Response characterization of highway bridge piers subjected to blast loading

摘要

Recent attacks on a number of bridges demonstrate clear evidence of the vulnerability characterizing transportation systems to terrorist attacks. This vulnerability being further enhanced by the fact that the security measures implemented for the highway bridges are often not at par with those in place for the milestone bridges. This has necessitated studies to effectively characterize the response of highway bridge piers subjected to blast loads. The study, presented here, concentrates on investigating the effects of various parameters such as scaled distance, blast type, axial load ratio, and reinforcement detailing in assessing the response of reinforced concrete bridge piers that form the part of a two span highway bridge. The analysis of the bridge was carried out in accordance with IRC 6:2017. It was observed that at lower scaled distances, the burst type and the axial load ratio significantly affect the response of the pier. For a constant ALR value of 0.15, a 91.55% reduction in the peak displacement value was observed on increasing the scaled distance from 0.5 to 1 m/kg(1/3). Furthermore, for the conventionally detailed piers, an increase in the ALR value at a scaled distance of 0.5 m/kg(1/3) was observed to be characterized by catastrophic failure due to the buckling of the longitudinal rebar on account of crushing of the compression concrete. Seismic detailing was also found to significantly improve the response of the columns, scilicet the use of seismic detailing, was noted to significantly reduce the peak displacement (40%).