Product Application of a Hybrid-Composite Beam System

This report presents the results of the Innovations Deserving Exploratory Analysis (IDEA) project on the manufacturing and testing of a prototype Hybrid-Composite Beam (HCB) bridge for railroad and highway applications. The HCB presented in this report is comprised of three main subcomponents: a shell, compression reinforcement and tension reinforcement. The compression reinforcement consists of self-consolidating concrete (SCC) which is pumped into a profiled conduit within the beam shell. The tension reinforcement consists of Hardwire® steel reinforcing fabrics which run along the bottom flanges of the beams. Whereas fiber reinforced polymer (FRP) materials are generally too expensive and too flexible when arranged in a homogeneous form, the strength and stiffness of the HCB are provided by a more efficient use of materials that are well suited to purely axial tension or compression. The classical arch shape of the compression reinforcing dramatically reduces the shear carried by the FRP webs. Due to the low density of the FRP materials and the ability to place the compression reinforcing in-situ, what results is an economical structural member that can be used in the framing system of a bridge structure in the same manner as a steel or prestressed concrete beam, but that is much lighter and well suited to accelerated bridge construction and also provides for a potentially longer service life. This report discusses the evolution of the HCB as it has led up to the world’s first railroad bridge utilizing advanced composite materials. The paper also discusses test results and performance from the full scale test.