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Otenti, Alexander A. (Alexander Alfred) 1981. "Design methodologies for the seismic retrofitting of bridges." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29407.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.<br>Includes bibliographical references (p. 52-53).<br>This paper formulates an earthquake design strategy for bridges. Earthquakes can cause extreme economic damage and loss of life. Structural engineers must be conscience of earthquake slip type, earthquake proximity, and local soil properties when designing a structure. Structures subjected to near-field seismic events feel much complex motions and frequencies than those subjected to far-field events. When designing a structure in a seismic zone it is crucial that the engineer examine a sample of previous earthquake records from the region. Earthquake data is organized into response spectra, time histories, and frequency histories. Response spectra display the spectral displacement, velocity, and acceleration in terms of periods and are of the most interest to structural engineers. Once all of the data is gathered and organized it is necessary to decide on a retrofit strategy. Retrofitting involves either strengthening the bridge or shifting the period out of the power range of the earthquake. This paper demonstrates the effectiveness of shifting the period by base isolation with two case studies of isolated bridges and a design example. The design example is a continuation of the Waldo-Hancock Bridge Master of Engineering project completed in 2004 by the author, Andrea Scotti, and Richard Unruh. A side span of the bridge was modeled in SAP 2000 Nonlinear and subjected to the El Centro and Northridge earthquakes that struck California in 1940 and 1996, respectively. Those earthquakes were chosen because there are no recorded earthquakes in the state of Maine.<br>(cont.) The resulting column shears and deck displacements were compared for no isolation and multiple periods of isolation. It was found that the expected result indicated by the response spectra of the two quakes closely matched the performance of the bridge.<br>by Alexander A. Otenti.<br>M.Eng.
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Mes, Derek. "Seismic retrofitting of concrete bridge columns by external prestressing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0005/MQ45242.pdf.
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Khin, Maung Zaw. "REHABILITAION OF MAJOR STEEL BRIDGES IN MYANMAR UNDER SEISMIC RISKS." Kyoto University, 2017. http://hdl.handle.net/2433/228234.
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Mehary, Selamawit Tesfayesus. "Assessment of Seismic Retrofit Prioritization Methodology for Oregon's Highway Bridges Based on the Vulnerability of Highway Segments." PDXScholar, 2018. https://pdxscholar.library.pdx.edu/open_access_etds/4509.
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Geologists have indicated that the question is not if a catastrophic earthquake will occur in Oregon but when one will occur. Scientists estimate that there is close to 40 percent conditional probability that a Cascadia subduction zone earthquake of magnitude 8.0 or above will strike Oregon in the next 50 years. In addition, the majority of Oregon's bridge inventory was built prior to the current understanding of bridge response and prior to current understanding of the expected earthquake demands. In order to minimize potential bridge damage in the case of an earthquake, one approach is to retrofit seismically deficient bridges. However, often times the decision maker is faced with the difficulty of selecting only a few bridges within the inadequate ones. Hence, the issue of prioritizing upgrading naturally arises. The goal of this study is to assess and refine bridge prioritization methodology to be utilized for ranking Oregon's bridge inventory. CFRP retrofit has been experimentally and analytically evaluated to demonstrate the effectiveness of the technique and was found to be an efficient and economical option. A vulnerability assessment estimates that close to 30 percent of Oregon's highway bridge inventory will sustain moderate damage to collapse. However, retrofitting two most common bridge types in the inventory will reduce the number of damaged bridges by about 70 percent. A cost-benefit assessment that takes into consideration direct and indirect costs associated with damaged bridges and retrofitting of bridges shows that the benefit is up to three times the cost to retrofit. The same principle was applied to rank twelve highway segments for seismic retrofit considered important by Oregon Department of Transportation. One selected segment was considered to be retrofitted and vulnerability assessed. The benefit to cost ratios for each assessment was compared and the highway segments were ranked accordingly. The top five segments in the ranking happen to be located in the East-West corridor connecting I-5 to US-101.
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Srivastava, Siddharth. "Assessment of critical parameters that affect the seismic performance of bridge steel pedestals." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3142.
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Lopez, Ibaceta Alvaro Francisco. "Seismic Performance of Substandard Reinforced Concrete Bridge Columns under Subduction-Zone Ground Motions." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/4977.
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A large magnitude, long duration subduction earthquake is impending in the Pacific Northwest, which lies near the Cascadia Subduction Zone (CSZ). Great subduction zone earthquakes are the largest earthquakes in the world and are the sole source zones that can produce earthquakes greater than M8.5. Additionally, the increased duration of a CSZ earthquake may result in more structural damage than expected. Given such seismic hazard, the assessment of reinforced concrete substructures has become crucial in order to prioritize the bridges that may need to be retrofitted and to maintain the highway network operable after a major seismic event. Recent long duration subduction earthquakes occurred in Maule, Chile (Mw 8.8, 2010) and Tohoku, Japan (Mw 9.0, 2011) are a reminder of the importance of studying the effect of subduction ground motions on structural performance. For this purpose, the seismic performance of substandard circular reinforced concrete bridge columns was experimentally evaluated using shake table tests by comparing the column response from crustal and subduction ground motions. Three continuous reinforced columns and three lap-spliced columns were tested using records from 1989 Loma Prieta, 2010 Maule and 2011 Tohoku. The results of the large-scale experiments and numerical studies demonstrated that the increased duration of subduction ground motions affects the displacement capacity and can influence the failure mode of bridge columns. Furthermore, more damage was recorded under the subduction ground motions as compared to similar maximum deformations under the crustal ground motion. The larger number of plastic strain cycles imposed by subduction ground motions influence occurrence of reinforcement bar buckling at lower displacement compared to crustal ground motions. Moreover, based on the experimental and numerical results, subduction zone ground motion effects are considered to have a significant effect on the performance of bridge columns. Therefore, it is recommended to consider the effects of subduction zone earthquakes in the performance assessment of substandard bridges, or when choosing ground motions for nonlinear time-history analysis, especially in regions prone to subduction zone mega earthquakes. Finally, for substandard bridges not yet retrofitted or upgraded seismically, the following performance limit recommendation is proposed: for the damage state of collapse, which is related to the ODOT's Life Safety performance level, the maximum strain in the longitudinal reinforcement should be reduced from 0.09 (in./in.) to a value of 0.032 (in./in.) for locations where subduction zone earthquakes are expected, to take into consideration the occurrence of bar buckling.
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Golzan, Seyyed Behnam. "Simplified design method for energy dissipating devices in retrofitting of seismically isolated bridges." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/8948.
