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Spatial Variation Of Seismic Ground Motions For Bridge Response Analysis In Complex Topographic Conditions
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Book Synopsis Spatial Variation of Seismic Ground Motions for Bridge Response Analysis in Complex Topographic Conditions by : Zhan Yu
Download or read book Spatial Variation of Seismic Ground Motions for Bridge Response Analysis in Complex Topographic Conditions written by Zhan Yu and published by . This book was released on 2010 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Spatial Variation of Seismic Ground Motions by : Aspasia Zerva
Download or read book Spatial Variation of Seismic Ground Motions written by Aspasia Zerva and published by CRC Press. This book was released on 2016-04-19 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spatial variation of seismic ground motions denotes the differences in the seismic time histories at various locations on the ground surface. This text focuses on the spatial variability of the motions that is caused by the propagation of the waveforms from the earthquake source through the earth strata to the ground surface, and it brings toge
Book Synopsis Stochastic Modelling and Analysis for Bridges Under Spatially Varying Ground Motions by : Deyi Zhang
Download or read book Stochastic Modelling and Analysis for Bridges Under Spatially Varying Ground Motions written by Deyi Zhang and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthquake is undoubtedly one of the greatest natural disasters that can induce serious structural damage and huge losses of properties and lives. The resulting destructive consequences not only have made structural seismic analysis and design much more important but have impelled the necessity of more realistic representation of ground motions, such as inclusion of ground motion spatial variations in earthquake modelling and seismic analysis and design of structures. Recorded seismic ground motions exhibit spatial variations in their amplitudes and phases, and the spatial variabilities have an important effect on the responses of structures extended in space, such as long span bridges. Because of the multi-parametric nature and the complexity of the problems, the development of specific design provisions on spatial variabilities of ground motions in modern seismic codes has been impeded. Eurocode 8 is currently the only seismic standard worldwide that gives a set of detailed guidelines to explicitly tackle spatial variabilities of ground motions in bridge design, providing both a simplified design scheme and an analytical approach. However, there is gap between the code-specified provisions in Eurocode 8 and the realistic representation of spatially varying ground motions (SVGM) and the corresponding stochastic vibration analysis (SVA) approaches. This study is devoted to bridge this gap on modelling of SVGM and development of SVA approaches for structures extended in space under SVGM. A complete and realistic SVGM representation approach is developed by accounting for the incoherence effect, wave-passage effect, site-response effect, ground motion nonstationarity, tridirectionality, and spectra-compatibility. This effort brings together various aspects regarding rational seismic scenarios determination, comprehensive methods of accounting for varying site effects, conditional modelling of SVGM nonstationarity, and code-specified ground motion spectra-compatibility. A comprehensive, systematic, and efficient SVA methodology is derived for long span structures under tridirectional nonstationary SVGM. An absolute-response-oriented scheme of pseudo-excitation method and an improved high precision direct integration method are proposed to reduce the enormous computational effort of conventional nonstationary SVA. A scheme accounting for tridirectional varying site-response effect is incorporated in the nonstationary SVA scheme systematically. The proposed highly efficient and accurate SVA approach is implemented and verified in a general finite element analysis platform to make it readily applicable in SVA of complex structures. Based on the proposed SVA approach, parametric studies of two practical long span bridges under SVGM are conducted. To account for spatial randomness and variability of soil properties in soil-structure interaction analysis of structures under SVGM, a meshfree-Galerkin approach is proposed within the Karhunen-Loeve expansion scheme for representation of spatial soil properties modelled as a random field. The meshfree shape functions are proposed as a set of basis functions in the Galerkin scheme to solve integral equation of Karhunen-Loeve expansion, with a proposed optimization scheme in treating the compatibility between the target and analytical covariance models. The accuracy and validity of the meshfree-Galerkin scheme are assessed and demonstrated by representation of covariance models for various homogeneous and nonhomogeneous spatial fields. The developed modelling approaches of SVGM and the derived analytical SVA approaches can be applied to provide more refined solutions for quantitatively assessing code-specified design provisions and developing new design provisions. The proposed meshfree-Galerkin approach can be used to account for spatial randomness and variability of soil properties in soil-structure interaction analysis.
