An Analysis on Collapse Margin for Highway CFST Arch Bridge Considering Uncertainty
In order to study the collapse margin capacity and earthquake loss of bridge structure based on the influence of uncertainty,an analysis method is proposed to calculate the bridge collapse margin ratio(CMR)based on the member damage margin ratio(DMR),and this method is used to evaluate the loss of the structure in the event of earthquake.Taking a highway CFST arch bridge as an example,firstly,the uncertainty of the model information is fully considered,and the Latin hypercube sampling is used to combine the model information parameters randomly.The OpenSees program is used to establish the elastic-plastic dynamic analysis model for arch bridge,and the nonlinear time-history analysis is carried out.Then the probabilistic seismic demand model of components is established by using probabilistic seismic demand analysis(PSDA)method.The vulnerability curve of components under continuous earthquake is determined,the vulnerability curve of the bridge is finally determined by analyzing the damage of different main load-bearing members in the event of earthquake,and the relationships among DMR,CMR,earthquake loss and uncertainty is explored.By comparing the 2 working conditions with different uncertainty,the result shows that(1)uncertainty has an important impact on CMR,DMR and earthquake loss assessment;(2)under the action of a given ground motion intensity,the DMR decreases with the uncertainty increase,resulting in an increase in the seismic loss of the component;(3)under the same earthquake,the components with smaller DMR are more likely to be destroyed than those with larger DMR;(4)under the influence of uncertainty,the change trend is consistent with that of DMR,because the CMR of bridge structure is obtained by DMR.Through the evaluation of DMR of members,fully considering the influence of uncertainty in the evaluation process is helpful to more accurately understand the collapse margin capacity of the structure and the loss in the event of earthquake.
NETL
NSTL
万方数据