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Abstract: Highway bridges have great values in a country because in case of any natural disaster they may serve as lines to save people’s lives. Being vulnerable under significant seismic loads, different methods can be considered to design resistant highway bridges and rehabilitate the existing ones. In this study, base isolation has been considered as one efficient method in this regards which in some cases reduces significantly the seismic load effects on the structure. By reducing the ductility demand on the structure without a notable increase of strength, the structure is designed to remain elastic under seismic loads. The problem associated with the isolated bridges, especially with elastomeric bearings, can be their excessive displacements under service and seismic loads. This can defy the purpose of using elastomeric bearings for small to medium span typical bridges where expansion joints and clearances may result in significant increase of initial and maintenance cost. Thus, supplementing the structure with dampers with some stiffness can serve as a solution which in turn, however, may increase the structure base shear. The main objective of this thesis is to provide a simplified method for the evaluation of optimal parameters for dampers in isolated bridges. Firstly, performing a parametric study, some directions are given for the use of simple isolation devices such as elastomeric bearings to rehabilitate existing bridges with high importance. Parameters like geometry of the bridge, code provisions and the type of soil on which the structure is constructed have been introduced to a typical two span bridge. It is concluded that the stiffness of the substructure, soil type and special provisions in the code can determine the employment of base isolation for retrofitting of bridges. Secondly, based on the elastic response coefficient of isolated bridges, a simplified design method of dampers for seismically isolated regular highway bridges has been presented in this study. By setting objectives for reduction of displacement and base shear variation, the required stiffness and damping of a hysteretic damper can be determined. By modelling a typical two span bridge, numerical analyses have followed to verify the effectiveness of the method. The method has been used to identify equivalent linear parameters and subsequently, nonlinear parameters of hysteretic damper for various designated scenarios of displacement and base shear requirements. Comparison of the results of the nonlinear numerical model without damper and with damper has shown that the method is sufficiently accurate. Finally, an innovative and simple hysteretic steel damper was designed. Five specimens were fabricated from two steel grades and were tested accompanying a real scale elastomeric isolator in the structural laboratory of the Université de Sherbrooke. The test procedure was to characterize the specimens by cyclic displacement controlled tests and subsequently to test them by real-time dynamic substructuring (RTDS) method. The test results were then used to establish a numerical model of the system which went through nonlinear time history analyses under several earthquakes. The outcome of the experimental and numerical showed an acceptable conformity with the simplified method.<br>Résumé: Les ponts routiers ont une grande valeur dans un pays parce qu’en cas de catastrophe naturelle, ils peuvent servir comme des lignes pour sauver des vies. Étant vulnérable sous des charges sismiques importantes, on peut considérer différentes méthodes pour concevoir des ponts routiers résistants et également pour réhabiliter des ponts existants. Dans cette étude, l'isolation de la base a été considérée comme une méthode efficace qui peut réduire significativement les effets des charges sismiques sur la structure. En réduisant la demande en ductilité sur la structure sans une augmentation notable de force, la structure est conçue pour rester élastique sous des charges sismiques. Le problème associé aux ponts isolés, particulièrement avec des appuis en élastomère, peut être leurs déplacements excessifs sous les charges de service et de séisme. Ceci peut défier l’objectif d'utiliser des appuis en élastomère pour les ponts typiques de petite portée où les joints de dilatation et les dégagements peuvent aboutir à une augmentation significative des frais d'exploitation et de maintenance. Ainsi, supplémenter la structure avec des amortisseurs d’une certaine rigidité peut servir de solution, ce qui peut cependant augmenter l’effort tranchant transmis à la sous-structure. Cette étude a pour but de fournir une méthode simplifiée afin d’évaluer les paramètres optimaux des amortisseurs dans les ponts isolés. Dans cette thèse, premièrement, basé sur une étude paramétrique, quelques directions sont données pour l'utilisation de dispositifs d'isolation simples, dont les appuis en élastomère, afin de réhabiliter des ponts existant avec une haute importance. Les paramètres comme la géométrie du pont, les clauses des normes et le type de sol sur lequel la structure est construite ont été appliqués sur un pont typique de deux portées. Il est conclu que les paramètres mentionnés peuvent déterminer l'emploi d'isolement de la base des ponts routiers. À la deuxième phase, basé sur le coefficient de réponse élastique des ponts isolés, une méthode de conception simplifiée d’amortisseur pour des ponts routiers réguliers isolés à la base a été présentée dans cette étude. En sélectionnant des objectifs pour la réduction du déplacement et la variation de l’effort tranchant, la rigidité et l'amortissement exigés d'un amortisseur hystérétique peuvent être déterminés. L’étude s’est poursuivie par une modélisation numérique d’un pont à deux portées pour vérifier l'efficacité de la méthode. Pour un modèle numérique d'un pont isolé typique, la méthode a été utilisée pour identifier des paramètres linéaires équivalents pour un certain déplacement et effort tranchant désigné. Par la suite, assumant un amortisseur de type hystérétique, les paramètres non linéaires de l’amortisseur ont été calculés et utilisés. La comparaison des résultats du modèle numérique sans amortisseur et avec l'amortisseur a démontré que la méthode proposée est suffisamment précise. Par la suite, un nouvel amortisseur hystérétique simple en acier a été conçu. Cinq spécimens ont été fabriqués de deux différents grades d’acier et ont été testés en combinaison avec un isolateur à l’échelle réelle dans le laboratoire de structures de l'Université de Sherbrooke. La procédure comprenait la caractérisation des spécimens par des tests cycliques en contrôle de déplacement et par la suite la réalisation d’essais par la méthode de sous-structuration dynamique en temps réel. Les résultats des essais ont été utilisés pour établir un modèle numérique du système qui a subi des analyses temporelles non linéaires sous plusieurs séismes. Le résultat des essais expérimentaux et numériques montrent une conformité acceptable avec la méthode simplifiée.
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Bazáez, Gallardo Ramiro Andrés Gabriel. "Achieving Operational Seismic Performance of RC Bridge Bents Retrofitted with Buckling-Restrained Braces." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3476.
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Typical reinforced concrete (RC) bridges built prior to 1970 were designed with minimum seismic consideration, leaving numerous bridges highly susceptible to damage following an earthquake. In order to improve the seismic behavior of substandard RC bridges, this study presents the seismic performance of reinforced concrete bridge bents retrofitted and repaired using Buckling-Restrained Braces (BRBs) while considering subduction zone earthquake demands. In order to reflect displacement demands from subduction ground motions, research studies were conducted to develop quasi-static loading protocols and then investigate their effect on structural bridge damage. Results suggested that subduction loading protocols may reduce the displacement ductility capacity of RC bridge columns and change their failure mode. The cyclic performance of reinforced concrete bridge bents retrofitted and repaired using BRBs was experimentally evaluated using large-scale specimens and the developed loading histories. Three BRB specimens were evaluated with the aim of assessing the influence of these components on the overall performance of the retrofitted and repaired bents. Additionally, subassemblage tests were conducted in an effort to study the response of these elements and to allow for refined nonlinear characterization in the analysis of the retrofitted and repaired systems. The results of the large-scale experiments and analytical studies successfully demonstrated the effectiveness of utilizing buckling-restrained braces for achieving high displacement ductility of the retrofitted and repaired structures, while also controlling the damage of the existing vulnerable reinforced concrete bent up to an operational performance level.
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Gemme, Marie-Claude. "Seismic retrofitting of deficient Canadian buildings." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/51576.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.<br>Includes bibliographical references (p. 74-77).<br>Many developed countries such as Canada and the United States are facing a significant infrastructure crisis. Most of their facilities have been built with little consideration of seismic design and durability issues. As a result, these structures are vulnerable to earthquake loadings and are in urgent need of repair and retrofit. This thesis provides a literature review of the vulnerability of Canadian infrastructures built prior to the development of seismic design provisions in actual codes of practice and standards. It describes the performance of typical structures under earthquake loading, such as unreinforced masonry buildings, flat slab concrete buildings and steel frame buildings. It then presents the most common retrofitting strategies applicable to low-rise buildings commonly found in major Canadian cities. A case study assessing the performance of hybrid base isolation systems is then presented. The performance of passive and semi-active hybrid base isolation system is evaluated through the use of a SIMULINK computer model of a typical two-story concrete frame building. A significant reduction in interstory displacement is achieved using the passive system and further reduction in base displacement and base shear is accomplished using the semi-active system.<br>by Marie-Claude Gemme.<br>M.Eng.
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Bouvier, Charlotte A. (Charlotte Aude Caroline) 1980. "Techniques of seismic retrofitting for concrete structures." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29327.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.<br>Includes bibliographical references (p. 59-62).<br>Recent earthquakes, starting with the 1971 San Fernando Earthquake in California, left major destructions, damaged the infrastructure, and raised questions about the vulnerability and design practice of structures, especially concrete structures. Design codes have being updated to include seismic previsions but structures build before 1971 have to be retrofitted. The focus of this paper is concrete structures. Surveys done after earthquakes have shown that the major problem with concrete structures is columns. Pre- 1971 detailing left column with lack of confinement as well as lap-slice in plastic hinge regions creating potential failures in flexure strength and/or ductility, and in shear. Other critical structural elements include, but are not limited to, gravity design frames, footings, shear walls, connections, and beams. There are two major categories of retrofit options for concrete structure; local and global methods. Local methods focus at the element level on a particular member that is deficient and in improving it to perform better. Those methods include adding concrete, steel, or composite to the outside of the member. All three methods are effective but each present some disadvantages: concrete is labor intensive, steel requires heavy construction equipments, and composites have high initial cost. Global methods concentrate at the structure level and retrofit to obtain a better overall behavior of the entire structure. The different global techniques are addition of shear walls or steel bracings, and base isolation. All three methods are effective. Shear walls are usually an expensive solution but they are flexible in their distribution allowing them to be hidden in the architecture. Steel bracings allow for openings but their connections to the existing structure can be problematic. Finally, base isolation is an option that is becoming increasingly popular and that provides good behavior in earthquake for low to mid high structures. The different systems presented all have some advantages and disadvantages and the option chosen for the retrofit depends on the existing structure requirement. The different system presented can be combined to provide more efficient and more flexible retrofit schemes.<br>by Charlotte A.C. Bouvier.<br>M.Eng.
