du revêtement réfractaire nécessite alors la connaissance du comportement multiaxial des matériaux réfractaires dans ces conditions d’utilisation. Afin de tenir compte de ces aspects dans la modélisation numérique, le critère de Drucker-Prager est souvent utilisé pour décrire le comportement mécanique des matériaux granulaires. En effet, le critère de Drucker-Prager correspond à une approche simple qui permet de décrire la dépendance de la contrainte à rupture en cisaillement en fonction de la pression hydrostatique. Néanmoins, l’utilisation de ce critère nécessite la connaissance de deux paramètres essentiels qui doivent être déterminés expérimentalement : la cohésion (d) traduisant la contrainte à la rupture en cisaillement sans pression hydrostatique appliquée, et l’angle de frottement (β) traduisant l’évolution de cette contrainte à rupture lorsque la pression hydrostatique augmente. De nombreux travaux expérimentaux sur ce type de caractérisation sont disponibles dans la littérature, en particulier dans le domaine de la géologie ou du génie civil. Mais, malheureusement, tous ces travaux traitent de techniques de caractérisation fonctionnant à température ambiante. Dans notre cas, la cohésion et l’angle de frottement doivent aussi être déterminés à haute température (jusqu’à 1500°C). La transposition à haute température des dispositifs développés pour des mesures à température ambiante, est tout simplement impossible. Ce travail propose donc une nouvelle approche pour réaliser de telles mesures dans le cas des matériaux réfractaires
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Xu, Chen. "Static and Fatigue Strength of Group Studs Shear Connector under Biaxial Loading Action." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/160990.
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Graham, Drew Abram. "Performance of log shear walls and lag screw connections subjected to monotonic and reverse-cyclic loading." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Spring2007/d%5Fgraham%5F030607.pdf.
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Garner, Michael Paul. "Loading Rate Effects on Axial Pile Capacity in Clays." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2016.pdf.
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Smart, Jason Vincent. "Capacity Resistance and Performance of Single-Shear Bolted and Nailed Connections: An Experimental Investigation." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/30863.
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The experimental study reported upon in this thesis focused on the development of physical data characterizing the behavior of single-shear, laterally-loaded connections when loaded up to and beyond capacity (i.e., maximum resistance). Specimens included a wide array of connection configurations common in wood construction. All connections were tested monotonically in tension under displacement-controlled loading, parallel to the grain. Results of these tests are presented and discussed. Test variables of nailed connections included nail diameter, side member material type, and side member thickness. Test variables of bolted connections included bolt diameter, commercial species grouping of the main and side members, and main member thickness.
Conclusions drawn from this research include mechanics-based explanations of numerous connection response trends observed with respect to test variables. Additionally, observed factors of safety and over-strengths of current design values are quantified on a capacity-basis.Master of Science
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Zangeneh, Kamali Abbas. "Shear Strength of Reinforced Concrete Beams subjected to Blast Loading : Non-linear Dynamic Analysis." Thesis, KTH, Bro- och stålbyggnad, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-104241.
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The experimental investigations performed on the behaviour of reinforce concrete elements subjected to blast loading have revealed that the shear mechanisms and ductility play important roles in the overall response and failure mode of such structures. The main aim of this master thesis is to study the possibility of using finite element method as a tool for predicting the dynamic response of blast loaded reinforced concrete beams and evaluation of their shear strength. In this study, the commercial software, ABAQUS/Explicit has been used by implementing appropriate constitutive material models in order to consider the material nonlinearity, stiffness degradation and strain rate effects. The results of some blast loaded tested beams have been used for verification and calibration of the model. As a secondary objective, the calibrated model used to study the influence of some important factors on the shear strength of reinforced concrete beams and investigate their effects on the failure mode. The results used as a reference and compared with the calculations according to some design codes for blast resistance design. The results of the present research show that the implemented nonlinear finite element model successfully simulates the dynamic responses including displacement/reaction force time histories and induced damage patterns of blast tested beams with reasonable accuracy. The results of performed parametric study confirm that the ductility play important role in the failure behaviour of studied beams. The numerical simulations show that dynamic response of a soft element is more ductile than the stiffer one and the shear forces are thereby limited. Thus, although a soft element fails by large deformations in flexure, a stiff element may experience a brittle shear failure mode for the same load intensity. The comparison between the results of numerical analysis and design codes calculation show that the American approach in shear design of reinforced concrete elements subjected to blast loading is relatively conservative, similar to static design approach and do not consider the effect of ductility in the shear design procedure. On the contrary, the procedure that Swedish guideline implemented somehow considers the effect of ductility on the shear strength of reinforced concrete elements subjected to impulsive loads. Further research should involve the using the developed finite element model as a tool in order to theoretically study the dynamic response of blast loaded reinforced concrete elements and their failure modes. The results of numerical simulations can be used as a reference to derive simplified computational methods for practical design purposes.
