Using Dead and Thermal Loads to Capture the Behavioral Changes of a Cable-Stayed Bridge

Abstract

To enhance the maintenance process of the Indian River Inlet Bridge, the Delaware Department of Transportation worked with the Center for Innovative Bridge Engineering (CIBrE) of the University of Delaware (UD) to install a structural health monitoring (SHM) system on the bridge during construction. The SHM system collects data in real time 24/7. For this research, data collected are transformed into 10-minute average values. These average values represent the response of the bridge to slowly changing thermal loads or to constant loads such as dead loads.

This paper presents a method for identifying damage from the structures’ strain vs. temperature response. The methodology is evaluated based on both actual response and response simulated using a calibrated finite element model (FEM).

Using data collected over 8 years since the bridge was opened to traffic, a finite element model (FEM) was used to evaluate the ability of the SHM to identify different types and severity of damage. To do this, different levels of severity were simulated, and their effect on the structural response was compared with the observed response, including the variability of that response. Using this approach, the ability to assess various levels of damage has been determined.