Book Synopsis Analysis of Local Variations in Free Field Seismic Ground Motion by : Jian-Chu Chen
Download or read book Analysis of Local Variations in Free Field Seismic Ground Motion written by Jian-Chu Chen and published by . This book was released on 1981 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthquake engineers are often faced with the problem of determining the temporal and spatial variation of near-surface seismic motions in a site. This type of information is needed for the evaluation of soil-structure interaction effects, liquefaction potential and the effects of local site conditions on surface motions. Actual ground motions are due to a complicated system of body waves and surface waves. However, it is usually assumed that near-surface motions consist only of vertically propagating waves. In order to examine the validity of this assumption for engineering design a theoretical investigation has been made into the nature of near-surface motions produced by horizontally propagating waves. These include inclined P-, SV-, and SH-waves, Rayleigh waves and Love waves in horizontally layered sites over a viscoelastic half space. The research involved five phases: (1) review of current knowledge, (2) development of new methods of site response analysis, (3) application to site response analysis, (4) application to soil-structure interaction analysis and, (5) evaluation of the relative importance of horizontally propagating waves in engineering design. (Author).
Book Synopsis Effects of Ground Motion Spatial Variations and Random Site Conditions on Seismic Responses of Bridge Structures by : Kaiming Bi
Download or read book Effects of Ground Motion Spatial Variations and Random Site Conditions on Seismic Responses of Bridge Structures written by Kaiming Bi and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] The research carried out in this thesis concentrates on the modelling of spatial variation of seismic ground motions, and its effect on bridge structural responses. This effort brings together various aspects regarding the modelling of seismic ground motion spatial variations caused by incoherence effect, wave passage effect and local site effect, bridge structure modelling with soil-structure interaction (SSI) effect, and dynamic response modelling of pounding between different components of adjacent bridge structures. Previous studies on structural responses to spatial ground motions usually assumed homogeneous flat site conditions. It is thus reasonable to assume that the ground motion power spectral densities at various locations of the site are the same. The only variations between spatial ground motions are the loss of coherency and time delay. For a structure located on a canyon site or site of varying conditions, local site effect will amplify and filter the incoming waves and thus further alter the ground motion spatial variations. In the first part of this thesis (Chapters 2-4), a stochastic method is adopted and further developed to study the seismic responses of bridge structures located on a canyon site. In this approach, the spatially varying ground motions are modelled in two steps. Firstly, the base rock motions are assumed to have the same intensity and are modelled with a filtered Tajimi- Kanai power spectral density function and an empirical spatial ground motion coherency loss function. Then, power spectral density function of ground motion on surface of the canyon site is derived by considering the site amplification effect based on the onedimensional seismic wave propagation theory. The structural responses are formulated in the frequency domain, and mean peak responses are estimated by the standard random vibration method. The dynamic, quasi-static and total responses of a frame structure (Chapter 2) and the minimum separation distances between an abutment and the adjacent bridge deck and between two adjacent bridge decks required in the modular expansion joint (MEJ) design to preclude pounding during strong ground motion shaking are studied (Chapter 3). The influence of SSI is also examined (in Chapter 4) by modelling the soil surrounding the pile foundation as frequency-dependent springs and dashpots in the horizontal and rotational directions. A method is proposed to simulate the spatially varying earthquake ground motion time histories at a canyon site with different soil conditions. This method takes into consideration the local site effect on ground motion amplification and spatial variations. The base rock motions are modelled by a filtered Tajimi-Kanai power spectral density function or a stochastic ground motion attenuation model, and the spatial variations of seismic waves on the base rock are depicted by a coherency loss function. The power spectral density functions on the ground surfaces are derived by considering seismic wave propagations through the local site by assuming the base rock motions consisting of outof- plane SH wave and in-plane combined P and SV waves with an incident angle to the site. The spectral representation method is used to simulate the multi-component spatially varying earthquake ground motions...
