Three-dimensional seismic fragility analysis method for bridge structure

Abstract

The invention discloses a three-dimensional seismic fragility analysis method for a bridge structure. The method aims at the condition that a common seismic fragility calculation method cannot be used for carrying out three-dimensional seismic fragility calculation at present. According to the method, damage state equations used for assessing seismic damage of bridge members under a three-dimensional seismic effect is proposed firstly; for calculating damage probabilities of the members, a three-dimensional seismic fragility calculation theory of the bridge structure is detailedly derived and established by applying an engineering structure reliability theory, a probability theory and a mathematical statistics method according to characteristics of the damage state equations; and on the basis of fully considering parameter uncertainty of the bridge structure and uncertainty of seismic oscillation, an incremental dynamic analysis method and a finite element method are introduced. According to the analysis method, a derivation process has a better theoretical basis, and a calculation result is more accurate and reliable; and the method makes a breakthrough progress in the field of fragility research, and one-dimensional seismic fragility analysis is upgraded to three-dimensional seismic fragility analysis in existing research field, so that fragility assessment of the bridge structure under the three-dimensional seismic effect is realized.

Description

technical field [0001] The invention relates to the technical field of seismic intensity analysis, in particular to a method for analyzing the three-dimensional seismic vulnerability of bridge structures. Background technique [0002] Earthquakes have been frequent in my country in recent years. Wenchuan, Yushu, Lushan, Yingjiang and other earthquakes have caused the collapse of a large number of buildings and bridge structures, causing heavy casualties and national economic losses. As the bridge structure of the traffic throat, once an earthquake occurs, it will collapse or severe damage, will inevitably affect the normal operation of the entire transportation network and hinder the disaster relief work after the earthquake, which will cause huge indirect losses. Pay attention to. [0003] The actual ground motion is a three-dimensional seismic motion in space, and the structural response of bridge structures under three-dimensional earthquake action is very complex, especia...

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Problems solved by technology

[0004] At present, scholars from all over the world widely use seismic vulnerability analysis methods to evaluate the seismic performance of various bridge structures. The vulnerability analysis under the action of two-dimensional earthquake (longitudinal + lateral) is carried out, but at this time only two-direction earthquake is applied, the definition of damage index and the assessment of vulnerability are still carried out in two directions, and the damage Considering all indicators comprehensively, there is no report on the analysis and research on the seismic vulnerability of bridges under the action of three-dimensional earthquake motion

This is mainly because the current vulnerability damage indicators used in bridge structures (such as section curvature, pier top displacement, curvature ductility ratio, deformation and energy dual indicators, etc.) can only represent the damage state under longitudinal or transverse earthquakes, but cannot Assess the damage under the action of earthquakes in other arbitrary directions, the current commonly used seismic vulnerability calculation methods cannot be used to carry out 3D seismic vulnerability

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