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Artykuły w czasopismach na temat "Anchorage test"
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Claro, Cristiane Aparecida de Assis, Rosana Villela Chagas, Ana Christina Elias Claro Neves i Laís Regiane da Silva-Concílio. "Comparative photoelastic study of dental and skeletal anchorages in the canine retraction". Dental Press Journal of Orthodontics 19, nr 1 (styczeń 2014): 100–105. http://dx.doi.org/10.1590/2176-9451.19.1.100-105.oar.
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OBJECTIVE: To compare dental and skeletal anchorages in mandibular canine retraction by means of a stress distribution analysis. METHODS: A photoelastic model was produced from second molar to canine, without the first premolar, and mandibular canine retraction was simulated by a rubber band tied to two types of anchorage: dental anchorage, in the first molar attached to adjacent teeth, and skeletal anchorage with a hook simulating the mini-implant. The forces were applied 10 times and observed in a circular polariscope. The stresses located in the mandibular canine were recorded in 7 regions. The Mann-Whitney test was employed to compare the stress in each region and between both anchorage systems. The stresses in the mandibular canine periradicular regions were compared by the Kruskal-Wallis test. RESULTS: Stresses were similar in the cervical region and the middle third. In the apical third, the stresses associated with skeletal anchorage were higher than the stresses associated with dental anchorage. The results of the Kruskal-Wallis test showed that the highest stresses were identified in the cervical-distal, apical-distal, and apex regions with the use of dental anchorage, and in the apical-distal, apical-mesial, cervical-distal, and apex regions with the use of skeletal anchorage. CONCLUSIONS: The use of skeletal anchorage in canine retraction caused greater stress in the apical third than the use of dental anchorage, which indicates an intrusive component resulting from the direction of the force due to the position of the mini-implant and the bracket hook of the canine.
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Long, Zhe, Zhi-xin Yan i Chun-bo Liu. "Shear Effects on the Anchorage Interfaces and Seismic Responses of a Rock Slope Containing a Weak Layer under Seismic Action". Mathematical Problems in Engineering 2020 (30.04.2020): 1–11. http://dx.doi.org/10.1155/2020/1424167.
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The shear effects on the anchorage interfaces under seismic action is a key problem requiring urgent investigation in the field of rock and soil anchorages. In this paper, the model of rock slope with a weak layer was constructed by pouring, and the large-scale shaking table model test was completed. The shear strain on the anchorage interfaces and the acceleration of the slope were collected using built measurement systems. The shear effects on the two anchorage interfaces (a bolt-grout interface and a grout-rock interface) and seismic responses of the slope under seismic action were investigated. The distribution laws of the shear stress on the two anchorage interfaces along the axial direction of the bolt under seismic action were gained. The variations of the peak acceleration amplification coefficient on the slope surface, the magnitude, and the growth rate of peak shear stress on the anchorage interfaces under seismic action with different excitation directions and intensities were obtained. Furthermore, the positive relationship between the shear effect on the anchorage interfaces and the seismic response of slope was revealed. This study provides support for theoretical research, numerical simulation analysis, and aseismic design of rock and soil anchorages under dynamic conditions.
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Wei, Xing, i Jun Li. "Theoretical and Experimental Study on Cable-to-Irder Anchorages in Long-Span Cable-Stayed Bridges with Steel Box Girder". Advanced Materials Research 255-260 (maj 2011): 1315–18. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.1315.
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Cable anchorages are among the most important elements in a cable-stayed bridge, which are complex in structure and bear heavy load. There are three main forms in anchorage zone between girder and cable in modern long-span cable-stayed bridge with steel box girder, which are ear-plate form, anchor-box form and anchor-plate form. Combining theoretical analysis with the static test, static behavior and stress transfer pathway of three typical cable-to-girder anchorages were analyzed, and the differences of stress distribution and stress concentration among anchorage zones were pointed out. Based on the Von.Mises strength criterion, bearing safety of three typical cable-to-girder anchorages was evaluated. Finally, the measures to reform stress distribution and reduce stress concentration are discussed. Some useful conclusions were obtained, which would benefit the design of cable-to-girder anchorages.
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Keum, Moon Seoung, Jae Yoon Kang, Jong Sup Park i Woo Tai Jung. "Performance Test of Swage Anchorage According to the Insert of CFRP Tendon". Key Engineering Materials 730 (luty 2017): 452–56. http://dx.doi.org/10.4028/www.scientific.net/kem.730.452.
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Despite of the numerous advantages offered by the CFRP tendon, there are still problems to be solved. Among them, finding an effective anchoring method considering the material properties of CFRP constitutes a typically pending problem. Being an orthotropic material, the CFRP tendon presents risk of breakage under forces acting perpendicularly to the direction of the fibers. This implies that a new type of anchor should be developed for the CFRP tendon since the anchorages used for conventional steel strands cannot be readily applied. Moreover, following the growing interest given to the CFRP tendon, research is being relentlessly conducted to develop dedicated anchorages with improved performance. Accordingly, this paper presents an experimental study on the anchor performance of the swage anchorage known to be the most compact among the various types of anchor. The tests revealed that the swage anchor without insert developed about 92% of the tensile strength of the CFRP tendon whereas the swage anchor with metallic winding insert developed 100% of the tensile strength. From these results, it appears that the anchorage with outer diameter of 24 mm develops anchor performance higher than 95% of the tensile performance of the CFRP tendon and can potentially be exploited for post-tensioning.
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Zhao, Lin, Xian Ming Zeng, Shi Min Li i Da Lu Lin. "Field Test Study of the Blast-Resistance Performance of Optimal Composite Anchorage Structure". Advanced Materials Research 250-253 (maj 2011): 1474–77. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.1474.
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This paper introduced the comparison test of new optimal composite anchorage structure and single anchorage structure. The measured results show that the particle acceleration of single anchorage structure is 2.22 times higher than that of the optimal composite anchorage structure. The dynamic strain of the former is 5.3~4.5 times higher than that of the latter. The blast-resistance of the optimal composite anchorage structure is 5.10 times higher than that of the single anchorage structure. Under the limit damage condition, the former is 4.13~3.40 higher than that of the latter. The optimal composite anchorage structure has excellent blast-resistance. Optimal weakened zone is between the reinforced support structure and the surround rock. Under the explosion condition, weakened zone is firstly deformed, cracked, crushed or densified, and at the same time, a great deal of blast energy is absorbed. Therefore, the crisis of the reinforced support structure is transferred into the weakened zone.
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McKay, K. S., i M. A. Erki. "Grouted anchorages for aramid fibre reinforced plastic prestressing tendons". Canadian Journal of Civil Engineering 20, nr 6 (1.12.1993): 1065–69. http://dx.doi.org/10.1139/l93-137.
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Nonmetallic prestressing tendons, made of fibre-reinforced composite materials, are being proposed as alternatives to steel prestressing tendons for bridges and parking garage structures, where corrosion is the leading cause of structural deterioration. One type of commercially available nonmetallic tendons is made of pultruded aramid fibres. One of the main problems for these tendons, which is common to all nonmetallic tendons, is that the high ratio of the axial to lateral strength of fibre-reinforced materials requires special attention to the type of anchorage used. For the aramid tendon, the simplest grouted anchorage consists of a steel tube filled with nonshrink grout, into which the end of the tendon is embedded. This note presents the test results of a parametric study on grouted anchorages for pultruded aramid tendons. Key words: prestressed concrete, nonmetallic tendons, aramid fibre, grouted anchorage.
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Pham, Quang-Quang, Ngoc-Loi Dang i Jeong-Tae Kim. "Smart PZT-Embedded Sensors for Impedance Monitoring in Prestressed Concrete Anchorage". Sensors 21, nr 23 (27.11.2021): 7918. http://dx.doi.org/10.3390/s21237918.
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This study investigates the feasibility evaluation of smart PZT-embedded sensors for impedance-based damage monitoring in prestressed concrete (PSC) anchorages. Firstly, the concept of impedance-based damage monitoring for the concrete anchorage is concisely introduced. Secondly, a prototype design of PZT-embedded rebar and aggregate (so-called smart rebar–aggregate) is chosen to sensitively acquire impedance responses-induced local structural damage in anchorage members. Thirdly, an axially loaded concrete cylinder embedded with the smart rebar–aggregate is numerically and experimentally analyzed to investigate their performances of impedance monitoring. Additionally, empirical equations are formulated to represent the relationships between measured impedance signatures and applied compressive stresses. Lastly, an experimental test on a full-scale concrete anchorage embedded with smart rebar–aggregates at various locations is performed to evaluate the feasibility of the proposed method. For a sequence of loading cases, the variation in impedance responses is quantified to evaluate the accuracy of smart rebar–aggregate sensors. The empirical equations formulated based on the axially loaded concrete cylinder are implemented to predict compressive stresses at sensor locations in the PSC anchorage.
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Kim, Min Sook, i Young Hak Lee. "Load Carrying and Hydrostatic Performances of Innovative Encapsulated Anchorage System for Unbonded Single Strand". Advances in Civil Engineering 2019 (25.08.2019): 1–16. http://dx.doi.org/10.1155/2019/7812623.
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A new anchorage system is proposed having a circular bearing plate and curvature between the bearing plate and the anchor head to improve stress concentration. A lid with a screw instead of the grouting method is also proposed to prevent moisture penetration. The details of the anchorage device have been chosen to reduce stress concentration based on the finite element analysis. Static load test, load transfer test, and hydrostatic test of fabricated devices were carried out according to ETAG 013 to evaluate the proposed design. As results, the anchorage slip and stabilization satisfied the recommendations of ETAG 013. The maximum load in the load transfer test was at least 1.1 times the ultimate tendon strength. The results of the hydrostatic test showed that the developed anchorage device is watertight to protect against corrosion. As a result of bursting force test, it was confirmed that the proposed anchorage device has more advantages than the conventional rectangular anchorage devices in terms of stress distribution.
