Parametric Study on Bridge Decks Reinforced with FRP Bars

Fiber reinforced polymers (FRP) bars have achieved a worldwide acceptance as an alternative to the steel bars due to their noncorrodible nature. Intensive research programs carried out on concrete bridge deck slabs reinforced with FRP to quantify the structural behavior of such element. The research present herein was conducted utilizing the Nonlinear Finite Element Analysis (NLFEA) to study and quantify the mode of failure for a typical concrete bridge deck reinforced with FRP bars. Punching shear and flexural behavior are the dominant mode of failure of FRP-reinforced bridge deck slab. The NLFEA were conducted to examine various parameters that have influence on the structural behavior of bridge deck slabs reinforced with FRP bars. Previous experimental and numerical research studies have investigated the behavior of laterally restrained FRP-reinforced concrete bridge deck slabs under wheel loading. Existing punching shear models are limited in their degree of accuracy due to the normalization approach and lack of consideration of all reinforcement parameters. This study reiterates the established parameters (i.e., longitudinal and transverse bars’ spacing and size) and assesses their influence through a numerical study to develop an empirical formula for calculating the punching shear capacity. The results revealed that the bar spacing has more influence than the bar size on the punching shear capacity; thus, normalizing the reinforcement amount into the reinforcement ratio, ρ, is no longer valid. An empirical punching shear capacity formula is developed herein using data collected from three previous experimental studies. The rationality of the developed formula was examined and tested based on experimental and numerical models. Moreover, the results obtained by the developed formula were compared with available punching shear models, which testified the accuracy and effectiveness of the developed formula. Subsequently, AASHTO LRFD Bridge Design Guide Specifications for GFRP-Reinforced Concrete allows the refined methods specified in Article 4.6.3.2 of AASHTO LRFD code to determines the live load force effect. Therefore, a parametric NLFEA study was conducted to evaluate the flexural behavior of FRP-reinforced concrete deck slabs. Based on the numerical results, a set of empirical equations were developed to predict the required applied load needed to reach the Service Limit State, Strength Limit State, and Creep Rupture Limit State. Finally, two sets of design aids were developed to ease the design process of FRP-reinforced bridge deck slabs.