Dissertations / Theses: 'Nonlinear time-history analyses'

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Cevik, Deniz. "Determination Of The Change In Building Capacity During Earthquakes." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607085/index.pdf.

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There is a great amount of building stock built in earthquake regions where earthquakes frequently occur. It is very probable that such buildings experience earthquakes more than once throughout their economic life. The motivation of this thesis arose from the lack of procedures to determine the change in building capacity as a result of prior earthquake damage. This study focuses on establishing a method that can be employed to determine the loss in the building capacity after experiencing an earthquake. In order to achieve this goal a number of frames were analyzed under several randomly selected earthquakes. Nonlinear time-history analyses and nonlinear static analyses were conducted to assess the prior and subsequent capacities of the frames under consideration. The structural analysis programs DRAIN-2DX and SAP2000 were employed for this purpose. The capacity curves obtained by these methods were investigated to propose a procedure by which the capacity of previously damaged structures can be determined. For time-history analyses the prior earthquake damage can be taken into account by applying the ground motion histories successively to the structure under consideration. In the case of nonlinear static analyses this was achieved by modifying the elements of the damaged structure in relation to the plastic deformation they experience. Finally a simple approximate procedure was developed using the regression analysis of the results. This procedure relies on the modification of the structure stiffness in proportion to the ductility demand the former earthquake imposes. The proposed procedures were applied to an existing 3D building to validate their applicability.

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Sendanayake, Sukhi Vanessa. "Seismic mitigation of steel modular buildings using novel inter-modular connections." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/180893/1/Sukhi%20Vanessa_Sendanayake_Thesis.pdf.

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This research proposes novel inter-modular connections to enable the safe and reliable performance of modular building structures under seismic actions. The proposed connections are designed to shift possible failure locations away from critical structural members to provide effective seismic mitigation. Ultimately, this would result in a purely modular building frame that would be capable of resisting gravity and lateral loads without supplementary concrete shear cores or walls.

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Ramanathan, Karthik Narayan. "Next generation seismic fragility curves for california bridges incorporating the evolution in seismic design philosophy." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44883.

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Quantitative and qualitative assessment of the seismic risk to highway bridges is crucial in pre-earthquake planning, and post-earthquake response of transportation systems. Such assessments provide valuable knowledge about a number of principal effects of earthquakes such as traffic disruption of the overall highway system, impact on the regions' economy and post-earthquake response and recovery, and more recently serve as measures to quantify resilience. Unlike previous work, this study captures unique bridge design attributes specific to California bridge classes along with their evolution over three significant design eras, separated by the historic 1971 San Fernando and 1989 Loma Prieta earthquakes (these events affected changes in bridge seismic design philosophy). This research developed next-generation fragility curves for four multispan concrete bridge classes by synthesizing new knowledge and emerging modeling capabilities, and by closely coordinating new and ongoing national research initiatives with expertise from bridge designers. A multi-phase framework was developed for generating fragility curves, which provides decision makers with essential tools for emergency response, design, planning, policy support, and maximizing investments in bridge retrofit. This framework encompasses generational changes in bridge design and construction details. Parameterized high-fidelity three-dimensional nonlinear analytical models are developed for the portfolios of bridge classes within different design eras. These models incorporate a wide range of geometric and material uncertainties, and their responses are characterized under seismic loadings. Fragility curves were then developed considering the vulnerability of multiple components and thereby help to quantify the performance of highway bridge networks and to study the impact of seismic design principles on the performance within a bridge class. This not only leads to the development of fragility relations that are unique and better suited for bridges in California, but also leads to the creation of better bridge classes and sub-bins that have more consistent performance characteristics than those currently provided by the National Bridge Inventory. Another important feature of this research is associated with the development of damage state definitions and grouping of bridge components in a way that they have similar consequences in terms of repair and traffic implications following a seismic event. These definitions are in alignment with the California Department of Transportation's design and operational experience, thereby enabling better performance assessment, emergency response, and management in the aftermath of a seismic event. The fragility curves developed as a part of this research will be employed in ShakeCast, a web-based post-earthquake situational awareness application that automatically retrieves earthquake shaking data and generates potential damage assessment notifications for emergency managers and responders.
Errata added at request of advisor and approved by Graduate Office, March 15 2016.

