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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1021

以政府預算保險管理台灣的地震風險 / Managing the earthquake risk of taiwan by government budget insurance

陳界志, Chen, Chieh Chih Unknown Date (has links)
台灣由於特殊的地理位置,所以地震、颱風等巨災所造成之損失時有所聞。這些巨災除造成交通、農業等經濟損失,更造成人員傷亡、房屋倒塌,也在每個人心中都刻畫難以抹滅的傷痛。為了因應這些巨災帶來的損失,台灣政府撥出許多補助費用予死傷及失蹤人民或其家屬,也提供某些房屋損失的補助。巨災不只危害個人,也同樣衝擊政府財政。 本文以台灣的地震風險為研究對象,並將地震損失劃分為經濟損失與財政損失。經濟損失泛指因地震所造成之一切直接損失,財政損失係指政府因災後所需之賑災與重建經費。因此本文不僅考慮地震所帶來的直接損失,同時也涵蓋政府對於災後的各項補助措施,以完整描述地震全面性的影響範圍。除描述地震整體影響外,本文另設計三種政府預算保險(比例式、自負額、給付最高額度與自負額並行等)作為風險管理機制。模擬說明有無風險管理機制輔助之下對地震損失所帶來之影響及其差異,可從中分析此保險的成本和效益。 本文主要使用國家地震工程研究中心提供之一般建築物損失資料表,輔以中央政府各主管機關對於其下轄業務範圍內之損失統計年報,從中取得因地震所造成之損失統計資料,例如傷亡與失蹤人數、房屋倒塌數、交通損失以及農業損失等,來建立損失模型。損失模型之建立係以模擬出之一般建築物損失為基礎,用迴歸分析評估其與其他損失之相關性,再建立其他損失模型。 本文之分析說明政府若能落實巨災風險管理,將產生極大的利益,在減少社會經濟損失方面尤為顯著。巨災風險管理是正面且必要之事,無論是住宅地震保險基金或政府預算保險,依初始規劃角度來看,政府皆扮演風險管理者的角色。 / Taiwan is usually hit and hurt by some natural catastrophes several times in a year due to its special location. Natural catastrophes brought not only losses of personal properties, agricultural products, and infrastructures but also casualties that brought painful, lasting feelings. In order to deal with the losses caused by natural catastrophes, Taiwan government released significant amount of consolation money for the dead, missing, and injured people. The government also compensate for some house losses. Catastrophes affect not only the private sector economy but also the public finance. This paper focuses on the impacts of the earthquake risk on economic losses and public finance losses of Taiwan. The economic losses include all reported losses while the public finance losses reflect the expenses paid for the post-disaster need, including disaster relief and reconstruction. Considering both the economic losses and public finance losses give us a better-informed picture about the consequences of natural catastrophes. After establishing the models for various types of losses, we analyze how government budget insurances can mitigate the natural catastrophe risks. We employ simulations to display the differences in the loss distributions with and without the insurance. The costs and benefits of the insurance can then be analyzed. Our model of the earthquake risk is based upon the scenario output generated by a model of the National Center for Research on Earthquake Engineering of Taiwan. We coupled the scenarios and official statistics on the earthquake losses to construct the building loss model. The models for other types of losses are then established using regression analyses. The above analyses demonstrate how the risk management on natural catastrophes taken by the government can benefit Taiwan. The benefits on the economic losses of the society are particularly apparent. Catastrophe risk management is positive and necessary. The Taiwan Residential Earthquake Insurance Fund and government budget insurance are the measures for the risk manager - the government.
1022

