Bridge Approach Settlements: Lessons Learned from Present Case Studies and Ground Improvement Solutions

Abstract

Settlement at bridge approaches is a typical problem found between the end of the bridge and highway pavement. This problem creates an uneven transition or a ‘bump’ in the roadway, and causes not only inconvenience to passengers but also increasing in maintenance and repairing work/costs to the highway agencies. In the United States, state departments of transportations (DOTs) have been spending over $100 million to alleviate the bump problems every year. Many researches had been carried out to study the causes of the bump problem and they are summarized in this paper. To identify factors leading to the bump problem in Texas, a survey questionnaire was send to all twenty five districts in Texas. In addition some field investigations were conducted at bridges in Quanah, Arlington and Cleburne. Results from the study reveal that subsurface void development, erosion and compressibility of fill material were found to be the main contributing factors to the bridge approach settlement in the State of Texas.