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Upreti, Manohar Raj. "BEHAVIOR OF FOUNDATION BEAM FOR SHEAR WALL STRUCTURAL SYSTEM WITH COUPLING BEAMS." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2635.
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The purpose of this study is to analyze the foundation beam linked between two shear walls in the presence of lateral loads. Mat foundation with shear walls is one of the most commonly used reinforced concrete structural systems to resist the lateral load. When two independent walls are connected with a link beam, also known as the coupling beam, the overturning resistance of the building is largely increased. However, the coupling beams are relatively weaker structures and can develop larger stresses. When there is a mat foundation, or pile cap in case of pile foundation, the part of the foundation which is right below the coupling beam where no shear wall is present, will also get large stresses due to the highly rigid nature of adjacent shear walls. Most of the lateral deformations are imposed only on the coupling beams and foundation beam. There is not much literature or design procedure found in books and codes to mitigate the high risks associated with the foundation beam between shear walls on its design vulnerability. This thesis is focused on the risks associated with exceptionally high forces on the foundation beam due to earthquake forces.
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Trutalli, Davide. "Insight into seismic behaviour of timber shear-wall systems." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424481.
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This Ph.D. dissertation is the result of a three-year research activity focused on structural and seismic engineering applied to innovative timber constructive systems. The main purpose is to give a contribution to international scientific research and current design practice about the seismic behaviour of timber shear-wall systems, which still represent an innovation in the construction industry and are being developed due to their favourable characteristics.
An initial overview on the use of main timber structural systems in seismic-prone areas for low- and medium-rise buildings is provided, within the context of current European seismic code.
The theme of the seismic design of timber shear-wall systems is discussed in the first part, giving close attention to linear and non-linear modelling criteria: various strategies are proposed and main characteristics are highlighted. Basic definitions and concepts proper of the seismic analysis of timber structures are provided. A particular attention is paid to the definition and application of the capacity design approach and the close link with the concept of behaviour factor is emphasized. Finally, the definition of behaviour factor, as product between an “intrinsic” capacity of the structure and a design over-strength value is proposed. This definition allows to characterize the structural systems with their proper dissipative capacity and to evaluate separately the safety reserve introduced by design.
The second part analyses the structural behaviour of the cross-laminated timber (CLT) technology, which represents one of the most common timber structural systems. The concepts of ductility, dissipative capacity, regularity and irregularity applied to CLT system are provided. The seismic response and the dissipative capacity of this system are firstly evaluated via an experimentally based procedure. Then, the evaluation of its intrinsic dissipative capacity is determined via non-linear numerical modelling with the aim of studying the correlation with the construction variables. Results show that the construction design decisions affect the seismic response and dissipative capacity of buildings, as opposed to apply a single behaviour factor value to the whole CLT technology. A statistical analysis applied to numerical results allowed also to propose analytical formulations for the computation of the suitable behaviour factor value for regular buildings. Then, the same analyses carried out on in-elevation non-regular buildings returned a correction factor to account for the reduction in dissipative capacity due to irregularity.
The application of the CLT technology to realize high-rise buildings is presented in the third part, analysing the behaviour of slender buildings with seismic resisting core and perimeter shear walls. The major limitations and drawbacks in realizing these structures in areas characterized by high seismic intensity and their implication in the design are reported.
The final part presents three novel structural systems as alternative to more common technologies, as CLT or platform frame. These innovative systems are characterized mainly by a diffuse dissipative and deformation capacity when subjected to seismic loads, while in CLT system such capacity is concentrated in connection elements. This different response is studied via quasi-static tests and numerical simulations. In detail, two non-glued massive timber shear walls and a mixed steel-timber wall with an innovative bracing system are presented.Questa tesi di dottorato è il risultato di tre anni di attività di ricerca in ambito ingegneristico strutturale applicato allo studio di sistemi costruttivi innovativi in legno. Il principale obiettivo è quello di fornire un contributo alla ricerca scientifica internazionale e ai metodi attuali di progettazione in merito alla risposta sismica di sistemi in legno a pareti sismo-resistenti, i quali rappresentano tutt’ora un’innovazione nel settore delle costruzioni e si stanno diffondendo grazie alle loro caratteristiche favorevoli. Una panoramica iniziale sull’utilizzo dei principali sistemi strutturali in legno in zone sismiche per la realizzazione di edifici bassi o di media altezza viene fornita e contestualizzata nella vigente normativa sismica europea. La prima parte della tesi affronta il tema della progettazione sismica di sistemi a pareti in legno, con particolare attenzione ai criteri di modellazione lineare e non lineare, proponendo diverse strategie ed evidenziandone le caratteristiche. In questa parte vengono forniti inoltre definizioni e concetti fondamentali propri dell’analisi sismica di strutture in legno. Un’attenzione particolare è riservata alla definizione e applicazione del “capacity design”, sottolineandone lo stretto legame con il concetto di fattore di struttura. Viene proposta infine una definizione del fattore di struttura come prodotto tra una parte intrinseca alla struttura e una sovraresistenza di progetto. Tale definizione permette di caratterizzare i sistemi strutturali con la propria capacità dissipativa e di valutare separatamente la riserva di sicurezza introdotta dalla progettazione. La seconda parte della tesi analizza il comportamento strutturale della tecnologia X-Lam (CLT), che rappresenta uno dei più comuni sistemi strutturali in legno. In questa parte vengono approfonditi i concetti di duttilità, capacità dissipativa, regolarità e irregolarità applicati al sistema X-Lam. La risposta sismica e la capacità dissipativa di questo sistema sono state preliminarmente valutate tramite una procedura analitico-sperimentale. Modelli numerici non-lineari hanno quindi permesso di valutarne la capacità dissipativa intrinseca in funzione delle variabili costruttive proprie del sistema. I risultati mostrano come le decisioni costruttive in fase di progettazione influenzino la risposta sismica dell’edificio; ciò è in contrasto all’applicazione di un unico valore del fattore di struttura per l’intera tecnologia X-Lam. Un’analisi statistica applicata a tali risultati numerici ha consentito di proporre formulazioni analitiche per il fattore di struttura per edifici regolari in funzione delle caratteristiche dell’edificio stesso. Infine, le stesse analisi condotte su edifici non regolari in altezza hanno fornito un coefficiente per tenere in conto della riduzione di capacità dissipativa a causa dell’irregolarità. Nella terza parte viene presentata un’applicazione della tecnologia X-Lam per costruire edifici alti, analizzando il comportamento di edifici snelli con nucleo sismo-resistente e pareti aggiuntive perimetrali. Vengono riportati inoltre le principali limitazioni e inconvenienti nel realizzare tali strutture in aree caratterizzate da elevata intensità sismica e le loro implicazioni nella progettazione. La parte finale descrive e analizza tre sistemi strutturali in legno innovativi, come alternative a tecnologie più comuni, quali X-Lam o platform-frame. Questi sistemi, soggetti ad azioni sismiche, sono caratterizzati da una capacità deformativa e dissipativa diffusa, al contrario del sistema X-Lam in cui tale capacità è concentrata principalmente negli elementi di connessione. Questa risposta differente è studiata attraverso test sperimentali quasi statici e simulazioni numeriche. In dettaglio, sono presentati e analizzati due sistemi a pareti massicce stratificate; realizzate senza l’uso di colla tra gli strati e una parete ibrida acciaio-legno con un sistema innovativo di controvento.
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Farnsworth, Michael Sterling. "Wall Shear Stress in Simplified and Scanned Avian Respiratory Airways." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/8818.
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Birds uniquely produce sound through a vocal organ known as a syrinx. The presence of wall shear stress acting on the airway cells of any organism will affect how airway cells develop and multiply. Unique features of avian airway geometry and breathing pattern might have contributed to the development of the syrinx. This thesis examines wall shear stress in the trachea and first bronchi of avian geometries using computational fluid dynamics. The computational fluid dynamic simulations underwent grid- and time-independence studies and were validated using particle image velocimetry. Parameters such as bird size, bronchial branching angle, and breathing waveform were examined to determine conditions that contributed to higher wall shear stress. Both simplified and CT scan-derived respiratory geometries were examined. Maximum wall shear stress for the simplified geometries was found to be highest during the inspiratory phase of breathing and was highest near the pessulus. Maximum wall shear stress in the CT scan-derived geometries was less phase-dependent and was highest near constrictions in the airway. Comparison between scanned and simplified geometry simulations revealed significant differences in wall shear stress magnitudes and flow features. If wall shear stress is found to be important in the development of the syrinx or the advantage of a syrinx, the thesis results are anticipated to aid in characterizing conditions that would have contributed to the development of the syrinx or advantages of syringeal vocal fold position over tracheal vocal fold position.
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Lim, Hyungsuk. "Performance of strand-based wood composite post-and-beam shear wall system." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/56823.
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This dissertation proposes a strand-based wood composite product to be utilized as the vertical members of post-and-beam (P&B) shear walls. Since the shear wall performance is largely governed by connection systems holding the wall components together, the research focuses on the structural behaviour of two key connection types: nail and hold-down connections. The experimental studies were designed to evaluate the effects of orthogonal properties, such as vertical density profile of the strand-based product, on the connection performance. Static load tests were conducted following ASTM standards and Japanese HOWTEC connection performance guidelines. The test results showed that the connections with fasteners mounted on the face-side of the composite product outperform the ones with fasteners mounted on the product’s edge-side. Subsequently, full-scale shear wall tests were conducted on three P&B wall types to study the effect of the fastener driving direction on the wall performance. The test results confirmed that the shear walls with face-driven nails outperforms the ones with edge-driven nails in terms of load carrying capacity.