Geochronology of Timor-Leste and seismo-tectonics of the southern Banda Arc

Ely, Kim Susan January 2009 (has links)
Arc–continent collision is a significant plate boundary process that results in crustal growth. Since the early stages of evolution are often obscured in mature orogens, more complete understanding of the processes involved in arc–continent collision require study of young, active collision settings. The Banda Arc presents an exceptional opportunity to study a young arc–continent collision zone. This thesis presents aspects of the geology and geochronology of Ataúro and the Aileu Complex of Timor-Leste, and the tectonics of the Banda Arc. / U–Pb dating of detrital zircons from the Aileu Complex by LA-ICPMS show major age modes at 270–440 Ma, 860–1240 Ma and 1460–1870 Ma. The youngest zircon populations indicate a maximum depositional age of 270 Ma. The detrital zircon age populations and evidence for juvenile sediments within the sequence favours a synorogenic setting of deposition of sediments sourced from an East Malaya – Indochina terrane. / Previous uncertainty in aspects of the cooling history for the Aileu Complex is resolved with 39Ar/40Ar geochronology of hornblende. Cooling ages of 6–10 Ma are established, with the highest metamorphic grade parts of the Complex yielding the older ages. Cooling ages of 10 Ma imply that metamorphism of the Aileu Complex must have commenced by at least ~12 Ma. Metamorphism at this time is attributed to an arc setting rather than the direct result of collision of the Australian continent with the Banda Arc, an interpretation consistent with the new provenance data. / Geological mapping of Ataúro, an island in the volcanic Banda Arc north of Timor, reveals a volcanic history of bi-modal subaqueous volcanism. 39Ar/40Ar geochronology of hornblende from dacitic lavas confirms that volcanism ceased by ~3 Ma. Following the cessation of volcanism, coral reef marine terraces have been uplifted to elevations of 700 m above sea level. Continuity of the terraces at constant elevations around the island reflects regional-scale uplift most likely linked to sublithospheric processes such as slab detachment. / North of Timor, the near complete absence of intermediate depth seismicity beneath the inactive segment of the arc is attributed to a slab window that has opened in the collision zone and extends to 350 km below the surface. Differences in seismic moment release around this slab window indicate asymmetric rupture, propagating to the east at a much faster rate than to the west. If the lower boundary of this seismic gap signifies the original slab rupture then the slab window represents ~4 m.y. of subsequent subduction and implies that collision preceded the end of volcanism by at least 1 m.y. / Variations in seismic moment release and stress state across the transition from subduction of oceanic crust to arc–continent collision in the Banda Arc are investigated using earthquake catalogues. It is shown that the slab under the western Savu Sea is unusual in that intermediate depth (70–300 km) events indicate that the slab is largely in down-dip compression at this depth range, beneath a region of the arc that has the closest spacing of volcanoes in the Sunda–Banda arc system. This unusual state of stress is attributed to subduction of a northern extension of the Scott Plateau. Present day deformation in the Savu Sea region may be analogous with the earliest stages of collision north of Timor.
1023

Fault plane structure of the 1995 Antofagasta Earthquake (Chile) derived from local seismological parameters