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Abdul, rahman Reem. "Experimental analysis of the confined behavior of concrete under static and dynamic shear loading." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI012/document.
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L'objectif de cette thèse est de caractériser le comportement confiné en cisaillement du béton sous chargement statique et dynamique. La méthode expérimentale reprend le concept de l'essai 'Punch Through Shear' qui consiste dans un premier temps à soumettre une éprouvette de béton à un chargement radial puis à appliquer au cours d'une deuxième étape un chargement axial qui permet de cisailler la partie centrale de l'échantillon.Deux méthodes ont été utilisées pour appliquer la contrainte de confinement à l'éprouvette avant de la soumettre à un chargement de cisaillement. La première méthode consiste à appliquer une pression hydrostatique via un fluide de confinement. Ces essais sont réalisés avec la presse Giga. La deuxième méthode consiste à utiliser une cellule métallique pré-déformée à l'aide d'une presse hydraulique. Durant le déchargement de la cellule, des contraintes de confinement sont transmises à l'éprouvette de béton. Cette cellule est instrumentée avec des jauges de déformation qui permettent de mesurer le niveau de confinement appliqué au béton.Les éprouvettes de béton confinées avec la cellule sont soumises à deux types de chargement : l'un statique avec une presse hydraulique normale et l'autre dynamique avec un système aux barres de Hopkinson. Cela permet d'étudier le comportement du béton en cisaillement confiné sur une large gamme de vitesse de déformation.Les résultats des campagnes d'essais montrent que la contrainte de cisaillement du béton augmente avec la pression de confinement. D'autre part, des échantillons saturés d'eau et d'autres séchés à l'étuve sont testés afin de vérifier l'influence de la teneur d'eau sur la résistance au cisaillement. Une résistance au cisaillement des échantillons de béton R30A7 sec supérieure à celle des échantillons saturés est observée sur la plage de déformation considérée. Une influence modeste de la vitesse de déformation en comparaison de ce qui est observé sous chargement en traction dynamique a été remarquée. De plus, un béton haute performance a été testé pour étudier l'influence de la composition du béton sur sa résistance au cisaillement. Il a été observé que la résistance au cisaillement du béton haute performance dépasse fortement celle du béton ordinaire. Les résultats obtenus sont comparés à ceux de la littérature, pour lesquelles des méthodes expérimentales différentes avaient été utiliséesThis PhD thesis focuses on studying the confined behavior of concrete under shear loading in static and dynamic conditions. An experimental method based on the Punch-Through Shear (PTS) test is used in order to investigate shear behavior in mode II conditions. The concept of this test is to first subject the specimen to a confining pressure and then an axial loading is applied to punch through the central portion of the core.In order to introduce confinement to the concrete sample prior to testing it under shear, two methods have been used. The first one is an active confinement applied by means of a high capacity triaxial press Giga. The second method consists in confining the sample with a pre-stressed metallic cell instrumented with hoop strain gages in order to evaluate the confinement acting in the ligament of the concrete sample.Samples confined with the pre-stressed cell are subjected to two types of loading; static and dynamic. The static tests are carried out by means of a normal hydraulic press while dynamic shear testing are performed using a modified Split Hopkinson Bar setup which allows to determine the shear response of concrete over a wide range of strain-rates.The results of test campaigns show that the shear strength of the concrete increases significantly with an increase of confining pressure. Furthermore, dry and saturated concrete samples have been tested in order to study the influence of saturation ratio on the shear behavior of concrete. The results show a higher shear strength with dry samples than in wet ones. Moreover, a small influence (compared to what was observed in dynamic tension) of the strain rate was observed. A high performance concrete was also studied to investigate the influence of concrete composition on its shear strength. It was observed that its shear strength strongly exceeds that of the ordinary concrete. The obtained results are compared with data from literature obtained with different experimental methods
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Stirling, Bradley James. "Flexural Behavior of Interlocking Compressed Earth Block Shear Walls Subjected to In-Plane Loading." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/593.
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This thesis investigates the flexural behavior of interlocking compressed earth block (ICEB) shear walls. In-plane cyclic tests were conducted to evaluate the performance of three flexure dominant large scale ICEB specimens: a slim wall with a 2:1 height to width aspect ratio, a flanged wall, and a wall with an opening at the center. Following the experimental investigation, two types of analyses were conducted for calculating the ultimate strength of flexure dominant ICEB walls: a nonlinear static analysis model assuming lumped plasticity and a plastic analysis model. In addition, incremental dynamic analysis was conducted to address the seismic performance of flexure dominant ICEB buildings. Based on the database from the incremental dynamic analysis, the collapse potential of demonstration ICEB buildings were compared for the countries of interest.
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Kornuta, Jeffrey Alan. "Characterization of lymphatic pump function in response to mechanical loading." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52208.