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Ballantyne, Brant Francis 1974. "Seismic isolation of bridges." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/80632.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.<br>Includes bibliographical references (leaves 41-42).<br>by Brant Francis Ballantyne.<br>M.Eng.
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Besing, Christa 1978. "The retrofitting of existing buildings for seismic criteria." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30137.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.<br>Includes bibliographical references (leaves 52-53).<br>This thesis describes the process for retrofitting a building for seismic criteria. It explains the need for a new, performance-based design code to provide a range of acceptable building behavior. It then outlines the procedure for retrofitting a building. This procedure begins with acquiring information about the existing building and its surroundings. The building owner or client then needs to work with the design professional to establish an acceptable performance level, or rehabilitation objective. A rehabilitation method must then be selected that determines how the building should be analyzed. The analysis of the building, including suggested rehabilitation strategies, must then be performed. Once the analysis indicates that the building will perform to its prescribed performance level, the rehabilitation strategies must then be implemented. The thesis ends with a description of two buildings that have recently been retrofitted, or are in the processes of being retrofitted. It gives an overview of the selected rehabilitation strategies and the reasoning behind their selection.<br>by Christa Besing.<br>M.Eng.
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Huaco, G., G. Huaco, and J. Jirsa. "Mechanical Splices for Seismic Retrofitting of Concrete Structures." Institute of Physics Publishing, 2020. http://hdl.handle.net/10757/651837.
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As an alternative to lap splicing, mechanical splices can be used for retrofit purposes. They are generally most economical than traditional lap splices when available spacing or length makes laps difficult to utilize. Mechanical splices are frequently used in new construction. However, their use is limited and not practical for use in retrofitted structures. However, if the bars to be joined do not need to be threaded in order to be connected with a special mechanical splice, such mechanical splices can be useful. It is presented a proposal of using two types of mechanical splices for retrofit purposes. Cycle Tension and cycle tension-compression tests are presented and discussed. It was found that mechanical splices are suitable and have acceptable response under seismic loads.
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Pinho, Rui. "Selective retrofitting of RC structures in seismic areas." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/7166.
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Chartrand, Valerie. "Seismic retrofitting of the Ste-Justine Hospital in Montreal." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/47780.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.<br>Includes bibliographical references (leaves 55-56).<br>Seismic engineering provides design and construction techniques so that buildings and other structures can survive the tremendous forces of earthquakes. While codes and design practices have resulted in greatly improved designs of new buildings, the main danger lies in the nation's inventory of existing vulnerable buildings. This thesis examines the seismic retrofitting project for the Ste-Justine Hospital in Montreal. The hospital was built in the 1950s, at a time when seismic engineering regulations were rudimentary and applied with inconsistency. The total floor area spanned by the hospital exceeds 65,000m², and none of the buildings have shear walls or bracing. The engineers have apparently been counting on the frame behavior of the continuous reinforced concrete structure to resist lateral forces. In their current conditions, the existing buildings do not meet the actual code requirements by a wide margin, and seismic retrofitting is a priority. This thesis presents different solutions for increasing the lateral rigidity of the buildings, based on the idea that the perturbation of health services, noise, vibrations, and dust has to be minimized. Exterior concrete shear walls adjacent to the facades were selected as the best option. The lateral stiffness provided by concrete shear walls with window openings and by steel cross bracings were compared using Etabs. The two models presented lateral displacements smaller than the deflection criterion of 1:300, but the concrete shear wall model was found to be the one generating the smallest displacements.<br>(cont.) Precisely, maximum deflections of 1:700 and 1:485 were obtained for the concrete model and the steel model, respectively. A cost analysis of the concrete shear wall option for one of the blocs of the hospital showed that the architectural interventions in this kind of project may cost as much as the structural modifications.<br>by Valerie Chartrand.<br>M.Eng.
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Williams, Ryan J. "Decision analysis for seismic retrofit of structures." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1470.
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Yang, Chengyu. "Seismic analysis of long span bridges including the effects of spatial variation of seismic waves on bridges /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202007%20YANG.
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Otten, Zachary David. "Seismic Retrofitting of a Historic Structure with Limited Construction Documentation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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Many buildings constructed during the middle of the 20th century were constructed with criteria that fall short of current requirements. Although shortcomings are possible in all aspects of the design, the inadequacies in terms of seismic design present a more pressing issue to human life. This risk has been seen in various earthquakes that have struck Italy recently, and subsequently, the codes have been altered to account for this underestimated danger. Structures built after these changes remain at risk and must be retrofitted depending on their use. This report centers around the Giovanni Michelucci Institute of Mathematics at the University of Bologna and the work required to modify the building so that it can withstand 60% of the current design requirements.
The goal of this particular report is to verify the previous reports written in Italian and present an accurate analysis along with intervention suggestions for this particular building. The work began with an investigation into the previous sources and work to find out how the structure had been interpreted. After understanding the building, corrections were made where required, and the failing elements were organized graphically to more easily show where the building needed the most work. Once the critical zones were mapped, remediation techniques were tested on the top floor, and the modeling techniques and effects of the interventions were presented to assist in further work on the structure.
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Liu, Zhu 1971. "Seismic prioritization of highway bridges in Canada." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31059.
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Most of the existing bridges in Montreal have not been designed to resist seismic forces. Although Montreal is not as highly exposed to earthquake hazards as New Zealand, Japan, California, or Vancouver, seismic hazards do exist. Seismic retrofitting has been considered as the most appropriate way to mitigate seismic hazards except for bridges that have a high retrofit cost and rather low importance. As the first step in seismic retrofitting, prioritization of bridges becomes a very important activity.<br>The goal of this thesis is to upgrade the current Canadian prioritization procedure using the latest information from the performance of bridges during recent earthquakes, as well as results from the latest research projects. The previous procedure used in Canada was developed in 1993, since then many changes have occurred relative to seismic retrofitting philosophy. An analytical procedure has replaced the previous simple numerical scoring procedure for the evaluation of vulnerability, and the evaluation of the importance of a bridge has also changed significantly, especially with the addition of new factors such as the ratio of replacement cost to retrofit cost, structure condition and remaining service life. The proposed procedure incorporates these new features and is applied and compared to eleven other procedures for twenty-four bridges administered by the Montreal Office of Transport Quebec.
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Thavaraj, Thuraisamy. "Seismic analysis of pile foundations for bridges." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0017/NQ48728.pdf.
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Schroeder, Brianna Lynn. "Seismic response assessment of skew highway bridges /." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1440918.
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Thesis (M.S.)--University of Nevada, Reno, 2006.<br>"December, 2006." Includes bibliographical references (leaves 183-186). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2006]. 1 microfilm reel ; 35 mm.
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Wan, Vivian Lai Ki. "Methods for improving seismic performance of bridges." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46134.
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Bai, Jong-Wha. "Seismic fragility and retrofitting for a reinforced concrete flat-slab structure." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/521.
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The effectiveness of seismic retrofitting applied to enhance seismic performance was assessed for a five-story reinforced concrete (RC) flat-slab building structure in the central United States. In addition to this, an assessment of seismic fragility that relates the probability of exceeding a performance level to the earthquake intensity was conducted. The response of the structure was predicted using nonlinear static and dynamic analyses with synthetic ground motion records for the central U.S. region. In addition, two analytical approaches for nonlinear response analysis were compared. FEMA 356 (ASCE 2000) criteria were used to evaluate the seismic performance of the case study building. Two approaches of FEMA 356 were used for seismic evaluation: global-level and member-level using three performance levels (Immediate Occupancy, Life Safety and Collapse Prevention). In addition to these limit states, punching shear drift limits were also considered to establish an upper bound drift capacity limit for collapse prevention. Based on the seismic evaluation results, three possible retrofit techniques were applied to improve the seismic performance of the structure, including addition of shear walls, addition of RC column jackets, and confinement of the column plastic hinge zones using externally bonded steel plates. Finally, fragility relationships were developed for the existing and retrofitted structure using several performance levels. Fragility curves for the retrofitted structure were compared with those for the unretrofitted structure. For various performance levels to assess the fragility curves, FEMA global drift limits were compared with the drift limits based on the FEMA member-level criteria. In addition to this, performance levels which were based on additional quantitative limits were also considered and compared with FEMA drift limits.