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Shenghua, Zhang, i Huang Ying. "Performance Test of OVM Anchorage and Coupling". Prestress Technology 3, nr 05 (1999): 2–3. http://dx.doi.org/10.59238/j.pt.1999.05.001.
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Manea, A. M., M. D. Iozsa, C. Stan i A. Ioniţă. "Finite element analysis for testing safety-belt anchorages". IOP Conference Series: Materials Science and Engineering 1235, nr 1 (1.03.2022): 012048. http://dx.doi.org/10.1088/1757-899x/1235/1/012048.
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Abstract The passive safety of the vehicle is ensured by designing optimized restraint systems to protect the occupants during the accident. The safety-belts have the role of restraining the occupants of the car on the seat during an impact or in the event of a rollover. Their retention prevents or minimizes the impact between the occupants and the interior components of the passenger compartment. Two simplified models of seat structures are proposed to determine the strength of the safety-belts anchorages. The test of the anchorage for safety-belts of the two seat models is performed in accordance with Regulation no. 14 UNECE. For the two seat models, a three-dimensional resistance structure was made. The 3D models of the seats were inserted in the FEA software. The analysis of the models is done by the finite element method with the Static Structural module of the FEA software. A tensile force is applied during the test on the safety-belts anchorages. The traction force shall be applied in the direction corresponding to the seating position, at an angle of 10°±5° above the horizontal, in a plane parallel to the median longitudinal plane of the vehicle. During the tests the safety-belt anchorages shall withstand the entire period of application of the traction force and the upper safety-belt anchorage shall not be displaced during the test forward of a transverse plane passing through the R point of the seat.
Rozprawy doktorskie na temat "Anchorage test"
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Wu, Zhongxin. "Effective Post-Tensioned Splicing System for Prestressed Concrete Piles". Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6605.
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Precast prestressed concrete piles are widely used in deep foundation construction. Due to unexpected site soil conditions and difficulties associated with transportation and handling long precast piles, splicing is sometimes necessary at the construction site.
Available splicing methods utilize steel type connections that are more suitable for reinforced concrete construction and result in limited tensile capacity at the splice. This dissertation describes studies associated with the development of a new post-tensioned splicing system using staggered, embedded anchorages. The new system has the potential to provide the same tensile capacity as a one piece prestressed pile.
To develop the post-tensioned splicing system it was necessary to conduct varied numerical analyses to solve immediate technical problems associated with the design, fabrication and testing of a prototype. This included the design of a self-stressing prestressing bed, optimization of the shape of the embedded anchorages and their layout within the piles being spliced. The focus of the dissertation is on non-linear finite element studies conducted to model the flexure behavior of prototype laboratory and full-sized spliced piles in comparison to their identical non-spliced counterpart.
Though finite element analysis of prestressed elements is not new, issues relating to modeling post-tensioned, spliced elements with embedded, staggered anchorages have not been the subject of any previous investigation and constitute the principal contribution of this study.
Nonlinear finite element analysis was conducted using ANSYS. The William-Warnke failure criterion used to establish concrete failure. A three-dimensional analysis was conducted in which SOLID65 element was used for modeling concrete and LINK8 for the prestressing strands. The post-tensioning ducts were modeled using PIPE20 elements. Perfect bond was assumed between the concrete and the ducts. Embedded anchorages were modeled as fixed locations within the concrete. Epoxy used to join the two splicing surfaces was modeled using contact elements. Since the layout of the post-tensioning ducts was staggered, a full model was required. In contrast, advantage was taken of symmetry for the analysis of the one piece controls.
The finite element model was able to accurately capture the flexural behavior of both the control and the spliced piles. The results suggested that tensile separation at the splice interface acted as a pivot about which the section rotated. As a result, the compression failure zone in the spliced pile was confined to a smaller region compared to the control.
The stress distribution in the spliced pile indicated that the concrete in the cover above the splice was crushed at the ultimate stage before the steel had yielded. As a result, the ultimate capacity of the spliced pile was controlled by concrete failure.
The results also indicated that, among the multiple layers of post-tensioning strands, only one approached yield while others remained in the elastic range. As a result, when the applied load was released, the spliced pile rebounded back to a large degree, which resulted in a much smaller residual permanent deformation. This behavior of a spliced pile can be beneficial for structures in a seismic zone because it will induce smaller secondary moments.
This study helped to refine and improve the new post-tensioned splicing system. Its availability makes it possible to extend and further improve the concept without the need for costly prototype fabrication and testing.
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Tronco, Paula Borges. "Efeitos da ancoragem em julgamentos e decisões no mercado imobiliário: uma análise a partir do nível de conhecimento dos decisores". Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/4610.
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Individuals often have difficulty identifying the heuristics that affect their decision-making
(NOFSINGER and BAKER, 2002). However, Menkhoff, Brozynki and Schmidt (2006) show
that individuals knowledgeable about the influence of heuristics in decision making may have
fewer episodes of bounded rationality compared to individuals unrelated to this knowledge.
According to Mussweiler et al. (2000), the Anchorage is one of the most striking influences
on judgment and decision making. In this context, the main objective of this research was to
verify the existence of heuristics in the anchoring of the numerical estimates of experts and
non-specialists in real estate, when subjected to experimental tasks related to the field of
domain expert and outside their field of knowledge, in order Thorsteinson et al. (2008), who
argue that the effects of Anchorage makers are reduced when subjects have more knowledge
about the problems in question. Thus, we performed a experiment with 324 subjects makers
were divided into groups for Calibration and Experimental Groups, through the application of
two decision-making tasks (T1 and T2), using the model Jacowitz and Kahneman (1995). It is
noteworthy that many studies have been conducted in Anchorage to verify the presence of the
anchoring heuristic in the process of judgment and decision making. However, this study,
besides the proposal to study the effects of Anchorage during the decision making process
related to quantitative, as the main contribution presented additional verification of the
manifestation of Anchorage as a control variable (knowledge) is removed from the decisionmaking
task. This procedure is called by Cozby (2006) a test handling, consisting in an
attempt to directly measure whether the manipulation of a variable has the intended effect on
the respondents. The results obtained through statistical t test for independent samples showed
that there is evidence of the anchoring heuristic in decision making of individual members of
the experimental group of non-experts (anchor and anchor low-high) in both T1 and T2. With
respect to experts, it was revealed that T1 is no evidence of the anchoring heuristic, which
corroborates the results found by Jacowitz and Kahneman (1995) and Luppe (2006).
However, in relation to the second decision-making task (T2), it was observed that the mean
differences were not statistically significant, implying that, at T2, are not found evidence of
Anchorage in the decision process of experts, contradicting the results by Norfhcraft and
Neale (1987) and Dorow (2009), who found evidence of Anchorage in the decision process
when they were real estate brokers who underwent estimates for the real estate market.Os indivíduos normalmente têm dificuldade em identificar as heurísticas que afetam suas tomadas de decisões (BAKER e NOFSINGER, 2002). No entanto, Menkhoff, Schmidt e Brozynki (2006) revelam que indivíduos conhecedores da influência das heurísticas no processo decisório podem apresentar menos episódios de racionalidade limitada se comparados aos indivíduos alheios a esse conhecimento. Segundo Mussweiler et al (2000), a Ancoragem consiste em uma das influências mais notáveis em julgamento e tomada de decisão. Neste contexto, o objetivo principal desta pesquisa consistiu em verificar a existência da heurística da Ancoragem nas estimativas numéricas de especialistas e não-especialistas em mercado imobiliário, quando submetidos a tarefas experimentais relacionadas ao campo de domínio do especialista e fora do seu campo de conhecimento, tendo em vista Thorsteinson et al. (2008), os quais argumentam que os efeitos da Ancoragem são reduzidos quando sujeitos decisores têm mais conhecimento acerca dos problemas em questão. Assim, foi realizado um quase-experimento com 324 sujeitos decisores, divididos em Grupos de Calibragem e Grupos Experimentais, por meio da aplicação de duas tarefas decisórias (T1 e T2), utilizando-se o Modelo de Jacowitz e Kahneman (1995). Ressalta-se que muitos estudos sobre Ancoragem têm sido realizados no sentido de verificar a presença da heurística da Ancoragem no processo de julgamento e tomada de decisão. No entanto, este estudo, além da proposta de estudar os efeitos da Ancoragem durante o processo decisório relacionado a decisões quantitativas, apresentou como principal contribuição adicional a verificação da manifestação da Ancoragem quando uma variável de controle (conhecimento) é retirada da tarefa decisória. Tal procedimento é denominado por Cozby (2006) como um Teste de Manipulação, consistindo em uma tentativa para medir diretamente se a manipulação de uma variável tem o efeito pretendido sobre os respondentes. Os resultados obtidos, por meio do teste estatístico t para amostras independentes, demonstraram que há evidências da heurística da Ancoragem no processo decisório dos indivíduos integrantes do Grupo Experimental de não-especialistas (âncora baixa e âncora alta), tanto em T1 quanto em T2. No que tange aos especialistas, foi possível perceber que em T1 há evidências da heurística da Ancoragem, corroborando com os resultados encontrados por Jacowitz e Kahneman (1995) e Luppe (2006). No entanto, em relação à segunda tarefa decisória (T2), observou-se que as diferenças de médias não foram estatisticamente significantes, inferindo-se que, em T2, não são encontradas evidências da Ancoragem no processo decisório dos especialistas, contrariando os resultados encontrados por Norfhcraft e Neale (1987) e Dorow (2009), os quais encontraram evidências da Ancoragem no processo decisório de corretores imobiliários quando foram submetidos à realização de estimativas referentes ao mercado de imóveis.
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Correia, Vinicius Costa. "Estudo da influência do uso de fibras de aço e de estribos no comportamento da ancoragem de barras". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-12072012-083304/.