Sobiesiak, Monika January 2004 (has links)
Fault planes of large earthquakes incorporate inhomogeneous structures. This can be observed in teleseismic studies through the spatial distribution of slip and seismic moment release caused by the mainshock. Both parameters are often concentrated on patches on the fault plane with much higher values for slip and moment release than their adjacent areas. These patches are called asperities which obviously have a strong influence on the mainshock rupture propagation. Condition and properties of structures in the fault plane area, which are responsible for the evolution of such asperities or their significance on damage distributions of future earthquakes, are still not well understood and subject to recent geo-scientific studies. <br><br> In the presented thesis asperity structures are identified on the fault plane of the M<sub>w</sub>=8.0 Antofagasta earthquake in northern Chile which occurred on 30th of July, 1995. It was a thrust-type event in the seismogenic zone between the subducting pacific Nazca plate and the overriding South American plate. In cooperation of the German Task Force for Earthquakes and the CINCA'95 project a network of up to 44 seismic stations was set up to record the aftershock sequence. The seaward extension of the network with 9 OBH stations increased significantly the precision of hypocenter determinations. They were distributed mainly on the fault plane itself around the city of Antofagasta and Mejillones Peninsula. <br><br> The asperity structures were recognized here by the spatial variations of local seismological parameters; at first by the spatial distribution of the seismic b-value on the fault plane, derived from the magnitude-frequency relation of Gutenberg-Richter. The correlation of this b-value map with other parameters like the mainshock source time function, the gravity isostatic residual anomalies, the aftershock radiated seismic energy distribution and the vp/vs ratios from a local earthquake tomograhpy study revealed some ideas about the composition and asperity generating processes. The investigation of 295 aftershock focal mechanism solutions supported the resulting fault plane structure and proposed a 3D similar stress state in the area of the Antofagasta fault plane. / Die Bruchflaeche grosser Erdbeben umfasst inhomogene Strukturen, die bisher hauptsaechlich in teleseismischen Untersuchungen nachgewiesen werden konnten. Haeufig werden begrenzte Bereiche auf einer Bruchflaeche beobachtet, die durch eine starke Konzentration des freigesetzten seismischen Moments und durch grosse Dislokationen gekennzeichnet sind. Diese Bereiche werden als 'asperities' bezeichnet, die offensichtlich starken Einfluss auf den Bruchverlauf des Hauptbebens ausueben. Beschaffenheit und Eigenschaften der Strukturen in einem Herdgebiet, die verantwortlich sind fuer die Bildung solcher 'asperities' und deren eventueller Bedeutung fuer Schadensverteilungen in zukuenftigen Erdbeben, sind Gegenstand aktueller geowissenschaftlischer Untersuchungen. <br><br> In der vorliegenden Arbeit werden 'asperity'-Strukturen auf der Bruchflaeche des M<sub>w</sub>=8.0 Antofagasta Erdbebens vom 30. Juli 1995 im Norden Chiles identifiziert. Es handelt sich hierbei um ein typisches Subduktionsbeben mit Aufschiebungscharakter, das in der seismogenen Zone zwischen der abtauchenden pazifischen Nazca-Platte und der ueberschiebenden suedamerikanischen Platte stattfand. Durch die Zusammenarbeit der Deutschen Task Force fuer Erdbeben und dem sich waehrend des Bebens bereits vor Ort befindlichen CINCA '95 Projektgruppe, konnte ein bis zu 44 Stationen umfassendes seismologisches Netzwerk zur Registrierung der Nachbeben errichtet werden. Vor allem die seeseitige Erweiterung des Netzes durch 9 OBH Stationen trug zur hohen Praezision der Hypozentrenbestimmung der Nachbeben bei, die sich hauptsaechlich auf der Bruchflaeche und damit im Kuestenbereich um die Stadt Antofagasta und der noerdlich gelegenen Halbinsel Mejillones verteilten. <br><br> Die 'asperity'-Strukturen konnten mittels raeumlicher Variationen von lokalen seismologischen Parametern erkannt werden; zunaechst durch die Verteilung des seimologischen b-Wertes auf der Bruchflaeche aus der Magnituden-Haeufigkeitsbeziehung von Gutenberg-Richter. Durch die Korrelation dieser Verteilung mit Parametern wie der Momentenrate aus dem Hauptbeben, der isostatischen Restanomalien des Gravitationsfeldes, der Verteilung der abgestrahlten seismischen Energie durch die Nachbeben und der vp/vs-Verhaeltnisse aus einer lokalen Erdbebentomographie konnten Rueckschluesse auf die Beschaffenheit und damit den Bildungsprozess der asperities gezogen werden. Die Untersuchung der Herflaechenloesungen die fuer 295 Nachbeben bestimmt wurden, ergab eine indirekte Bestaetigung der gefundenen Strukturen und wies auf die Existenz eines 3D Spannungszustands im Bereich der Bruchflaeche des Antofagasta Bebens hin.
1024

Soft computing based spatial analysis of earthquake triggered coherent landslides