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Poon, Emmet D. "Effect of column retrofitting on the seismic response of concrete frames." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0015/MQ55024.pdf.
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Wu, Y. F. "Seismic retrofitting of rectangular reinforced concrete columns with partial interaction plating /." Title page, abstract and table of contents only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phw9591.pdf.
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Li, Dekun. "Seismic hazard analysis for bridge design in the Hong Kong region /." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23436049.
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Choi, Eunsoo. "Seismic analysis and retrofit of mid-America bridges." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/21538.
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Delemont, Michael A. "Seismic retrofit of bridges using shape memory alloys." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/32787.
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Drak, El Sebai Aguiade. "Comparisons of international seismic code provisions for bridges." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40713.
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This thesis presents a comparison between the AASHTO-2004, BSI-EN1998-2:2005, NBCC-2005 and the 2007 proposed AASHTO LRFD seismic design provisions with that of the 2006 CSA S6 Canadian Highway Bridge Design Code (CHBDC). A regular 2 span-90m long bridge was used to apply the seismic design loads determined from the codes investigated. The superstructure consists of a 2-lane prestressed concrete box girder, supported by a single column and two abutments. The single column is a 2400 mm circular pier with two different amounts of longitudinal reinforcements. One column had 36-45M longitudinal bars, transversely tied with 15M bars spaced at 50 mm. The second column contained 36-55M bars. The design of the bridge was carried out for three different seismic regions, Montreal, Toronto and Vancouver. In addition, the soil conditions were assumed to match those of NEHRP Soil Profile Types B and E. The research compared the effects of the seismic design spectra and overstrength factors in developing the design moments, shears and displacement ductility demands of the bridge. This research provides recommendations for updating the current CHBDC seismic design provisions.<br>Cette thèse présente une comparaison entre les normes « AASHTO-2004 », « BSI-EN1998-2:2005 », « CNB-2005 » ainsi qu’une comparaison entre les exigences de la nouvelle norme « AASHTO LRFD 2007 » et la norme « CSA-S6 2006 » du Code Canadien sur le Calcul des Ponts. Un pont régulier de deux travées ayant une longueur de 90 m à fait l’objet d’une analyse conformément aux exigences des divers normes et codes relatives à la conception parasismique. La superstructure consiste en un système composé d’une poutre-caisson en béton précontraint alors que l’infrastructure consiste d’un poteau et de deux culées. Le poteau (de diamètre de 2400 mm) avait deux quantités différentes d’armature longitudinales (36 barres - 45M et 36 barres - 55M) avec des armatures transversales ayant un espacement de 50 mm. Le pont à été conçu selon les exigences parasismiques de trois divers zones sismiques dont : Montréal, Toronto et Vancouver. Les conditions de sol de types B et E de la norme « NEHRP » ont été utilisées lors de l’analyse. De plus, cette étude a comparé l’effet de divers spectres sismiques et facteurs de surcharge lors du calcul des moments et des efforts de cisaillement ainsi que lors de l’analyse de la ductilité de la structure. Enfin, ce projet de recherche propose des recommandations pour mettre à jour les provisions parasismiques du Code Canadien sur le Calcul des Ponts.
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Lee, Do Hyung. "Inelastic seismic analysis and behaviour of RC bridges." Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/8936.
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Shattarat, Nasim Khalil. "Seismic behavior and retrofit of outrigger knee joints." Online access for everyone, 2004. http://www.dissertations.wsu.edu/Dissertations/Summer2004/n%5Fshattarat%5F073004.pdf.
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Coulombe, Chantal. "Seismic retrofit of a reinforced concrete bridge bent." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99754.
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This research project is the second part of a research program carried out by Itagawa (2005) who studied the seismic response of a half-scale model of an existing Montreal bridge built in the 1960's. This project studies the seismic behaviour of the retrofit carried out on the frame structure studied in the first part of the research program. The retrofit was made following the requirements of the current Canadian Highway Bridge Design Code (CHBDC). The philosophy of the CHBDC is to provide flexural yielding in the ductile elements so that brittle failure modes such as shear are prevented. This capacity-design approach resulted in a ductile response and significant energy dissipation of the retrofitted structure.<br>The retrofit was designed in accordance with the CHBDC provisions. The cap beam and the beam-column joint regions were strengthened with a reinforced concrete sleeve containing additional transverse and longitudinal bars so that plastic hinging would form in the columns. This retrofit represents minimum intervention to improve the response of the frame. The retrofit frame was then subjected to both gravity loads and reversed cyclic loading to simulate seismic loading on the structure. The predictions of the response of the retrofitted frame provided reasonable estimates of first yielding in the column and the general yielding of the frame. Although the columns would not meet the requirements for ductile columns, they had sufficient shear strength and did exhibit a displacement ductility of about 2.3.
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Durucan, Cengizhan. "Seismic Retrofitting Of Reinforced Concrete Buildings Using Steel Braces With Shear Link." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610956/index.pdf.
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The catastrophic damage to the infrastructure due to the most recent major earthquakes around the world demonstrated the seismic vulnerability of many existing reinforced concrete buildings. Accordingly, this thesis is focused on a proposed seismic retrofitting system (PSRS) configured to upgrade the performance of seismically vulnerable reinforced concrete buildings. The proposed system is composed of a rigid steel frame with chevron braces and a conventional energy dissipating shear link. The retrofitting system is installed within the bays of a reinforced concrete building frame. A retrofitting design procedure using the proposed seismic retrofitting system is also developed as part of this study. The developed design methodology is based on performance-based design procedure. The retrofitting design procedure is configured to provide a uniform dissipation of earthquake input energy along the height of the reinforced concrete building. The PSRS and a conventional retrofitting system using squat infill shear panels are applied to an existing school and an office building. Nonlinear time history analyses of the buildings in the original and retrofitted conditions are conducted to assess the efficiency of the PSRS. The analyses results revealed that the PSRS can efficiently alleviate the detrimental effects of earthquakes on the buildings. The building retrofitted with PSRS has a more stable lateral force-deformation behavior with enhanced energy dissipation capability than that of the one retrofitted with squat infill shear panels. For small intensity ground motions, the maximum inter-story drift of the building retrofitted with the PSRS is comparable to that of the one retrofitted with squat infill shear panels. But for moderate to high intensity ground motions, the maximum inter-story drift of the building retrofitted with the PSRS is considerably smaller than that of the one retrofitted with squat infill shear panels.
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Bouchard, Keith M. (Keith Michael). "A performance-based approach to retrofitting unreinforced masonry structures for seismic loads." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38944.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2007.<br>Includes bibliographical references (leaves 58-59).<br>The structural inadequacy of existing unreinforced masonry (URM) buildings to resist possible seismic loading is a serious problem in many parts of the United States, including the Northeast and Midwest. The fact that many of these buildings are deemed historic structures or house critical facilities, like firehouses, emphasizes the need for an effective retrofitting program. The Federal Emergency Management Agency published a performance-based design code - FEMA 356 - in 2000 to use for analyzing and retrofitting existing structures. This code includes procedures for URM buildings. This paper applies these performance-based analysis procedures to a URM shear wall and compares the results to a modified analysis proposed by researchers. The wall is then rehabilitated using two common retrofit methods and again analyzed using the code. Recommendations are made for practicing engineers when evaluating URM structures for seismic loads.<br>by Keith M. Bouchard.<br>M.Eng.
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Muca, Matilda, and Celine Haikal. "Seismic analysis and retrofitting of an existing multi-storey building in Stockholm." Thesis, KTH, Betongbyggnad, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231453.