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O comportamento estrutural do concreto armado depende da união entre o concreto e a armadura. Esta união se estabelece por meio da aderência, que funciona como um mecanismo de transferência de tensões e garante a compatibilidade de deformações entre a armadura e o concreto. Este trabalho tem como objetivo investigar os efeitos da adição de fibras de aço e armadura transversal no comportamento da ancoragem. A investigação experimental foi feita por meio de dois tipos de ensaio de arrancamento de barras, sendo eles o modelo-padrão do RILEM-CEB-FIP e modelo proposto pelo autor, este considerando barras de pontas retas e com ganchos de 90º. Todos os modelos utilizaram comprimento aderente igual a cinco vezes o diâmetro da barra. As armaduras longitudinais eram compostas por barras de 10 mm e 16 mm e a resistência à compressão média do concreto era igual a 50 MPa no dia do ensaio. Foram utilizadas fibras de aço com ganchos nas extremidades, com relação de aspecto igual a 65, comprimento igual a 35 mm e fração volumétrica de 2% (157 Kg/m³). Também foram realizadas comparações com modelos teóricos, analisados através do estudo de bibliografias existentes e das normas NBR 6118:2003 e ACI-318-08. Os resultados experimentais mostraram que os estribos e as fibras exercem influência significativa na resistência ao fendilhamento do concreto. Observou-se ainda que, para os corpos de prova com barras de aço de 10 mm e 16 mm com pontas retas, as fibras estudadas exerceram pequena influência na resistência ao arrancamento.The structural behavior of reinforced concrete depends on connection behavior of concrete and steel. This union is established by means of bond, which serves as a mechanism to transfer forces and ensure the compatibility of deformation between the reinforcement and the concrete. This research aims investigating the effects of the use of steel fibers and stirrups on the behavior of the anchorage. An experimental investigation was carried out by means of pull-out tests according to the RILEM-CEB-FIP standard model and pull-out tests of straight and with 90º hooked bars, with a bonded length of five times the bar diameter. The longitudinal reinforcement bars were of 10 mm and 16 mm and concrete compressive strength was 50 MPa at the day of test. Steel fibers with hooked ends, aspect ratio of 65, and length of 35 mm and volumetric fraction of 2% (157 kg /m³) were used. Comparisons with theoretical models, analyzed through the literature review and recommendations of NBR 6118:2003 and ACI-318-08 were also performed. The experimental results showed that the stirrups and the fibers have significant influence on the cracking of the concrete. It was also observed that, for the specimens with steel bars of 10 mm and 16 mm with straight anchorage, the fibers had small influence on the pull-out resistance.
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Bennitz, Anders. "Mechanical anchorage of prestressed CFRP tendons : theory and tests /". Luleå : Division of Structural engineering, Department of Civil, Mining and Environmental Engineering, Luleå University of Technology, 2008. http://epubl.ltu.se/1402-1757/2008/32/.
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Bagge, Niklas. "Structural assessment procedures for existing concrete bridges : Experiences from failure tests of the Kiruna Bridge". Doctoral thesis, Luleå tekniska universitet, Byggkonstruktion och brand, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63000.
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Assessing existing bridges is an important task in the sustainable management ofinfrastructure. In practice, structural bridge assessments are usually conducted usingtraditional and standardised methods, despite knowledge that these methods oftenprovide conservative estimates. In addition, more advanced methods are available, suchas nonlinear finite element (FE) analysis, that are used for research purposes and cansimulate the structural behaviour of bridges more accurately. Therefore, it would beuseful to develop practical and reliable procedures for refined assessments using theseadvanced techniques.Focusing on the ultimate load-carrying capacity of existing concrete bridges, this thesispresents a procedure for structural assessments. The fundamental idea is to improve theassessment successively, as necessary to predict bridges’ structural behaviour adequately.The procedure involves a multi-level assessment strategy with four levels of structuralanalysis, and an integrated framework for safety verification. At the initial level (Level 1)of the multi-level strategy, traditional standardised methods are used, no failures arecovered implicitly in the structural analysis and action effects are verified using localresistances calculated using analytical models. In the subsequent enhanced levels (Levels2 – 4), nonlinear FE analysis is used for stepwise integration of the verification of flexural,shear-related and anchorage failures into the structural analysis. The framework for safetyverifications includes partial safety factor (PSF), global resistance safety factor (GRSF) andfull probabilistic methods. Within each of these groups, verifications of desired safetymargins can be conducted with varying degrees of complexity.To demonstrate and evaluate the proposed structural assessment procedure, comparativestudies have been carried out, based on full-scale tests of a prestressed concrete bridge.This was the Kiruna Bridge, located in the northernmost city in Sweden, which was duefor demolition as part of a city transformation project, necessitated by large grounddeformations caused by the large nearby mine. Thus, it was available for destructiveexperimental investigation within the doctoral project presented in this thesis. The bridgehad five continuous spans, was 121.5 m long and consisted of three parallel girders with a connecting slab at the top. Both the girders and slab were tested to failure to investigatetheir structural behaviour and load-carrying capacity. Non-destructive and destructivetests were also applied to determine the residual prestress forces in the bridge girders andinvestigate the in situ applicability of methods developed for this purpose. The so-calledsaw-cut method and decompression-load method were used after refinement to enabletheir application to structures of such complexity. The variation of the experimentallydetermined residual prestress forces was remarkably high, depending on the sectioninvestigated. There were also high degrees of uncertainty in estimated values, and thusare only regarded as indications of the residual prestress force.Level 1 analysis of the multi-level assessment strategy consistently underestimatedcapacity, relative to the test results, and did not provide accurate predictions of the shearrelatedfailure observed in the test. With linear FE analysis and local resistance modelsdefined by the European standard, Eurocode 2, the load-carrying capacity wasunderestimated by 32 % for the bridge girder and 55 % for the bridge deck slab. At theenhanced level of structural analysis (Level 3), nonlinear FE analyses predicted thecapacities with less than 2 % deviation from the test results and correctly predicted thefailure mode. However, for existing bridges there are many uncertainties, for instance,the FE simulations were sensitive to the level of residual prestressing, boundaryconditions and assumed material parameters. To accurately take these aspects intoaccount, bridge-specific information is crucial.The complete structural assessment procedure, combining the multi-level strategy andsafety verification framework, was evaluated in a case study. Experiences from theprevious comparative studies were used in an assessment of the Kiruna Bridge followingthe Swedish assessment code. The initial assessment at Level 1 of the multi-level strategyand safety verification, using the PSF method, indicated that the shear capacity of one ofthe girders was critical. The most adverse load case (a combination of permanent loads,prestressing and variable traffic loads) was further investigated through enhancedstructural analyses implicitly accounting for flexural and shear-related failures (Level 3).Nonlinear FE analysis and safety evaluation using the PSF method, several variants of theGRSF method and the full probabilistic analysis for resistance indicated that the permittedaxle load for the critical classification vehicle could be 5.6 – 6.5 times higher than thelimit obtained from the initial assessment at Level 1. However, the study also indicatedthat the model uncertainty was not fully considered in these values. The modeluncertainty was shown to have strong effects on the safety verification and (thus)permissible axle loads. The case study also highlighted the need for a strategy forsuccessively improving structural analysis to improve understanding of bridges’ structuralbehaviour. The refined analysis indicated a complex failure mode, with yielding of thestirrups in the bridge girders and transverse flexural reinforcement in the bridge deck slab,but with a final shear failure of the slab. It would be impossible to capture suchcomplexity in a traditional standardised assessment, which (as mentioned) indicated thatthe shear capacity of the girder limited permissible axle loads. However, nonlinear FEanalyses are computationally demanding, and numerous modelling choices are required.Besides a strategy for rationally improving the analysis and helping analysts to focus oncritical aspects, detailed guidelines for nonlinear FE analysis should be applied to reduce the analyst-dependent variability of results and (thus) the model uncertainty. Clearly, toensure the validity of bridge assessment methods under in situ conditions, theirevaluations should include in situ tests. This thesis presents outcomes of such tests, therebyhighlighting important aspects for future improvements in the assessment of existingbridges.
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Lorenz, Enrico. "Endverankerung und Übergreifung textiler Bewehrungen in Betonmatrices". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-170583.