Turel, Mesut 08 November 2011 (has links)
Earthquake triggered landslides cause loss of life, destroy structures, roads, powerlines, and pipelines and therefore they have a direct impact on the social and economic life of the hazard region. The damage and fatalities directly related to strong ground shaking and fault rupture are sometimes exceeded by the damage and fatalities caused by earthquake triggered landslides. Even though future earthquakes can hardly be predicted, the identification of areas that are highly susceptible to landslide hazards is possible. For geographical information systems (GIS) based deterministic slope stability and earthquake-induced landslide analysis, the grid-cell approach has been commonly used in conjunction with the relatively simple infinite slope model. The infinite slope model together with Newmark's displacement analysis has been widely used to create seismic landslide susceptibility maps. The infinite slope model gives reliable results in the case of surficial landslides with depth-length ratios smaller than 0.1. On the other hand, the infinite slope model cannot satisfactorily analyze deep-seated coherent landslides. In reality, coherent landslides are common and these types of landslides are a major cause of property damage and fatalities. In the case of coherent landslides, two- or three-dimensional models are required to accurately analyze both static and dynamic performance of slopes. These models are rarely used in GIS-based landslide hazard zonation because they are numerically expensive compared to one dimensional infinite slope models. Building metamodels based on data obtained from computer experiments and using computationally inexpensive predictions based on these metamodels has been widely used in several engineering applications. With these soft computing methods, design variables are carefully chosen using a design of experiments (DOE) methodology to cover a predetermined range of values and computer experiments are performed at these chosen points. The design variables and the responses from the computer simulations are then combined to construct functional relationships (metamodels) between the inputs and the outputs. In this study, Support Vector Machines (SVM) and Artificial Neural Networks (ANN) are used to predict the static and seismic responses of slopes. In order to integrate the soft computing methods with GIS for coherent landslide hazard analysis, an automatic slope profile delineation method from Digital Elevation Models is developed. The integrated framework is evaluated using a case study of the 1989 Loma Prieta, CA earthquake (Mw = 6.9). A seismic landslide hazard analysis is also performed for the same region for a future scenario earthquake (Mw = 7.03) on the San Andreas Fault.
1025

Probabilistic Seismic Hazard Assessment Of Ilgaz - Abant Segments Of North Anatolian Fault Using Improved Seismic Source Models

Levendoglu, Mert 01 February 2013 (has links) (PDF)
Bolu-Ilgaz region was damaged by several large earthquakes in the last century and the structural damage was substantial especially after the 1944 and 1999 earthquakes. The objective of this study is to build the seismic source characterization model for the rupture zone of 1944 Bolu-Gerede earthquake and perform probabilistic seismic hazard assessment (PSHA) in the region. One of the major improvements over the previous PSHA practices accomplished in this study is the development of advanced seismic source models in terms of source geometry and reoccurrence relations. Geometry of the linear fault segments are determined and incorporated with the help of available fault maps. Composite magnitude distribution model is used to properly represent the characteristic behavior of NAF without an additional background zone. Fault segments, rupture sources, rupture scenarios and fault rupture models are determined using the WG-2003 terminology. The Turkey-Adjusted NGAW1 (G&uuml / lerce et al., 2013) prediction models are employed for the first time on NAF system. The results of the study is presented in terms of hazard curves, deaggregation of the hazard and uniform hazard spectrum for four main locations in the region to provide basis for evaluation of the seismic design of special structures in the area. Hazard maps of the region for rock site conditions and for the proposed site characterization model are provided to allow the user perform site-specific hazard assessment for local site conditions and develop site-specific design spectrum. The results of the study will be useful to manage the future seismic hazard in the region.
1026