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Throughout the years earthquakes are a huge concern for structures; causing losses of peoples’ lives, damages and collapse of homes. Usually, most of the buildings that collapse or have serious damages are mostly old buildings that do not fulfil any longer the updated regulations and building codes concerning seismic design. The purpose of this Master’s thesis is to analyse and strengthen an existing building given by the company Sweco, by using proper and innovative retrofitting techniques; considering Eurocode 8 and collected data from previous studies. The selected building is a seven-storey structure in Stockholm; consists of prefabricated concrete and steel elements and is tested under seismic loading to investigate the global behaviour of the structure using the software MIDAS GEN. Two analyses are performed; assessment analysis which includes modelling of the given structure where the structural capacities are studied. The second analysis is the seismic analysis which includes two secondary analyses; before seismic retrofitting and after seismic retrofitting respectively. In the seismic analysis before the seismic retrofitting is applied, the main scope is to identify the most critical positions of the building where it behaves abnormally and the displacements are high enough in order to modify the structure to decrease displacements. Moreover, the frequencies were obtained and examined. The second seismic analysis includes the modified structure; where it was tested with different alternative methods of seismic retrofitting in order to identify which technique is the most proper one to optimise the strength and the structural performance of the given building. Finally, it appeared that a combination of seismic retrofitting methodologies was the most suitable selection. The selected combination consists of steel bracings and prefabricated reinforced concrete walls (shear walls). After performing the seismic retrofitting analysis, results of the frequencies and displacements of the structure were acquired and compared with the un-retrofitted analysis. The obtained results displayed that using this structural modification improved by increasing the frequency in the transverse direction (y) by 57.2%, in the longitudinal direction (x) by 27.6% and rotational along the z-axis by 12.9%; lastly, by decreasing the displacements in the x- and y-direction remarkably. Consequently, a combination of innovative seismic retrofitting methods appeared to be more effective, achieving a more resistant building under seismic hazards, by improving the stability and ductility of the structure. This gives rise to further researches and investigations for future solutions regarding seismic retrofitting applications and methodologies.<br>Jordbävningar är skakningar i marken som orsakar förluster av människors liv och leder till skador och kollaps av byggnader. Vanligtvis är de flesta byggnader som har allvarligt skadats eller kollapsat, äldre byggnader som inte längre uppfyller de uppdaterade byggreglerna för seismisk design. Syftet med detta examensarbete är att analysera och stärka en befintlig byggnad som har distribuerats av konsult företaget Sweco; lämpliga och innovativa seismisk eftermonteringsmetoder har använts för att förbättra byggnadens tillstånd med hjälp av insamlat vetenskapliga artiklar, tidskrifter och tidigare examensarbete samt svensk standard (Eurokod 8 - för dimensionering av bärverk med avseende på jordbävning). Den utdelade byggnaden är sju våningar hög och ligger i Stockholm. Den består av prefabricerade betong- och stålelement. Byggnaden kommer att testas under seismisk belastning med hjälp av programvaran MIDAS GEN, för att sedan examinera byggnadens globala beteende. Två analyser har utförts; en bedömningsanalys som innefattar granskning av den givna byggnadens kapacitet. Den andra analysen är den seismiska analysen som omfattar två sekundära analyser; en ’före applikation av seismisk eftermonteringsmetod’ och en ’efter applikation av seismisk eftermonteringsmetod’. I den första seismiska analysen, identifieras de mest kritiska positionerna där byggnadens beteende är avvikande med höga förskjutningar och låga frekvenser; således, är behovet av att modifiera och förbättra byggnadens prestanda betydande. Den andra seismiska analysen innefattar den modifierade byggnaden, som har testats med olika alternativa seismiska eftermonteringsmetoder för att identifiera vilken teknik som är mest passande för att optimera byggnadens hållfasthet, elasticitet och prestanda. Efter många experimentella försök, framgick det att en kombination av varierande seismiska eftermonteringsmetoder var det mest lämpliga urvalet. Den valda kombinationen består av stålfackverk och skjuvväggar. Efter genomförandet av den seismiska eftermonteringsanalysen erhölls resultat av frekvensen och förskjutningarna av byggnaden som sedan jämfördes med den första seismiska analysen, innan en eftermonteringsmetod var tillämpad. De erhållna resultaten visade att valet av denna modifikation har förbättrat byggnadens prestanda genom att öka frekvensen i tvärriktningen (y) med 57,2%, i längdriktningen (x) med 27.6% och rotationsfrekvensen längs z-axeln med 12.9%; slutligen, genom att minska förskjutningarna i x- och y-riktningen anmärkningsvärt. Följaktligen, verkade en kombination av varierande seismiska eftermonteringsmetoder vara effektiv, vilket resulterade i en seismisk resistent byggnad med avsevärt god hållfasthet, elasticitet och stabilitet. Denna forskning ger upphov till ytterligare efterforskningar och undersökningar för framtida lösningar avseende seismiska eftermonteringsapplikationer och metoder.
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Endeshaw, Mesay Abebaw. "Seismic retrofit of rectangular bridge columns using CFRP wrapping." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Spring2008/M_Endeshaw_030408.pdf.
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Padgett, Jamie Ellen. "Seismic Vulnerability Assessment of Retrofitted Bridges Using Probabilistic Methods." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14469.
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The central focus of this dissertation is a seismic vulnerability assessment of retrofitted bridges. The objective of this work is to establish a methodology for the development of system level fragility curves for typical classes of retrofitted bridges using a probabilistic framework. These tools could provide valuable support for risk mitigation efforts in the region by quantifying the impact of retrofit on potential levels of damage over a range of earthquake intensities. The performance evaluation includes the development of high-fidelity three-dimensional nonlinear analytical models of bridges retrofit with a range of retrofit measures, and characterization of the response under seismic loading. Sensitivity analyses were performed to establish an understanding of the appropriate level of uncertainty treatment to model, assess, and propagate sources of uncertainty inherent to a seismic performance evaluation for portfolios of structures. Seismic fragility curves are developed to depict the impact of various retrofit devices on the seismic vulnerability of bridge systems. This work provides the first set of fragility curves for a range of bridge types and retrofit measures. Framework for their use in decision making for identification of viable retrofit measures, performance-based retrofit of bridges, and cost-benefit analyses are illustrated. The fragility curves developed as a part of this research will fill a major gap in existing seismic risk assessment software, and enable decision makers to quantify the benefits of various retrofits.
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Carvajal, Uribe Juan Carlos. "Seismic embankment-abutment-structure interaction of integral abutment bridges." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/35577.
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This research thesis is product of a joint study between the Ministry of Transportation and Infrastructure (BCMoT) and the University of British Columbia (UBC) to evaluate the effect of Embankment-Abutment-Structure Interaction (EASI) in the estimation of seismic demands of Integral Abutment Bridges (IABs).
IABs consist of a continuous concrete deck integrated with abutments supported on flexible foundations. These structures have become very popular due to the elimination of costly and maintenance prone expansion joints and bearings. Analytical studies and strong-motion earthquake data have shown that the seismic response of the approach embankments in the far field affects the response of IABs. However, current seismic analysis procedures neglect the far-field embankment response because of the complexity in modeling this type of dynamic interaction. Therefore, a simple and accurate model that allows bridge designers to include EASI in the calculation of the seismic demands of IABs is needed.
This thesis develops a simple dynamic model, called 3M-EASI, for calculating the seismic response of IABs taking into account EASI. The proposed model consists of two far-field embankment components connected to the bridge structure component by spring-dashpot elements that represent the near-field components. The main contribution of this thesis is the development of the far-field embankment component using equivalent-linear analysis. The 3M-EASI model was verified with time-history analyses of 2D continuum soil finite element models of full-height IABs using the computer program ABAQUS.
The analyses indicated that the far-field embankment response affects the response of IABs if the following conditions act simultaneously: (a) the near-field stiffness is greater than 0.4 times the bridge stiffness, and (b) the period of the far-field embankment components is longer than 0.7 times the period of the bridge-near-field system. The 3M-EASI model is shown to be rational, accurate, computationally efficient, and easy to implement in bridge design.
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De, La Puente Altez Alejandro Gaspar. "Seismic microzonation and vulnerability of highway bridges in Montreal." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100346.