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Balling, Lukas. "A Comparison of Optimized Nonlinear Time History Analysis and the Equivalent Lateral Forces Method for Brace Design." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2086.pdf.

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Delgado, M., M. Delgado, A. Rosales, and V. Arana. "Evaluation of the Evacuation of Essential Buildings: Interaction of Structural and Human Behaviour through Nonlinear Time-History Analysis and Agent-Based Modelling." Institute of Physics Publishing, 2020. http://hdl.handle.net/10757/651838.

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In this article, a performance assessment of the evacuation system is established for educational buildings. Structural and geotechnical information of the building is collected and introduced into a database. A similar procedure was realized for the information related to the occupants. Using this information, a) the structural fragility and localized collapse were determined and b) the interaction of the person with the partial collapse was established. For the first aspect, nonlinear time history was used, and for the second, the agent-based modeling was applied to recreate the reaction of people that face the micro collapse. Therefore, the important results of this evaluation are: 1) To localize collapsed beans and columns that make inoperable evacuation routes, 2) to localize bottleneck areas that people concentration during evacuation, and 3) quantification of affected people, in terms of persons caught up in the building that cannot evacuate.

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Taghinezhadbilondy, Ramin. "Extending Use of Simple for Dead Load and Continuous for Live Load (SDCL) Steel Bridge System to Seismic Areas." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2986.

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The steel bridge system referred to as Simple for Dead load and Continuous for Live load (SDCL) has gained popularity in non-seismic areas of the country. Accordingly, it results in many advantages including enhanced service life and lower inspection and maintenance costs as compared to conventional steel systems. To-date, no research studies have been carried out to evaluate the behavior of the SDCL steel bridge system in seismic areas. The main objective of this research was to extend the application of SDCL to seismic areas. The concept of the SDCL system was developed at the University of Nebraska-Lincoln and a complete summary of the research is provided in five AISC Engineering Journal papers. The SDCL system is providing steel bridges with new horizons and opportunities for developing economical bridge systems, especially in cases for which accelerating the construction process is a priority. The SDCL steel bridge system also provides an attractive alternative for use in seismic areas. The SDCL concept for seismic areas needed a suitable connection between the girder and pier. In this research, an integral SDCL bridge system was considered for further investigation. The structural behavior and force resistance mechanism of the proposed seismic detail considered through analytical study. The proposed connection evaluated under push-up, push-down, inverse and axial loading to find the sequence of failure modes. The global and local behavior of the system under push-down forces was mainly similar to non-seismic detail. The nonlinear time history analysis indicated that there is a high probability that bottom flange sustains tension forces under seismic events. The finite element model subjected to push-up forces to simulate the response of the system under the vertical component of seismic loads. However, the demand-capacity ratio was low for vertical excitation of seismic loads. Besides finite element results showed that continuity of bottom flange increased ductility and capacity of the system. While the bottom flange was not continuous, tie bars helped the system to increase the ultimate moment capacity. To model the longitudinal effect of earthquake loads, the model subjected under inverse forces as well as axial forces at one end. In this case scenario, dowel bars were most critical elements of the system. Several finite element analyses performed to investigate the role of each component of preliminary and revised detail. All the results demonstrated that continuity of the bottom flange, bolts area (in the preliminary detail), tie bars over the bottom flange (in the revised detail) were not able to provide more moment capacity for the system. The only component increased the moment capacity was dowel bars. In fact, increasing the volume ratio of dowel bars could be able to increase the moment capacity and prevent premature failure of the system. This project was Phase I of an envisioned effort that culminated in the development of a set of details and associated design provisions to develop a version of the SDCL steel bridge system, suitable for the seismic application. Phase II of this project is an ongoing project and currently the component specimen design and test setup are under consideration. The test specimen is going to be constructed and tested in the structures lab of Florida International University. A cyclic loading will be applied to the specimen to investigate the possible damages and load resistance mechanism. These results will be compared with the analysis results. In the next step, as phase III, a complete bridge with all the components will be constructed in the structures lab at the University of Nevada-Reno. The connection between steel girders will be an SDCL connection and the bridge will be subjected to a shake table test to study the real performance of the connection due to earthquake excitation.

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Demirel, Ismail Ozan. "A Nonlinear Equivalent Frame Model For Displacement Based Analysis Of Unreinforced Brick Masonry Buildings." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612772/index.pdf.

