Seismic assessment of deep water bridges in reservoir considering hydrodynamic effects using endurance time analysis

Abstract

Hydrodynamic effects have a significant impact on the seismic performance of deep water bridges in reservoir. Currently, three-dimensional numerical fluid-structure interaction models are widely used for seismic analysis of such bridges with huge computational time. In this paper, endurance time analysis (ETA) was used as an alternative approach to reduce the simulation effect. The effectiveness and accuracy of this approach were studied by comparing with incremental dynamic analysis (IDA). Firstly, an iterative method based on spectral modification techniques of ground motions was proposed in order to reduce the computational time in developing the endurance time acceleration functions (ETAFs). Then, the generated ETAFs compatible with Chinese seismic code were validated with IDA curves using a coupled water-pier numerical system based on potential-based fluid elements. Finally, a typical deep water bridge in a reservoir was selected as a case study and was modeled by a three-dimensional solid element model to investigate the seismic responses of bridges at different water depths. The accuracy of added-mass method with fiber-based beam-column element models was also evaluated. It can be concluded that the proposed method for generating the ETAFs is an efficient alternative method and the endurance time method can provide sufficiently accurate estimation of hydrodynamic effects.