A detailed mechanics-based finite-element connection model RHYST was also developed to predict the load-displacement relationship of a nail connection. It was developed based on an existing connection model HYST which idealizes a dowel-type connector driven into a wood medium as an elasto-plastic beam embedded in a nonlinear foundation that only acts in compression. RHYST assumes that the lateral response of the wood medium does not decrease at any compressive displacement. The presented model takes into account the contribution of the fastener’s vertical displacements on the response of the foundation. The simulation results of RHYST agreed well with the reversed-cyclic nail connection test results in terms of load carrying capacity and energy dissipation. The model is also able to simulate strength and stiffness degradation between the repeated loading cycles. Moreover, the applicability of RHYST was confirmed by incorporating it as a subroutine in a finite-element shear wall model WALL2D. The simulation results of WALL2D with RHYST showed a good agreement with the wall test results.Forestry, Faculty of
Graduate
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Carneal, Jason Bradley. "Integration and Validation of Flow Image Quantification (Flow-IQ) System." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/35322.
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The first aim of this work was to integrate, validate, and document, a digital particle image quantification (Flow-IQ) software package developed in conjunction with and supported by Aeroprobe Corporation. The system is tailored towards experimental fluid mechanics applications. The second aim of this work was to test the performance of DPIV algorithms in wall shear flows, and to test the performance of several particle sizing algorithms for use in spray sizing and average diameter calculation. Several particle sizing algorithms which assume a circular particle profile were tested with DPIV data on spray atomization, including three point Guassian, four point Gaussian, and least squares algorithms. A novel elliptical diameter estimation scheme was developed which does not limit the measurement to circular patterns. The elliptic estimator developed in this work is able to estimate the diameter of a particle with an elliptic shape, and assumes that the particle is axisymmetric about the x or y axis. Two elliptical schemes, the true and averaged elliptical estimators, were developed and compared to the traditional three point Gaussian diameter estimator using theoretical models. If elliptical particles are theoretically used, the elliptical sizing schemes perform drastically better than the traditional scheme, which is limited to diameter measurements in the x-direction. The error of the traditional method in determining the volume of an elliptical particle increases dramatically with the eccentricity. Monte Carlo Simulations were also used to characterize the error associated with wall shear measurements using DPIV. Couette flow artificial images were generated with various shear rates at the wall. DPIV analysis was performed on these images using PIV algorithms developed by other researchers, including the traditional multigrid method, a dynamically-adaptive DPIV scheme, and a control set with no discrete window offset. The error at the wall was calculated for each data set. The dynamically adaptive scheme was found to estimate the velocity near the wall with less error than the no discrete window offset and traditional multigrid algorithms. The shear rate was found to be the main factor in the error in the velocity measurement. In wall shear velocity measurement, the mean (bias) error was an order of magnitude greater than the RMS (random) error. A least squares scheme was used to correct for this bias error with favorable results. The major contribution of this effort stems from providing a novel elliptical particle sizing scheme for use in DPIV, and quantifies the error associated with wall shear measurements using several DPIV algorithms. A test bed and comprehensive user's manual for Flow-IQ v2.2 was also developed in this work.Master of Science
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TUNC, GOKHAN. "RC/COMPOSITE WALL-STEEL FRAME HYBRID BUILDINGS WITH CONNECTIONS AND SYSTEM BEHAVIOR." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1020441384.
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Just, Paul J. III. "A State of the Art Review of Special Plate Shear Walls." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1459155417.
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Ma, Siyao. "Numerical study of pin-supported cross-laminated timber (CLT) shear wall system equipped with low-yield steel dampers." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57747.
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This thesis presents a numerical study of a novel rocking cross-laminated timber (CLT) shear wall system for low- to mid-rise constructions. The system takes advantage of the high in-plane stiffness of CLT coupled with low-yield steel dampers to control the rocking motion of the CLT shear walls during earthquakes. The low-yield steel dampers connected between two rigid CLT wall panels provide the mechanism needed to dissipate the earthquake energy. This concentrates the damage in the dampers, allowing the system to be repaired efficiently after major earthquakes. Numerical models of the CLT shear wall system have been developed using both OpenSees Navigator and ABAQUS software. Models of low-yield steel damper systems were calibrated using available experimental results. With the rigid floor/roof assumption, a simplified OpenSees model of the CLT shear wall system was demonstrated to be effective and reasonably accurate in predicting the response of the system under large excitations. Therefore, it is efficient and reliable to apply the OpenSees model to study the seismic response of CLT shear wall buildings. A case study of a six-storey CLT shear wall building located in Vancouver, Canada was studied; and, detailed parameteric studies were conducted to investigate the influences of the damper type (damper shear strength), number of dampers, damper location, different earthquake records versus target earthquake design response spectrum, and earthquake peak ground acceleration (PGA) on the building response. It was determined that an optimized damper design with comprehensive consideration of these five factors can provide a building with a small roof drift ratio, as well as minor damages on the dampers. Concepts and examples for connection design are also provided.Forestry, Faculty of
Graduate
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Helvey, Jacob. "Experimental Investigation of Wall Shear Stress Modifications due to Turbulent Flow over an Ablative Thermal Protection System Analog Surface." UKnowledge, 2015. http://uknowledge.uky.edu/me_etds/57.
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Modifications were made to the turbulent channel flow facility to allow for fully developed rough quasi-2D Poiseuille flow with flow injection through one surface and flow suction through the opposing surface. The combination of roughness and flow injection is designed to be analogous to the flow field over a thermal protection system which produces ablative pyrolysis gases during ablation. It was found that the additional momentum through the surface acted to reduce skin friction to a point below smooth-wall behavior. This effect was less significant with increasing Reynolds number. It was also found that the momentum injection modified the wake region of the flow.
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Liu, Janet. "Design of a Novel Tissue Culture System to Subject Aortic Tissue to Multidirectional Bicuspid Aortic Valve Wall Shear Stress." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1527077368757049.
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Hassan, Mohamed. "INELASTIC DYNAMIC BEHAVIOR AND DESIGN OF HYBRID COUPLED WALL SYSTEMS." Doctoral diss., University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4437.
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A key consideration in seismic design of buildings is to ensure that the lateral load resisting system has an appropriate combination of strength, stiffness and energy dissipation capacity. Hybrid coupled wall systems, in which steel beams are used to couple two or more reinforced concrete shear walls in series, can be designed to have these attributes and therefore have the potential to deliver good performance under severe seismic loading. This research presents an investigation of the seismic behavior of this type of structural system. System response of 12- and 18-story high prototypes is studied using transient finite element analyses that accounts for the most important aspects of material nonlinear behavior including concrete cracking, tension stiffening, and compressive behavior for both confined and unconfined concrete as well as steel yielding. The developed finite element models are calibrated using more detailed models developed in previous research and are validated through numerous comparisons with test results of reinforced concrete walls and wall-beam subassemblages. Suites of transient inelastic analyses are conducted to investigate pertinent parameters including hazard level, earthquake record scaling, dynamic base shear magnification, interstory drift, shear distortion, coupling beam plastic rotation, and wall rotation. Different performance measures are proposed to judge and compare the behavior of the various systems. The analyses show that, in general, hybrid coupled walls are particularly well suited for use in regions of high seismic risk. The results of the dynamic analyses are used to judge the validity of and to refine a previously proposed design method based on the capacity design concept and the assumption of behavior dominated by the first vibration mode. The adequacy of design based on the pushover analysis procedure as promoted in FEMA-356 (2000) is also investigated using the dynamic analysis results. Substantial discrepancies between both methods are observed, especially in the case of the 18-story system. A critical assessment of dynamic base shear magnification is also conducted, and a new method for estimating its effects is suggested. The method is based on a modal combination procedure that accounts for presence of a plastic hinge at the wall base. Finally, the validity of limitations in FEMA-368 (2000) on building height, particularly for hybrid coupled wall systems, is discussed.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil and Environmental Engineering
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Boivin, Yannick. "Assessment of the seismic performance of a 12-storey ductile concrete shear wall system designed according to the NBCC 2005 and the CSA A23.3 2004 standard." Mémoire, [S.l. : s.n.], 2006. http://savoirs.usherbrooke.ca/handle/11143/1329.
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Younes, Imad Sabeh. "Transfer matrix analysis of frame-shear wall systems." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280922.
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Atasoy, Mehmet. "Lateral Stiffness Of Unstiffened Steel Plate Shear Wall Systems." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609219/index.pdf.
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Finite element method and strip method are two widely used techniques for analyzing steel plate shear wall (SPSW) systems. Past research mostly focused on the prediction of lateral load capacity of these systems using these numerical methods. Apart from the lateral load carrying capacity, the lateral stiffness of the wall system needs to be determined for a satisfactory design. Lateral displacements and the fundamental natural frequency of the SPSW system are directly influenced by the lateral stiffness. In this study the accuracy of the finite element method and strip method of analysis are assessed by making comparisons with experimental findings. Comparisons revealed that both methods provide in general solutions with acceptable accuracy. While both methods offer acceptable solutions sophisticated computer models need to be generated. In this study two alternative methods are developed. The first one is an approximate hand method based on the deep beam theory. The classical deep beam theory is modified in the light of parametric studies performed on restrained thin plates under pure shear and pure bending. The second one is a computer method based on truss analogy. Stiffness predictions using the two alternative methods are found to compare well with the experimental findings. In addition, lateral stiffness predictions of the alternate methods are compared against the solutions provided using finite element and strip method of analysis for a class of test structures. These comparisons revealed that the developed methods provide estimates with acceptable accuracy and are simpler than the traditional analysis techniques.
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Mirza, Adeel R. "Evaluation of AISC Steel Coupling Beam Embedment Length in Composite Ordinary Shear Walls." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543577095290297.
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Kurata, Masahiro. "Strategies for rapid seismic hazard mitigation in sustainable infrastructure systems." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31770.