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Although performance based assessment procedures are mainly developed for reinforced concrete and steel buildings, URM buildings occupy significant portion of building stock in earthquake prone areas of the world as well as in Turkey. Variability of material properties, non-engineered nature of the construction and difficulties in structural analysis of perforated walls make analysis of URM buildings challenging. Despite sophisticated finite element models satisfy the modeling requirements, extensive experimental data for definition of material behavior and high computational resources are needed. Recently, nonlinear equivalent frame models which are developed assigning lumped plastic hinges to isotropic and homogenous equivalent frame elements are used for nonlinear modeling of URM buildings. The work presented in this thesis is about performance assessment of unreinforced brick masonry buildings in Turkey through nonlinear equivalent frame modeling technique. Reliability of the proposed model is tested with a reversed cyclic experiment conducted on a full scale, two-story URM building at the University of Pavia and a dynamic shake table test on a half scale, two story URM building at the Ismes Laboratory at Bergamo. Good agreement between numerical and experimental results is found. Finally, pushover and nonlinear time history analyses of three unreinforced brick masonry buildings which are damaged in 1995 earthquake of Dinar is conducted using the proposed three dimensional nonlinear equivalent model. After displacement demands of the buildings are determined utilizing Turkish Earthquake Code 2007, performance based assessment of the buildings are done.

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Arslan, Hakan. "A Numerical Study On Response Factors For Steel Wall-frame Systems." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610811/index.pdf.

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A numerical study has been undertaken to evaluate the response of dual systems which consist of steel plate shear walls and moment resisting frames. The primary objective of the study was to investigate the influence of elastic base shear distribution between the wall and the frame on the global system response. A total of 10 walls and 30 wall-frame systems, ranging from 3 to 15 stories, were selected for numerical assessment. These systems represent cases in which the elastic base shear resisted by the frame has a share of 10%, 25%, or 50% of the total base shear resisted by the dual system. The numerical study consisted of 1600 time history analyses employing three-dimensional finite elements. All 40 structures were separately analyzed for elastic and inelastic response by subjecting to the selected suite of earthquake records. Interstory drifts, top story drift, base shears resisted by the wall and the frame were collected during each analysis. Based on the analysis results, important response quantities such as the response modification, the overstrength, the displacement amplification and ductility reduction factors are evaluated herein. Results are presented in terms of several measures such as the interstory drift ratio and the top story drift ratio. A discussion related to the influence of load share on the response factors is given.

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Gunel, Orhun Ahmet. "Influence Of The Shear Wall Area To Floor Area Ratio On The Seismic Performance Of Existing Reinforced Concrete Buildings." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615678/index.pdf.

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An analytical study is performed to evaluate the influence of shear wall area to floor area ratio on the behavior of existing mid-rise reinforced concrete buildings under earthquake loading. The seismic performance of five existing school buildings with shear wall ratios between 0.00% and 2.50% in both longitudinal and transverse directions and their strengthened counterparts are evaluated. Based on the structural properties of the existing buildings, additional buildings with varying shear wall ratios are designed. Consequently, twenty four buildings with different floor plans, number of stories, cross-sectional properties of the members and material strengths are acquired. Nonlinear time-history analyses are performed for all buildings by utilizing the software program, SAP2000 v14.2.0. under seven different ground motion records. The results indicated that roof drifts and plastic deformations reduce with increasing shear wall ratios, but the rate of decrease is lower for higher shear wall ratios. Buildings with 1.00% shear wall ratio have significantly lower roof drifts and plastic deformations when compared to buildings with 0.00% or 0.50% shear wall ratio. Roof drifts and plastic deformations are minimized when the shear wall ratio is increased to 1.50%. After this limit, addition of shear walls has only a slight effect on the seismic performance of the analyzed buildings.

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Oxborrow, Graham Thomas. "Optimized Distribution of Strength in Buckling-Restrained Brace Frames in Tall Buildings." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1794.