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The lymphatic system is crucial for normal physiologic function, performing such basic functions as maintaining tissue fluid balance, trafficking immune cells, draining interstitial proteins, as well as transporting fat from the intestine to the blood. To perform these functions properly, downstream vessels (known as collecting lymphatics) actively pump like the heart to dynamically propel lymph from the interstitial spaces of the body to the blood vasculature. However, despite the fact that lymphatics are so important, there exists very little knowledge regarding the details of this active pumping. Specifically, it is known that external mechanical loading such as fluid shear stress and circumferential stress due to transmural pressure affect pumping response; however, anything other than simple, static relationships remain unknown. Because mechanical environment has been implicated in lymphatic diseases such as lymphedema, understanding these dynamic relationships between lymphatic pumping and mechanical loading during normal function are crucial to grasp before these pathologies can be unraveled. For this reason, this thesis describes several tools developed to study lymphatic function in response to the unique mechanical loads these vessels experience both in vitro and ex vivo. Moreover, this work investigates how shear stress sensitivity is affected by transmural pressure and how the presence of dynamic shear independently affects lymphatic contractile function.
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Toothman, Adam James. "Monotonic and Cyclic Performance of Light-Frame Shear Walls with Various Sheathing Materials." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31016.
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The racking performance of light-frame shear walls subjected to monotonic and cyclic loading is the focus of this thesis. The sheathing materials investigated are oriented strandboard (OSB), hardboard, fiberboard, and gypsum wallboard. The objectives of this study were to (1) obtain and compare performance characteristics of each sheathing material; (2) compare the effects of monotonic loading versus the cyclic loading response; (3) investigate the contribution of gypsum in walls with dissimilar sheathing materials on opposite sides of the wall; and (4) study the effects of using overturning anchors. The monotonic tests, which incorporated the use of hold-downs, were performed according to ASTM E564. Half of the cyclic tests were performed with hold-downs, and half were performed without hold-downs. The cyclic tests were performed according to the recently adopted cyclic testing procedure ASTM E2126.
A total of forty-five walls were tested with various configurations. The size of the walls was 1.2 x 2.4m (4 x 8ft). Two tests were performed with each sheathing material subjected to each type of loading: monotonic, cyclic with hold-downs, and cyclic without hold-downs. Two tests were then performed with OSB, hardboard, or fiberboard on one side of the wall and gypsum on the other side of the wall to study the effects of using dissimilar sheathing materials on the shear walls. The OSB and hardboard exhibited similar performance, and were the strongest of the four sheathing materials. Fiberboard performed better than gypsum, but worse than OSB and hardboard. In general, the performance indicators decreased when the walls were subjected to cyclic loading. The contribution of gypsum to walls with hold-downs was significant, but was not linearly additive. The use of hold-downs had a large effect on the performance of the walls. All shear wall performance indicators decreased when hold-downs were not included, with an average reduction of 66% in the peak load.
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Bredel, Daniel. "Performance Capabilities of Light-Frame Shear Walls Sheathed With Long OSB Panels." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32849.
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In this investigation, thirty-six shear walls measuring 8 feet (2.4 m) in width and possessing heights of 8, 9 and 10 feet (2.4, 2.7 and 3.0 m) were subjected to the reversed, cyclic loading schedule of the standard CUREE protocol in order to determine the performance capabilities of shear walls greater than 8 feet (2.4 m) in height sheathed with long panels. Of the thirty-six walls, a total of twelve walls measuring 9 and 10 feet (2.7 and 3.0 m) in height were sheathed with 4 x 8 feet (1.2 x 2.4 m) panels which required additional blocking members between the studs of the frame. Values obtained from the tests performed on these walls provided a direct comparison to those obtained from the walls of equal height, but sheathed with a long panel capable of spanning the entire height of the wall. The capabilities of long panels were investigated when used as the sheathing elements of shear walls with and without a mechanical hold-down device attached to the base of the end stud. An advantage of the long panel was investigated in which it was extended past the bottom plate and down onto the band joist to determine if significant resistance to the uplift present in walls without mechanical hold-down devices could be provided. Also, the effects of orienting the fibers of a 4 x 9 feet (1.2 x 2.7 m) panel in the alternate direction were examined.
Average values of the parameters produced by walls sheathed with long panels either matched or exceeded those of its counterpart sheathed with 4 x 8 feet (1.2 x 2.4 m) panels in all configurations except the 10 feet (3.0 m) tall wall without hold-down devices. In fact, 4 x 9 feet (1.2 x 2.7 m) panels increased the performance of 9 feet (2.7 m) tall walls equipped with hold-down restraint significantly.
Extending the long panels past the bottom plate and down onto the band joist improved the performance of both 8 and 9 feet (2.4 and 2.7 m) tall prescriptive shear walls significantly.
Walls sheathed with panels made of fibers oriented in the alternate direction performed identically to those sheathed with panels of typical fiber orientation until the point of peak load. Once peak load was reached, walls sheathed with panels of alternate oriented fibers failed in a more sudden and brittle manner.Master of Science
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Knudson, Caleb Jesse. "Investigation into the effects of variable row spacing in bolted timber connections subjected to reverse cyclic loading." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/c_knudson_110906.pdf.