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Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2010.Committee Co-Chair: DesRoches, Reginald; Committee Co-Chair: Leon, Roberto T.; Committee Member: Craig, James I.; Committee Member: Goodno, Barry; Committee Member: White, Donald W. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Kurban, Can Ozan. "A Numerical Study On Response Factors For Steel Plate Shear Wall Systems." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610741/index.pdf.
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Design recommendations for steel plate shear wall (SPSW) systems have recently been introduced into seismic provisions for steel buildings. Response modification, overstrength, and displacement amplification factors for SPSW systems presented in the design codes were based on professional experience and judgment. A numerical study has been undertaken to evaluate these factors for SPSW systems. Forty four unstiffened SPSWs possessing different geometrical characteristics were designed based on the recommendations given in the AISC Seismic Provisions. Bay width, number of stories, story mass, and steel plate thickness were considered as the prime variables that influence the response. Twenty records were selected to include the variability in ground motion characteristics. In order to provide a detailed analysis of the post-buckling response, three-dimensional finite element analyses were conducted for the 44 structures subjected to the selected suite of earthquake records. For each structure and earthquake record two analyses were conducted in which the first one includes geometrical nonlinearities and the other one includes both geometrical and material nonlinearities, resulting in a total of 1760 time history analysis. In this thesis, the details of the design and analysis methodology are given. Based on the analysis results response modification, overstrength and displacement amplification factors for SPSW systems are evaluated.
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Lee, Seung Yeol. "Static and dynamic reliability analysis of frame and shear wall structural systems." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/280463.
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Effective and accurate algorithms are developed to evaluate the reliability of frame and shear wall structural system subjected to both static and dynamic loadings. The basic deterministic finite element algorithm is based on the assumed stress-based finite element method in which the tangent stiffness can be expressed in explicit form and fewer elements are required to realistically capture the structural behavior. These features are desirable for developing an efficient reliability analysis algorithm for both static and dynamic cases. The presence of shear walls is represented by plate elements. The stiffness matrix for the combined system is then developed. To verify the accuracy of the deterministic algorithm, a 2-bay 2-story building consisting of five similar frames is considered. Only one frame is assumed to have shear walls. The responses of the frame with shear walls subjected to static and dynamic loadings are evaluated. The responses of the same structural system are also evaluated using a commercially available computer program. The results match very well, implying that the deterministic algorithm developed in this study is accurate. The deterministic algorithm is then extended to consider the uncertainty in the random variables. For the static case, a stochastic finite element-based approach consisting of the reliability approach, the first-order reliability analysis procedure and the finite element method is proposed. For the dynamic case, a hybrid approach consisting of the response surface method, the finite element method, the first-order reliability method and the linear iterative scheme is used. The unique feature of this algorithm is that the earthquake loading can be applied in the time domain. The material and cross-sectional properties, the damping and the magnification factors of earthquake time histories are considered to be random variables in this study. The reliability of a frame without and with shear walls is evaluated for the strength and serviceability performance functions. The results are verified using the Monte Carlo simulation technique.
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Guskey, Christopher R. "NEAR WALL SHEAR STRESS MODIFICATION USING AN ACTIVE PIEZOELECTRIC NANOWIRE SURFACE." UKnowledge, 2013. http://uknowledge.uky.edu/me_etds/27.
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An experimental study was conducted to explore the possible application of dynamically actuated nanowires to effectively disturb the wall layer in fully developed, turbulent channel flow. Actuated nanowires have the potential to be used for the mixing and filtering of chemicals, enhancing convective heat transfer and reducing drag. The first experimental evidence is presented suggesting it is possible to manipulate and subsequently control turbulent flow structures with active nanowires. An array of rigid, ultra-long (40 μm) TiO2 nanowires was fabricated and installed in the bounding wall of turbulent channel flow then oscillated using an attached piezoelectric actuator. Flow velocity and variance measurements were taken using a single sensor hot-wire with results indicating the nanowire array significantly influenced the flow by increasing the turbulent kinetic energy through the entire wall layer.
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Seckiner, Soner. "Parametric Analysis Of Inelastic Interaction In Frame-wall Structural Systems." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613654/index.pdf.
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The purpose of this thesis is to investigate the inelastic action in the reinforced concrete frame-wall structures analytically and with that analysis to follow the plastic formation of the structure. For this purpose, six mid-rise reinforced concrete buildings with frame-wall are modeled and analyzed to understand the effect of the height and base shear force ratio of the wall on the nonlinear interaction between reinforced concrete wall and frame members under static lateral loads and ground motion excitations. The parametric analysis is conducted by assuming planar response of the buildings under loadings.
The buildings are generated considering the limit design concept suggested by Turkish Earthquake Code 2007 and Turkish Standards TS500, and the frame-wall members are modeled by using spread plasticity elements and fiber discretization of sections. In the analysis stage, each element section is divided into confined and unconfined regions for detailed modeling of the building by using OpenSEES nonlinear finite element program. Two dimensional analyses are conducted under static and dynamic loadings. For static pushover analyses, three different lateral load cases (Triangular, Uniform and First-Mode Lateral Load Patterns) are considered. For dynamic analyses, eight different ground motions are used. These ground motions are scaled to the corresponding design response spectrum suggested by Turkish Earthquake Code 2007 by using RSPMATCH program. Using the result of the complex and simplified analyses, inter-story drift ratios, plastic rotations and internal force distributions of the buildings are investigated.
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Madsen, Lasse P. B. "Control of seismic response of buildings using damping systems in shear walls." Thesis, Queensland University of Technology, 2001. https://eprints.qut.edu.au/36149/1/36149_Madsen_2001.pdf.
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When buildings are subjected to random, unpredictable loads such as earthquakes, explosions and wind, it is imperative to dissipate some, and preferably, most of the
input energy through pre-determined and well designed mechanisms. This is done so that less energy is available to deform the structure, thereby avoiding its failure and
collapse. Structures using traditional materials such as concrete and steel can employ 'plastic hinges' to achieve stable hysteretic behaviour at non-collapse inducing
locations within the framing system. This behaviour achieves varying degrees of amping, which is usually limited to 5% of critical. In addition to using plastic
hinges, the input energy can also be absorbed by the use of damping devices. This study investigates the influence of mechanical control on structural systems through the application of strategically located component elements with reliable damping and stiffuess properties that can modulate the response. The effects of
installing such damping elements at two particular locations have been investigated.
These positions are between the shear walls near the coupling beams and within cutout sections of the wall elements in multi-storey structures. These specially
manufactured energy dissipaters are assumed to be most beneficial when placed close to the source of excitation - the lower levels for earthquakes and explosions,
and the upper levels for winds. Results have indicated that reasonable response reduction was possible by using such dampers.
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Johnson, Kevin Robert. "In Vivo Coronary Wall Shear Stress Determination Using CT, MRI, and Computational Fluid Dynamics." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14482.
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Wall shear stress (WSS) has long been identified as a factor in the development of atherosclerotic lesions. Autopsy studies have revealed a strong tendency for lesion development at arterial branch sites and along the inner walls of curvature areas that, in theory, should experience low WSS. Calculations of coronary artery WSS have typically been based upon average models of coronary artery geometry with average flow conditions and then compared to average lesion distributions. With all the averaging involved, a more detailed knowledge of the correlation between WSS and atherosclerotic lesion development might be obscured. Recent advancements in hemodynamic modeling now enable the calculation of WSS in individual subjects. An image-based approach for patient-specific calculation of in vivo WSS using computational fluid dynamics (CFD) would allow a more direct study of this correlation. New state-of-the-art technologies in multi-detector computed tomography (CT) and 3.0 Tesla magnetic resonance imaging (MRI) offer potential improvements for the measurement of coronary artery geometry and blood flow.
The overall objective of this research was to evaluate the quantitative accuracy of multi-detector CT and 3.0 Tesla MRI and incorporate those imaging modalities into a patient-specific CFD model of coronary artery WSS. Using a series of vessel motion phantoms, it has been shown that 64-detector CT can provide accurate measurements of coronary artery geometry for heart rates below 70 beats per minute. A flow phantom was used to validate the use of navigator-echo gated, phase contrast MRI at 3.0 Tesla to measure velocity of coronary blood flow. Patient-specific, time-resolved CFD models of coronary WSS were created for two subjects. Furthermore, it was determined that population-average velocity curves or steady state velocities can predict locations of high or low WSS with high degrees of accuracy compared to the use of patient-specific blood flow velocity measurements as CFD boundary conditions. This work is significant because it constitutes the first technique to non-invasively calculate in vivo coronary artery WSS using image-based, patient-specific modeling.
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Iotti, Fabio. "Non dissipative seismic retroffitting of a frame structure using shear walls." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15031/.
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Evaluation of the technical and economical feasibility of two different design approaches for seismic retrofitting of RC frame structure:
- Conventional Approach: Design of a new ductile structural core serving as a stair shaft
-Non-conventional Approach: Use of an external structural coating system designed assuming a non-dissipative behavior
The work is subdivided in two main parts. In the first one, a series of information contained in the literature, both historical and technical, has been collected to provide for the necessary background both for seismic analysis and retrofitting design in order to define the two retrofitting strategies.
In the second part the design of the RC walls is presented in detail and finally confronted, from a technical and economical point of view.
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Eixenberger, Joseph G. "Seismic Analysis of and Provisions for Dry-Stack Concrete Masonry Wall Systems with Surface Bond in Low-Rise Buildings." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6547.
