Performance and Behavior of Hybrid Composite Beam Bridge in Virginia: Live Load Testing

Abstract

The hybrid composite beam (HCB) system is an innovative structural technology that has been recently used in bridge construction within the U.S. transportation network. This investigation focused on evaluating the in-service performance of a newly constructed HCB bridge superstructure located on Route 205 in Colonial Beach, Virginia. In the live-load-testing program, the bridge superstructure was instrumented with a series of internal and external strain gauges to evaluate the structural response. The test was conducted using tandem axle dump trucks under both quasi-static and dynamic conditions, and results obtained from the experimental investigation were used to determine three key behavior characteristics: lateral load distribution, internal load-sharing behavior, and dynamic load allowance (DLA). With respect to the live load performance, the HCB system relatively conformed to the provisions of the AASHTO specifications for beam-type bridges but did exhibit some characteristics of a flexible system when considering the dynamic response. It was also noted that the load-sharing behavior within the HCB system is noncomposite and even nonlinear as a result of local phenomena internal to the HCBs, which may be attributed to local arch bending and slippage between the tension steel and the resin matrix, suggesting that the internal components can actually behave independently.