Investigation of the Causes of Bridge Abutment Failure and Its Remedial Measures on Gravel Road in Westa Shaw Zone

Abstract

Every year, many bridges are collapsed due to natural and human factors which results in tremendous effects on the economic growth especially in developing countries. As among the principal causes of bridge failures, the bridge abutment failure has the potential to cause substantial damage to the bridge and it is affecting the whole system of the road. This study were aimed to investigate the causes of bridge abutment failure on gravel road and to provide the remedial measures on their failures. The study was covered the bridge constructed on gravel road in West Shawa Zone from 2002 to 2012 that facing defects. The study applied a descriptive and exploratory research design and Purposive sampling techniques. From total population bridges, six (6) collupsed bridges were selected purposively. To examine the causes of abutment failure, critical review of relevant literature, laboratory test and site inspection through design review and as-built data was checked. Geological data obtained from the laboratory tests were analyzed by using GeoSlope 9.1. software. This softeware was used to analyze different geotechnical computations like slid and slope stability analysis. ArcGIS and ArcSWAT software were used in delineting rivers catchment area and in determining abutment scouring. The results of the study were found scour depth problem, river bank instability and abutment foundation slid, and design error which results from insufficient data for design, unsuitable materials and construction defect.Their effects were results in overturing, crack and collupes of the abutments. The remedial measures are construction materials’ quality and the on going costruction process of bridge should be strictly supervised and controlled, All geotechnical properties and other factors should be investigated before designing bridges inorder to alleviate scour depth, slope instability, under estimation of stream flow depth and narrowing river way problems