Full textAbstract:
Masonry is one of the oldest forms of construction materials that is still in use today. However, construction practices in the modern age demand faster and more economical practices. Dry-stack masonry, or masonry that doesn't use mortar to bind the blocks together, is a unique system to make masonry more economical. Though several systems of dry-stack masonry have been suggested little to no data exists as most of these systems are patented. This research used dry-stacked normal weight concrete masonry units with an eccentrically placed reinforcement. The wall system is connected through a surface bond and lacks any geometric connection. Previously, research has been conducted on the wall system for its axial compressive capacity, but little information is known about its ability to withstand lateral forces such as earthquakes. Research was conducted on the wall system in order to determine the seismic parameters, including the force reduction factor, overstrength factor, and the displacement amplification factor. To determine these factors the guidelines from the Federal Emergency Management Agency (FEMA) Quantification of Building Seismic Performance Factors 2009 were followed. The guidelines are explicit that both experimental data and computer modeling are needed to quantify these parameters. Experimental data was obtained from a diagonal tension test, and an in-plane shear test. The diagonal tensions test provided preliminary values on the shear modulus and shear resistance. The in-plane shear test was of primary interest and what would be used to verify the computer model. Computer modeling of the wall system was accomplished with Vector 2. Initially the computer modeling was done to reproduce experimental data. Then, a parametric study was performed using the model to see what component of the wall most effected its capacity. This analysis showed that the surface bond was the component of the wall that most affects its capacity. Finally, the computer model was run through the FEMA Far-Field earthquake suite to gather data on the strength and ductility. Values of the force reduction factor, overstrength factor, and displacement amplification factor were determined based on the time history analysis and pushover analysis on the computer model.
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Tassotti, Luca. "Seismic analysis and design of innovative steel and concrete hybrid coupled wall systems." Doctoral thesis, Università Politecnica delle Marche, 2015. http://hdl.handle.net/11566/242920.
Full textAbstract:
L’applicazione del concetto di fusibile strutturale nei sistemi sismo-resistenti ha portato allo sviluppo di diverse soluzioni strutturali, tra queste sono compresi i promettenti sistemi ibridi acciaio calcestruzzo. Questi sistemi sono ottenuti tramite una combinazione in serie di elementi in acciaio e in calcestruzzo armato con l’obiettivo di sfruttare al loro meglio le potenzialità di ciascun materiale. In questo lavoro viene indagato il comportamento sismico del sistema innovativo ibrido a parete accoppiata (HCSW), sviluppato nel progetto di ricerca europeo INNO-HYCO (INNOvative HYbrid and COmposite steel-concrete structural solutions for building in seismic area). La soluzione sismo-resistente è composta da una parete in calcestruzzo armato accoppiata a colonne laterali di acciaio tramite link sostituibili con l’obiettivo di sfruttare sia la rigidezza della parete, necessaria a limitare il danneggiamento della costruzione sotto l’azione di terremoti di bassa intensità, che la duttilità dei link di acciaio, necessaria a dissipare l’energia dei sismi di medio-alta intensità. Il comportamento sismico del sistema viene valutato tramite analisi statiche non lineari (pushover) e analisi dinamiche non lineari incrementali (IDA). Per questi scopi, inizialmente è stato progettato un insieme di casi studio realistici, poi è stato sviluppato un modello agli elementi finiti a fibre, validato successivamente tramite confronti con risultati sperimentali comprendendo quantità di risposta locali e globali. Infine, viene mostrata una selezione dei risultati ottenuti, includendo parametri di risposta locale e globale, per mettere in luce le potenzialità dei sistemi innovativi proposti e la concreta possibilità di sviluppare un comportamento duttile nel quale le deformazioni plastiche nei link sono attese prima dello snervamento della parete. Inoltre, i risultati finali permettono di fornire un supporto per l’identificazione delle soluzioni ottimali che potrebbero risultare competitive rispetto a sistemi esistenti.The concept of structural fuse applied to earthquake resistant systems has led to the development of several seismic-resistant structural solutions, including interesting steel and concrete hybrid systems. These systems are obtained through a combination in series of steel elements and reinforced concrete elements with the aim of exploiting at their best the potentialities of each material. In this work the seismic behaviour of an innovative hybrid coupled shear wall (HCSW) system, developed in the European research project INNO-HYCO (INNOvative HYbrid and COmposite steel-concrete structural solutions for building in seismic area), is investigated. The earthquake resistant solution is composed by a reinforced concrete wall coupled to steel side columns by means of easily replaceable steel links with the objective to exploit both the stiffness of reinforced concrete wall, necessary to limit building damage under low-intensity earthquakes, and the ductility of steel links, necessary to dissipate energy under medium- and high-intensity earthquakes. The seismic behaviour of the system is assessed through nonlinear static (pushover) analysis and multi-record nonlinear incremental dynamic analysis (IDA). For this purpose, firstly a set of realistic case studies is designed, then a finite element model is developed into the platform Opensees and validated through comparisons against experimental tests including local and global responses quantities. A selection of results including global and local response quantities is shown in order to highlight the potentialities of the proposed innovative HCSW systems and the actual possibility to develop a ductile behaviour where plastic deformation are attained in the steel links before yielding in the reinforced concrete wall. The final results permit to provide a support for the identification of optimal solutions that could be competitive against existing seismic resistant structural systems.
26
Janbakhsh, Setareh. "A Ventilation Strategy Based on Confluent Jets : An Experimental and Numerical Study." Doctoral thesis, Linköpings universitet, Energisystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-117442.
Full textAbstract:
This study presents air distribution systems that are based on confluent jets; this system can be of interest for the establishment of indoor environments, to fulfill the goals of indoor climate and energy-efficient usage. The main objective of this study is to provide deeper understanding of the flow field development of a supply device that is designed based on wall confluent jets and to investigate the ventilation performance by experimental and numerical methods. In this study, the supply device can be described as an array of round jets on a flat surface attached to a side wall. Multiple round jets that issue from supply device apertures are combined at a certain distance downstream from the device and behave as a united jet or so-called confluent jets. Multiple round jets that are generated from the supply device move downward and are attached to the wall at the primary region, due to the Coanda effect, and then they become wall confluent jets until the floor wall is reached. A wall jet in a secondary region is formed along the floor after the stagnation region. The characteristics of the flow field and the ventilation performance of conventional wall confluent jets and modified wall confluent jets supply devices are investigated experimentally in an office test room. The study of the modified wall confluent jets is intended to improve the efficiency of the conventional one while maintaining acceptable thermal comfort in an office environment. The results show that the modified wall confluent jets supply device can provide acceptable thermal comfort for the occupant with lower airflow rate compared to the conventional wall confluent jets supply device. Numerical predictions using three turbulence models (renormalization group (RNG k– ε), realizable (Re k– ε), and shear stress transport (SST k– ω) are evaluated by measurement results. The computational box and nozzle plate models are used to model the inlet boundary conditions of the nozzle device. In the isothermal study, the wall confluent jets in the primary region and the wall jet in the secondary region, when predicted by the three turbulence models, are in good agreement with the measurements. The non-isothermal validation studies show that the SST k– ω model is slightly better at predicting the wall confluent jets than the other two models. The SST k– ω model is used to investigate the effects of the nozzle diameter, number of nozzles, nozzle array configuration, and inlet discharge height on the ventilation performance of the proposed wall confluent jets supply device. The nozzle diameter and number of nozzles play important roles in determining the airflow pattern, temperature field, and draught distribution. Increased temperature stratification and less draught distribution are achieved by increasing the nozzle diameter and number of nozzles. The supply device with smaller nozzle diameters and fewer nozzles yields rather uniform temperature distribution due to the dominant effect of mixing. The flow behavior is nearly independent of the inlet discharge height for the studied range. The proposed wall confluent jets supply device is compared with a mixing supply device, impinging supply device and displacement supply device. The results show that the proposed wall confluent jets supply device has the combined behavior of both mixing and stratification principles. The proposed wall confluent jets supply device provides better overall ventilation performance than the mixing and displacement supply devices used in this study. This study covers also another application of confluent jets that is based on impinging technology. The supply device under consideration has an array of round jets on a curve. Multiple jets issue from the supply device aperture, in which the supply device is positioned vertically and the jets are directed against a target wall. The flow behavior and ventilation performance of the impinging confluent jets supply device is studied experimentally in an industrial premise. The results show that the impinging confluent jets supply device maintains acceptable thermal comfort in the occupied zone by creating well-distributed airflow during cold and hot seasons.
27
FORTNEY, PATRICK JOSEPH. "THE NEXT GENERATION OF COUPLING BEAMS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1115837131.
Full text
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Chatterjee, Aritra. "Structural System Reliability with Application to Light Steel-Framed Buildings." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/74879.
Full textAbstract:
A general framework to design structural systems for a system-reliability goal is proposed.
Component-based structural design proceeds on a member to member basis, insuring acceptable failure probabilities for every single structural member without explicitly assessing
the overall system safety, whereas structural failure consequences are related to the whole
system performance (the cost of a building or a bridge destroyed by an earthquake) rather
than a single beam or column failure. Engineering intuition tells us that the system is
safer than each individual component due to the likelihood of load redistribution and al-
ternate load paths, however such conservatism cannot be guaranteed without an explicit
system-level safety check. As a result, component-based structural designs can lead to both
over-conservative components and a less-than-anticipated system reliability.
System performance depends on component properties as well as the load-sharing network,
which can possess a wide range of behaviors varying from a dense redundant system with
scope for load redistribution after failure initiates, to a weakest-link type network that fails as
soon as the first member exceeds its capacity. The load-sharing network is characterized by
its overall system reliability and the system-reliability sensitivity, which quantifies the change in system safety due to component reliability modifications. A general algorithm is proposed
to calculate modified component reliabilities using the sensitivity vector for the load-sharing
network. The modifications represent an improvement on the structural properties of more
critical components (more capacity, better ductility), and provide savings on less important
members which do not play a significant role.