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Die sichere Einleitung und Übertragung der wirkenden Kräfte ist Bedingung für die Funktionsfähigkeit und die vollständige Ausnutzung der Tragfähigkeit von Textilbetonbauteilen und -verstärkungsschichten. So kann es bei ungünstiger Konfiguration und Anordnung der Einzelkomponenten des Verbundbaustoffes zur Ausbildung einer Vielzahl verschiedener Verbundversagensformen kommen. Diese umfassen neben der Bildung von verbundschädigenden Delaminations- und Spaltrissen lokale Abplatzungen der Betondeckung oder einen vorzeitigen Auszug der Garne aus dem Beton. Besonders beansprucht sind in diesem Zusammenhang die bei einer Anwendung von Textilbeton erforderlichen Endverankerungs- und Stoßbereiche der textilen Bewehrungen. Zur sicheren Ausbildung und Bemessung dieser wichtigen Detailpunkte liegen jedoch momentan noch keine umfassenden und zusammenhängenden Untersuchungen vor. Hauptziel der vorliegenden Dissertation war daher eine systematische Erforschung und Beschreibung des Tragverhaltens von Textilbeton in Endverankerungs- und Übergreifungsbereichen. Eine funktionierende und schädigungsfreie Verbundkraftübertragung bildet die Grundlage für die sichere Lasteinleitung und -übertragung. Daher wurden im ersten Teil der Arbeit ausführliche Untersuchungen zur Charakterisierung der zwischen Bewehrungstextil und Feinbetonmatrix wirkenden Kräfte und -mechanismen durchgeführt. Nach der Entwicklung eines geeigneten Versuchsaufbaus erfolgten umfangreiche Parametervariationen zur experimentellen Überprüfung des textilspezifischen Verbundverhaltens. Den Schwerpunkt der Untersuchungen bildete die Identifikation und Bewertung der aus verschiedenen Verarbeitungsparametern der textilen Bewehrungen resultierenden Verbundeinflüsse. Die Versuchsergebnisse ermöglichen die Bestimmung der zugehörigen Verbundspannungs-Schlupf-Beziehungen (VSB) mithilfe eines erarbeiteten Modellierungsverfahrens. Die so ermittelten Verbundkennwerte bilden die Grundlage für die weiteren rechnerischen Untersuchungen. Im zweiten Teil der Arbeit erfolgten Forschungen zum Tragverhalten von Endverankerungsbereichen. Hierbei stand der im Regelfall bemessungsrelevante Grenzzustand eines vorzeitigen Auszuges der Textilien aus der Betonmatrix im Mittelpunkt. Die Arbeiten umfassten experimentelle und theoretische Untersuchungen zur Beschreibung der Kraftübertragung. Aufbauend auf die ermittelten Verbundkennwerte wird ein unabhängiger analytischer Auswertealgorithmus zur Beschreibung des Verbundtragverhaltens in Endverankerungsbereichen dargestellt. Dieser ermöglicht eine detaillierte rechnerische Bestimmung der erforderlichen Endverankerungslängen von Textilbeton in Abhängigkeit konkreter bzw. untersuchter Bewehrungstextilien. Den dritten Forschungsschwerpunkt bildeten Untersuchungen zum Tragverhalten von Übergreifungsstößen in Textilbetonbauteilen. Mithilfe von umfassenden experimentellen und theoretischen Analysen an unterschiedlich konfigurierten und bewehrten Textilbetonen konnten die maßgebenden Versagensmechanismen untersucht und grundlegende Vorgaben für die Bemessung und Ausführung der Übergreifungsbereiche abgeleitet werden. Die gewonnenen Erkenntnisse wurden anhand von großformatigen Bauteilversuchen mit entsprechend konstruierten Übergreifungsstößen bestätigt. Zum Abschluss wird ein vereinfachtes Ingenieurmodell vorgestellt. Dieses erlaubt eine allgemeingültige und hinreichend genaue Bemessung der untersuchten Detailpunkte unter Beachtung der maßgebenden GrenzzuständeThe safe introduction and transmission of forces is a requirement for the workability as well as the possibility to make full use of the load bearing capacities of components and strengthening layers made of textile reinforced concrete. Accordingly, an unfavourable configuration and arrangement of the composite material’s individual components can lead to various modes of bond failure. These can result from the formation of bond damaging delamination cracks and longitudinal matrix splitting, local spalling of the concrete layer in the outer reinforcement layers or early yarn pull-out from the concrete. In this context, the areas of end anchorage and lap joints of the textile reinforcement, which cannot be avoided when using textile reinforced concrete, are particularly prone to failure. However, no comprehensive and coherent investigations regarding the safe configuration and dimensioning of these essential details are available yet. Consequently, systematic research into textile reinforced concrete’s load-bearing behaviour in the areas of end anchorage and lap joints and the subsequent description was the main goal of this dissertation. A working and damage-free transmission of bond force is the basis for a faultless load transmission and introduction. As a result, extensive tests concerning the characterization of the mechanisms and forces acting between reinforcing textile and fine grained concrete matrix were carried out as the first part of the investigations. After an appropriate test setup had been developed, a great variety of parameters was applied to experimentally examine the bond behaviour specific to the textile. The determination of the influencing factors resulting from various parameters in the textile reinforcement’s processing was a focus in the research. Based on a specifically developed modelling technique, the test results could be used to calculate the corresponding bond stress-slip-relation. The bond parameters, which were determined like this, served as the basis for the following calculations. The second part of the investigations was concerned with the load-bearing behaviour in end anchorage areas. In this case, the limit state of a yarn pull-out from the concrete matrix, which is usually essential for the dimensioning, was at the centre of attention. The investigations encompassed experimental and theoretical tests regarding the description of the force transmission. Based on the determined compound parameters, an independent analytic evaluation algorithm, which served to describe the load carrying behaviour of the bond in the end anchorage area, was presented. Through this algorithm, the detailed calculation of the required end anchorage lengths of textile reinforced concrete depending on the specific reinforcement textile was possible. The third research focus was on tests regarding the load-bearing behaviour of lap joints in textile reinforced concrete components. With the help of comprehensive experimental and theoretical analyses of variously configured and reinforced textile reinforced concretes, the decisive failure mechanisms were examined. Furthermore, fundamental demands for the dimensioning and execution of the lap joint areas could be derived. The findings were confirmed through tests on large-sized building components with corresponding lap joints. At the end of the investigations, a simplified engineering model is presented. This model makes a universally valid and exact dimensioning of the examined details possible while also paying attention to the decisive limit states
7
Abd, Ghani Murad. "Gestion des risques relatifs à la stabilité des arbres paysagers : biomécanique et architecture du système racinaire". Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13634/document.
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L’impact de la perte racinaire sur l’ancrage d’Eugenia grandis Wight et de Pinus pinaster Ait ainsi que la capacité de trois différentes espèces d’arbres (Fagus sylvatica L, Abies alba Mill et Picea abies L) à résister au déracinement ou à la rupture sous l’effet d’un éboulement en pente raide ont été étudiés au moyen de tests de treuillage et le creusement de tranchées (tree winching and trenching tests) et les résultats ont été corrélés avec la structure du système racinaire. Aucune différence n’a été observée entre TMcrit et la distance de creusement de tranchée sur E. grandis. Les résultats obtenus ont révélé qu’en termes de rigidité rotationnelle de l’ancrage des arbres (TARS) et de TMcrit, la stabilité mécanique n’a pas été significativement affectée par le creusement de tranchées en sol argilo-sableux en raison de la profondeur d’enracinement des racines pivotantes (« sinker roots ») qui se sont formées près du tronc et en raison de la taille de la plaque racinaire qui augmente la rigidité et constitue donc une composante importante de l’ancrage d’E. grandis. Toutefois, pour P. pinaster, la stabilité mécanique a été significativement affectée par le creusement de tranchée, probablement en raison de la coupe des racines latérales qui a considérablement altéré la taille de la plaque racinaire et, en conséquence, la somme des surfaces en section (CSA= cross-sectional area) de la plupart des racines latérales et d’un certain nombre de racines traçantes, ce qui constitue une des composantes essentielles de l’ancrage d’arbres P. pinaster adultes plantés en podzol sableux. Pour les espèces forestières de protection plantées en pente raide, les résultats obtenus ont révélé que les espèces d’arbre présentant un système racinaire profondément enfoui et fortement ramifié avec une grande proportion de racines obliques (par exemple, le hêtre et le sapin pectiné) seront mieux ancrées et auront une meilleure fonction anti-éboulement que epicéa commun qui possède un système racinaire superficiel et peu profond. Les connaissances apportées par cette étude peuvent être utilisées pour la sélection et la production d’arbres qui résistent aux risques naturels ainsi qu’aux risques provoqués par l’HommeThe impact of root loss on tree anchorage on Eugenia grandis Wight and Pinus pinaster Ait and the ability of three different trees species (Fagus sylvatica L, Abies alba Mill and Picea abies L) to resist uprooting or breakage due to rockfall on steep slopes were investigated using tree winching and trenching tests and results correlated to root system architecture. No differences were found between TMcrit and trenching distance in E. grandis trees. The results showed that in terms of Tree Anchorage Rotational Stiffness (TARS) and TMcrit, mechanical stability was not significantly affected by trenching on sandy clay soil, due to rooting depth of the sinkers which occurred close to the trunk and root plate size which provide greater stiffness thus play a major component of anchorage in E. grandis. However, in P. pinaster, mechanical stability was significantly affected by trenching, possibly due to severing of lateral roots greatly altered the size of the root plate and subsequently root CSA of major lateral roots and number of sinkers, which are crucial components in anchorage of mature P. pinaster trees grown on sandy podzol soil. For protection forest species grown on steep slopes, the results showed that tree species with deep, highly branched root systems with a higher proportion of oblique roots (e.g. European beech and Silver fir) will be better anchored and provide better protective function against rockfall as compared to Norway spruce that possessed a superficial plate-like root system. The knowledge gained from this study can be utilized in selection and production of trees which are resistant to both man made or natural hazards
8
Engelmann, Michael. "Spannglasträger – Glasträger mit vorgespannter Bewehrung". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-229676.