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Ground Ambient Noise (GAN) readings were recorded across the island of Montreal and the recordings were processed using the horizontal-to-vertical spectral ratio technique. One-dimensional non-linear soil dynamic analyses were performed over a large database of boreholes in Montreal using the computer program SHAKE. The resulting predominant frequencies of vibration were used as the main parameter to define the seismic microzonation of the island of Montreal. The frequencies are mapped and used to identify twelve zones with potential seismic amplification problems. The largest ratio was obtained in the zone located at the eastern tip of the island of Montreal where long-period motions are predominant in the deep clay deposits.<br>The Incremental Dynamic Analysis (IDA) technique was used to study the seismic vulnerability of two typical lifeline highway overpass bridges in Montreal. The moment resisting frame components of the two bridges were studied and evaluated for different cases reflecting the condition of the concrete columns and their reinforcement, in accordance with the Canadian Highway Bridge Design Code (CHBDC). The frames were subjected to a wide range of earthquakes as part of the IDA study. The insufficient shear reinforcement of some frame elements of both bridges predicted a premature shear failure, which controlled the seismic behaviour of the frames. The predicted failures occurred at a lower spectral acceleration level than the acceleration specified by the CHBDC for both lifeline bridges.<br>A minimum-intervention retrofitting approach was devised for each one of the overpass bridges. In both cases, provisions were made to ensure that flexural yielding would occur before shear failures of the critical elements. The retrofitted frames are predicted to sustain higher levels of spectral acceleration in excess of 0.8 g.
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Tehrani, Payam. "Seismic behaviour and analysis of continuous reinforced concrete bridges." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110577.
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This study focuses on the seismic analysis and behaviour of continuous 4-span bridges. Different methods of analyses including linear multi-mode analysis, inelastic time history analysis and incremental dynamic analysis (IDA) are used for the seismic evaluations of bridges in this study.This thesis includes two main parts. In the first part the seismic behaviour of bridges with different column heights (i.e., irregularity due to different column stiffnesses) is studied. The seismic evaluations are carried out in the transverse and longitudinal directions of bridges to recognize the important aspects which influence the seismic behaviour. Parametric studies were carried out for a number of bridges in the transverse and the longitudinal directions. To perform a large number of designs and analyses, a computer program was developed to design the bridges, perform the modelling and extract and evaluate the analysis results. The effects of different column heights, different column diameters, different superstructure mass and stiffness, as well as different abutment conditions on the seismic response of bridges were studied using elastic and inelastic analyses. The results from the elastic and inelastic analyses were compared to demonstrate the limitations of the linear analyses for the seismic design and evaluation of irregular bridges. The effects of including nonlinear abutment models with different stiffness and strengths were also studied in the longitudinal response of the bridges. Seismic ductility demands and concentration of ductility demands were evaluated and the maximum demand to capacity ratios were predicted for a wide range of bridges studied. The use of different regularity indices to predict the seismic response of bridges was also investigated.In the second part of the thesis, the use of incremental dynamic analysis for seismic evaluation of bridges is studied. The influence of different record selection methodologies including the UHS-based, CMS-based and epsilon-based methods on the predictions of the IDA results is investigated. In addition, the effects of different earthquake types including crustal, subduction interface and subduction inslab earthquakes on the IDA results are studied. Three large record sets were selected for three earthquake types and a fast algorithm was developed for the incremental dynamic analysis to evaluate the collapse capacity of different bridge configurations subjected to different earthquake types. The IDA results were also predicted for different subsets of records with specific characteristics. The effects of spectral shapes and epsilon values were also considered using seismic hazard deaggregation results.<br>Cette étude se concentre sur l'analyse sismique et sur le comportement des ponts à 4 portées continues. Différentes méthodes d'analyse, telles que la méthode multimode linéaire, la méthode temporelle non linéaire et la méthode d'analyse dynamique incrémentale (ADI), sont utilisées pour l'évaluation sismique de ponts.Cette thèse se divise en deux parties principales. Dans la première partie, le comportement sismique des ponts composés de colonnes de différentes hauteurs (c'est-à-dire, irrégularité causée par différentes raideurs de colonne) est étudié. Les évaluations sismiques sont réalisées dans les directions transversal et longitudinal des ponts afin de considérer les aspects importants qui influencent le comportement sismique. Des études paramétriques furent réalisées pour un certain nombre de ponts (c'est-à-dire 648 ponts dans la direction transversale et plus de 2500 cas dans la direction longitudinale). Afin d'effectuer un grand nombre de dimensionnements et d'analyses, un programme informatique fut développé pour dimensionner des ponts, effectuer la modélisation et extraire et évaluer les résultats d'analyse. Les effets de différentes hauteurs de colonne, de différents diamètres de colonne, de différentes masses et raideurs de la superstructure, et de différentes conditions de butée sur la réponse sismique des ponts furent étudiés en utilisant des analyses élastiques et inélastiques. Les résultats des analyses élastiques et inélastiques furent comparés afin de démontrer les limitations des analyses linéaires pour le dimensionnement et l'évaluation sismique des ponts irréguliers. Les effets sur la réponse longitudinale des ponts de modèles de butée non linéaires considérant différentes résistances et raideurs (incluant différentes longueurs d'espace de joint et différents nombres de piles) furent également étudiés. Les demandes sismiques en ductilité et la concentration des demandes en ductilité furent évaluées et la demande maximale des ratios en capacité fut prédite pour un large éventail de ponts étudiés. L'utilisation de différents indices de régularité pour prédire la réponse sismique des ponts fut aussi examinée.Dans la seconde partie de la thèse, l'utilisation de l'ADI pour l'évaluation sismique des ponts est étudiée. L'influence de différentes méthodes de sélection d'enregistrement (incluant les méthodes basées sur l'aléa sismique, le spectre moyen conditionnel et l'epsilon) sur les prédictions obtenues avec l'ADI est examinée. De plus, l'effet de considérer différents types de tremblement de terre (incluant des tremblements de terre de surface et de subduction) sur les résultats de l'ADI est étudié. Présentement, seulement les tremblements de terre de surface sont utilisés pour l'évaluation de la performance sismique des structures. Les procédures actuelles ne sont pas nécessairement appropriées pour les régions soumises à des tremblements de terre de subduction. Trois ensembles d'enregistrement furent sélectionnés pour trois types de tremblement de terre (c'est-à-dire un total de 3 x 78 = 234 enregistrements). Un algorithme à calcul rapide fut développé pour l'ADI afin d'évaluer la capacité à l'effondrement de différentes configurations de pont soumises à différents types de tremblement de terre. Les résultats de l'ADI furent également prédits pour différents sous-ensembles d'enregistrements ayant des caractéristiques spécifiques (c'est-à-dire des valeurs d'epsilon positives, des faibles facteurs d'échelle, etc.). Les effets des spectres de réponse et des valeurs d'epsilon furent aussi considérés en utilisant les résultats de désagrégation du risque sismique.
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Zaghi, Arash Esmaili. "Seismic design of pipe-pin connections in concrete bridges." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3387806.
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Liu, Qin. "A study of seismic design spectra for highway bridges." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ27001.pdf.
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Liu, Qin Carleton University Dissertation Engineering Civil and Environmental. "A Study of seismic design spectra for highway bridges." Ottawa, 1997.
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Mosleh, Araliya. "Seismic vulnerability assessment of existing concrete highway Iranian bridges." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17173.
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Doutoramento em Engenharia Civil<br>Sismos recentes mostram que as pontes são uma das infraestruturas mais
vulneráveis dos sistemas de transporte rodoviário, e comprovam a
necessidade de avaliação da vulnerabilidade deste tipo de estruturas,
especialmente as projetadas segundo a filosofia patente nos códigos antigos.
A avaliação da vulnerabilidade sísmica das pontes rodoviárias localizadas em
áreas de elevada perigosidade sísmica e a estimativa do seu desempenho
sísmico representam tarefas importantes para a segurança dos sistemas de
transporte.
Neste contexto, esta investigação tem como objetivo estudar a vulnerabilidade
sísmica das pontes de betão armado existentes no Irão. O trabalho foca-se
principalmente nas seguintes tarefas: desenvolvimento de análises
estatísticas, classificação das pontes mais comuns no Irão, seleção da ação
sísmica representativa, definição de estados de dano, estudo dos efeitos das
práticas de construção e, finalmente, análise de curvas de fragilidade para
avaliar a vulnerabilidade sísmica de pontes tipo representativas das obras
existentes no Irão.