Probabilistic Seismic Hazard Assessment For Earthquake Induced Landslides

Balal, Onur 01 January 2013 (has links) (PDF)
Earthquake-induced slope instability is one of the major sources of earthquake hazards in near fault regions. Simplified tools, such as Newmark&rsquo / s Sliding Block (NSB) Analysis are widely used to represent the stability of a slope under earthquake shaking. The outcome of this analogy is the slope displacement where larger displacement values indicate higher seismic slope instability risk. Recent studies in the literature propose empirical models between the slope displacement and single or multiple ground motion intensity measures such as peak ground acceleration or Arias intensity. These correlations are based on the analysis of large datasets from global ground motion recording database (PEER NGA-W1 Database). Ground motions from earthquakes occurred in Turkey are poorly represented in NGA-W1 database since corrected and processed data from Turkey was not available until recently. The objective of this study is to evaluate the compatibility of available NSB displacement prediction models for the Probabilistic Seismic Hazard Assessment (PSHA) applications in Turkey using a comprehensive dataset of ground motions recorded during earthquakes occurred in Turkey. Then the application of selected NSB displacement prediction model in a vector-valued PSHA framework is demonstrated with the explanations of seismic source characterization, ground motion prediction models and ground motion intensity measure correlation coefficients. The results of the study is presented in terms of hazard curves and a comparison is made with a case history in Asarsuyu Region where seismically induced landslides (Bakacak Landslides) had taken place during 1999 D&uuml / zce Earthquake.
1027

Automated damage assessment of reinforced concrete columns for post-earthquake evaluations

German, Stephanie Ann 10 April 2013 (has links)
An automated method in damage state assessment of reinforced concrete columns for the purpose of establishing a rapid and quantitative post-earthquake safety and structural evaluation procedure is proposed. Several techniques from the fields of computer vision and image processing are employed in order to develop a set of methods capable of automatically detecting spalled regions on the surface of reinforced concrete columns as well as the properties of cracks and spalled regions on these surfaces. The resulting properties of the observed visible damage on the reinforced concrete column surfaces are then utilized to automatically estimate the existing condition and safety of the column. The damage state is quantified according to the maximum drift capacity of the column. The methods proposed in this research were implemented in a Microsoft Visual Studio .NET environment, and tested on real images of damaged columns. The test results indicated that the methods could automatically detect spalled regions and retrieve the properties of spalling and cracks on reinforced concrete column surfaces in images or video frames, and further, that this retrieved information could be accurately translate to a meaningful assessment of the column's existing damage state in the form of the maximum drift capacity.
1028

Passive Seismic Protection of Cable-Stayed Bridges Applying Fluid Viscous Dampers under Strong Motion