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Glas und Beton sind sich in wesentlichen Materialeigenschaften ähnlich: Beide zeigen gegenüber einer hohen Druckfestigkeit eine vergleichsweise geringe Zugfestigkeit und versagen spröde. Diese Analogie führte zur Entwicklung bewehrter Glasträger, die sich durch eine aufgeklebte Stahllasche an ihrer Biegezugkante auszeichnen. Dadurch wurden die Übertragung von Zugkräften auch im Rissfall möglich, sodass ein duktiles Bauteilverhalten erreicht und der im Konstruktiven Glasbau notwendige Nachweis der Resttragfähigkeit erfüllt wird. Glasträger mit verbundlos vorgespannter Bewehrung – Spannglasträger – stellen die Fortführung dieses Analogiegedankens dar. Neben einer gezielten Steigerung der Erstrisslast, können die Träger planmäßig überhöht werden. Damit wird einer bisher üblichen Überdimensionierung mit der Anordnung nicht ausgenutzter „Opferscheiben“ entgegen gewirkt und sichere sowie materialeffiziente Konstruktionen mit maximaler Transparenz ermöglicht. Diese Konstruktionsweise wurde bislang ausschließlich für einzelne Sondierungsuntersuchungen in breiter Variantenvielfalt genutzt. Eine Systematik und einheitliche Bezeichnungsweise ist nicht vorhanden. Darüber hinaus beschränken sich verfügbare Ergebnisse auf die Beschreibung der Tragfähigkeit, ohne die Resttragfähigkeit explizit zu belegen oder die Dauerhaftigkeit nachzuweisen. Mit dieser Arbeit wurde anhand einer Analogiebetrachtung zum Eurocode 2 eine Bezeichnungsweise für bewehrte und vorgespannte Glasträger entwickelt und für vorhandene Konstruktionen erfolgreich angewendet. Darin zeigt sich, dass der Stand der Technik auf diese Weise charakterisierbar ist. Zusätzlich wird die These aufgestellt, dass sich das Tragverhalten von Spannglasträgern wie im Stahlbeton- und Spannbetonbau beschreiben und die auftretenden Spannkraftverluste analog berechnen lassen. Diese These wird mithilfe experimenteller Studien als Kern dieser Arbeit untersucht und durch eine ergänzende numerische Modellierung bestätigt. Zunächst wird das Tragverhalten im Kurzzeit-Biegeversuch an 15 Prüfkörpern unter variierten Bewehrungsgraden und Vorspannkräften untersucht. Dabei zeigen sich gesteigerte Erstrisslasten sowie ein sicheres Verhalten im Anschluss an die Belastung. Durch die Vorspannung wird das Tragverhalten gezielt beeinflusst. Zusätzlich erbringt eine zerstörungsfreie Untersuchungsreihe an 28 Prüfkörpern unter konstanter Gebrauchslast über 1000 Stunden erstmals eine Beschreibung der auftretenden Spannkraftverluste. Diese sind maßgeblich von der horizontalen Durchbiegung sowie der daraus resultierenden Belastung der Zwischenschicht im Verbund-Sicherheitsglas abhängig. Aus der Größenordnung der Verluste lässt sich schlussfolgern, dass eine Begrenzung dieses Verformungsanteils sowie eine konstruktive Entlastung der Zwischenschicht notwendig sind. Zudem wird die Änderung der Vorspannkraft unter einer Temperaturlast beschrieben. Im Ergebnis zeigt sich, dass dieser Lastfall mittels der linearen Balkentheorie beschreibbar und der damit assoziierte Spannkraftverlust berechenbar ist. Die Resttragfähigkeit von 24 Spannglasträgern wird mithilfe eines eigens entwickelten Prüfverfahrens bestätigt. Während die Bewehrung einerseits eine Überbrückung von Rissflanken ermöglicht, verursacht die Vorspannkraft andererseits im teilzerstörten Tragsystem bisweilen ein frühzeitiges Versagen. Daher wird empfohlen, die baukonstruktive Detailentwicklung zu intensivieren, um einen größeren Sicherheitsvorteil aus der Konstruktionsweise zu generieren. Die Arbeit beinhaltet erstmals eine systematische Datensammlung zum Tragverhalten von Spannglasträgern. Es zeigt sich, dass auf eine Anordnung von „Opferscheiben“ zugunsten einer steigenden Materialeffizienz nicht nur verzichtet werden kann, sondern im Sinne eines effektiven Tragverhaltens verzichtet werden muss. Mit der vorgeschlagenen Bezeichnungsweise, den abgeleiteten konstruktiven Maßnahmen sowie den gezeigten Untersuchungsmethoden besteht nunmehr die Möglichkeit, sichere und dauerhafte Spannglasträger zu entwerfen und deren Trageffizienz zu belegenGlass and concrete share essential material characteristics: Their compressive strength exceeds their tensile strength considerably and both of them fail in a brittle manner. This analogy led to the development of reinforced glass beams, which are improved by means of adhesively bonded steel sections in the tensile zone. This improvement allowed for a direct transfer of tensile loads in a post-breakage state and resulted in a ductile structural element, which met the special demand of structural glass for a sufficient residual loadbearing capacity. Glass beams with unbonded, post-tensioned reinforcement – Spannglass Beams – carry this analogy concept on. The members will comprise an increased initial fracture strength and may be uplifted intentionally. This development has rendered the need for over-dimensioning by removing unnecessary sacrificial layers, which will result in a material efficient structure and will maximise transparency. Solely single exploratory investigations have used this idea in a wide variety of options so far. There is neither a uniform classification nor a consistent nomenclature. Furthermore, available results are limited to the concise description of the short-term load-bearing properties without proving the residual load-bearing capacity explicitly and confirming longterm durability. This thesis describes the development and the application of a nomenclature for reinforced and pre-compressed glass beams in an analogy study according to Eurocode 2. The state of technology can be characterised in this manner. Additionally, the research describes the load-bearing behaviour as well as the calculation of the loss of pre-stress of Spannglass Beams by analogy with concrete structures. As the key section of this thesis, this statement is examined by means of comprehensive experimental studies and completed by a numerical calculation. Primarily, the load-bearing behaviour of 15 specimens in short-term bending tests and a variety of reinforcement ratios and pre-stress levels were determined. The results show an increase of initial fracture strength as well as safe behaviour after failure. The pre-stress changes the load-bearing performance significantly. Furthermore, a non-destructive study including a constant loading for 1000 h describes the loss of pre-stress in 28 specimens for the first time. The horizontal deflection and the thus resulting shear stresses of the interlayer material of a laminated glass section are the critical parameters. From the magnitude of losses it may be concluded that the deflections need to be limited and the interlayer foils need to be relieved from stress. Moreover, the structural response during a change in temperature is in good agreement with the results obtained from linear beam theory. This allows for an estimation of the associated losses. Finally, a specifically developed test approach confirms the residual load-bearing capacity of 24 specimens. The reinforcement shows the ability to bridge cracks in the glass. However, it should be noted that pre-stress occasionally causes an early failure of the partially broken Spannglass cross-section. Therefore, intensifying the development of structural details in order to generate an increased advantage concerning safety is recommended. This contribution contains a systematic acquisition of analytical, experimental and numerical data regarding the loadbearing characteristics of Spannglass Beams for the first time. The use of a sacrificial layers is not necessary. Even more, to reach the most effective load-bearing behaviour, it is necessary to abandon them completely. Implementing the developed nomenclature, realising the recommended structural provisions and using the proposed methods, it is now possible to compose safe and durable Spannglass Beams as well as prove their structural efficiency
9
Schultz, Deanna D. "College and career ready? Perceptions of high school students related to WorkKeys assessments". Thesis, 2011. http://hdl.handle.net/1957/26784.
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Concern about college and career readiness has been expressed in both the
business and education arenas. Employers are calling for entry-level employees with
basic academic skills and educators are being held accountable for student
achievement in academic areas similar to those required by employers. In this
environment, WorkKeys has emerged as a set of assessments that could respond to the
needs of both employers and educators and serve as an indicator to test takers of their
readiness for further education or a career. In Alaska, state policymakers selected
WorkKeys for use with high school juniors in an effort to measure both college and
career readiness, and statewide testing was implemented in the fall of 2010.
While past studies involving WorkKeys have focused on assessment results
related to workforce development, academic indicators, or demographic variables, the
purpose of this study was to describe the college and career readiness perceptions of
high school juniors related to the WorkKeys Reading for Information, Locating
Information, and Applied Mathematics assessments. A survey administered to 178
urban high school juniors at the time they received their WorkKeys results gathered student perceptions of the WorkKeys assessments in general as well as perceptions of
college and career readiness.
The key findings of this study were that student perceptions of college and
career readiness were much higher than the results of the assessments indicated, and
students found value in using WorkKeys results for college and career planning. This
suggested the assessment results would be useful in career development interventions
with students. This was the first year of mandatory WorkKeys assessments in the state
and further study is recommended to gather rural student perceptions, further explore
factors that students believe make the assessments useful, and determine the influence
of the assessments and related interventions on academic self-efficacy.Graduation date: 2012
10
Lorenz, Enrico. "Endverankerung und Übergreifung textiler Bewehrungen in Betonmatrices". Doctoral thesis, 2014. https://tud.qucosa.de/id/qucosa%3A28744.
Pełny tekst źródłaStreszczenie:
Die sichere Einleitung und Übertragung der wirkenden Kräfte ist Bedingung für die Funktionsfähigkeit und die vollständige Ausnutzung der Tragfähigkeit von Textilbetonbauteilen und -verstärkungsschichten. So kann es bei ungünstiger Konfiguration und Anordnung der Einzelkomponenten des Verbundbaustoffes zur Ausbildung einer Vielzahl verschiedener Verbundversagensformen kommen. Diese umfassen neben der Bildung von verbundschädigenden Delaminations- und Spaltrissen lokale Abplatzungen der Betondeckung oder einen vorzeitigen Auszug der Garne aus dem Beton. Besonders beansprucht sind in diesem Zusammenhang die bei einer Anwendung von Textilbeton erforderlichen Endverankerungs- und Stoßbereiche der textilen Bewehrungen.
Zur sicheren Ausbildung und Bemessung dieser wichtigen Detailpunkte liegen jedoch momentan noch keine umfassenden und zusammenhängenden Untersuchungen vor. Hauptziel der vorliegenden Dissertation war daher eine systematische Erforschung und Beschreibung des Tragverhaltens von Textilbeton in Endverankerungs- und Übergreifungsbereichen.
Eine funktionierende und schädigungsfreie Verbundkraftübertragung bildet die Grundlage für die sichere Lasteinleitung und -übertragung. Daher wurden im ersten Teil der Arbeit ausführliche Untersuchungen zur Charakterisierung der zwischen Bewehrungstextil und Feinbetonmatrix wirkenden Kräfte und -mechanismen durchgeführt. Nach der Entwicklung eines geeigneten Versuchsaufbaus erfolgten umfangreiche Parametervariationen zur experimentellen Überprüfung des textilspezifischen Verbundverhaltens. Den Schwerpunkt der Untersuchungen bildete die Identifikation und Bewertung der aus verschiedenen Verarbeitungsparametern der textilen Bewehrungen resultierenden Verbundeinflüsse. Die Versuchsergebnisse ermöglichen die Bestimmung der zugehörigen Verbundspannungs-Schlupf-Beziehungen (VSB) mithilfe eines erarbeiteten Modellierungsverfahrens. Die so ermittelten Verbundkennwerte bilden die Grundlage für die weiteren rechnerischen Untersuchungen.