O primeiro capítulo resume trabalhos no domínio da caracterização da
sismicidade na área geográfica em estudo, em função das diferentes placas
tectónicas e da distribuição das zonas de rotura prováveis, com base em
informação recolhida em sismos passados e uma revisão geral dos estudos
anteriores e a pesquisa bibliográfica, nomeadamente em termos de curvas de
fragilidade para as pontes com base em diferentes abordagens. O Capítulo 2
descreve os tipos de ponte mais comuns existentes no Irão e classifica-as de
acordo com as suas características estruturais primárias.
Capítulo 3 explicar os modelos analíticos não lineares 3-D das estruturas de
pontes amostra usando modelos analíticos detalhados para os seus
componentes. O Capítulo 4 é dedicado à seleção de um conjunto de registos
sísmicos reais que sejam representativos das diferentes fontes sísmicas. O
Capítulo 5 é dedicado à definição de estados limite de dano. Neste capítulo, foi
realizada uma revisão das propostas para a avaliação dos estados limite de
dano disponíveis na literatura. Para isso, diferentes tipos de incertezas
associadas a parâmetros que influenciam o comportamento das pontes foram
consideradas, nomeadamente em termos de seção e altura dos pilares,
presença da emenda da armadura longitudinal e vão. Além disso, a influência
das propriedades dos materiais com base na resistência à compressão do
betão e da resistência do aço são analisadas e os resultados são tratados em
termos de curvas de fragilidade para cada classe de pontes considerada. O
Capítulo 6 apresenta os principais resultados da análise sísmica tridimensional
realizada sobre vários casos de estudo. Capítulos 7 indicam o estudo da
resposta estocástica de pontes de betão considerando a incerteza na rigidez
de rolamento e de encosto. Finalmente, no capítulo 8, as principais conclusões
são tiradas a partir do trabalho desenvolvido no âmbito do presente estudo.<br>Past earthquakes occurred in seismically active areas around the world show
that bridges are one of the most vulnerable components of the highway
transportation systems, and evidence the need to study the vulnerability of
bridges, especially the ones designed with the old codes. Thus, the seismic
vulnerability assessment of the highway bridges located in high seismic hazard
areas and the assessment of the bridges’ performance under seismic demands
play an important role for the safety of transportation systems.
In this context, this research aimed to study the seismic vulnerability of existing
old concrete bridges in Iran. The research work was mainly focused on the
following tasks: identification of the most common bridges in Iran, ground
motion selection, damage state definition, real construction practices and finally
the analysis of fragility curves to assess the seismic vulnerability of common
bridges in Iran.
The first chapter presents the study of seismicity in a geographical area of
interest for this study, covered by different tectonic plates and distribution of
probable rupture zones of past earthquakes and the general overview of
previous studies and a literature survey developed to generate the bridge
fragility curves based on different approaches. Chapter 2 describes the most
common existing ordinary highway bridges and classifies them according to
their primary structural characteristics. Chapter 3 explains the 3-D nonlinear
analytical models of the sample bridge structures using detailed analytical
models for its components. Chapter 4 is devoted to the procedure followed in
the selection of earthquake ground motion records that are representative of
the different seismic sources, based on ground motion intensity. Chapter 5
addresses aspects related with the definition of damage limit states. In this
chapter, a review of the damage states definitions and strategies available in
the literature is also made. For this, different types of bridges uncertainties, in
terms of column height, superstructure type, lap splice and span length are
investigated for the selected case studies. Also, the influence of material
properties, namely the compressive strength of concrete and the yield strength
of steel is described. In Chapter 6 the results are generated in terms of fragility
curves for each bridges class. Chapter 7 indicates the study of the stochastic
response of concrete bridges considering the uncertainty in the bearing and
abutment stiffness. Finally in chapter 8, the main conclusions are drawn from
the work developed within the present study.
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Al-Sadoon, Zaid. "Seismic Retrofitting of Conventional Reinforced Concrete Moment-Resisting Frames Using Buckling Restrained Braces." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34755.
Full textAbstract:
Reinforced concrete frame buildings designed and built prior to the enactment of modern seismic codes of the pre-1970’s era are considered seismically vulnerable, particularly when they are subjected to strong ground motions. It is the objective of this research to develop a new and innovative seismic retrofit technology for seismic upgrading of nonductile or limited ductility reinforced concrete frame buildings involving the implementation of buckling restrained braces. To achieve this objective, combined experimental and analytical research was conducted. The experimental research involved tests of large-scales reinforced concrete frames under slowly applied lateral deformation reversals, and the analytical research involved design and nonlinear analysis of laboratory specimens, as well as design and dynamic inelastic response history analysis of selected prototype buildings in eastern and western Canada. The research project started with a comprehensive review of the building code development in Canada to assess the progression of seismic design requirements over the years, and to select a representative period within which a significant number of engineered buildings were designed and constructed with seismic deficiencies. A similar review of seismic design and detailing provisions of the Canadian Standard Association (CSA) Standard A23.3 on Design of Concrete Structures was also conducted for the same purpose. Six-storey and ten-storey prototype buildings were designed for Ottawa and Vancouver, using the seismic provisions of the 1965 National Building Code of Canada, representative of buildings in eastern and western Canadian. Preliminary static and dynamic linear elastic analyses were performed to assess the effectiveness of upgrading the ten-storey reinforced concrete building designed for Ottawa. The retrofit methods studied consisted of lateral bracing by adding reinforced concrete shear walls, diagonal steel braces, or diagonal steel cable strands. The results indicated that the retrofit techniques are effective in limiting deformations in non-ductile frame elements to
the elastic range. The numerical analyses were used to demonstrate the effectiveness of Buckling Restrained Braces (BRBs) as a retrofit method for seismically deficient reinforced concrete frame buildings. The experimental phase of research consisted of two, 2/3rd scale, single bay and single storey reinforced concrete frames, designed and constructed based on a prototype sixstorey moment resisting frame building located in Ottawa and Vancouver, following the
requirements of the 1965 edition of the NBCC. One test specimen served as a bare
control frame (BCF) that was first tested, repaired and retrofitted (RRF) to evaluate the effectiveness of the proposed retrofit methodology for buildings subjected to
earthquakes in the City of Ottawa. The control frame was assessed to be seismically
deficient. The second frame served as a companion non-damaged frame (RF) that was retrofitted with a similar retrofit concept but for buildings subjected to earthquakes in the City of Vancouver.
A new buckling restrained brace (BRB) was conceived and developed to retrofit existing sub-standard reinforced concrete frames against seismic actions. The new BRB consists of a ductile inner steel core and an outer circular sleeve that encompasses two circular steel sections of different diameters to provide lateral restraint against buckling in compression of inner steel core. Mortar is placed between the two circular sections to provide additional buckling resistance. The inner core is connected to novel end units that allow extension and contraction during tension-compression cycles under seismic loading while providing lateral restraint against buckling within the end zones. The end units constitute an original contribution to the design of Buckling Restrained Braces (BRBs), providing continuous lateral restraint along the core bar. The new technique has
been verified experimentally by testing four BRBs on the two test structures under
simulated seismic loading. The test results of the BRB retrofitted frames indicate
promising seismic performance, with substantial increases in the lateral load and
displacement ductility capacities by factors of up to 3.9 and 2.6, respectively. In addition, the test results demonstrate that the BRB technology can provide excellent drift control, increased stiffness, and significant energy dissipation, while the reinforced concrete frames continue fulfilling their function as gravity load carrying frames. The above development was further verified by an exhaustive analytical study using SAP2000. At the onset, analyses were conducted to calibrate and verify the analytical models. Two-dimensional, one-bay, one-storey models, simulating the BCF and RRF test frames, were created. The models were subjected to incrementally increasing lateral displacement reversals in nonlinear static pushover analyses, and the results were compared with those obtained in the test program. Material nonlinearity was modeled using “Links” to incorporate all lumped linear and nonlinear properties that were defined with moment-rotation properties for flexural frame members and with force-displacement properties for the diagonal buckling restrained braces. Comparison with test data demonstrated good agreement of the frame behaviour in the elastic and post-elastic ranges, and the loading and unloading stiffness. The research program was further augmented with nonlinear dynamic time history analyses to verify the feasibility of the new retrofit technique in multi-storey reinforced concrete frame buildings located in Canada and their performances relative to the performance-based design objectives stated in current codes. Prior to conducting the analyses, 450 artificial earthquake records were studied to select the best matches to the Uniform Hazard Spectra (UHS) according to the 2010 edition of the NBCC for Ottawa and Vancouver. Furthermore, additional analyses were conducted on buildings for the City of Ottawa based on amplified Uniform Hazard Spectrum compatible earthquake records. The nonlinear time-history response analyses were conducted using a model that permits inelasticity in both the frame elements and the BRBs.The results indicated that reinforced concrete buildings built before the 1970’s in the City of Ottawa do not require seismic retrofitting; they remain within the elastic range under current code-compatible earthquake records. The structural building performance is
within the Immediate Occupancy level, and all structural elements have capacities
greater than the force demands. In the City of Vancouver, buildings in their virgin state experienced maximum interstorey drifts of 2.3%, which is within the Collapse Prevention structural performance level. Improved building performance was realized by retrofitting the exterior frames with multiple uses of the BRB developed in this research project. The seismic shear demands were reduced in the columns, while limiting the deformations in the non-ductile frame elements to the elastic range. The lateral interstorey drift was limited to 0.92%, which lies within the Life Safety structural performance level.