The general methodology is applied to light steel-framed buildings under seismic loads.
The building is modeled with non-linear spring elements representing its subsystems. The
stochastic response of this model under seismic ground motions provides load-sharing, system
reliability and sensitivity information, which are used to propose target diaphragm and shear
wall reliability to meet a building reliability goal. Finally, diaphragm target reliability is
used to propose modified component designs using stochastic simulations on geometric and
materially non-linear finite-element models including every individual component.Ph. D.
29
Bower, Owen J. "Analytical Investigation into the Effect of Axial Restraint on the Stiffness and Ductility of Diagonally Reinforced Concrete Coupling Beams." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1211065883.
Full text
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Al, Ateah Ali H. "NUMERICAL STUDY OF MULTIPLE ROCKING SELF-CENTERINGROCKING CORE SYSTEMS WITH BUCKLING-RESTRAINED COLUMNSFOR MID-RISE BUILDINGS." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1511816354436547.
Full text
31
Lungu, Dan. "Testing and analysis of Midply(TM) Shear Wall System." Thesis, 2000. http://hdl.handle.net/2429/10422.
Full textAbstract:
The thesis details a six-month period of experimental studies of the structural properties
of the MIDPLY™ Wall System, which has being developed through a three-year testing
program.
The MIDPLY™ shear wall was invented by Dr. Erol Varoglu, formerly with Forintek
Canada Corp. and Prof. S.F. Stiemer (University of British Columbia), US Patent
US5782054: Wood wall structure. The system provides greater lateral resistance to
earthquakes and high winds loads. The name MIDPLY™ refers to its configuration: the
plywood or OSB panel is placed between the studs. The improved performance is due to
this special rearrangement of wall framing components and sheathing used in standard
shear walls. The new fabrication system uses typical building methods and standard
building materials, but a prefabricated production may be desirable to ensure the quality
of the product.
The objective of the project is to establish the proof-of-concept for the MIDPLY™ Wall
System, design and construction method. The structural properties are being developed
through testing of full-scale specimens subjected to monotonic (ramp), cyclic and
dynamic displacement schedules. Several anchoring techniques and hold-down
connectors have been developed and tested. The tests were performed mainly on 2.44m x
2.44m and 1.22m x 2.44m MIDPLY™ shear walls.
In the investigations covered by this thesis, were designed and tested 30 walls and were
primarily studied:
• Alternate hold-down connections that prevent the fracture of the end studs of the
MIDPLY™ wall by using MSR lumber or inverted-triangle hold-downs with
different bolt spacing, bolt diameters, hold-down length and placement along the
stud.
• Alternate hold-down connectors: steel rods and double shear hold-downs.
• The performance of MIDPLY™ walls under pseudo-dynamic tests.
• The performance of MIDPLY™ walls used as insert segments in standard shear
walls.
• The performance of MIDPLY™ walls with openings. Special attention was given to
the connection details between header and MIDPLY™ walls to achieve desired pinor
moment-connection.
• The performance of MIDPLY™ walls affected by shrinkage.
• The performance of repaired MIDPLY™ walls.
One can conclude that, there are many real-life applications of the system, using the
superior structural performance of the MIDPLY™ walls. Thus, future studies will
conduct to a final package of design values needed for structural engineers, architects and
designers.
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Jhang, Chyuan, and 張權. "Seismic Behavior of Low Yield Point Steel Shear Wall System." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/dz96aj.
Full textAbstract:
博士國立臺灣科技大學
營建工程系
94
This research is aimed at studying the structural behavior of low yielding point (LYP) steel shear wall system. A series of analytical and experimental studies were carried out to examine the stiffness, strength, deformation, and energy dissipation of the LYP steel shear wall system. The first series of study is to examine the shear buckling of the LYP steel shear panels. The experimental results agree with that from analytical study very well. The second series of experimental work is to study the behavior of the LYP steel shear wall with H-beams and H-columns as its boundary elements. Both moment connections and shear connections were studied. Good energy dissipation capacities were obtained for all specimens. The third part of this study is the seismic behavior of multi-story shear wall system. Excellent deformation capacities were obtained from both rigid frame-shear wall system and simple frame-shear wall system. The story drift angle can be as high as 6% and still maintains stable characteristics. A two-force strip model was also proposed to simulate the LYP shear wall for the elastic and inelastic behavior. Good correlations were found between experimental and analytical studies. Furthermore, applications of LYP shear wall system in the building design were examined by comparing the elastic and inelastic behavior of different structural systems. Based on these research findings, guild lines for the design of LYP steel shear wall systems were proposed.
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Siao, You-Jing, and 蕭尤菁. "Seismic Behavior of Low Yield Steel Plate Shear Wall System." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/15284045926913149099.
Full textAbstract:
碩士國立臺灣科技大學
營建工程系
96
Low yield steel plate shear wall system have such advantages of good strength , high stiffness and large ductility ,therefore it is a excellent earthquake resistant structure. The steel plate has very low yielding strength ,so the structure behavior at nonlinear stage is very different from the behavior at elastic stage. This research is aimed to investigate the behavior of Low yield steel plate shear wall system at non-linear stage. This study adopted two analysis schemes in SAP2000. One is nonlinear static pushover analysis for investigating (1) the interaction between the shear wall and frame (2) the deformation and energy dissipation of the system. The other is nonlinear dynamic analysis for investigating the distribution of story shear force with fifteen different earthquake excitation records. The results of two methods are compared. The major results are: 1.The interaction between shear wall and frame is intense at elastic stage , however, it become less after the structure enter highly nonlinear stage. 2.The deform shape of whole structure is dominated by the shear wall because the stiffness and strength of shear wall is much larger than frame. 3.The results of nonlinear static pushover analysis (first mode only) are closed to the results of nonlinear dynamic analysis when the structure was excited by earthquakes of soft soil condition. 4.For shear wall system subjected to earthquake of hard soil condition, the first mode pushover analysis produce results with large deviation. The second mode influence should be included.
34
Buitelaar, Marlen. "Static and dynamic testing of MIDPLY TM shear wall system." Thesis, 2001. http://hdl.handle.net/2429/12747.
Full textAbstract:
The work documented in this thesis constitutes the second year of the three-year
MIDPLY™ project. The MIDPLY™ shear wall system is a new invention for
strengthening new and existing light frame timber buildings against earthquakes and high
' winds. The system needed to be tested before its implementation in the field (US Patent
US5782054: Wood Wall Structure).
As part of an ongoing research project undertaken by Forintek Canada Corp. and the
University of British Columbia, the MIDPLY™ shear wall system was designed, tested,
and developed in order to procure an improved product over the conventional shear wall
presently used in construction.
The objective of this project was three-fold:
1. Improve the behaviour of timber shear walls by utilizing conventional timber
products combined with new technology - the MIDPLY™ wall.
2. Quantify the improvements though full-scale static and dynamic testing of the
MIDPLY™ shear walls.
3. Determine failure modes and load-displacement characteristics of the MIDPLY™
walls.
The work in this thesis comprises of static testing, dynamic testing, structural modeling,
and shear wall connection design and implementation. Several configurations of 2.44m x
2.44m walls were tested statically at Forintek Canada Corp., where from three
configurations were chosen to be tested dynamically at the Earthquake Engineering
Laboaratory at UBC. The configurations of MIDPLY™ walls were tested under two
different earthquake records.
In total, 40 static tests, which include monotonic and reversed cyclic tests, and 6 dynamic
tests were performed as part of the scope of this thesis. Throughout the testing, the
parameters that were varied were lumber size, stud spacing, lumber type, loading
protocol, hold down connection type, and vertical loading.
The results of the testing clearly showed the strengths and weaknesses of the MIDPLY™
shear wall system. Two strengths were that the MIDPLY™ wall could withstand higher
loads and displacements than the conventional light frame timber shear wall used in most
buildings in North America. Also, some common failure modes from other walls were
eliminated. The weakness was that the wall sometimes failed in a brittle manner through
end-stud failure. The future plans of the MIDPLY™ project include new connection designs to further
improve racking performance.
35
Chang, Jing-Tang, and 張景棠. "Seismic Responses of Multi Story Coupled Steel Plate Shear Wall System." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/43423915896928699609.
Full textAbstract:
碩士國立臺灣大學
土木工程學研究所
97
In recent years, the steel plate shear wall system has gradually gained recognition and acceptance. Both research and construction involving this system has increased. In the steel plate shear wall system, the designer must choose strong boundary elements for the tension field. The purpose of this research is to investigate the effectiveness of a reduced column capacity design requirement by allowing the plastic hinge to form at approximately one quarter column high above the column base. Moreover, this research adopts the moment connection details for the link beam between the two steel plate shear wall systems, know as a coupled steel plate shear wall (C-SPSW). In this system, two steel plate shear walls can work together to resist the lateral force. Therefore, the C-SPSW system will not only have higher stiffness, strength and greater energy dissipation ability, but will also reduce the axial force in the internal columns. In this research, the author followed the current Taiwan and AISC seismic steel building code to design a six-story prototype building to study the flowing two topics: the capacity design procedure of a coupled steel plate shear wall system, and the effects of the relaxed column capacity. Extensive finite elements analysis has been conducted to analyze the building’s elastic and inelastic responses. This research also includes a cyclic test of a reduced scale, sub-structure of the prototype C-SPSW at NCREE using the Multi-axial Testing System (MATS) facility, applying constant force control in the vertical direction, cyclic displacement control in the horizontal direction. Assuming the building’s lateral force distribution is like an inverted triangle, the overturning moment from the third story was computed on line from the horizontal actuator force feedback. The cyclic overturning moments were satisfactorily applied using MATS controller. From this research, the following conclusions can be drawn: 1. The test results confirm that by allowing the plastic hinge to form at 1/4 high above the column base, the size of the column can be reduced. Before the overall story drift reached 0.02 radian, the C-SPSW specimen performed very well. When the overall story drift reached 0.05 radian, the inward deformations of the two columns became evident, but the lateral force resisting performance of the C-SPSW specimen remained satisfactory. 2. The shear link beam design for the C-SPSW specimen is found effective. The 2nd-story shear link deformations reached 0.04 radian when the overall story drift reached 0.05 radian. 3. The MATS controller allows the constant axial loads, cyclically increasing lateral displacements, and the corresponding overturning moments successfully applied on the C-SPSW substructure specimen.
