Seismic risk assessment of reticulated shell structures considering multiple uncertainties

Abstract

Seismic risk assessment can quantitatively predict the damage caused by earthquakes. This method has been widely used in many structures, but it is seldom used in reticulated shell structures, and the uncertainty factors are not fully considered. First, a two-parameter damage criterion suitable for reticulated shell structures is proposed based on the Park-Ang damage model. Second, multiple uncertainty analysis is carried out. Based on the traditional method of considering only the uncertainties of record-to-record and structural design parameters, the uncertainties of performance indicators are obtained by the Latin hypercube sampling (LHS) method according to the probability distribution of the parameters in the two-parameter damage criterion. The modelling uncertainty is obtained by the comparison results of the tests and numerical simulations of the reticulated shells. For the first time, the evaluation concept of the construction uncertainty of reticulated shells is proposed by considering node errors. Finally, seismic risk assessments of two large-scale shaking table reticulated shell test models are carried out, and the influence of each uncertainty on the exceedance probability of the reticulated shells in 50 years is analysed. The results show that the two-parameter damage criterion can effectively evaluate the damage to reticulated shell structures and that the structural damage index values D at the four performance points are 0.3, 0.6, 1.0, and ∞. The modelling uncertainty has the greatest impact on the 50-year exceedance probability of the reticulated shells, and the exceedance probabilities in 50 years are 3 to 4.9 times the probabilities determined when only considering the uncertainties of record-to-record, structural design parameters, and performance indicators. The 50-year exceedance probabilities considering these five types of uncertainties are 3 to 9 times the probabilities determined when only considering the uncertainties of record-to-record and structural design parameters, indicating that the traditional method can underestimate the potential risks of reticulated shell structures. The two-parameter damage criterion and the multiple uncertainty analysis method proposed in this paper can be used for the seismic risk assessment system of reticulated shell structures.