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Xu, Jiaming. "Computational modelling of concrete structures subjected to high impulsive loading." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20954.
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The behaviour of concrete structures subjected to high impulsive loading such as blast involves complex responses at the constituent material as well as local to global structural levels. To fully describe the processes involved, detailed numerical simulation is generally required and it is in fact commonly employed nowadays in this field of investigations. However, the demands on a rigorous computational model with the capability to represent different regimes of responses throughout the entire process, namely the stress wave stage under the immediate impulsive (blast) loading, the development of local composite mechanism (such as shear), and finally the global bending / residual structural state, have not been established nor thoroughly investigated in the literature. This thesis aims to fill in this gap and develop an effective and efficient modelling framework for reinforced concrete (RC) structures under impulsive loading, with a particular focus on the analysis of complex dynamic shear mechanisms and the residual structural capacities. This thesis uses a benchmark RC slab as a testbed to firstly examine the validity of commonly applied finite element setup and typical material models for the analysis of the structural response into the global deformation phase and the residual state. This is followed by a detailed scrutiny of the demands on the concrete material model in terms of preserving a realistic representation of the tension/shear behaviour and the significance of such features in simulating realistically the structural response in a reinforced concrete environment. Deficiencies of a widely used concrete material model, namely the Karagozian and Case concrete (KCC) model, in this respect are investigated and a modification scheme to the relevant aspects of the material model is proposed. The modification is demonstrated to result in satisfactory improvement in terms of ensuring more robust simulation of reinforced concrete response to blast loading. To deal with the inevitable modelling uncertainties in the part of concrete surrounding reinforcing bars in a numerical model, an equivalent transitional layer model is proposed for use in finite element modelling of RC structures subjected to impulsive loading. The main objectives of the equivalent transitional layer are to achieve a consist transfer of stress between rebar to concrete outside the transitional zone, and to maintain a realistic relative “sliding” displacement between the outer edge of the transitional layer and the rebar, while the inner edge of the transitional layer is perfectly bonded (with node-sharing) to the rebar. With appropriate descriptions of the softening and failure of the material for the transitional layer, the deformation profile and the strength can be reasonably represented in a consistent manner using the perfect-bond scheme which is commonly adopted in this field of applications. The transitional layer also incorporates features to ensure mesh-independent bond strength. Validation of proposed transitional layer model is carried out against results from RC pullout and beam experiments. The above modelling framework is subsequently employed to investigate the dynamic shear resistance of RC beam/slab under impulsive loading, recognising that the information on the dynamic shear strength in very scarce in the literature. The influence of loading rate on the change of shear span, which alters the shear resistance mechanism and generally results in an increase of the shear capacity, is discussed. The influence of the strain rate enhancement of the material strength on the dynamic shear capacity is also evaluated.
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Jacobs, William P. V. "Performance of Pressure Sensitive Adhesive Tapes In Wood Light-Frame Shear Walls." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32795.
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The performance of connections and full-scale shear walls constructed with acrylic foam pressure sensitive adhesive (PSA) tape is the focus of this thesis. The objectives of this study were first to investigate the bonding characteristics of adhesive tape to wood substrates and then to expand this investigation to cover adhesive-based shear walls subjected to high wind and seismic loadings. A total of 287 monotonic connection tests and 23 reversed cyclic wall tests were performed to achieve these objectives. Connection tests were performed in accordance with ASTM D 1761-88 (2000), and walls were tested using the CUREE (Consortium of Universities for Earthquake Engineering) general displacement-based protocol.
Variables investigated within the main study were the following: the use of OSB versus plywood sheathing, the effect of priming and surface sanding on adhesion, and the comparison of connections involving mechanical fasteners with those that utilized only adhesive tape or a combination of the two. It was found that an application pressure of 207 kPa (30 psi) or greater was needed to form a sound bond between the acrylic foam adhesive tape and a wood substrate. Properly bonded OSB and plywood connections provided fairly ductile failure modes. Full-scale walls constructed with adhesive tape performed similarly to traditional wall configurations, while walls constructed with a combination of adhesive tape and mechanical fasteners provided significant gains in strength and toughness. The results of this study serve to provide a foundation for expanding the engineering uses of acrylic foam adhesive tape for structural applications.
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Azimikor, Nazli. "Out-of-plane stability of reinforced masonry shear walls under seismic loading : cyclic uniaxial tests." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42113.
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In recent years, widespread application of low-rise masonry construction, including post-disaster buildings like fire halls, has become limited in seismic regions of Canada. This is because the Canadian Masonry Design Standard (CSA S304.1-04) [Canadian Standard Association 2004] mandates stringent requirements on the design of ductile reinforced masonry (RM) shear walls, especially with regard to their height-to-thickness (h/t) ratios, which were restricted to ensure against out-of-plane instability. This failure mechanism has been observed in the end zones of reinforced concrete shear walls loaded in-plane in experimental research and in past earthquakes. However, there is a lack of similar evidence for RM shear walls; this is a motivation for the research program described in this thesis.