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Nonlinear time history analysis is increasingly being used in the design of tall steel structures, but member sizes still must be determined by a designer before an analysis can be performed. Often the distribution of story strength is still based on an assumed first mode response as determined from the Equivalent Lateral Force (ELF) procedure. For tall buckling restrained braced frames (BRBFs), two questions remain unanswered: what brace distribution will minimize total brace area, while satisfying story drift and ductility limits, and is the ELF procedure an effective approximation of that distribution? In order to investigate these issues, an optimization algorithm was incorporated into the OpenSees dynamic analysis platform. The resulting program uses a genetic algorithm to determine optimum designs that satisfy prescribed drift/ductility limits during nonlinear time history analyses. The computer program was used to investigate the optimized distribution of brace strength in BRBFs with different heights. The results of the study provide insight into efficient design of tall buildings in high seismic areas and evaluate the effectiveness of the ELF procedure.

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Comlekoglu, Hakki Gurhan. "Effect Of Shear Walls On The Behavior Of Reinforced Concrete Buildings Under Earthquake Loading." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12611277/index.pdf.

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An analytical study was performed to evaluate the effect of shear wall ratio on the dynamic behavior of mid-rise reinforced concrete structures. The primary aim of this study is to examine the influence of shear wall area to floor area ratio on the dynamic performance of a building. Besides, the effect of shear wall configuration and area of existing columns on the seismic performance of the buildings were also investigated. For this purpose, twenty four mid-rise building models that have five and eight stories and shear wall ratios ranging between 0.51 and 2.17 percent in both directions were generated. These building models were examined by carrying out nonlinear time-history analyses using PERFORM 3D. The analytical model used in this study was verified by comparing the analytical results with the experimental results of a full-scale seven-story reinforced concrete shear wall building that was tested for U.S.-Japan Cooperative Research Program in 1981. In the analyses, seven different ground motion time histories were used and obtained data was averaged and utilized in the evaluation of the seismic performance. Main parameters affecting the overall performance were taken as roof and interstory drifts, their distribution throughout the structure and the base shear characteristics. The analytical results indicated that at least 1.0 percent shear wall ratio should be provided in the design of mid-rise buildings, in order to control observed drift. In addition
when the shear wall ratio increased beyond 1.5 percent, it was observed that the improvement of the seismic performance is not as significant.

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Bayhan, Beyhan. "Buildings Under Recurring Near-field Earthquakes." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612424/index.pdf.

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Prior to this study, to our best knowledge, no cast-in-place, older-type RC building has ever been subjected to near-field strong ground motions from three major earthquakes. This happened in an indirect way in Turkey over a time span of eleven years. Three identical buildings belonging to Ministry of Public Works and Resettlement (MPWR) that had been built to the same design templates, experienced March 13th 1992 Erzincan earthquake in Erzincan, November 12th 1999 Dü
zce earthquake in Bolu and May 1st 2003 Bingö
l earthquake in Bingö
l, respectively. The ground motion sensor stations were fortuitously nearby in an adjacent single-story building in Bolu and Bingö
l. The station in Erzincan was in a single-story building about 2 km away from the case study building but we assume that the record applies to the building there. These three data represent characteristics of near-field ground motions and the distance of the sensor stations to the nearest fault trace was less than 10 km. The buildings sustained varying degrees of damage during the earthquakes and their damage survey was employed through site investigations. Given that the damage information, input motions, design drawings and material properties of the buildings are all known, this provided an opportunity to predict the structural damage to these buildings by proper modeling using the tools of current computational performance assessment procedures. In this circumstance, three dimensional (3D) analytical models of the MPWR buildings have been performed. Bi-directional excitations have been applied to the models by nonlinear time history analyses (NTHA). The results illustrate that NTHA are capable of indicating the occurrence of shear failure in captive columns
however, they overestimate the global damage level for all buildings. The overestimation is more significant in Erzincan case where the building sustained a pulse-type motion without significant distress.

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Marrs, Nicholas Reidar. "Seismic Performance Comparison of a Fixed-Base versus a Base-Isolated Office Building." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1004.

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The topic of this thesis is base isolation. The purpose of this thesis is to offer a relative understanding of the seismic performance enhancements that a typical 12-story steel office building can achieve through the implementation of base isolation technology. To reach this understanding, the structures of a fixed-base office building and a base-isolated office building of similar size and layout are designed, their seismic performance is compared, and a cost-benefit analysis is completed. The base isolation system that is utilized is composed of Triple Friction Pendulum (TFP) bearings. The work of this thesis is divided into four phases. First, in the building selection phase, the structural systems (SMF and SCBF), layout, location (San Diego, CA), and design parameters of the buildings are selected. Then, in the design phase, each structure is designed using modal response spectrum analysis in ETABS. In the analysis phase, nonlinear time history analyses at DBE and MCE levels are conducted in PERFORM-3D to obtain the related floor accelerations and interstory drifts. Finally, in the performance assessment phase, probable damage costs are computed using fragility curves and FEMA P-58 methodology in PACT. Damage costs are computed for each building and seismic demand level and the results are compared.

