Reinforcement-Free Decks Using Modified Strut-and-Tie Model

This study presents a new method for predicting the strength of reinforcement-free bridge decks. The concept presented for the reinforcement-free bridge deck includes removing steel reinforcement, using compressive membrane action in the deck by tying concrete wide-flanged girders together, and introducing a polypropylene fiber to control shrinkage cracks. A modified strut-and-tie model (STM) that considers geometrical nonlinearity that can capture punching or flexural failure of the restrained bridge deck between the girders is proposed. The model provides a two-dimensional axisymmetric representation of the behavior of the reinforcement-free deck. Results from the proposed STM analysis method are compared to nonlinear finite element method (FEM) analysis results. Findings suggest that the proposed method is a practical and effective replacement for the time-consuming FEM analysis when the clear deck spans are 5ft or less.