The research consists of several major tasks. First, a review of the literature on previous experimental research studies on RM shear walls was conducted, followed by comprehensive investigation into the parameters affecting out-of-plane instability of RM shear walls,. Based on the results of this literature review, the first phase of the experimental program was designed with a focus on modeling the RM wall end zone and understanding the mechanism of lateral instability. Five full-scale specimens representing the wall end zones were constructed and subjected to reversed cyclic axial tension and compression until failure. The effect of varying h/t ratios of the plastic hinge zone, as well as level of axial tensile strain on the out-of-plane instability was examined.
Based on the results of the experimental study, it was concluded that the level of applied tensile strain in the wall end zone is one of the critical factors governing its lateral instability. Therefore, the maximum tensile strain that may be imposed on a moderately ductile RM wall end-zone is determined based on a kinematic relationship between the axial strain and the out-of-plane displacement. A preliminary mechanic model has been proposed to predict the maximum tensile strain before instability takes place. The model can be incorporated into design provisions related to the thickness of shear walls of a given height. A comparison with the experimental results showed that the model offers conservative prediction of the maximum tensile strain.
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Mohamed, Abdelkhalek Saber Omar [Verfasser]. "Behaviour of retrofitted masonry shear walls subjected to cycling loading / von Abdelkhalek Saber Omar Mohamed." Karlsruhe : Inst. für Massivbau und Baustofftechnologie, 2004. http://d-nb.info/1001582128/34.
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Yingling, Vanessa Rose. "Shear loading of the lumbar spine, modulators of motion segment tolerance and the resulting injuries." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22252.pdf.
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Schreiber, Sascha K. "Punching shear capacity of slab-column connections with steel-fibre reinforcement under lateral cyclic loading." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60493.pdf.
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Al-Azzawi, Zaid Mohammed Kani. "Capacity of FRP strengthened steel plate girders against shear buckling under static and cyclic loading." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25453.
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Civil engineers are presently faced with the challenge of strengthening and repairing many existing structures to assure or increase their structural safety. The reasons for this include changes in the use of structures, and increased traffic loads on bridges. In Iraq, for example, several highway bridges needed to accommodate increased axle load during the transportation of huge turbines for electricity generating stations. The requirement for structural strengthening and repair methods is, however, driven by the worldwide need to ensure the safety and sustainability of our aging infrastructure which is deteriorating at a rate faster than it can be renovated. The ever increasing damage caused by environmental effects and the corrosion of steel and deterioration of concrete, reduce structural safety and lead to disruption for the users, which can have serious economic consequences. In a plate girder bridge, the plate girders are typically I-beams made up from separate structural steel plates (rather than rolled as a single cross-section), which are welded or, in older bridges, bolted or riveted together to form the vertical web and horizontal flanges of the beam. The two primary functions of the web plate in a plate girder are to maintain a relative distance between the top and bottom flanges and to resist the induced shear stresses. In most practical ranges of plate girder bridges’ spans, the induced shear stresses are relatively low compared to the bending stresses in the flanges induced by flexure. As a result the web plate is generally chosen to be much thinner than the flanges. The web panel consequently buckles at a relatively low shear force. For steel girder structures dominated by cyclic loading, as is the case with repeated vehicle axle loads on bridges, this can lead to the so-called ‘breathing’ phenomenon; an out-of-plane buckling displacement that can induce high secondary bending stresses at the welded plate boundaries. In the current work, a novel FRP strengthening technique using bonded shapes is applied to resist these out of plane deformations, and hence reduce the breathing stresses, and improve the fatigue life of the plate girder which is very different to the majority of applications of FRP strengthening that exploit the FRP for its direct tensile strength and stiffness. The objective of the current experimental programme is to strengthen thinwalled steel girders against web shear buckling using a corrugated CFRP or GFRP panel bonded externally along the compression diagonal of the web plate. The programme was divided into three main phases, including: (1) the development of a new preformed corrugated FRP panel, and (2, 3) testing its performance in two main experimental series. The initial series involved tests on 13 steel plates strengthened with the proposed preformed corrugated FRP panel and subjected to in-plane shear loading using a specially manufactured “picture-frame” arrangement designed to induce the appropriate boundary conditions and stresses in the web plates. This initial test series investigated the performance of different forms of strengthening under static load, in preparation for another series of cyclic tests to investigate their fatigue performance. The test variables included FRP type (CFRP or GFRP), form of FRP (closed or open section), number of FRP layers, and orientation of GFRP fibres used to produce the FRP panel. In the second series, six specimens were manufactured to simulate the end panel of a plate girder. These were strengthened with the optimized FRP panel from the initial series and tested for shear buckling under repeated cyclic loading with a stress range 40-80% of the static ultimate capacity. A considerable increase in the stiffness of the strengthened specimens is evident in the observed reductions of the maximum out-of-plane displacement. The stiffness of the strengthened specimens is assessed to be increased by a factor ranging between 3 to 9 times