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Tan, Mustafa Tumer. "Seismic Strengthening Of A Mid-rise Reinforced Concrete Frame Using Cfrps: An Application From Real Life." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610562/index.pdf.

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SEISMIC STRENGTHENING OF A MID-RISE REINFORCED CONCRETE FRAME USING CFRPs: AN APPLICATION FROM REAL LIFE Tan, Mustafa Tü
mer M.S., Department Of Civil Engineering Supervisor: Prof. Dr. Gü
ney Ö
zcebe Co-Supervisor: Assoc. Prof. Dr. BariS Binici May 2009, 162 pages FRP retrofitting allows the utilization of brick infill walls as lateral load resisting elements. This practical retrofit scheme is a strong alternative to strengthen low to mid-rise deficient reinforced concrete (RC) structures in Turkey. The advantages of the FRP applications, to name a few, are the speed of construction and elimination of the need for building evacuation during construction. In this retrofit scheme, infill walls are adopted to the existing frame system by using FRP tension ties anchored the boundary frame using FRP dowels. Results of experiments have previously shown that FRP strengthened infill walls can enhance lateral load carrying capacity and reduce damage by limiting interstory drift deformations. In previous, analytical studies, a detailed mathematical model and a simplified version of the model for compression struts and tension ties was proposed and verified by comparing model estimations with test results. In this study, an existing 9-storey deficient RC building located in Antakya was chosen to design and apply a hybrid strengthening scheme with FRPs and reduced number of shear walls. Linear elastic analysis procedure was utilized (force based assessment technique) along with the rules of Mode Superposition Method for the reftrofit design. FRP retrofit scheme was employed using the simplified model and design was conducted such that life safety performance criterion is satisfied employing elastic spectrum with 10% probability of exceedance in 50 years according to the Turkish Earthquake Code 2007. Further analytical studies are performed by using Modal Pushover and Nonlinear Time-History Analyses. At the end of these nonlinear analyses, performance check is performed according to Turkish Earthquake Code 2007, using the strains resulting from the sum of yield and plastic rotations at demand in the critical sections. CFRP retrofitting works started at October 2008 and finished at December 2008 for the building mentioned in this study. Eccentric reinforced concrete shearwall installation is still being undertaken. All construction business is carried out without evacuation of the building occupants. This project is one of the first examples of its kind in Turkey. Keywords: CFRP, Carbon Fiber Reinforced Polymers, Masonry Infill Walls, Reinforced Concrete Infill Walls, Mid-Rise Deficient Structures, Turkish Earthquake Code 2007, Modal Pushover Analysis, Nonlinear Time History Analysis, Linear Elastic Building Assessment

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Dehghanpoor, Sichani Ahmad. "Soil-pile-superstructure systems under combined horizontal and vertical strong ground motions." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/207885/1/Ahmad_Dehghanpoor%20Sichani_Thesis.pdf.

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Highway bridges considered as important but possibly vulnerable superstructures must be studied under natural hazards, such as earthquakes, tsunamis, hurricanes. This thesis was a novel investigation on reinforced concrete bridges under coupled horizontal and vertical ground motions. A variety of ground motions has been examined for different classification of bridges and novel conclusions have been presented in the probabilistic and deterministic frameworks.

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Utkutug, Deniz. "A Parametric Study Investigating The Inertial Soil-structure Interaction Effects On Global And Local Deformation Demands Of Multistory Steel Mrf Structures Resting On Surface Rigid Mat Foundations." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610490/index.pdf.

