Reliability analyses of RC bridge piers subjected to barge impact using efficient models

Barge impact is a potential hazard for bridge piers located in navigation waterways. The dynamic impact process is influenced by many factors, including barge mass, impact velocity, oblique impact angle, water elevation, material properties of pier members, soil properties, etc. The uncertainties involved in these factors need to be considered for reliability analyses of bridge piers subjected to barge impact. Empirical formulas such as those provided by AASHTO Guide Specification are extensively used for estimating the impact loading. However, such equivalent static method ignores the important dynamic effects involved in the impact event. High-resolution finite-element (FE) simulation is another commonly-used strategy for analyzing the dynamic impact process. However, FE simulation is expensive regarding both calculation time and computing resources, especially when a large number of simulations are required. The coupled multi-degree-of-freedom model (CMM) previously proposed by the authors can transform the full barge impact model (FBIM) into a simplified model that is efficient for dynamic analyses of the pier subjected to barge impact. This paper aims to conduct reliability analyses of the RC pier subjected to barge impact using the simplified model developed on the basis of CMM considering soil-pile interactions. The randomness of barge mass, impact velocity, oblique impact angle, water elevation, material properties of pier members and soil properties are considered. Sensitivity analyses are conducted to figure out the sensitive random variables.