the stiffness of the corresponding unstrengthened specimen, depending upon the type of the FRP panel used and the aspect ratio of the tested specimens. The breathing phenomena is also significantly reduced, consequently the surface, membrane and secondary bending stresses are reduced. The 45° strengthening scheme succeeded the best both in reducing the breathing stresses and increasing the ultimate shear capacity of the specimen by 88%. Fatigue analyses indicated that the proposed strengthening technique is able to considerably elongate the life expectancy of the strengthened plate girders by a factor ranging between 2.5 and 7 depending on the applied cyclic load amplitude. In addition, the proposed strengthening technique did not show any debonding or delamination under both static and cyclic loading which makes it a good candidate for strengthening thin-walled structural members, especially, when ductility is a concern. In fact, the proposed strengthening technique succeeded in improving the energy absorption capacity of the strengthened specimens by a factor ranging between 1.5 and 2.5 times the corresponding control specimen which means that the ductile failure type associated with shear buckling of steel plate girders is not only maintained, but it was improved as well. This type of ductile failure is not common in other types of FRP strengthening techniques. Finally, a geometrical and material non-linear finite element model is presented both for the steel and composite sections which showed very good correlation with test results and was capable of predicting both the strength and deformational behaviour of the tested specimens. This numerical model is used for a parametric study to support the proposed design method.
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Woo, Thomas Robert. "Effects of Seawater on the Mechanical Behavior of Composite Sandwich Panels Under Monotonic Shear Loading." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/898.
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Abstract
Salt water environments are very harsh on materials that are used within them. Many issues are caused by either corrosion and/or internal degradation to the materials themselves. Composites are better suited for this environment due to their high strength to weight ratios and their corrosion resistance, but very little is known about the fracture mechanics of composites. The goal of this study is to gain a better understanding for the behavior of a composite boat hull under a shear loading, similar to the force water applies on the hull as the boat moves through the water; then attempt to strengthen the composite sandwich panel against the shear loading.
A parametric study was conducted to investigate monotonic in-plane shear loading for composite sandwich panels used in commercial naval vessels. In order to model a conventional composite boat hull, test specimens were composite sandwich panels made of a Divinycell H100 foam core with four layers of fiberglass on both sides of the core. Specimens were tested under a monotonic loading with a rate of 0.2 in/min, and tested until complete failure using the standard test.
Seawater specimens were manufactured in the same manner as the original test specimens, but then were submersed in either filtered seawater or the ocean. The differences between the filtered pieces and the ocean allowed us to determine if any changes found in the composite sandwich panels were related to environment conditions or if the changes were related to the saltwater interaction itself. To create these different environments the seawater specimens were taken to the Avila pier where 36 specimens were placed in a tub that was fed filtered saltwater, while 30 specimens were placed in a plastic mesh with weights and lowered to a depth of approximately 30 ft. in the ocean. Three specimens were then removed at monthly intervals from both filtered and ocean environments.
Shear Keys were created as a method to strengthen the composite sandwich panels against the shear force that the previous specimens had been tested to. Eight Shear Keys were then placed into groves cut into the foam core (four on each side) and the four fiberglass layers were laid on top.
Testing showed that the seawater did have an initial effect on the composite sandwich panels. The filtered pieces showed a decrease in yield strength and stiffness the longer they were subjected to the seawater. The raw unfiltered pieces placed in the ocean saw an even higher decrease in their yield strength and decrease in stiffness. However, for both the unfiltered and raw specimens there was an increase in the ultimate strength and fracture point of the specimens. The effects of the sea water seemed to taper off after the 3rd month however.
The Shear Key specimens were tested with a 4mm and an 8mm Shear Key. The 8mm Shear Keys showed a decrease in shear strength, which was primarily due to removing too much material from the core and weakening the specimen. It was concluded that the decrease in area created a force concentration at the deepest part of the Shear Key causing the premature failure. The 4mm Shear Key showed an increase in the yield strength, ultimate strength, and fracture point. A finite model was built to simulate the original test specimen along with the 4mm and 8mm Shear Key cases, and the results were compared to the experimental results.
The numerical results showed that it was possible to relate the experimental results to the linear or elastic portion of the plots. There was a difference between the maximum displacement of the model and the actual specimens, but this was attributed to potential inaccurate comparison of the loading on the model compared to the actual specimens. The correlation between the model itself and the experimental data was close enough to conclude that it could be used for predicting baseline trends.
Further investigation of the specimens should include looking into the effects of a cyclic shear loading on the specimens. This combined with the seawater element used in this thesis would provide further insight to the initial degradation seen in the seawater specimens, and could potentially provide a closer relation to current hull failures. In addition to including a cyclic loading another numerical model should be created. A model that could be constrained both locally and globally would provide more accurate results. The FEM should also include the ability to run a crushable foam core model within the solver which would also increase the accuracy of the numerical solution.