Im zweiten Teil der Arbeit erfolgten Forschungen zum Tragverhalten von Endverankerungsbereichen. Hierbei stand der im Regelfall bemessungsrelevante Grenzzustand eines vorzeitigen Auszuges der Textilien aus der Betonmatrix im Mittelpunkt. Die Arbeiten umfassten experimentelle und theoretische Untersuchungen zur Beschreibung der Kraftübertragung. Aufbauend auf die ermittelten Verbundkennwerte wird ein unabhängiger analytischer Auswertealgorithmus zur Beschreibung des Verbundtragverhaltens in Endverankerungsbereichen dargestellt. Dieser ermöglicht eine detaillierte rechnerische Bestimmung der erforderlichen Endverankerungslängen von Textilbeton in Abhängigkeit konkreter bzw. untersuchter Bewehrungstextilien.
Den dritten Forschungsschwerpunkt bildeten Untersuchungen zum Tragverhalten von Übergreifungsstößen in Textilbetonbauteilen. Mithilfe von umfassenden experimentellen und theoretischen Analysen an unterschiedlich konfigurierten und bewehrten Textilbetonen konnten die maßgebenden Versagensmechanismen untersucht und grundlegende Vorgaben für die Bemessung und Ausführung der Übergreifungsbereiche abgeleitet werden. Die gewonnenen Erkenntnisse wurden anhand von großformatigen Bauteilversuchen mit entsprechend konstruierten Übergreifungsstößen bestätigt.
Zum Abschluss wird ein vereinfachtes Ingenieurmodell vorgestellt. Dieses erlaubt eine allgemeingültige und hinreichend genaue Bemessung der untersuchten Detailpunkte unter Beachtung der maßgebenden Grenzzustände.The safe introduction and transmission of forces is a requirement for the workability as well as the possibility to make full use of the load bearing capacities of components and strengthening layers made of textile reinforced concrete. Accordingly, an unfavourable configuration and arrangement of the composite material’s individual components can lead to various modes of bond failure. These can result from the formation of bond damaging delamination cracks and longitudinal matrix splitting, local spalling of the concrete layer in the outer reinforcement layers or early yarn pull-out from the concrete. In this context, the areas of end anchorage and lap joints of the textile reinforcement, which cannot be avoided when using textile reinforced concrete, are particularly prone to failure. However, no comprehensive and coherent investigations regarding the safe configuration and dimensioning of these essential details are available yet. Consequently, systematic research into textile reinforced concrete’s load-bearing behaviour in the areas of end anchorage and lap joints and the subsequent description was the main goal of this dissertation. A working and damage-free transmission of bond force is the basis for a faultless load transmission and introduction. As a result, extensive tests concerning the characterization of the mechanisms and forces acting between reinforcing textile and fine grained concrete matrix were carried out as the first part of the investigations. After an appropriate test setup had been developed, a great variety of parameters was applied to experimentally examine the bond behaviour specific to the textile. The determination of the influencing factors resulting from various parameters in the textile reinforcement’s processing was a focus in the research. Based on a specifically developed modelling technique, the test results could be used to calculate the corresponding bond stress-slip-relation. The bond parameters, which were determined like this, served as the basis for the following calculations. The second part of the investigations was concerned with the load-bearing behaviour in end anchorage areas. In this case, the limit state of a yarn pull-out from the concrete matrix, which is usually essential for the dimensioning, was at the centre of attention. The investigations encompassed experimental and theoretical tests regarding the description of the force transmission. Based on the determined compound parameters, an independent analytic evaluation algorithm, which served to describe the load carrying behaviour of the bond in the end anchorage area, was presented. Through this algorithm, the detailed calculation of the required end anchorage lengths of textile reinforced concrete depending on the specific reinforcement textile was possible. The third research focus was on tests regarding the load-bearing behaviour of lap joints in textile reinforced concrete components. With the help of comprehensive experimental and theoretical analyses of variously configured and reinforced textile reinforced concretes, the decisive failure mechanisms were examined. Furthermore, fundamental demands for the dimensioning and execution of the lap joint areas could be derived. The findings were confirmed through tests on large-sized building components with corresponding lap joints. At the end of the investigations, a simplified engineering model is presented. This model makes a universally valid and exact dimensioning of the examined details possible while also paying attention to the decisive limit states.
Książki na temat "Anchorage test"
1
Wimpey Offshore Engineers and Constructors. The strength of grouted pile-sleeve connections: Tests carried out by Wimpey Laboratories Limited. London: HMSO, 1986.
Znajdź pełny tekst źródła
2
Lade, P. Cyclic triaxial tests of the Bootlegger Cove Formation, Anchorage, Alaska. [Washington, D.C.]: U.S. G.P.O., 1988.
Znajdź pełny tekst źródła
3
Lade, P. Cyclic triaxial tests of the Bootlegger Cove Formation, Anchorage, Alaska. Washington, DC: Dept. of the Interior, 1988.
Znajdź pełny tekst źródła
4
Stadem, Catherine. The history of theatre in Anchorage, Alaska 1915-2005: From a wilderness tent to a multimillion dollar stage. Lewiston: The Edwin Mellen Press, 2009.
Znajdź pełny tekst źródła
5
Stadem, Catherine. The history of theatre in Anchorage, Alaska 1915-2005: From a wilderness tent to a multimillion dollar stage. Lewiston: The Edwin Mellen Press, 2009.
Znajdź pełny tekst źródła
6
The history of theatre in Anchorage, Alaska 1915-2005: From a wilderness tent to a multimillion dollar stage. Lewiston: The Edwin Mellen Press, 2009.
Znajdź pełny tekst źródła
7
Stadem, Catherine. The history of theatre in Anchorage, Alaska 1915-2005: From a wilderness tent to a multi-million dollar stage. Lewiston, N.Y: Edwin Mellen Press, 2009.
Znajdź pełny tekst źródła
8
Nightingale, Claire, i Jonathan Sandy. Illustrated Questions in Orthodontics. Oxford University Press, 2014. http://dx.doi.org/10.1093/oso/9780198714828.001.0001.
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Illustrated Questions in Orthodontics takes a problem-based approach to orthodontics, offering a unique resource for undergraduate dentists. This book contains a comprehensive set of questions mapped to undergraduate orthodontics curricula, including chapters on examination and diagnosis, treatment planning, pathology, appliances, and anchorage. Each chapter is packed with high-quality clinical photographs and x-rays to help readers to test their skills in identifying and describing various orthodontic problems and presentations. Furthermore, every question is answered with extensive feedback, setting each topic in a clinical context in order to teach as well as test. The ideal revision resource for undergraduate dentists looking to test and consolidate their knowledge ahead of placements and exams, Illustrated Questions in Orthodontics will also form a useful tool for postgraduate dentists and orthodontic therapists.
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Allern, Elin Haugsgjerd, i Tània Verge. Still Connecting with Society? Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198758631.003.0005.
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How parties structure their interaction with social groups is a key determinant of their capacity to provide linkage between the institutions of government and the public at large. This chapter investigates the extent to which modern political parties use formal measures to connect to relevant societal interests and strengthen their anchorage in society. The analysis centres on parties’ use of formal rules governing affiliation and representation to link with externally organized interests and parties’ establishment of sub-organizations with representation rights within the party. The chapter authors develop and test several hypotheses concerning cross-country and within-country sources of variation in formal linkage and test them empirically. In addition, they examine whether formal status and representation rights shape parties’ ability to represent descriptively the associated latent social interests focusing on the case of women and ethnic minorities.
Części książek na temat "Anchorage test"
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Wang, Lei. "Secondary Anchorage and Prestress Loss of Fractured Strand in PT Beams". W Strand Corrosion in Prestressed Concrete Structures, 167–91. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-2054-9_7.
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AbstractThe effect of corrosion-induced strand fracture on residual prestress of post-tensioned concrete beams should be investigated fully to ensure the structural safety. An experimental test with five specimens is designed to investigate the secondary anchorage and residual prestressing force in locally corroded post-tensioned concrete beams after strand fracture. Then, an analytical method is proposed to determine the damage control section of locally corroded post-tensioned concrete beams after strand fracture for the flexural capacity evaluation. Following this, a numerical model is established to predict the secondary transfer length and residual prestress of fractured strand in post-tensioned concrete beams.
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Ren, Fei-fan, Zhuang Li, Guan Wang i Qi-hua Zhao. "Centrifugal Model Tests on Anchorage Mechanism of Rockbolts Considering Tensile-Lateral Shearing Coupled Effect". W Proceedings of GeoShanghai 2018 International Conference: Fundamentals of Soil Behaviours, 101–11. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0125-4_11.
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Zhao, T., C. Liu i Y. Tan. "Pull-out rheological test of anchorage system and evolution characteristic study of interfacial stress". W Rock Mechanics: Achievements and Ambitions, 443–46. CRC Press, 2011. http://dx.doi.org/10.1201/b11438-87.
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Ceroni, F., i M. Pecce. "Bond tests on concrete elements with CFRP and anchorage systems". W FRP Composites in Civil Engineering - CICE 2004, 153–61. Taylor & Francis, 2004. http://dx.doi.org/10.1201/9780203970850.ch14.
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Hamilton, Martin. "The Concept of Cultural Genocide". W The Preservation of Art and Culture in Times of War, 129—C5.N120. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780197610565.003.0006.
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Abstract The concept of “cultural genocide” was considered for, but eventually dismissed from the text of the Convention on the Prevention and Punishment of the Crime of Genocide (1948). At the heart of the concept of cultural genocide lies the idea that cultural groups may be destroyed by destroying the material expressions or “anchorage” of their culture. This idea tells us something about the critical value that we ascribe to cultural heritage. This chapter scrutinizes this proposed value relation between cultural heritage and cultural groups through an examination of the concept of cultural genocide. The first part of the chapter deals with the values underlying the original concept of cultural genocide, including the idea of the importance of cultural heritage for the surviving of a people. To this aim, the chapter will examine the normative evolution of the concept of cultural genocide from its origins to the 1948 Genocide Convention, including an analysis of the drafting of the Convention and the reason why cultural genocide was left out. The second part of the chapter evaluates how international law, both at its normative and enforcement level, deals with the concept of cultural genocide today—especially in the context of deliberate and systematic targeting and destruction of cultural heritage in armed conflict. Finally, this will be held up against the lack of a systematic account of the effects on cultures of losing the material expressions of their cultural heritage.
