Effectiveness Analysis on the Protection Measures for the Mountain Bridge Piers against Rockfall

Abstract

In order to study effectiveness of measures taken to protect mountain bridge piers against rockfall in the upper reaches of the Minjiang River in Sichuan, based on non-linear explicit dynamic analysis, a numerical model was established to analyze the effectiveness using Holmquist–Johnson –Cook(HJC) damage constitutive model .And the numerical stability of calculation was tested in accordance with energy conservation principle. Four working conditions of bridge pier, namely ordinary non-protection, encryption stirrups, thickening plain concrete protection layer, being wrapped in steel tube, had been analyzed.Then by studying the response characteristics of the pier including the maximum damage depth of concrete, stress of longitudinal rebar, failure volume of concrete, different effectiveness of the three protective measures was compared . The rationality of analysis was verified by comparing with experimental results.The study shows that the HJC constitutive model can simulate the behavior of concrete under impact load well, and respectively protective effect of being wrapped in steel tube , thickening plain concrete protection layer, encryption stirrups, is weaker than the previous one.