Book Synopsis Structural Response to Spatially Varying Earthquake Ground Motion by : Ernesto Heredia-Zavoni
Download or read book Structural Response to Spatially Varying Earthquake Ground Motion written by Ernesto Heredia-Zavoni and published by . This book was released on 1993 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Spatially Varying Ground Motions on Bridge Response by : Bo Li
Download or read book Effects of Spatially Varying Ground Motions on Bridge Response written by Bo Li and published by . This book was released on 2014 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adjacent bridge structures can move relatively to each other in an earthquake, resulting in pounding or more severely, unseating. Pounding occurs when the relative closing movement is larger than the structural gap whereas girder unseating takes place due to the relative opening movements being larger than the seating length provided. Relative displacements arise from unequal fundamental frequencies of adjacent bridge structures, spatial variation of ground motions and different soil-structure interaction (SSI). The objective of this thesis is to investigate the influence of these factors, especially spatial variation of ground motions on the bridge response. To achieve the objective, a series of experiments were conducted on the bridge models made of polyvinylchloride (PVC) using either shake tables or inertial actuators. Ground motions of the soft soil, shallow soil and strong rock conditions based on the New Zealand design spectra were simulated. The ground motions of the soft soil condition were further classified as highly, intermediately and weakly correlated ground motions to account for coherency loss effect of excitation spatial variation. These experiments include testing a 1:125 scale bridge with three identical bridge segments to study the effect of spatially varying ground motions with pounding, testing the same model but with the footings on sand contained by rubber boxes to consider the effects of spatially varying ground motions and SSI with pounding, testing one of those bridge segments with movable abutments to investigate the effect of excitation spatial variation considering abutment excitation and pounding, testing a 1:125 scale bridge model with two identical bridge segments with artificial plastic hinges to study the effect of spatially varying ground motions on inelastic bridge response with pounding, and field testing a 1:22 scale bridge segment subjected to spatially varying ground motions to determine the minimum total gap of a modulus expansion joint required to avoid pounding. A total of 8660 tests were performed. Research found that spatial variation of ground motions can increase the relative displacement of adjacent bridge girders and pounding forces. Based on the experimental results, the New Zealand Transport Agency (NZTA) Bridge manual was reviewed. It was found that the current NZTA Bridge manual is unable to suggest sufficient minimum seating length to accommodate the measured relative opening displacements. A set of empirical equations is therefore proposed to calculate adequate minimum support seating lengths to prevent girder unseating.
Book Synopsis Structural Health Monitoring of Long-Span Suspension Bridges by : You Lin Xu
Download or read book Structural Health Monitoring of Long-Span Suspension Bridges written by You Lin Xu and published by CRC Press. This book was released on 2011-08-31 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long span suspension bridges cost billions. In recent decades, structural health monitoring systems have been developed to measure the loading environment and responses of these bridges in order to assess serviceability and safety while tracking the symptoms of operational incidents and potential damage. This helps ensure the bridge functions properly during a long service life and guards against catastrophic failure under extreme events. Although these systems have achieved some success, this cutting-edge technology involves many complex topics that present challenges to students, researchers, and engineers alike. Systematically introducing the fundamentals and outlining the advanced technologies for achieving effective long-term monitoring, Structural Health Monitoring of Long-Span Suspension Bridges covers: The design of structural health monitoring systems Finite element modelling and system identification Highway loading monitoring and effects Railway loading monitoring and effects Temperature monitoring and thermal behaviour Wind monitoring and effects Seismic monitoring and effects SHMS-based rating method for long span bridge inspection and maintenance Structural damage detection and test-bed establishment These are applied in a rigorous case study, using more than ten years' worth of data, to the Tsing Ma suspension bridge in Hong Kong to examine their effectiveness in the operational performance of a real bridge. The Tsing Ma bridge is the world's longest suspension bridge to carry both a highway and railway, and is located in one of the world’s most active typhoon regions. Bridging the gap between theory and practice, this is an ideal reference book for students, researchers, and engineering practitioners.
Book Synopsis Okumen. Dokumentation. Vol.1. Um Amt und Herrenmahl. 2.Aufl by :
Download or read book Okumen. Dokumentation. Vol.1. Um Amt und Herrenmahl. 2.Aufl written by and published by . This book was released on 1974 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Spatial Variation of Ground Motions on Large Multiply-supported Structures by : Hong Hao
Download or read book Effects of Spatial Variation of Ground Motions on Large Multiply-supported Structures written by Hong Hao and published by . This book was released on 1989 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: July 1989.
