Development and assessment of efficient models for barge impact processes based on nonlinear dynamic finite element analyses

The impact of vessels straying out of control poses a serious hazard for bridge piers located in navigation waterways. In order to accurately predict the dynamic responses of the bridge piers subjected to barge impact and to design bridge piers which can resist such impact, the impact forces need to be accurately defined. Empirical formulas such as those provided by AASHTO Guide Specification are currently extensively used for predicting the equivalent static impact forces. Whilst such equivalent static methods cannot accurately reflect the actual dynamic phenomena in a barge impact event, sophisticated finite-element (FE) simulations are computationally expensive. This paper aims to establish a coupled model which can replicate the complex full barge impact model (FBIM) with sufficient accuracy. In this coupled model, the barge model is simplified into a mass-spring model (MSM) whilst the pier is modeled using discrete masses and discrete beam elements. The parameters introduced by MSM are determined using the proposed strategies in this paper. Linear elastic pier columns with fixed bases and cantilevered tops are employed to assess the prediction quality of the proposed coupled model for different impact scenarios.