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"Aquatic Stewardship Education in Theory and Practice". W Aquatic Stewardship Education in Theory and Practice, redaktor Barbara A. Knuth. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569902.ch1.
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<i>Abstract</i>.—Patterns of human behavior, consumption, and resource use have contributed to declines in fisheries populations and degradation of aquatic habitat. Recreational anglers and boaters are among the key stakeholders who should be concerned about such changes and empowered to adopt behaviors that minimize adverse impacts on aquatic environments. Definitions of aquatic stewardship should include focus on human behaviors, which may be externally or internally motivated, and contribute to a local, regional, or global impact. The National Outreach and Communication Program, prepared and implemented through the collaborative efforts of the Sport Fishing and Boating Partnership Council and the Recreational Boating and Fishing Foundation, sets forth a vision for increasing sportfishing and boating participation and enhancing aquatic stewardship. Many other government and nongovernment organizations also strive to enhance aquatic stewardship. This proceedings volume results from a symposium on The Theory and Practice of Aquatic Stewardship Education, held at the 135th annual meeting of the American Fisheries Society in Anchorage, Alaska. The goal of the symposium and this text is to advance our understanding of (1) how stewardship is defined in theory and practice, (2) the approaches that are necessary to promote and foster desirable stewardship behaviors, and (3) how measures of aquatic stewardship might be used to evaluate progress toward goals. We emphasize the importance of including both recreational fishing and boating activities in discussions of aquatic stewardship.
Streszczenia konferencji na temat "Anchorage test"
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Gomes, Marcelo F., Eduardo Catalani, Daniel Rodrigues i Klemer Santiago. "Energy Distribution at Safety Belt Anchorage Test". W 25th SAE BRASIL International Congress and Display. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2016. http://dx.doi.org/10.4271/2016-36-0280.
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Tong-bin Zhao, Yun-liang Tan i Ze Zhang. "Development of mechanical test platform for anchorage system and test on interface stress". W 2011 International Conference on Electric Technology and Civil Engineering (ICETCE). IEEE, 2011. http://dx.doi.org/10.1109/icetce.2011.5776211.
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Shirai, Eiji, Kazutoshi Eto, Akira Umemoto, Toshiaki Yoshii, Masami Kondo, Masatsugu Monde i Koichi Tai. "Inelastic Seismic Test of the Small Bore Piping and Support System: Part 1 — Seismic Proving Test of the Small Bore Piping System". W ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61342.
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Seismic safety is one of the major key issues of nuclear power plant safety in Japan. It is demonstrated that nuclear piping possesses large safety margins in the various piping ultimate test reports. But it is appeared that there still remain some technical uncertainties about the phenomenon when both piping and supports show inelastic behavior in the extremely high seismic excitation level. In order to obtain the influence of the inelastic behavior of the support to the whole piping system response, and the subsequent interaction when both piping and supports show inelastic behavior, the following two tests have been started. • Support element test: Load-displacement characteristics of the support system including U-bolt, support itself and concrete anchorage are obtained by the forced displacement test. • Seismic proving test of piping system: The small bore piping and support system consisted of three dimensional piping, supports, U-bolts, and concrete anchorages will be excited on the table by the extremely higher seismic level. This paper introduces the major results of seismic proving test of piping and support system. The support element test results is presented in the paper of part 2, and the simulation analyses of these tests are summarized in the paper of part 3 [1, 2].
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Guodong, Zheng. "Comparative Analysis of Finite Element Computation and Model Test of Anchorage". W 2015 8th International Conference on Intelligent Computation Technology and Automation (ICICTA). IEEE, 2015. http://dx.doi.org/10.1109/icicta.2015.82.
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"Load Transfer Test of Post-Tensioned Anchorage Zones in High Strength Concrete". W Feb. 2017 International Conferences. EIRAI, 2017. http://dx.doi.org/10.17758/eirai.f0217314.
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Kumar, Rakesh, i Aditya Malladi. "New Simulation Methodology for Improved Visual Interaction between Physical Test and CAE in Seat Anchorage Test". W International Mobility Conference. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2016. http://dx.doi.org/10.4271/2016-28-0226.
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Jeffrey R Keaton. "Modified Slake Durability Test Applicability for Soil". W International Symposium on Erosion and Landscape Evolution (ISELE), 18-21 September 2011, Anchorage, Alaska. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2011. http://dx.doi.org/10.13031/2013.39209.
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Gupta, Akshat. "Seat Belt Dynamic Test Performance Sensitivity to Anchorage Location Tolerance of 50 mm". W NuGen Summit. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2019. http://dx.doi.org/10.4271/2019-28-2398.
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Duraisamy, Youventharan, Rokiah Binti Othman, Mohd Arif Sulaiman, Ramadhansyah Putra Jaya i Siti Noor Linda Taib. "Suitability of <i>Eugenia oleina</i> in Tropical Slope as Bio-Anchorage System". W World Sustainable Construction Conference Series 2022. Switzerland: Trans Tech Publications Ltd, 2023. http://dx.doi.org/10.4028/p-27d8m5.
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Landslide is a major geological hazard and poses high risk to most countries in the tropical regions. This problem is more severe in places like Malaysia where residual soil is abundant. High temperature and humidity will easily disintegrate soil particles and therefore loosen the bonding between the soil and the root system. The main goal is to elucidate the interaction mechanism of bio-inspired soil anchorage system to enhance bonding between residual soil matrix in tropical region. Hence, this research aims to establish correlation between the pattern of root and its tensile strength to reinforce tropical residual slope. Basic soil property tests and classification protocols were carried out in the laboratory. Root tensile test results from the laboratory was correlated with field pull-out test data. Slope stability in the area where the plant roots were introduced have been disturbed. The factor of safety of slope with bio-anchorage system was one third of the slope with grass. The findings provide the best solution from the bioinspired soil anchorage system for tropical slope. Hence, the plant species that works well in residual soil for the purpose of reinforcing tropical slope was identified and recommended. As a result, many serious landslides and slope failures in residual soil could be avoided in the tropical region. Therefore, slope stabilization technique such as the bio-inspired soil anchorage system once established can reduce the dependency on conventional concrete wall.
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Sharma, Mukesh, Ratnadeep Dewan i Amit Singh. "Experimental Evaluation of Performance of Effective Upper Belt Anchorage (EUBA), Lower Belt Anchorage (LBA) and Floor Deformation under Different Test Configuration as per ECE R14". W SAE World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2008. http://dx.doi.org/10.4271/2008-01-0185.
Pełny tekst źródłaRaporty organizacyjne na temat "Anchorage test"
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Schiller, Brandon, Tara Hutchinson i Kelly Cobeen. Cripple Wall Small-Component Test Program: Wet Specimens I (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/dqhf2112.
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This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4: Testing and focuses on the first phase of an experimental investigation to study the seismic performance of retrofitted and existing cripple walls with sill anchorage. Paralleled by a large-component test program conducted at the University of California [Cobeen et al. 2020], the present study involves the first of multiple phases of small-component tests conducted at the UC San Diego. Details representative of era-specific construction, specifically the most vulnerable pre-1960s construction, are of predominant focus in the present effort. Parameters examined are cripple wall height, finish materials, gravity load, boundary conditions, anchorage, and deterioration. This report addresses the first phase of testing, which consisted of six specimens. Phase 1 including quasi-static reversed cyclic lateral load testing of six 12-ft-long, 2-ft high cripple walls. All specimens in this phase were finished on their exterior with stucco over horizontal sheathing (referred to as a “wet” finish), a finish noted to be common of dwellings built in California before 1945. Parameters addressed in this first phase include: boundary conditions on the top, bottom, and corners of the walls, attachment of the sill to the foundation, and the retrofitted condition. Details of the test specimens, testing protocol, instrumentation; and measured as well as physical observations are summarized in this report. In addition, this report discusses the rationale and scope of subsequent small-component test phases. Companion reports present these test phases considering, amongst other variables, the impacts of dry finishes and cripple wall height (Phases 2–4). Results from these experiments are intended to provide an experimental basis to support numerical modeling used to develop loss models, which are intended to quantify the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100, Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings.
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Schiller, Brandon, Tara Hutchinson i Kelly Cobeen. Cripple Wall Small-Component Test Program: Wet Specimens II (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/ldbn4070.
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This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4 (WG4): Testing, whose central focus was to experimentally investigate the seismic performance of retrofitted and existing cripple walls. This report focuses stucco or “wet” exterior finishes. Paralleled by a large-component test program conducted at the University of California, Berkeley (UC Berkeley) [Cobeen et al. 2020], the present study involves two of multiple phases of small-component tests conducted at the University of California San Diego (UC San Diego). Details representative of era-specific construction, specifically the most vulnerable pre-1960s construction, are of predominant focus in the present effort. Parameters examined are cripple wall height, finish style, gravity load, boundary conditions, anchorage, and deterioration. This report addresses the third phase of testing, which consisted of eight specimens, as well as half of the fourth phase of testing, which consisted of six specimens where three will be discussed. Although conducted in different phases, their results are combined here to co-locate observations regarding the behavior of the second phase the wet (stucco) finished specimens. The results of first phase of wet specimen tests were presented in Schiller et al. [2020(a)]. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load onto ten cripple walls of 12 ft long and 2 or 6 ft high. One cripple wall was tested with a monotonic loading protocol. All specimens in this report were constructed with the same boundary conditions on the top and corners of the walls as well as being tested with the same vertical load. Parameters addressed in this report include: wet exterior finishes (stucco over framing, stucco over horizontal lumber sheathing, and stucco over diagonal lumber sheathing), cripple wall height, loading protocol, anchorage condition, boundary condition at the bottom of the walls, and the retrofitted condition. Details of the test specimens, testing protocol, including instrumentation; and measured as well as physical observations are summarized in this report. Companion reports present phases of the tests considering, amongst other variables, impacts of various boundary conditions, stucco (wet) and non-stucco (dry) finishes, vertical load, cripple wall height, and anchorage condition. Results from these experiments are intended to support advancement of numerical modeling tools, which ultimately will inform seismic loss models capable of quantifying the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100,Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings.