Book Synopsis The Effect of the Spatial Variation of Earthquake Ground Motions on the Response of Large Structures by : Issa-Modi Idé
Download or read book The Effect of the Spatial Variation of Earthquake Ground Motions on the Response of Large Structures written by Issa-Modi Idé and published by . This book was released on 1989 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Spatial Variation of Ground Motions on Large Multiple Supported Structures by : Hong Hao
Download or read book Effects of Spatial Variation of Ground Motions on Large Multiple Supported Structures written by Hong Hao and published by . This book was released on 1989 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Spatial Variation of Earthquake Ground Motion and Development of Bridge Fragility Curves by : Vinita Saxena
Download or read book Spatial Variation of Earthquake Ground Motion and Development of Bridge Fragility Curves written by Vinita Saxena and published by . This book was released on 2000 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Physical Characterization of Seismic Ground Motion Spatial Variation and Conditional Simulation for Performance-based Design by : Songtao Liao
Download or read book Physical Characterization of Seismic Ground Motion Spatial Variation and Conditional Simulation for Performance-based Design written by Songtao Liao and published by . This book was released on 2006 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Spatial Variation of SMART 1 Array Earthquake Ground Motions by : John M. Cunniff
Download or read book Spatial Variation of SMART 1 Array Earthquake Ground Motions written by John M. Cunniff and published by . This book was released on 1988 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Instrumental Systems for Diagnostics of Seismic Response of Bridges and Dams by :
Download or read book Instrumental Systems for Diagnostics of Seismic Response of Bridges and Dams written by and published by . This book was released on 2001 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Geostatistical and Network Analysis of Non-stationary Spatial Variation in Ground Motion Amplitudes by : Yilin Chen
Download or read book Geostatistical and Network Analysis of Non-stationary Spatial Variation in Ground Motion Amplitudes written by Yilin Chen and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: When an earthquake causes shaking in a region, the amplitude of shaking varies spatially. Ground motion models have been developed to predict the median and standard deviation of ground motion intensity measures. However, the remaining variation in ground motion prediction ``residuals'' is significant, and shows spatial correlations at scales of tens of kilometers in separation distance. These correlations are important when assessing the risk to spatially distributed infrastructure or portfolios of properties. State of the art today is to assume that these spatial correlations depend mainly on separation distance (stationarity assumption). This dissertation aims to advance spatial correlation models of ground motions, by conducting a comprehensive correlation study on various data sets, evaluating key assumptions of current models, and proposing a novel framework for modeling spatial correlations. First, this dissertation proposes a method of site-specific correlation estimation and techniques for quantifying non-stationary spatial variations. Applying these methods to various data sets, factors related to non-stationary spatial correlations are investigated. Using physics-based ground motion simulations, it studies the dependency of non-stationary spatial correlations on source effects, path effects, and relative location to rupture. Using data from recent well-recorded earthquakes in New Zealand, it analyzes site-specific and region-specific correlations in ground motion amplitude for Wellington and Christchurch, and observed strong non-stationarity in spatial correlations. Results suggest that heterogeneous geologic conditions appear to be associated with the non-stationary spatial correlation. Second, this dissertation formulates a framework for detecting and modeling non-stationary correlations. By utilizing network analysis techniques, it proposes a community detection algorithm to find regions in spatial data with higher correlations. Applying this algorithm to physics-based ground motion simulations, it detects communities of earthquake stations with high correlation to uncover underlying reasons for non-stationarity in spatial correlations. Factors associated with the communities of high correlation are identified. Results suggest that communities of high correlation in ground shaking tend to be associated with common geological conditions and relative location along the rupture strike direction. In addition, it applies the algorithm to a mixed-source data set from the simulations, and compares correlation characteristics of simulations and instrumental data. Results suggest that the mixed-source data tend to average out the non-stationary influence of source and path effects from a single rupture. Finally, this dissertation presents a framework for quantifying uncertainty in the estimation of correlations, and true variability in correlations from earthquake to earthquake. A procedure for evaluating estimation uncertainty is proposed and used to evaluate several methods that have been used in past studies to estimate correlations. The proposed procedure is also used to distinguish between estimation uncertainty and the true variability in model parameters that exist in a given data set. Results suggest that a Weighted Least Squares fitting method is most effective for correlation model estimation. Fitted correlation model parameters are shown to have substantial estimation uncertainty even for well-recorded earthquakes, and underlying true variability is relatively stable among well-recorded and poorly recorded earthquakes.
