SPR 14-486: Differential Bridge End Settlement Evaluation & Prediction

The Kentucky Transportation Cabinet (KYTC), and many other state transportation agencies, continually struggle with differential settlement at bridge ends. At the most basic level the issue is the fact that a bridge is typically constructed to rest on inelastic material while the approaching roadway is often constructed on elastic material. Over time these two materials typically settle at significantly different rates. These issues present a potential hazard at bridge ends for motorists, particularly motorcyclists, and are a constant source of maintenance spending. Differential settlement at bridge ends has been a frequently studied issue by many research institutions and state transportation agencies. In this body of work, most have taken the approach to investigate the settlement and offer methods for minimizing it to eliminate the bump. Little has been done to accept the problem and determine methods to predict settlement and develop remediation plans during project development that minimize the lifecycle cost of the facility. The current work focuses on the issue at the macro level and will develop a settlement predictive model based on historic data from a wide range of Kentucky roads and bridges. The inputs to the model are anticipated to be project characteristics such as design, geologic conditions, and geographic regions. This will provide project development stakeholders with the most effective historic design and construction methods for given project characteristics.