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Munter, J. A. Results of an aquifer test at Peters Creek, municipality of Anchorage, Alaska. Alaska Division of Geological & Geophysical Surveys, 1986. http://dx.doi.org/10.14509/1267.
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Updike, R. G., i C. A. Ulery. A geotechnical cross section for downtown Anchorage using the electric-cone-penetration test. Alaska Division of Geological & Geophysical Surveys, 1986. http://dx.doi.org/10.14509/2402.
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Schiller, Brandon, Tara Hutchinson i Kelly Cobeen. Cripple Wall Small-Component Test Program: Dry Specimens (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/vsjs5869.
Pełny tekst źródłaStreszczenie:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER) and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measures and documents seismic performance of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Three primary tasks support the earthquake loss-modeling effort. They are: (1) the development of ground motions and loading protocols that accurately represent the diversity of seismic hazard in California; (2) the execution of a suite of quasi-static cyclic experiments to measure and document the performance of cripple wall and sill anchorage deficiencies to develop and populate loss models; and (3) nonlinear response history analysis on cripple wall-supported buildings and their components. This report is a product of Working Group 4: Testing, whose central focus was to experimentally investigate the seismic performance of retrofitted and existing cripple walls. This present report focuses on non-stucco or “dry” exterior finishes. Paralleled by a large-component test program conducted at the University of California, Berkeley (UC Berkeley) [Cobeen et al. 2020], the present report involves two of multiple phases of small-component tests conducted at University of California San Diego (UC San Diego). Details representative of era-specific construction–specifically the most vulnerable pre-1960s construction–are of predominant focus in the present effort. Parameters examined are cripple wall height, finish style, gravity load, boundary conditions, anchorage, and deterioration. This report addresses all eight specimens in the second phase of testing and three of the six specimens in the fourth phase of testing. Although conducted in different testing phases, their results are combined here to co-locate observations regarding the behavior of all dry finished specimens. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load onto eleven cripple walls. Each specimen was 12 ft in length and 2-ft or 6-ft in height. All specimens in this report were constructed with the same boundary conditions on the top, bottom, and corners of the walls. Parameters addressed in this report include: dry exterior finish type (shiplap horizontal lumber siding, shiplap horizontal lumber siding over diagonal lumber sheathing, and T1-11 wood structural panels), cripple wall height, vertical load, and the retrofitted condition. Details of the test specimens, testing protocol (including instrumentation), and measured as well as physical observations are summarized. Results from these experiments are intended to support advancement of numerical modeling tools, which ultimately will inform seismic loss models capable of quantifying the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100 Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings.
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Schiller, Brandon, Tara Hutchinson i Kelly Cobeen. Cripple Wall Small-Component - Test Program: Comparisons (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/lohh5109.
Pełny tekst źródłaStreszczenie:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER) and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4 (WG4): Testing, whose central focus was to experimentally investigate the seismic performance of retrofit and existing cripple walls. Amongst the body of reports from WG4, in the present report, a suite of four small cripple wall test phases, in total 28 specimens, are cross compared with varied exterior finishes, namely stucco (wet) and non-stucco (dry) exterior finishes. Details representative of era specific construction, specifically the most vulnerable pre-1960s construction are of predominant focus in the present effort. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load onto cripple walls of 12 ft in length and 2 ft or 6 ft in height. All specimens in this report were constructed with the same boundary conditions and tested with the same vertical load. Parameters addressed in this report include: wet exterior finishes (stucco over framing, stucco over horizontal lumber sheathing, and stucco over diagonal lumber sheathing); and dry exterior finishes (horizontal siding, horizontal siding over diagonal sheathing, and T1-11 wood structural panels) with attention towards cripple wall height and the retrofit condition. The present report provides only a brief overview of the test program and setup; whereas a series of three prior reports present results of test groupings nominally by exterior finish type (wet versus dry). As such, herein the focus is to cross compare key measurements and observations of the in-plane seismic behavior of all 28 specimens.
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Cobeen, Kelly, Vahid Mahdavifar, Tara Hutchinson, Brandon Schiller, David Welch, Grace Kang i Yousef Bozorgnia. Large-Component Seismic Testing for Existing and Retrofitted Single-Family Wood-Frame Dwellings (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/hxyx5257.
Pełny tekst źródłaStreszczenie:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. Quantifying the difference of seismic performance of un-retrofitted and retrofitted single-family wood-frame houses has become increasingly important in California due to the high seismicity of the state. Inadequate lateral bracing of cripple walls and inadequate sill bolting are the primary reasons for damage to residential homes, even in the event of moderate earthquakes. Physical testing tasks were conducted by Working Group 4 (WG4), with testing carried out at the University of California San Diego (UCSD) and University of California Berkeley (UCB). The primary objectives of the testing were as follows: (1) development of descriptions of load-deflection behavior of components and connections for use by Working Group 5 in development of numerical modeling; and (2) collection of descriptions of damage at varying levels of peak transient drift for use by Working Group 6 in development of fragility functions. Both UCSD and UCB testing included companion specimens tested with and without retrofit. This report documents the portions of the WG4 testing conducted at UCB: two large-component cripple wall tests (Tests AL-1 and AL-2), one test of cripple wall load-path connections (Test B-1), and two tests of dwelling superstructure construction (Tests C-1 and C-2). Included in this report are details of specimen design and construction, instrumentation, loading protocols, test data, testing observations, discussion, and conclusions.
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Schiller, Brandon, Tara Hutchinson i Kelly Cobeen. Comparison of the Response of Small- and Large-Component Cripple Wall Specimens Tested under Simulated Seismic Loading (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/iyca1674.
Pełny tekst źródłaStreszczenie:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 4: Testing, whose central focus was to experimentally investigate the seismic performance of retrofitted and existing cripple walls. Two testing programs were conducted; the University of California, Berkeley (UC Berkeley) focused on large-component tests; and the University of California San Diego (UC San Diego) focused on small-component tests. The primary objectives of the tests were to develop descriptions of the load-deflection behavior of components and connections for use by Working Group 5 in developing numerical models and collect descriptions of damage at varying levels of drift for use by Working Group 6 in developing fragility functions. This report considers two large-component cripple wall tests performed at UC Berkeley and several small-component tests performed at UC San Diego that resembled the testing details of the large-component tests. Experiments involved imposition of combined vertical loading and quasi-static reversed cyclic lateral load on cripple wall assemblies. The details of the tests are representative of era-specific construction, specifically the most vulnerable pre-1945 construction. All cripple walls tested were 2 ft high and finished with stucco over horizontal lumber sheathing. Specimens were tested in both the retrofitted and unretrofitted condition. The large-component tests were constructed as three-dimensional components (with a 20-ft 4-ft floor plan) and included the cripple wall and a single-story superstructure above. The small-component tests were constructed as 12-ft-long two-dimensional components and included only the cripple wall. The pairing of small- and large-component tests was considered to make a direct comparison to determine the following: (1) how closely small-component specimen response could emulate the response of the large-component specimens; and (2) what boundary conditions in the small-component specimens led to the best match the response of the large-component specimens. The answers to these questions are intended to help identify best practices for the future design of cripple walls in residential housing, with particular interest in: (1) supporting the realistic design of small-component specimens that may capture the response large-component specimen response; and (2) to qualitatively determine where the small-component tests fall in the range of lower- to upper-bound estimation of strength and deformation capacity for the purposes of numerical modelling. Through these comparisons, the experiments will ultimately advance numerical modeling tools, which will in turn help generate seismic loss models capable of quantifying the reduction of loss achieved by applying state-of-practice retrofit methods as identified in FEMA P-1100Vulnerability-Base Seismic Assessment and Retrofit of One- and Two-Family Dwellings. To this end, details of the test specimens, measured as well as physical observations, and comparisons between the two test programs are summarized in this report.
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Reis, Evan. Development of Index Buildings, (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, listopad 2020. http://dx.doi.org/10.55461/fudb2072.
Pełny tekst źródłaStreszczenie:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 2: Development of Index Buildings and focuses on the identification of common variations and combinations of materials and construction characteristics of California single-family dwellings. These were used to develop “Index Buildings” that formed the basis of the PEER–CEA Project testing and analytical modeling programs (Working Groups 4 and 5). The loss modeling component of the Project (Working Group 6) quantified the damage-seismic hazard relationships for each of the Index Buildings.
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Reis, Evan, Yousef Bozorgnia, Henry Burton, Kelly Cobeen, Gregory Deierlein, Tara Hutchinson, Grace Kang i in. Project Technical Summary (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, grudzień 2020. http://dx.doi.org/10.55461/feis4651.
Pełny tekst źródłaStreszczenie:
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER) and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER-CEA Project.” The overall objective of the PEER–CEA project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 7: Reporting and is a summary of the PEER–CEA Project work performed by Working Groups 1–6. This report does not present new information apart from the rest of the project, and its purpose is to serve as a reference for researchers and catastrophe modelers wishing to understand the objectives and key findings of the project. The key overall findings of the PEER–CEA Project are summarized in Chapters 8 and 10, which describe the efforts of the WG5 and WG6 Working Groups. The reader is referred to the individual reports prepared by the Working Groups for comprehensive information on the tasks, methodologies, and results of each.