36
Wang, Teng, and 王騰. "Pulsatile Flows and Wall Shear Stress in Renal Arterial System Model." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/98216540397202801179.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
97
The pulsatile flow characteristics and evolution process in a model which simulate the renal artery of human being is diagnosed by using the particle tracking flow visualization method (PTFV) and the particle image velocimeter (PIV). The renal artery model is made of transparent plexiglas material which has different dimension with three tubes (abdominal artery, left renal artery and right renal artery). Mixture of glycerol and water at 37oC is used in the experiment as a working fluid to mimic the blood flow. To simulate the pulsating blood as it came out from the human heart, a “pulsatile blood pump” is used. A 72 strokes/minute (1.2Hz) stroke rate, with a volume flow rate of 4 L/min and a 45%/55% systole/diastole ratio is adopted in this study. The temporal/spatial evolution processes of the flow pattern, velocity distribution, and wall shear stress during systolic and diastolic phases are presented and discussed. During the systole stroke, the separation of boundary layer from the inner wall near the branch is shown in the PIV results. These characteristic flow structures induce reverse and low speed flows therefore would increase the probability of plaque deposition around the inner wall of the renal artery. The measured shear stresses around the branch junctions are low while the measured shear stresses at the outer wall of the renal artery are high. The high shear stress at the outer wall of the renal artery might crack the fibrolipid plaque and collagenous cap of atherosclerotic. This would induce rapid assembling of platelets on the exposed connective tissues which form the thrombosis. Furthermore it diminishes the transport of oxygen and metabolites supplied to the organ.
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Su, Chii-Tung, and 蘇啟東. "A Study on Column and Shear Wall Layout in Building Structural System Preliminary Design." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/92512455750875062085.
Full textAbstract:
碩士國立成功大學
建築學系碩博士班
93
Loading capacity of column is essential for the seismic-resistant capacity of a building structure. The primary assessment of columns’ size is key to affect the displacement of the structure. Too large columns waste space,but too small can’t resist seismic force. This study on the relationship of loading capacity of columns and a reasonable requirement of seismic-resistant capacity of a building not only provide a preliminary seismic-resistant analysis for architectural professionals but also for building seismic diagnosis. Japanese seismic -resistant analysis and new method of the seismic-resistant design about loading capacity of the unit column and the wall/floor area ratios have some data for us to use.In order to find specific dynamic relationship between that of data and seismic-resistant capacity,some related factors such as different seismic force,height of building, stiffness ratio of column and girder are considered. To analyze with computer program ETABS and compare with different building model and weight by setting spans of building, numbers of floor, seismic force, story –drift ratio and height , charts can be established to estimate the relationship of columns and seismic-resistnt capacity . After confirming relationship between value W/EI and seismic force,then change different factor one by one to analyze different height, seismic force, number of floor, stiffness ratio of columns and girders and the like, the correction factors which can be applied for any type of building with one basic model data to estimate seismic force in easy way. The study in this thesis can obtain not only proper I value of columns from drift ratio, but also data of drift ratio from I value of the building.It is expected to understand the relation ship of columns and seismic –resistant capacity of a building. It can efficiently decrease displacement,increase stiffness of the structure and strengthen the seismic-resistant capacity after pure framework is joined to the R.C shear-walls . But it can make large difference with different location of R.C shear-walls for strengthening seismic -resistant capacity of a building . It affect a lot more to increase the length of the shear-walls area than that of thickness. The effect is more obvious with increasing thickness of R.C.shear-walls at the center or symmentry.
38
Keller, David. "Development of a steel plate shear wall bridge pier system conceived from a multi-hazard perspective." 2008. http://proquest.umi.com/pqdweb?did=1546798891&sid=2&Fmt=2&clientId=39334&RQT=309&VName=PQD.
Full textAbstract:
Thesis (M.S.)--State University of New York at Buffalo, 2008.Title from PDF title page (viewed Nov. 20, 2008). Available through UMI ProQuest Digital Dissertations. Thesis adviser: Bruneau, Michel. Includes bibliographical references.
39
SHUKLA, RAJAT. "TO STUDY FLAT PLATE STRUCTURAL SYSTEM AND COMPARE IT’S BEHAVIOR WITH MOMENT RESISTING FRAME AND SHEAR WALL SYSTEM UNDER LATERAL LOADS." Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/15339.
Full textAbstract:
In the present scenario, the buildings being constructed in India are increasing in Heights. The
metropolitans are witnessing higher and higher towers with each coming day. Though, the average height
of these new buildings may be ranging between 25-30 stories, there are a number of structures which are
fairly high and need better structural understanding to give economical and safer designs.
Majority of structures in India are based on the traditional Moment resisting frame concept in which the
beams and columns cater to the gravity loads as well as the lateral loads by virtue of its moment resisting
capacity. But this system is not efficient for buildings with heights greater than 15 stories. Hence, a
different concept of shear wall is being widely used as a suitable alternative. With shear walls lateral force
resisting capacity of buildings is improved drastically. With the use of shear wall structural system
together with special moment resisting frame or with ordinary moment resisting frame the height of
building has increased to 30 stories.
But, in order to achieve economy, aesthetics and architectural requirements a new structural system which
comprises of only slab and column mechanism is being looked upon. This structural system is called as
flat plate system in which the thickness of slab remains constant and columns rest directly on the slabs
without any drops or beams. This system not only has an aesthetic edge over traditional beam-column
system or flat slab system, but also proves to be economical because of lower construction time and lesser
storey height.
In this paper we have studied the behavior of flat plate system with increase in height. The study
comprises of buildings with and without shear wall systems. The problem areas of using flat plate system
have been discussed in this paper, which primarily comprise of unbalanced moment transfer of moment
from column to slab, and lesser stiffness of the building as a whole to resist lateral loads.
The behavior of flat plate system has also been compared with the traditional beam column moment
resisting frame system and their differences have been studied.
Analysis of Flat plate under gravity loading has also been performed in computer software and is
compared with the direct design method of IS 456.
Future scope of this paper includes economical comparison of the moment resisting frame structure and
flat plate structure.
40
"Characterizing the Impact of Low Shear Modeled Microgravity on Population Dynamics, Biofilm Formation and Silver Susceptibility of Microbial Consortia Isolated from International Space Station Potable Water." Master's thesis, 2019. http://hdl.handle.net/2286/R.I.55615.
Full textAbstract:
abstract: Understanding how microorganisms adapt and respond to the microgravity environment of spaceflight is important for the function and integrity of onboard life support systems, astronaut health and mission success. Microbial contamination of spacecraft Environmental Life Support Systems (ECLSS), including the potable water system, are well documented and have caused major disruption to spaceflight missions. The potable water system on the International Space Station (ISS) uses recycled wastewater purified by multiple processes so it is safe for astronaut consumption and personal hygiene. However, despite stringent antimicrobial treatments, multiple bacterial species and biofilms have been recovered from this potable water system. This finding raises concern for crew health risks, vehicle operations and ECLSS system integrity during exploration missions. These concerns are further heightened given that 1) potential pathogens have been isolated from the ISS potable water system, 2) the immune response of astronauts is blunted during spaceflight, 3) spaceflight induces unexpected alterations in microbial responses, including growth and biofilm formation, antimicrobial resistance, stress responses, and virulence, and 4) different microbial phenotypes are often observed between reductionistic pure cultures as compared to more complex multispecies co-cultures, the latter of which are more representative of natural environmental conditions. To advance the understanding of the impact of microgravity on microbial responses that could negatively impact spacecraft ECLSS systems and crew health, this study characterized a range of phenotypic profiles in both pure and co-cultures of bacterial isolates collected from the ISS potable water system between 2009 and 2014. Microbial responses profiled included population dynamics, resistance to silver, biofilm formation, and in vitro colonization of intestinal epithelial cells. Growth characteristics and antibiotic sensitivities for bacterial strains were evaluated to develop selective and/or differential media that allow for isolation of a pure culture from co-cultures, which was critical for the success of this study. Bacterial co-culture experiments were performed using dynamic Rotating Wall Vessel (RWV) bioreactors under spaceflight analogue (Low Shear Modeled Microgravity/LSMMG) and control conditions. These experiments indicated changes in fluid shear have minimal impact on strain recovery. The antimicrobial efficacy of silver on both sessile co-cultures, grown on 316L stainless steel coupons, and planktonic co-cultures showed that silver did not uniformly reduce the recovery of all strains; however, it had a stronger antimicrobial effect on biofilm cultures than planktonic cultures. The impact of silver on the ability of RWV cultured planktonic and biofilm bacterial co-cultures to colonize human intestinal epithelial cells showed that, those strains which were impacted by silver treatment, often increased adherence to the monolayer. Results from these studies provide insight into the dynamics of polymicrobial community interactions, biofilm formation and survival mechanisms of ISS potable water isolates, with potential application for future design of ECLSS systems for sustainable human space exploration.Dissertation/Thesis
Masters Thesis Molecular and Cellular Biology 2019
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Li, Chao-Hiein, and 李昭賢. "Seismic Design of Steel Plate Shear Wall Systems." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/28152177724115211602.
