Static Structural Implications of Bridge Pile Bents by Vessel Impact under Scoured Conditions

Local scour has been a leading cause of bridge failure. The erosion of the soil at the bottom of the piles causes changes in the structural integrity of the bridge. Bridge piles are most vulnerable during the occurrence of scour and the process of the scour holes refilling. Outside forces such as vessel impact can occur and cause failure at that time. This solidifies the reason for providing insight on the structural implications of vessel impact on bridge substructures under scoured conditions in hopes that failure can be prevented. This research involves using FB-Multipier; a nonlinear finite element based program to analyze bridge pile bent induced with impact forces under scoured conditions. The first part of the research deals with exploring the working condition of pile bent under normal flood and scour conditions. The second part deals with the addition of vessel impact striking the substructure. The occurrence of these two conditions occurs under the assumption of an extreme load event occurring. The changes monitored in the piles were as follows: lateral resistance in the piles when scour occurs; demand/capacity; their fixity based on scour depth; and pile-load interaction. The parameters such as soil properties, bent dimensions, and hydraulic data are modeled after the Ernest Lyons West Island Access Bridge in Florida. This provides actual data that can be used as considerations for similar bridges. The results mimic the expectations established in the hypothesis. Besides this, interaction behavior of the applied force and piles are found. First off, the location of the applied lateral force is important. It greatly influences the static changes. Maximum shear occurs at the top of the soil during the unscoured and scoured conditions. Maximum negative moment does indeed occur at the fixity depth.