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Huang, He. "Experimental study of NiTi alloy under shear loading over a large range of strain rates." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066072.
Full textAbstract:
Ce travail décrit une étude expérimentale sur des tôles en Ni-Ti à température ambiante en cisaillement plan simple, et pour des vitesses de déformation de 10-4 à 103/s. En quasi-statique (10-4-10-2/s), la mesure optique du champ de déplacement est indispensable à cause du faible déplacement (0.3mm). Des essais à vitesse de déformation intermédiaire (10-1-101/s) ont été réalisés avec la Machine MTS modifiée, capable d'aller à 300mm/s. Une caméra rapide est nécessaire pour suivre ces tests. Enfin, des barres de Hopkinson sont utilisées pour les essais à haute vitesse (102-103/s).Les efforts se sont concentrés sur la méthodologie afin d'explorer les limites expérimentales. Au niveau mécanique, des efforts ont été apportés sur la conception des montages des mors pour combiner des exigences contradictoires. Au niveau mesure, des caméras optiques fonctionnant jusqu'à 5M images/s ont été utilisées. La texture des images, la peinture, la lumière, la taille d'élément et l'incertitude sont analysées. De plus, la caméra infrarouge est utilisée pour confirmer l'observation optique sous faibles vitesses de déformation.Finalement, des essais ont été réalisés pour 7 ordres de grandeurs de la vitesse de déformation, avec identification de la relation contrainte-déformation et observation de l'évolution de la bande de transformation. On observe : (i) Une augmentation de la contrainte avec la vitesse de déformation. (ii) Un champ de déformation non homogène, même en faible vitesse, avec une bande à 10 degrés par rapport à la direction de cisaillement. (iii) Deux bandes séparées à haute vitesse (102/s), ce qui indique que la bande de localisation dépend de la vitesse de chargementThis work describes an experimental study on a NiTi alloy at the ambient temperature (Pseudoelastic behavior) under the double in-plane shear loading over strain rates from 10-4 to 103/s. Under quasi-static loadings (10-4-10-2/s), the optical full-field measurement is necessary because of the very small displacement (0.3mm). The intermediate loading rates (10-1-101/s) are realized with a modified MTS machine able to load at 300mm/s. Moreover, a high-speed camera is needed to follow such tests. Finally, the Split Hopkinson bars are used to perform tests at impact loading rates (102-103/s).The main effort has been made on the methodological study to explore the experimental possibility. For the mechanical level, the attention has been paid on the design of the clamping system to cope with the contradictory requirements. For the measuring level, different optical cameras with sampling rate till to 5M frames/second are used. The texture, the painting, the lightening, the element size and the uncertainty are analyzed. Furthermore, an infrared camera was used at lower loading rates to confirm the DIC measurement.The tests are continually performed over 7 decades of the strain rate. The nominal stress-strain curves and the detailed observation of the transformation band evolution are measured. The main findings are as follows: (i) Regular stress increase with the strain rate; (ii) an inhomogeneous strain field under in-plane shear condition, even at very low strain rates, with a band at 10 degrees from the shear direction under lower strain rates. (iii) Two separated bands at the strain rate of 102/s, which suggests that the localized transformation bands are rate dependent
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Love, Bryan Matthew. "Multiscale Analysis of Failure in Heterogeneous Solids Under Dynamic Loading." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/29650.
Full textAbstract:
Plane strain transient finite thermomechanical deformations of heat-conducting particulate composites comprised of circular tungsten particulates in nickel-iron matrix are analyzed using the finite element method to delineate the initiation and propagation of brittle/ductile failures by the nodal release technique. Each constituent and composites are modeled as strain hardening, strain-rate-hardening and thermally softening microporous materials. Values of material parameters of composites are derived by analyzing deformations of a representative volume element whose minimum dimensions are determined through numerical experiments. These values are found to be independent of sizes and random distributions of particulates, and are close to those obtained from either the rule of mixtures or micromechanics models.
Brittle and ductile failures of composites are first studied by homogenizing their material properties; subsequently their ductile failure is analyzed by considering the microstructure. It is found that the continuously varying volume fraction of tungsten particulates strongly influences when and where adiabatic shear bands (ASB) initiate and their paths. Furthermore, an ASB initiates sooner in the composite than in either one of its constituents.
We have studied the initiation and propagation of a brittle crack in a precracked plate deformed in plane strain tension, and a ductile crack in an infinitely long thin plate with a rather strong defect at its center and deformed in shear. The crack may propagate from the tungsten-rich region to nickel-iron-rich region or vice-a-versa. It is found that at the nominal strain-rate of 2000/s the brittle crack speed approaches Rayleigh's wave speed in the tungsten-plate, the nickel-iron-plate shatters after a small extension of the crack, and the composite plate does not shatter; the minimum nominal strain-rate for the nickel-iron-plate to shatter is 1130/s. The ductile crack speed from tungsten-rich to tungsten-poor regions is nearly one-tenth of that in the two homogeneous plates. The maximum speed of a ductile crack in tungsten and nickel-iron is found to be about 1.5 km/s.