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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.
Full textAbstract:
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.<br>Errata added at request of advisor and approved by Graduate Office, March 15 2016.
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Price, Thomas. "Influence of embankment/superstructure interaction on the seismic response of bridges /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10199.
Full text
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Nielson, Bryant G. "Analytical Fragility Curves for Highway Bridges in Moderate Seismic Zones." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7542.
Full textAbstract:
Historical seismic events such as the San Fernando earthquake of 1971 and the Loma Prieta earthquake of 1989 did much to highlight the vulnerabilities in many existing highway bridges. However, it was not until 1990 that this awareness extended to the moderate seismic regions such as the Central and Southeastern United States (CSUS). This relatively long neglect of seismic issues pertaining to bridges in these moderate seismic zones has resulted in a portfolio of existing bridges with seismic deficiencies which must be assessed and addressed.
An emerging decision tool, whose use is becoming ever increasingly popular in the assessment of this seismic risk, is that of seismic fragility curves. Fragility curves are conditional probability statements which give the probability of a bridge reaching or exceeding a particular damage level for an earthquake of a given intensity level. As much research has been devoted to the implementation of fragility curves in risk assessment packages, a great need has arisen for bridge fragility curves which are reliable, particularly for those in moderate seismic zones. The purpose of this study is to use analytical methods to generate fragility curves for nine bridge classes which are most common to the CSUS. This is accomplished by first considering the existing bridge inventory and assessing typical characteristics and details from which detailed 3-D analytical models are created. The bridges are subjected to a suite of synthetic ground motions which were developed explicitly for the region. Probabilistic seismic demand models (PSDM) are then generated using these analyses. From these PSD models, fragility curves are generated by considering specific levels of damage which may be of interest. The fragility curves show that the most vulnerable of all the bridge nine bridge classes considered are those utilizing steel girders. Concrete girder bridges appear to be the next most vulnerable followed by single span bridges of all types. Various sources of uncertainty are considered and tracked throughout this study, which allows for their direct implementation into existing seismic risk assessment packages.
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Mori, Atsushi. "Investigation of the behaviour of seismic isolation systems for bridges." Thesis, University of Canterbury. Department of Civil Engineering, 1993. http://hdl.handle.net/10092/2455.
Full textAbstract:
The thesis is concerned with the experimental and analytical investigations into the behaviour of
laminated elastomeric and lead-rubber bearings as seismic isolation bearings for bridges.
Seismic isolation as a seismic design option has become popular over the past decade. During last
several years, Japan, Italy and the U.S.A. have been making great progress following the great
contribution of New Zealand in this area. Despite new developments in seismic isolation systems, the
New Zealand lead-rubber bearings (LRB) still lead with their reputation for reliable performance. The
design methods for lead-rubber bearings applied for both bridges and buildings are provided in each of
these countries but with differences to allow for variations in codes and design applications. However
the basic concepts of these design methods are similar and are partially based on empirical
backgrounds.
Acknowledging the above status, the experimental and analytical investigations into the lead-rubber
and laminated elastomeric bridge bearings were carried out under compression, shear and rotation
loading states. A maximum bearing compressive strain of about 6% was reached in the compression
tests. In the shear tests, a maximum bearing shear strain of 200% was reached in the load-deflection
response and the lead-rubber bearings showed almost the same shear stiffness as the elastomeric
bearings after yield of the lead. The rotation tests were performed over the limitations stipulated in the
current design codes showing a constant linear stiffness independent of the axial load levels on the
bearings. The analytical investigation using the finite element method indicated that the steel shims in
the bearings might exceed the yield point somewhere between 100% and 150% bearing shear stains,
The shear strains in the rubber due to different types of loading calculated by the existing code
relationships, and which are usually the governing factor for the bearing design, were not in reasonable
agreement with the analytically obtained values except under compression. The relationships for
predicting load-deflection response of the bearings used in the bearing design methods always gave
excessive values when compared with the experimentally and analytically obtained values.
Based on the findings in the experimental and analytical work, several recommendations for the design
of seismic isolation bridge bearings are presented. Moreover, the dynamic response analysis for
bridges incorporating seismic isolation systems is carried out under different seismic excitations to
confirm the benefits of the seismic isolation systems. As a consequence, for continuous multi-span
long bridges the benefits due to seismic isolation in terms of reducing member forces in the bridge and
keeping the dynamic behaviour of bridge piers uniform regardless of travelling velocities of the
seismic wave are greater when compared with those for standard bridge structures.
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Gao, Yulin. "Optimal seismic retrofitting level for bridges based on benefit-cost analysis." Thesis, 2001. http://hdl.handle.net/2429/11722.
Full textAbstract:
There are a large number of seismically deficient bridges in British Columbia that need to
be strengthened to protect public safety in future earthquakes: Many upgrading options
are available for seismic rehabilitation of these bridges, such as No Retrofitting, Safety
Level Retrofitting, and Functional Level Retrofitting, etc. The search of the optimal
solution among various feasible options is a complicated decision problem. The big
amount of money spent for seismic retrofitting needs to be justified based on the
economic and safety decisions, and they involve considerations of risk and cost.
A reliability-based risk decision model is constructed in the thesis to try to facilitate an
answer to the seismic retrofitting of bridges. The methodology and procedures of decision
analysis are demonstrated through a case study bridge.
The global linear, elastic response spectrum analysis is undertaken to obtain seismic
demand and the component capacity/demand ratios are computed to identify the critical
structural components. Seismic deficiencies and failure mechanism of the identified
critical components are evaluated by local inelastic push over analysis.
Two seismic retrofitting schemes are designed to counteract the seismic deficiencies. The
effect of seismic retrofitting on the structural behavior during earthquake excitations is
evaluated. The retrofitting costs of both schemes are calculated.
Structural failure probability during future earthquakes is calculated by the simple
FORM/SORM approach. Latin Hypercube Sampling (LHS) is used to generate random
variables to obtain seismic demand and seismic capacity, which are fitted to the
probability distribution functions. Both the failure probabilities of original bridge and
retrofitted bridge are computed. The reduced failure probability due to seismic retrofitting
is obtained.
Seismic damage analysis is undertaken to compute damage indices of the bridge before
and after seismic retrofitting, which are used for mapping out economic losses. Both
direct and indirect economic losses are estimated. An expected value of the future
earthquake damage costs are calculated and discounted to the present year. Present values
of the total costs including retrofitting cost and future seismic financial damages for all
retrofitting schemes are calculated. Then a benefit-cost analysis based on the constructed
decision model is undertaken to determine the optimal seismic retrofitting level for the
bridge.
It concludes that for the case study bridge considered in this research, the optimal seismic
retrofitting option is the level II retrofitting, which aims to keep normal or a limited
traffic flow immediately after an earthquake of 10% exceedence probability in 50 years.
Sensitivity analysis is made to explore the effect of change of input variables on the
decision outcome.