  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. In this system, the superstructure consists of a
conventional reinforced concrete deck supported by Hybrid Composite Beams. Each
beam is comprised of a glassfiber reinforced polymer (FRP) box shell containing
a tied parabolic concrete arch. Inclined stirrups provide shear integrity and
enforce composite action between the HCBs and the concrete deck. This paper
focuses on evaluating the in-service performance of a newly constructed HCB
bridge superstructure located on Route 205 in Colonial Beach, Virginia. A live
load test was conducted using tandem axle dump trucks under both quasi-static
and dynamic conditions. Results obtained from the experimental investigation
were used to determine three key behavior characteristics. Dynamic
amplification and lateral load distribution were found to be reasonable in
comparison to the assumed design values. The testing program also included
internal and external measurement systems to help characterize the load sharing
behavior of the HCB on an element level. The main load carrying elements are
the deck in compression and the steel ties in tension, and the FRP shell did
not act compositely with the internal components.