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In reality, dynamic response of a structure supported on a compliant soil may vary significantly from the response of same structure when supported on a rigid base. A parametric study is conducted for the analysis of the variation in the global and the local deformation demands caused by the inertial soil-structure interaction effects. For the purposes of the study, nonlinear dynamic analyses are performed on 7 steel moment-resisting frame models, which are prepared by the virtue of fixed-base and flexible-base (interacting) conditions. Foundation is modeled with the Truncated Cone Model (Wolf, 1994) with the frequency independent coefficients. Free-field earthquake acceleration records are selected to conform to NEHRP equivalent Site Classes C and D. The study is limited to the structures founded on surface rigid mat foundations subjected to vertically propagating horizontally polarized coherent shear waves. Statistical analysis based on multiple linear regression procedure is performed to represent the variation in the response. Within the scope of the study, the wave parameter and the aspect ratio are observed to be directly proportional to the variation in the response, as a general trend. Maximum beneficial contribution of the SSI is found to be 6% in both global and local deformation demands. In addition, the contribution of inertial interaction effects is found to be in a decreasing trend for the increasing levels of ductility demands. Finally, upper limits of wave parameter for H/R=0.5, 1, 2 and 3 are calculated where the variation in the demands are capped at 1.0.

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Aguirre, Herrera Santiago Alberto, and Barazorda Elio Andre Vidal. "Comportamiento estructural de una edificación esencial de mediana altura usando aisladores de base y disipadores SLB." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/654612.

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Este artículo consiste en analizar una nueva alternativa de control antisísmico de alta tecnología para la construcción de hospitales en el Perú, que en su normativa exige el uso de aislamiento de base para edificaciones esenciales. Para ello, se opta por la evaluación estructural de una edificación construida con aisladores sísmicos y la misma con implementación del sistema de disipación de energía SLB (Shear Link Bozzo). Los resultados analizados, para cada técnica estudiada de control antisísmico, son: derivas de entrepiso, aceleraciones de piso, balance energético y análisis de rotulas plásticas, en base a la filosofía de funcionalidad continua.
This article consists of analyzing a new high-tech anti-seismic control alternative for the construction of hospitals in Peru, which in its regulations requires the use of base insulation for essential buildings. For this, the structural evaluation of a building constructed with seismic isolators is chosen and the same with the implementation of the SLB (Shear Link Bozzo) energy dissipation system. The results analyzed for each anti-seismic control technique studied are: mezzanine drifts, floor accelerations, energy balance and analysis of plastic hinges, based on the philosophy of continuous functionality.
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Coronel, Huanca Dennys Luis, and Rojas Marcos Visney Mamani. "Respuesta sísmica de estructuras de concreto armado con un análisis tiempo historia no lineal usando acelerogramas artificiales." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/654933.

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La escasez de registros sísmicos de gran magnitud en algunas regiones del mundo limita la determinación de la respuesta sísmica de una edificación. En este sentido, los acelerogramas artificiales representan una alternativa para definir el evento sísmico porque consideran las condiciones específicas del sitio en estudio. Esta investigación analiza la respuesta sísmica de las estructuras para diversos registros sísmicos artificiales generados de espectros de diseño para distintas condiciones geotécnicas. El procedimiento de análisis empleado será el dinámico tiempo historia no lineal para obtener una mayor precisión en la respuesta sísmica. Los resultados obtenidos muestran que las derivas de entrepiso de las señales artificiales creadas con la función de intensidad de Liu se ajustan mejor a las derivas obtenidas del sismo real escalado.
The lack of large seismic records in some world regions limits the determination of the seismic response of a building. For that reason, artificial accelerograms represent an alternative to define the seismic event because they consider specific conditions of study site. This research analyses the structures seismic response for various artificial seismic records generated from design spectra and different geotechnical conditions. Dynamic nonlinear time history analyzing was used to obtain greater precision in the seismic response. The results obtained show that the mezzanine drifts of the artificial signals created with the Liu intensity function better fit the drifts obtained from the scaled real earthquake.
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Hsiao, Chia-Hung, and 蕭佳宏. "Effects of Dual-Core Self-Centering Braces and Sandwiched Buckling-Restrained Braces on Seismic Behaviors of Steel Frames:Tests and Nonlinear Time History Analyses." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/bn235h.

