In Situ Data Analysis for Condition Assessment of an Existing Prestressed Concrete Bridge

Condition assessment of existing bridge structures is a valuable tool for bridge owners to make reasonable and optimal maintenance and management decisions. Structural condition assessment based on monitoring data is well-recognized within the civil engineering community as an efficient method to understand structural behavior and performance. One of the significant issues related to structural health monitoring is how to accurately interpret monitoring data in order to provide reliable condition assessment results. In this study, monitoring data obtained from a structural health monitoring system installed on an existing three-span prestressed concrete bridge are analyzed for condition assessment. The central span of the bridge contains eight precast post-tensioned girders with half joints, which are located at the ends of cantilevered lengths of the side girders. The half joints also contain external strengthening. The objective of this study is to conduct purely data-based investigations to explore the feasibility of using several condition indicators to identify any changes occurring to the bridge condition. These indicators include the maximum strain responses in the girders and vertical strengthening rods of half joints, transverse moment-distribution factors, and neutral-axis locations. Measured strain data from a number of events recorded from the structural health monitoring (SHM) system are analyzed, and the distribution as well as statistical characteristics of the afore-mentioned indicators are considered for bridge condition assessment.