Meso and multiscale analyses have revealed that microstructural details strongly influence when and where ASBs initiate and their paths. ASB initiation criteria for particulate composites and their homogenized counterparts are different.Ph. D.
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Sharifimehr, Shahriar. "Multiaxial Fatigue Analysis under Complex Non-proportional Loading Conditions." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1544787705876488.
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Albright, Dustin Graham. "The Effects of Bolt Spacing on the Performance of Single-Shear Timber Connections Under Reverse-Cyclic Loading." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/34324.
Full textAbstract:
Much previous experimentation related to wood structures has employed monotonic loading to replicate static situations. However, instances of natural hazards have raised interest in the response of structural connections to dynamic loads. This increased interest led the Consortium of Universities for Research in Earthquake Engineering (CUREE) to develop a testing protocol for reverse-cyclic loading, which involves cycling loads through zero in order to test specimens in both tension and compression. With the CUREE testing protocol in place, recent research has been devoted to understanding the effects of reverse-cyclic loading on multiple-fastener connections.
Experimentation by Heine (2001), Anderson (2002), Billings (2004) and others contributed to a better understanding of bolted connection behavior under reverse-cyclic loading. However, some questions remained. Billings was unable to consistently produce yield modes III and IV, meaning that her suggested bolt spacing of seven times the bolt diameter (7D) could not be applied to connections subject to these yield modes without further testing. In addition, the work of Anderson and Billings raised questions regarding the proper measurement of bending yield strength in bolts and the relationship between the bending yield strength and the tensile yield strength. These topics are each addressed by this project and thesis report.
Results of the connection testing presented in this report can be used in conjunction with the work of Anderson and Billings to critically evaluate the 4D between-bolt spacing recommended by the National Design Specification (NDS) for Wood Construction (AF&PA, 2001). Results of the bolt testing provide a supplement to the search for a reliable method for the measurement of bending yield strength in bolts.Master of Science
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Andrejic, Mateja. "Effects of Curing Cycle and Loading Rates on the Bearing Stress of Double Shear Composite Joints." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1549.
Full textAbstract:
In the last few decades, there has been a shift to using more lightweight materials for the potential of fuel consumption reduction. In the Aerospace Industry, conventional metal structures are being replaced by advanced composite structures. The major advantage of an advanced composite structure is the huge reduction in the number of parts and joints required. Also composite materials provide better resistance to creep, corrosion, and fatigue. However, one cannot eliminate all the joints and attachments in an aircraft’s structure. Eliminating structural joints is impractical in present-day aircraft because of the requirements for inspection, manufacturing breaks, assembly and equipment access, and replacement of damaged structures. Currently, composite joints are overdesigned which leads to weight penalties. Understanding how to optimize the ultimate bearing strength of a composite joint by altering the cure cycle might be beneficial to the composite joint design process.
This study investigates, through numerical and experimental analysis, the mechanical behavior of double shear joints. The first task is to test Aluminum double shear joint specimens inside the double shear joint fixture at a loading rate of 0.05 in./min. (quasi-static). The second task is to numerically model and validate the aluminum double shear joint specimen. The third task is to test the Unidirectional MTM 49 carbon fiber pre-preg double shear composite joint specimens with two different cure cycles and five different loading rates (0.05 in./min., 0.1 in./min., 1 in./min., 2 in./min. and 6 in./min.). The double shear composite joint specimens are made, using a heat press, with a quasi-isotropic laminate orientation of [0 0 +45 -45 +45 -45 90 90]s. The first cure cycle used is called the alternate cure cycle, which is Cytec’s MTM 49 Unidirectional Carbon Fiber pre-preg material cure cycle, and the second cure cycle used is called the datasheet cure cycle, which is Umeco's MTM 49 Unidirectional Carbon Fiber pre-preg material cure cycle. The recommended datasheet cure cycle and an alternate cure cycle are both compared to see how they affect the mechanical characteristics of the matrix along with the bearing stress. The fourth task is to adjust the Aluminum double shear joint numerical model for the double shear composite joint specimen. The numerical results for both the Aluminum and the composite specimens are in agreement with the experimental results. The theoretical in-plane material properties of the quasi-isotropic laminate were in agreement with the experimental results. One can see that at 0.05 in./min. and 0.1 in./min. (for both cure cycles) the composite double shear specimens carried more load compared to the higher loading rates of 1 in./min., 2 in./min. and 6 in./min. The tensile modulus of elasticity of an Aluminum sample is measured using a crosshead displacement, a strain gage and an extensometer. The crosshead displacement yielded very inaccurate results when compared to the strain gage and the extensometer.