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碩士
國立臺灣大學
土木工程學研究所
103
Dual-Core Self-Centering Brace (DC-SCB) uses tendons to constrain steel compression members and end plates of the brace,on the same time,it provides self-centering properties under brace in tension and compression that is stored to zero residual deformation.Under same strain of tendons,dual-core SCB has two times brace deformation capacity than conventional single-core SCB (or reduce to half the additional strain of tendons under same brace deformation capacity),that effectively reduce the elastic strain demand of tendons.Sandwiched Buckling-Restrianed Brace (SBRB) uses two identical restraining members that sandwich the Energy-Dissipative core with fully tensioned high-strength bolts to prevent core buckling and have stable hysteretic response.This research is based on Chou and Chen,2015 two story Dual-Core Self-Centering Brace Frame (DC-SCBF),change Dual-Core Self-Centering Brace (DC-SCB) in second floor into Sandwiched Buckling-Restrianed Brace (SBRB) that as known as Special Mixed Brace Frame (SMBF).Do seismic tests and time history tests then compare the result with Dual-Core Self-Centering Brace Frame (DC-SCBF) and Sandwiched Buckling-Restrianed Brace Frame (SBRBF).The objective of research is about two different stiffness braces use in a building,what kind of influence will happened to this building? compare the result with Dual-Core Self-Centering Brace Frame (DC-SCBF) and Sandwiched Buckling-Restrianed Brace Frame (SBRBF).The test results shows three braced frames have good seismic behavior,braces do not destroy and show good seismic behavior,too.This work study also uses the Platform of Inelastic Structural Analysis for 3D System software (PISA3D) to analyze the test of three frames and also compare with the test results and predictions which are proved similar.The analysis results shows three frames can use PISA3D software to do parametic study and design.

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Xue, Yusong. "Capacity Design Optimization of Steel Building Frameworks Using Nonlinear Time-History Analysis." Thesis, 2012. http://hdl.handle.net/10012/6879.

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This study proposes a seismic design optimization method for steel building frameworks following the capacity design principle. Currently, when a structural design employs an elastic analysis to evaluate structural demands, the analysis results can be used only for the design of fuse members, and the inelastic demands on non-fuse members have to be obtained by hand calculations. Also, the elastic-analysis-based design method is unable to warrant a fully valid seismic design since the evaluation tool cannot always capture the true inelastic behaviour of a structure. The proposed method is to overcome these shortcomings by adopting the most sophisticated nonlinear dynamic procedure, i.e., Nonlinear Time- (or Response-) History Analysis as the evaluation tool for seismic demands. The proposed optimal design formulation includes three objectives: the minimum weight or cost of the seismic force resisting system, the minimum seismic input energy or potential earthquake damage and the maximum hysteretic energy ratio of fuse members. The explicit design constraints include the plastic rotation limits on individual frame members and the inter-story drift limits on the overall performance of the structure. Strength designs of each member are treated as implicit constraints through considering both geometric and material nonlinearities of the structure in the nonlinear dynamic analysis procedure. A multi-objective Genetic Algorithm is employed to search for the Pareto-optimal solutions. The study provides design examples for moment resisting frames and eccentrically braced frames. In the examples some numerical strategies, such as integrating load and resistance factors in analysis, grouping design variables of a link and the beams outside the link, rounding-off the objective function values, are introduced. The design examples confirm that the proposed optimization formulation is able to conduct automated capacity design of steel frames. In particular, the third objective, to maximize the hysteretic energy ratio of fuse members, drives the optimization algorithm to search for design solutions with favorable plastic mechanisms, which is the essence of the capacity design principle. For the proposed inelastic-analysis-based design method, the seismic performance factors (i.e., ductility- and overstrength-related force reduction factors) are no longer needed. Furthermore, problem-dependent capacity design requirements, such as strong-column-weak-beam for moment resisting frames, are not included in the design formulation. Thus, the proposed design method is general and applicable to various types of building frames.

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Hsieh, Chu-Hung, and 謝居宏. "Nonlinear Time-History Analysis for bridge which equip with sliding rubber bearing and shear key." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/64007416054324479083.

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Kyriakopoulos, Nikolas. "Upgrade of Seismically Deficient Steel Frame Structures Built in Canada Between the 1960s and 1980s Using Passive Supplemental Damping." Thesis, 2012. http://hdl.handle.net/1807/33281.