Valdebenito, Galo E. 29 May 2009 (has links)
Terremotos recientes han demostrado la gran vulnerabilidad de algunos puentes ante movimiento fuerte. Los de tipo atirantado constituyen una tipología estructural muy atractiva, y que actualmente es empleada para muchos fines prácticos, por lo que es necesaria su protección sísmica. Entre las actuales estrategias de protección, el uso de dispositivos pasivos es la más robusta, económica y apropiada opción para mejorar el desempeño sísmico de estructuras, de entre los que destacan los sistemas de disipación de energía adicional como una buena alternativa. Debido a sus capacidades, fácil recambio y mantención, así como su buen comportamiento mecánico, los amortiguadores de fluidos viscosos son un excelente sistema de disipación de energía para proteger grandes estructuras contra eventos sísmicos intensos. Es por ello que el análisis, evaluación y comparación de la respuesta sísmica no lineal de puentes atirantados de hormigón, con y sin la incorporación de amortiguamiento viscoso suplementario, con el propósito de investigar su efectividad ante eventos sísmicos, es el principal objetivo de esta investigación aplicada. Para alcanzar lo antes expuesto, se definieron previamente ocho modelos teóricos de puentes atirantados basados en los internacionalmente conocidos puentes de Walter [Walter, 1999], considerando variaciones del esquema de atirantamiento, nivel del tablero, tipo de tablero y espaciamiento de los cables. Como punto de partida para el análisis dinámico no lineal, se realizó un análisis estático no lineal para todos los casos. Luego, se llevó a cabo una caracterización dinámica de los puentes mediante un análisis modal. Como primera aproximación a la respuesta sísmica de los modelos, se ejecutó un análisis mediante espectros de respuesta para cada caso, con el propósito de comparar el comportamiento sísmico en función de las principales variaciones consideradas, y para seleccionar los dos modelos más representativos para ser analizados usando análisis no lineal paso-a-paso. En seguida, se analizaron las estructuras elegidas en el paso previo mediante uso de análisis temporal no lineal por integración directa, sin la consideración de amortiguamiento viscoso suplementario, y tomando en cuenta sismos de campo lejano y campo cercano. En este sentido, se aplicaron cinco eventos sísmicos artificiales para el análisis de campo lejano, y cinco eventos reales que incorporasen pulsos de velocidad de período largo para el análisis de campo cercano, según el Capítulo 3. Finalmente, el análisis de la ubicación óptima de los amortiguadores, un estudio paramétrico tendiente a seleccionar los parámetros óptimos de los mismos, y el análisis paso-a-paso no lineal considerando los amortiguadores viscosos definitivos, fueron investigados con la idea de comparar las respuestas en función de la naturaleza del evento sísmico y el tipo de atirantamiento de los cables, considerando los mismos eventos sísmicos antes expuestos. Los resultados de la investigación muestran que la aplicación de amortiguamiento viscoso suplementario es una eficiente estrategia para incrementar el amortiguamiento de una estructura, absorbiendo una gran cantidad de la energía de entrada, y controlando la respuesta de estructuras de período largo, sobre todo en la dirección longitudinal, en donde se manifiestan las mayores respuestas. Más de un 55% de la energía de entrada puede ser disipada usando éstos dispositivos, los cuales resultan ser igualmente efectivos para sismos de campo lejano y campo cercano, con independencia del esquema de atirantamiento empleado, por lo que constituyen una excelente estrategia de protección pasiva. Debido a la gran no linealidad de éstas estructuras, el método del espectro de respuesta debe ser considerado sólo como primera aproximación al problema, y para propósitos comparativos. Para resultados más precisos, y para aplicaciones de diseño, el análisis no lineal paso-a-paso es siempre la mejor opción. Por otro lado, ésta investigación prueba el despreciable efecto del esquema de atirantamiento en la respuesta sísmica, así como el importante aumento de la respuesta cuando son tomados en cuenta los efectos tipo pulso de la directividad de la falla, característicos de sismos de fuente cercana. / Recent seismic events have demonstrated the vulnerability of some bridges under strong ground motions. Cable-stayed bridges are an attractive bridge typology currently used for many practical purposes, constituting important structural systems to be protected against earthquakes. Amongst the current seismic protection strategies, the use of passive devices is the most robust, economic and well-suited option to improve the seismic performance of structures, in which additional energy dissipation systems is good choice. Because of their capacities, easy replacement and maintenance, as well as their interesting mechanical properties, fluid viscous dampers could be an excellent additional energy dissipation system to protect large structural systems against strong earthquakes. For that reason, the analysis, assessment and comparison of the nonlinear seismic response of concrete cable-stayed bridges, with and without the incorporation of nonlinear fluid viscous dampers in order to investigate their effectiveness for seismic protection purposes, is the main objective of this applied research. To reach the proposed objectives, firstly, eight theoretical cable-stayed bridge models based on the well-known Walter's Bridges [Walter, 1999] were defined; considering variations of the stay cable layout, deck level, deck type and stay spacing. As a starting point of the nonlinear dynamic analysis, a nonlinear static analysis was performed for all the cases. After that, the dynamic characterization of the models was carried out by means of a modal analysis. As a first approach of the seismic response of the bridges, response spectrum analysis was performed in order to compare the seismic behaviour as function of the main variations considered, and to select the two most representative bridges to be analyzed using nonlinear time history analysis. The following stage was the seismic analysis of the selected bridge models from the previous step, applying nonlinear direct integration time history analysis, without additional energy dissipation devices, and considering both far-fault and near-fault ground motions. In these sense, five artificially generated earthquake events were considered for the far-fault analysis, as long as five real earthquake events containing long-period velocity pulses were included for the near-fault analysis, according to Chapter 3. Finally, the analysis of the optimal layout of the dampers, a parametric study to select the optimal damper parameters and the nonlinear step-by-step analysis considering the incorporation of the definitive fluid viscous dampers were investigated in order to compare the seismic responses as a function of the earthquake nature and stay cable layout, taking into account the same earthquake events before mentioned. Results of this investigation show that application of fluid viscous dampers as additional passive energy dissipation systems is a very efficient strategy to increase the damping of a structure, absorbing a significant amount of the seismic input energy, and controlling the seismic response of long-period structures, mainly in the longitudinal direction, where the main responses occur. More than 55% of the input energy can be dissipated with these devices, being equally efficient for far-fault and near-fault ground motions, independent on the stay cable layout, which constitutes a very promising strategy to protect cable-stayed bridges against earthquakes. Because of the highly nonlinear behaviour of those structures, response spectrum analysis must be considered only as first approach to the seismic response and for comparative purposes. For more accurate analysis results, and for design applications, nonlinear time-history analysis is a necessary choice. Likewise, it is demonstrated that the effect of the stay cable layout on the nonlinear seismic response of the bridges is not very important, as well as an important increase of the seismic response when forward rupture directivity pulse effects are considered, a characteristic of near-source ground motions.
1029

