Experimental and numerical study on the residual seismic performance of post-blast RC piers

Abstract

Aiming to evaluate the serviceability performance of bridge piers after potential terrorist attacks or accidental explosions, the residual seismic performance of post-blast reinforced concrete (RC) piers was studied by performing the test and numerical simulation. Firstly, the field explosion and successive lateral cyclic loading tests were performed on two 1/2-scale RC piers, and a single lateral cyclic loading test was performed on two intact control piers for comparison. The test data such as the incident overpressure-time histories, as well as the damage profiles, hysteretic curves and skeleton curves of piers, etc. were obtained and fully discussed. Then, an integrated finite element (FE) analysis approach based on the explicit–implicit switching algorithm was proposed to reproduce the dynamic and quasi-static responses of RC piers under blast and successive lateral cyclic loadings. Furthermore, four commonly used concrete material models were systematically compared and evaluated based on the basic mechanical property, explosion, and lateral cyclic loading tests. Finally, by comparing with the test data, the applicability of concrete material models and corresponding parameters, as well as the proposed integrated FE analysis approach for the residual seismic performance analysis of post-blast RC piers were verified comprehensively. It is concluded that: (i) after 0.5 kg TNT explosion, the positive yield and peak forces obtained from the lateral cyclic loading test are close to those of the intact control piers, whereas the negative yield and peak forces decrease to 66 % and 70 % of the intact ones; (ii) after 1.0 kg TNT explosion, the positive yield and peak forces are 77 % and 81 % of the intact values, while the negative yield and peak forces are only 37 % and 42 % of the intact ones; (iii) by replacing the explicit algorithm with implicit algorithm during the residual seismic performance analysis, the computational cost is saved by about 70 times; (iv) Winfrith concrete model can better predict the residual seismic performance of post-blast RC piers, with the deviations limited in 20 %. The present work can provide a reference for the designer and researchers in evaluating the seismic performance of the post-blast RC bridge piers during the whole service life.