Structural Behavior of Bridge Decks with Cast-in-Place and Precast Concrete Barriers: Numerical Modeling

Abstract

Nonlinear finite-element (NLFE) calculations were used to compare and optimize the load transfer and failure mode of precast and cast-in-place bridge barriers subjected to transverse loads on bridge deck overhangs. The NLFE calculations were validated by successfully simulating the behavior of concrete barriers anchored to bridge deck overhangs and submitted to static transverse loading. The behaviors of three different barrier configurations—a normal concrete cast-in-place barrier, high-performance fiber-reinforced concrete (HPFRC) precast barriers, and HPFRC precast barriers with barrier-to-barrier connections—anchored to slab overhangs were accurately simulated with NLFE models. The validated models were then used to investigate the impact of the fiber orientation in the HPFRC precast barriers, the effect of the precast barrier length, the eccentric load application, and the utilization of a HPFRC slab overhang. The fiber orientation of the HPFRC precast barriers was shown to be well oriented to resist the applied overturning moment. The adequate performance of 4-m-long precast barrier modules commonly used in actual industrial projects was confirmed, although the reduced load-carrying capacity of a smaller 2-m-long precast barrier with shear keys also surpasses the design requirements. The precast barrier length was as critical to the structural performance as an eccentrically applied load. The HPFRC slab allowed the reduction of crack spacing and crack-opening widths and increased the rigidity and load-carrying capacity of the bridge deck overhang.