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碩士臺灣大學
土木工程學研究所
95
In recent years, several researchers have confirmed that steel plate shear wall (SPSW) systems have the advantage of using a very small amount of steel while achieving significant lateral stiffness to resist horizontal earthquake forces. However, the capacity design of the boundary elements in the SPSW frames has not been fully developed. In addition, researches conducted on the narrow SPSW systems (large height-to-width ratio) are rather limited, even though the narrow SPSW system is more desirable for architectural demand. In this research, a methodology for the capacity design of the boundary elements in an SPSW system is proposed. The reliability of the proposed capacity design method is verified by a series of analytical and experimental studies. Seismic performance of the narrow SPSW frames is also investigated by the experiment tests. The restrained SPSW system is constructed with horizontal restrainers made from a pair of steel tube members sandwich over the steel panel from the two sides using through bolts and pin-connected to the column flanges. Past research results have indicated that restrainers can successfully reduce the large out-of-plane displacement of the steel pate. In this research, extensive analytical studies demonstrate that the restrainers are able to reduce the flexural and shear demands of the columns and the axial load demand of the beams. It also promotes the development of the tension field action in the steel panel. Tests confirmed that properly using the horizontal restrainers, the size of the boundary elements can be reduced. Recommendation on the seismic design of the restrained SPSW systems is also provided in this research. Four 2-story 2.14-meter wide by 6.5-meter narrow SPSW frames were constructed and cyclically tested to a roof drift of 0.05 radians in National Center for Research on Earthquake Engineering (NCREE). The low yield strength steel plates of 2.6mm were adopted for all four specimens. Two out of four SPSWs were constructed with horizontal restrainers. The key parameter of this series of tests is the size of the boundary elements of the specimens. Tests results confirm that the proposed capacity design method is effective in predicting the forming location and sequence of the plastic hinges. Tests also confirm that the restrained SPSW systems are more economical and have better seismic performance and serviceability than unrestrained SPSW systems.
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CHEN, BO-WEN, and 陳泊文. "Seismic Performance of Steel-Concrete-Steel Composite Shear Wall Systems." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/8mnmjz.
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碩士國立高雄第一科技大學
營建工程系碩士班
106
The concrete-filled steel plate composite walls are made of two steel face plates with infill concrete and connected together by shear connectors. The functions of connectors are to transfer the shearing force between steel plates and concrete, to postpone the buckling of steel face plates, and to extend the tension field of the steel face plates. Since it has good stiffness and strength, the composite structure was extensively used in nuclear power plants to resist the axial and lateral forces. To apply the element in the building structure systems. We have to research the effect of boundary element to the shear strength of concrete-filled steel plate composite walls. To find the relationship between the boundary element and the test results. This experiment aims to investigate seismic performance of the concrete-filled steel plate composite walls subjected to cyclic in-plane shear force under zero axial loads. The experiment was conducted at Tainan Laboratory of National Center of Research Earthquake Engineering by the bi-axial dynamic testing system (BATS). Four specimens have the same aspect ratio of 1.0 with size of 1200x1200x106 mm³. The ultimate strength of specimens is controlled by shear force rather than bending moment under low axial load. The investigating parameters include perforation of the composite walls, types of boundary element, and effect of compressive concrete strut. The strength of concrete-filled steel plate composite walls is evaluated by the code ANSI/AISC N690s1-15 and ACI349-M06, and literature from Varma et al. (2011) and Epackachi et al. (2015). It is found that the strength of specimen without boundary column and perforation is in good agreement with aforementioned predictions. However, seismic behavior of composite walls with perforation is more complex than the single steel plate shear walls, and the prediction results is about 63~76% by use Bhowmick et al. (2014) theory. It’s significantly underestimated the shear strength of the tests. The shear strength theory of this paper, apply the AISC 2010 and the design code of reinforced concrete. Reference the test results of literature, and use steel ratio to control the prediction of the strength.
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Fikri, Rijalul, and Rijalul Fikri. "Cyclic Behaviors of Reinforced Concrete and Hybrid Coupled Shear Wall Systems." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/78957408501821340530.
Full textAbstract:
碩士國立臺灣科技大學
營建工程系
101
Shear wall has been used extensively as the major lateral resistant system in structural design due to its large in-plane rigidity. Sometimes, perforated shear wall is needed because of architectural or practical needs. A single shear wall is then divided into several individual walls connected by a series of beams along the story height. This system is referred as coupled shear wall system and beams used to connect two walls are referred as coupling beams. When coupled shear wall system is subjected to earthquake-type lateral load, shear forces transferred by coupling beams create tensile and compressive actions in the individual shear wall; also referred as coupled action, which counteracts a portion of overturning moments and hence, reduces the moment demand in the individual shear wall. An ideal coupled shear wall system is similar to a framed structure where plastic hinges are expected to form in most of coupling beams over the entire height of the structure, followed by yielding at the base of each shear wall. To achieve the prescribed advantages of coupled wall system, coupling beams must sustain the designed shear forces and satisfactory energy dissipation abilities under large displacement reversals. For reinforced concrete coupled wall system, several researches (Paulay and Binney, 1974; Shiu et al., 1978) have found that diagonal reinforcements are necessary for coupling beams with span to depth ratio less than 2. However, the construction of this diagonal reinforcement create considerable steel congestions both in coupling beam itself and special boundary zone of shear wall. Alternative solutions have been studied in many researches. Among all, hybrid coupled shear wall system has been discussed widely (Harries et. al., 1993; El-Tawil et. al. 2010). Most of hybrid coupled shear wall system use steel coupling beam. Experimental results confirmed that steel web yielding in shear can provide satisfactory hysteretic response (Harries, 2001). However, the installation of embedded steel coupling beam into boundary zone of the shear wall creates another construction challenge. In this research, using LYP steel plate as a cost-effective solution for new coupling beam design is proposed. A recent study conducted by Chen and Yen (2008) and Chen and Jhang (2000) demonstrated that shear panel using steel plate with low yield point (LYP) exhibit excellent deformation and energy dissipation capacities. Two half-scaled coupled shear wall specimens were tested in this research. Specimen CW – RC consists of two reinforced concrete shear walls and four diagonally reinforced concrete coupling beams while Specimens CW – S consists of two reinforced concrete shear walls and four steel coupling beams featuring LYP steel web in the middle. Based on the experimental result, the Specimen CW – RC has a better displacement ductility and higher initial stiffness compare to Specimen CW – S. It is also observed that a ductile behavior of coupled shear wall can be achieved if the shear wall is properly proportioned to a ductile coupling beam.
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Mousavi, Azad Kasmaei Shahaboddin. "Seismic performance evaluation of reinforced concrete shear wall seismic force resisting systems." Thesis, 2008. http://spectrum.library.concordia.ca/976276/1/MR63212.pdf.
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Building codes in various jurisdictions including Canada are moving towards performance-based design approaches where a structure is designed not only to have adequate strength, but also for the required performance attributes, such as, adequate deformability. From that point of view, performance assessment of structures in the design phase plays an important role in the implementation of the above concept. The focus of this article is to study the seismic performance and torsional sensitivity of reinforced concrete shear wall buildings designed using the seismic provisions of the National Building Code of Canada (NBCC 2005) and the Canadian standard on reinforced concrete buildings (CSA-A23.3-04). The buildings considered here are of regular plan and the height is limited to what is permitted for the use of the Equivalent Static Load (ESL) method of the building code. A set of three reinforced concrete buildings of four, eight and sixteen storey heights are designed here. The buildings are assumed to be located in Vancouver and various levels of accidental mass eccentricity up to 10% as permitted in the ESL method, are considered. After the preliminary design of the buildings using the ESL method, dynamic elastic Response Spectrum Analysis "RSA" has been performed to compare the base shear and make appropriate refinement in the design as suggested in NBCC. The buildings are then analyzed using inelastic dynamic analysis with fifteen recorded accelerograms of past earthquakes. The earthquake records are selected such that the peak velocity to acceleration ratio of each record is compatible to the seismicity of Vancouver. The ground motion records are scaled to fit the design spectrum using two different methods, The performance parameters such as the demand to capacity ratios for storey drift, plastic rotation, and storey shear are extracted from the results of the inelastic dynamic analysis. The statistical quantities such as mean, standard deviation and the maximum values of the demand to capacity ratios are found to be well below the acceptable limits, while the storey shear, exceed the limit in all cases. It also is observed that none of the buildings are torsionally sensitive within the code specified range of eccentricity for which ESL method is applicable. The changes in the dynamic response due to the change in eccentricity are almost proportional within the range of eccentricity considered here. Another point to note here is that while results for the four and eight storey buildings are not very sensitive to the method of scaling of the ground motion records, for the sixteen storey building, it is not so.
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CHEN, ZHI-CHENG, and 陳志誠. "Aseismic analysis of R.C. high-rise buildings infilled with shear wall systems." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/42079167569843011196.
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Chen, Ying-Yin, and 陳盈吟. "The Finite Element Analysis of Reinforcement Concrete and Hybrid Coupled Shear Wall Systems." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/16502038458099129158.