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A typical 1960s Type 2 Construction steel MRF hospital structure in Quebec, representative of a prevalent construction philosophy of the time, was investigated and modelled in OpenSees using an advanced strength degradation model. The structure was then subjected to a nonlinear time-history analysis (NLTHA) for Montreal (MTL) and Vancouver (VAN) ground motions and was found to be deficient under the design hazard levels. Retrofits were proposed for the two orthogonal frames at both sites using a performance-based approach. An experimental program determined that the connections had less ductility than expected and began deteriorating around 2.0% interstorey drift. The OpenSees model was updated according to the experimental connection behaviour and the predicted NLTHA performance of the structure worsened. The proposed retrofit designs for both orthogonal frames in both MTL and VAN were updated with the new connection behaviour and final retrofit designs were proposed.

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Ferreira, Carlos Filipe Martins. "Análise dinâmica de um edifício antigo de alvenaria através de um modelo de macro-elementos." Master's thesis, 2017. http://hdl.handle.net/1822/70580.

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Dissertação de mestrado integrado em Engenharia Civil
As construções em alvenaria representam uma boa parte do património edificado habitacional, cultural e de serviços, quer a nível nacional quer internacional, o qual importa preservar e reabilitar. A reabilitação urbana do património edificado é um problema social, não apenas pelo seu valor económico, mas também pela necessidade de segurança dos seus habitantes e das pessoas em geral. Contudo, as estruturas de alvenaria têm características intrínsecas que as fazem vulneráveis a ações horizontais, quando não devidamente concebidas. Existem diferentes métodos de análise sísmica para previsão, de forma mais ou menos rigorosa, do comportamento dos edifícios e dos efeitos induzidos às estruturas devido às ações laterais. O objetivo do presente trabalho é a análise de um edifício antigo característico de Lisboa, o edifício Gaioleiro, utilizando uma aproximação intermédia. Ou seja, que é aplicada uma análise dinâmica a um modelo de macro-elementos em alternativa à aplicação de análises pseudo-dinâmicas a modelos mais refinados, com vista à sua validação para uso à escala urbana com um esforço computacional reduzido. A presente dissertação visa contribuir para o desenvolvimento de um estado de conhecimento e de ferramentas adequadas e acessíveis aos projetistas de reabilitação estrutural de edifícios em alvenaria. Para além do enquadramento sobre a temática, é aplicada a análise dinâmica não-linear com integração no tempo a um edifício Gaioleiro, com o uso de software de cálculo apropriado. Os resultados da análise são depois comparados, em termos da resposta sísmica, com aqueles obtidos num estudo anterior de simulação em plataforma sísmica e análise com elementos finitos do mesmo edifício. Posteriormente, é feita uma análise paramétrica relativamente a um modelo de referência do edifício, com variação das propriedades mecânicas da alvenaria, com o intuito de perceber a sua influência no comportamento sísmico da estrutura. Foi possível concluir que a aproximação intermédia usada permite obter bons resultados, quando as condicionantes e restrições do modelo são bem controladas.
Masonry constructions represent a large amount of the habitational, cultural and service buildings, both nationally and internationally, which need to be preserved and rehabilitated. The urban rehabilitation of the building stock is a societal problem, not only because of its economic value, but also because of the need of safety for their inhabitants and for the general population. However, masonry structures have intrinsic characteristics which make them vulnerable to seismic actions, when not properly designed. Urban centres present an immediate real danger, because of the large density of population and old masonry buildings. This perception has also contributed for the disuse of masonry structures in areas with considerable seismic hazard. There are different methods for seismic analysis of building structures to predict, with more or less accuracy, the building behavior and the effects to the structures due to the horizontal actions. The objective of this work is the analysis of a characteristic ancient building in Lisbon, the Gaioleiro building, using an intermediate approach. This means that a dynamic analysis is applied to a macro-element model as an alternative to the application of pseudodynamic analyses to more refined models, aiming at their validation for use at urban scale with a reduced computational effort. The present dissertation aims to contribute to the development of an adequate state-ofthe- art and tools accessible to designers of structural rehabilitation to masonry buildings. Beyond the framework of the matter, nonlinear dynamic time history analysis is applied to a Gaioleiro building, using suitable computer codes. The results are then compared with the results obtained from previous performed shaking table tests and finite element analyses of the same building. Finally, a parametric analysis is made relatively to a reference model of the building, by varying the masonry properties, in order to understand their influence in the seismic behaviour of the structure. It was possible to conclude that the used intermediate approach provides suitable results, when the constraints of the model are well controlled.

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Dissertations / Theses on the topic 'Nonlinear time-history analyses'

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