Seismic Fragility Analysis And Risk Assessment Of Quayside Container Crane

Quayside container crane is an important handling equipment in the container port.With the development of the large scale of the container crane,it is more likely to be damaged from strong earthquake.Due to the randomness and uncertainty of the seismic responses of the structure,it is necessary to evaluate the seismic safety performance of container cranes under different intensity of earthquake from the prospective of the probability.Based on the theory of Performance-based Earthquake Engineering,the numerical simulation,shaking table test and probabilistic method are used in this paper to study seismic fragility analysis and probabilistic seismic risk of four typical container cranes.This study includes:(1)The finite element models are established according to the characteristics of container cranes,and the modal analysis and dynamic time history analysis are carried out.By comparing seismic responses of different seismic input models or different wheel rail constraint models,it is verified that the maximum port drift angle as the seismic performance indicators is reasonable.The scaled crane model shaking table test is used to verify the feasibility of the critical portal uplift indicators.(2)A method for defining the damage states and performance levels of container cranes is developed,and the probabilistic seismic capacity analysis for container cranes is studied.The elastic-plastic finite element models are built on the foundation of constitutive relation the empirical formulas of thin-walled stiffened box section.The seismic performance index values based on the mean estimates of structural random parameters are obtained.Using latin hypercube sampling method,the seismic performance index values of container cranes are obtained when considering uncertaineties of structure.(3)The probabilistic seismic demand analysis of the container cranes is performed by using 40 seismic waves conform to site characteristics as seismic inputs.The sensitivities to seismic responses of structure uncertaineties of container cranes are analyzed by tornado diagram methods.Those uncertain parameters with the low sensitivity degree are setting to deterministic parameters to improve the analysis efficiency.The IDA caculation is carried out with ground motion intensity of PGA and S_a.The results of IDA are statistical analyzed to build up the probabilistic seismic demand models based on the maximum port drift angle.(4)According to the results of probabilistic seismic capacity analysis and probabilistic seismic demand analysis of container cranes,the seismic fragility curves of the cranes are obtained,and a comparison between the full-probability and part-probabilistic vulnerability is performed.A seismic vulnerability calculation method of both states is proposed based on the time ratios of working state and non-working state.Combined the seismic fragility curves of the container cranes,a qualitative performance-based seismic safety assessment is carried out.(5)The seismic hazards of different seismic basic intensity areas in China are studied according to the probability model of ground motion.Based on the seismic fragility of container cranes and seismic hazards,the probabilistic seismic damage risk for one year and different service period are obtained by the Monte Carlo simulation analysis method,and the seismic risk of container cranes are assessed.