Dynamic performance of triple-column bridge pier under barge collision br

Growing incidents of pier cracks or even failure of the whole structure induced by ship-pier collision have attracted social attention to the safety of water-crossing bridges. In this study, finite element (FE) models are successfully established to gain insight into the collision between a modified barge and a three-column bridge pier in the non-navigable zone. Firstly, numerical models of the bridge pier and barge are satisfactorily verified against experimental results, through which the dynamic performance of the bridge under typical collision scenarios is investigated with respect to the kinetic energy, internal energy, and impact force. A new performance index, i.e., internal energy power slope (IEPS), calculated from the second derivative of the structural internal energy, is then proposed to prescribe the damage states of the impacted column. The usefulness and applicability of the IEPS are further explored through structural reliability analysis and a parametric study. Moreover, the efficacy of two protective jackets made in alloy honeycomb (AH) and aluminum foam (AF) for enhancing the structural anti-impact capacity is investigated by comparing the associated values of IEPS. It is observed that the proposed IEPS has a strong correlation with the structural damage state, and thus can be favourably used as a new performance metric for analyzing barge-pier collisions. The results also evidence that adopting UHPC (ultra- high performance concrete), densifying stirrup spacing, and adding protective jackets are effective measures to reduce the IEPS and hence improve the structural anti-impact capacity