Full textAbstract:
碩士國立臺灣科技大學
營建工程系
104
Previous studies indicate the reinforced concrete (RC) shear wall is a cost-effective seismic resisting element. A row of regular openings are commonly required on the wall due to architectural or practical needs. In this case, the wall is divided into two or more individual walls. This system is referred as coupled shear wall system and the beam, typically with small span-to-depth ratio, is referred as the coupling beam. Because of its small span-to-depth, RC coupling beam design is governed by shear. Traditional reinforcement layout for RC flexural member is not able to develop design strength and satisfactory deformation capacity. Some researchers propose the use of steel coupling beam. However, the design recommendations for steel coupling beams are primarily developed based on tests results of coupling beam subassemblages and finite element analyses. Large experimental work conducted previously showed that hybrid coupled shear wall specimen using the low-yield point steel coupling beam did not perform as expected. Finite element model is constructed in this study in order to provide more information and design recommendation for the hybrid coupled shear wall system. The analytical results indicate that the coupling ratio of the coupled shear wall system can be rationally estimated using member nominal strengths. For diagonally reinforced concrete coupling beams, its nominal shear strength evaluated from flexural capacity is recommended. For low-yield point steel coupling beams, the use of ASIC (2010) design equation underestimates its shear capacity. A multiplier of 3 is proposed to evaluate the nominal shear capacity of the low-yield point steel coupling beam. Analytical results also indicate that shear is not uniform distributed between the walls as the system is subjected to coupling effect. The compressive wall takes shear that can be two to three times greater than the tensile wall. For practical design, this study suggests to first evaluate system coupling effect using the member nominal strengths. To have satisfactory system deformation capacity, it is necessary to limit axial force and shear stress less than 0.15P_0 and 0.50√(f_c^' ) MPa, respectively, for the wall subjected to compression.
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Wang, Pei-cheng, and 王培正. "An Intelligent Consultant System for Preliminary Design of Building Shear Walls." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/16382466071914657660.
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碩士淡江大學
土木工程研究所
83
Taiwan is an earthquake active area. Earthquake resistant design plays a very important role in structural design of buildings. The goal of the thesis is to develop a knowledge- based expert system framework for building earthquake resis- tant design that incorporates experiential knowledge and de- sign methods of domain experts. Through the use of the system , novice designers can get the results and suggestion of pr- eliminary design rapidly , and the whole design and analysis tasks can be implemented more efficiently. The framework is developed using Kappa-PC, an AI software development environment by Intellicorp, Inc. Building shear wall design is the application domain used to analyze the feasibility of the framework. After collecting information of shear wall design and interviewing with domain experts, a kn- owledge base is constructed. According to the different char- acters of domain knowledge, two knowledge representation met- hods, frames and rules, are used in the system. Furthermore, the program design of the system is in an object-oriented fashion. Owing to inheritance and reusability offered by obj- ect-oriented programming,the tasks of programming are simpli- fied, and the knowledge about shear wall design is represented systematically. The system provides very friendly user inter- faces, which enable users to communicate with the system eas- ily and to accomplish the preliminary design of shear walls. Users also can make comparison between design cases using the design evaluation function provided by the system and choose an adequate design.
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Martinez, Martinez Joel. "Seismic Performance Assessment of Multi-Storey Buildings with Cold Formed Steel Shear Wall Systems." Thesis, 2007. http://hdl.handle.net/10012/3080.
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Cold-Formed Steel (CFS) is a material used in the fabrication of structural and non-structural elements for the construction of commercial and residential buildings. CFS exhibits several advantages over other construction materials such as wood, concrete and hot-rolled steel (structural steel). The outstanding advantages of CFS are its lower overall cost and non-combustibility. The steel industry has promoted CFS in recent decades, causing a notable increase in the usage of CFS in building construction. Yet, structural steel elements are still more highly preferred, due to the complex analysis and design procedures associated with CFS members. In addition, the seismic performance of CFS buildings and their elements is not well known.
The primary objective of this study is to develop a method for the seismic assessment of the lateral-load resistant shear wall panel elements of CFS buildings. The Performance-Based Design (PBD) philosophy is adopted as the basis for conducting the seismic assessment of low- and mid-rise CFS buildings, having from one to seven storeys. Seismic standards have been developed to guide the design of buildings such that they do not collapse when subjected to specified design earthquakes. PBD provides the designer with options to choose the performance objectives to be satisfied by a building to achieve a satisfactory design. A performance objective involves the combination of an earthquake (i.e., seismic hazard) and a performance level (i.e., limit state) expected for the structure. The building capacity related to each performance level is compared with the demand imposed by the earthquake. If the earthquake demand is less than the building capacity, the structure is appropriately designed.
The seismic performance of a CFS building is obtained using pushover analysis, a nonlinear method of seismic analysis. This study proposes a Simplified Finite Element Analysis (SFEA) method to carry out the nonlinear structural analysis. In this study, lateral drifts associated with four performance levels are employed as acceptance criteria for the PBD assessment of CFS buildings. The lateral drifts are determined from experimental data.
In CFS buildings, one of the primary load-resistant elements is Shear Wall Panel (SWP). The SWP is constructed with vertically spaced and aligned C-shape CFS studs. The ends of the studs are screwed to the top and bottom tracks, and structural sheathing is installed on one or both sides of the wall. For the analysis of CFS buildings, Conventional Finite Element Analysis (CFEA) is typically adopted. However, CFEA is time consuming because of the large number of shell and frame elements required to model the SWP sheathing and studs. The SFEA proposed in this study consists of modeling each SWP in the building with an equivalent shell element of the same dimensions; that is, a complete SWP is modeled by a 16-node shell element. Thus, significantly fewer elements are required to model a building for SFEA compared to that required for CFEA, saving both time and resources. A model for the stiffness degradation of a SWP is developed as a function of the lateral strength of the SWP. The model characterizes the nonlinear behaviour of SWP under lateral loading, such that a realistic response of the building is achieved by the pushover analysis.
The lateral strength of a SWP must be known before its seismic performance can be assessed. In current practice, the lateral strength of a SWP is primarily determined by experimental tests due to the lack of applicable analytical methods. In this investigation, an analytical method is developed for determining the ultimate lateral strength of SWP, and associated lateral displacement. The method takes into account the various factors that affect the behaviour and the strength of SWP, such as material properties, geometrical dimensions, and construction details.
To illustrate the effectiveness and practical application of the proposed methodology for carrying out the PBD assessment of CFS buildings, several examples are presented. The responses predicted by the SFEA are compared with responses determined experimentally for isolated SWP. In addition, two building models are analyzed by SFEA, and the results are compared with those found by SAP2000 (2006). Lastly, the PBD assessment of two buildings is conducted using SFEA and pushover analysis accounting for the nonlinear behaviour of the SWP, to demonstrate the practicality of the proposed technology.
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Chatterjee, Arghya Kamal. "Seismic response analysis of steel plate shear wall systems using detailed and simplified models." Thesis, 2013. http://spectrum.library.concordia.ca/977160/1/Chatterjee_MASc_S2013.pdf.
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Ductile Steel Plate Shear Walls (SPSWs) have been accepted widely as a very effective lateral load resisting system. However, their use in retrofit works is very limited because of the design inefficiency arising from the use of thicker than required commercially available infill plates. Consequently the ductility demand for the surrounding framing members is higher than required. SPSWs utilizing light-gauge cold-formed infill plates could be a viable alternative for rehabilitation of seismically deficient buildings. This thesis presents a numerical study using finite element models on the behavior of unstiffened light-gauge steel plate shear walls with welded infill plate connection. The detailed finite element models include both material and geometric non-linearity. This research describes in detail the validation of the key finite element models by comparing the results with that from the available experimental studies. Excellent correlation between the test results and the finite element analysis results has been achieved.
For seismic performance evaluation of a multi-storey building with SPSWs, detailed finite element models or a strip model can be used to represent the SPSW components. However, development and analysis of such models often require undesirable effort and excess time for high-to-medium rise buildings. A simplified model is developed in this research to study the behavior of SPSW system. In the simplified model, discrete elements are used for the framing members and the behavior of the infill plate is represented by equivalent diagonal bracing members. The simplified model, Equivalent Braced Model, is developed through repeated static and dynamic validations with experiment and detailed finite element models. The proposed Equivalent Braced Model would facilitate a simplification to the structural modeling of large buildings with SPSWs in order to evaluate the seismic performance using regular structural analysis tools and can prove to be a potential aid in performance-based seismic design of SPSW buildings. Finally, the developed equivalent braced model and the detailed finite element model are used to analyze three multi-storey light-gauge SPSWs (four-storey, six-storey and ten-storey) designed according to the capacity design approach.
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Huang, Jhih-Young, and 黃志揚. "An Investigation of Earthquake Energy Dissipation Effects for Reinforced Concrete Structural Systems with Non-stiffness Shear Wall and Advanced Damping Mechanism." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/13960140881327117959.
Full textAbstract:
碩士義守大學
土木與生態工程學系碩士班
99
The purpose of this study is to investigate the Earthquake Energy Dissipation Effects for Reinforced Concrete Structural Systems with Non-stiffness Shear Wall and Advanced Damping Mechanism. In damping, the energy of the vibrating system is dissipated by various mechanisms. As a result, the damping in actual structures is usually represented in a highly idealized manner. For multiple purposes the actual damping can be idealized satisfactorily by a linear viscous damper or dashpot. The damping coefficient is selected so that the vibration energy dissipated is equivalent to the energy dissipated in all the damping mechanisms, combined, present in the actual structure. The equivalent viscous damper is intended to model the energy dissipation at deformation amplitudes within the linear elastic limit of the overall structure. Over this range of deformations, the damping coefficient c determined from experiments may vary with the deformation amplitude. This nonlinearity of the damping property is usually not considered explicitly in dynamic analyses. It may be handled indirectly by selecting a value for the damping coefficient that is appropriate for the expected deformation amplitude, usually taken as the deformation associated with the linearly elastic limit of the structure. The larger deformation related with the more energy dissipated can be assumed. New damping equipments have been generated to amplify the deformation of the structure. For the original structure does notchangethe natural frequency of the system shall be equipped with non-shear wall stiffness in the original structure of the system, the non-shear wall stiffness is also easy to install high-performance organizations and damping energy dissipation corresponding damper. The new damping equipments could be implemented efficiently to the reinforced concrete structures for earthquake energy dissipation.