Live-Load Distribution Factors for Composite Bridges with Precast Inverted T-Beams

Abstract

Short- to medium-span composite bridges constructed with adjacent precast inverted T-beams and cast-in-place topping are intended to provide a higher degree of resistance against reflective cracking and time-dependent effects compared with voided slab and adjacent box beam systems. This paper presents the results of an analytical and experimental study performed on the first inverted T-beam bridge in Virginia. The purpose of the investigation was to quantify live-load distribution factors for shear and moment for the composite precast inverted T-beam bridge. A finite-element model of Phase I of the bridge was created and the live-load distribution factors were analytically determined. Additionally, live-load tests using a stationary truck were performed with the purpose of quantifying live-load distribution factors for moment and validating the results from the finite-element analyses. The live-load tests featured four transverse truck positions on the bridge. It is concluded that it is appropriate to estimate live-load distribution factors using provisions for cast-in-place slab-span bridges.