地理情報システムを用いた確率論的耐震性能評価システム

北原, 武嗣, kitahara, Takeshi, 伊藤, 義人, Itoh, Yoshito 03 1900 (has links)
No description available.
1030

Parameterized Seismic Reliability Assessment and Life-Cycle Analysis of Aging Highway Bridges

Ghosh, Jayadipta 16 September 2013 (has links)
The highway bridge infrastructure system within the United States is rapidly deteriorating and a significant percentage of these bridges are approaching the end of their useful service life. Deterioration mechanisms affect the load resisting capacity of critical structural components and render aging highway bridges more vulnerable to earthquakes compared to pristine structures. While past literature has traditionally neglected the simultaneous consideration of seismic and aging threats to highway bridges, a joint fragility assessment framework is needed to evaluate the impact of deterioration mechanisms on bridge vulnerability during earthquakes. This research aims to offer an efficient methodology for accurate estimation of the seismic fragility of aging highway bridges. In addition to aging, which is a predominant threat that affects lifetime seismic reliability, other stressors such as repeated seismic events or simultaneous presence of truck traffic are also incorporated in the seismic fragility analysis. The impact of deterioration mechanisms on bridge component responses are assessed for a range of exposure conditions following the nonlinear dynamic analysis of three-dimensional high-fidelity finite element aging bridge models. Subsequently, time-dependent fragility curves are developed at the bridge component and system level to assess the probability of structural damage given the earthquake intensity. In addition to highlighting the importance of accounting for deterioration mechanisms, these time-evolving fragility curves are used within an improved seismic loss estimation methodology to aid in efficient channeling of monetary resources for structural retrofit or seismic upgrade. Further, statistical learning methods are employed to derive flexible parameterized fragility models conditioned on earthquake hazard intensity, bridge design parameters, and deterioration affected structural parameters to provide significant improvements over traditional fragility models and aid in efficient estimation of aging bridge vulnerabilities. In order to facilitate bridge management decision making, a methodology is presented to demonstrate the applicability of the proposed multi-dimensional fragility models to estimate the in-situ aging bridge reliabilities with field-measurement data across a transportation network. Finally, this research proposes frameworks to offer guidance to risk analysts regarding the importance of accounting for supplementary threats stemming from multiple seismic shocks along the service life of the bridge structures and the presence of truck traffic atop the bridge deck during earthquake events.

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