Study of Debris Flow Impact on Bridge Pier

Abstract

The destructive nature of debris has ability to transport large boulders and wooden material along with the flow whose impact can pose serious safety risks to a bridge. In this study an effort has been made to study the impact of varying debris densities on a bridge pier.  The experimentation was carried out in Hydraulics Laboratory, Civil Engineering Department, University of Engineering and Technology Taxila. Hexagonal wooden pier model was used. Wooden sticks of uniform size and mass were used to act as debris in flow. Respective discharges were determined against different flow velocities. Dial gauge was installed carefully beside the bridge pier in a way that deflections were easily measurable. This debris of masses 189, 253, 316, 379 and 442 grams was floated on water for five trials at discharges of 10.3, 12.8, 16, 23.8 and 28.9 liters per second. Debris hit the pier and caused a deflection in it. These deflections were measured by a dial gauge. The results show that with increasing debris mass and intensity of flow velocity, the impact on the pier bridge in term of deflection increased. A hydraulic structure's health can be monitored using the findings of the current study.