Finite Element Analysis of Fiber Reinforced Concrete Slabs under Torsion

This study has investigated the behavior and strength of steel fiber-reinforced concrete slabs under torsion using Finite Element Analysis (FEA). The research has focused on the effects of steel fiber volume ratio and reinforcement bar size on the torsional properties of concrete slabs.

A 3D solid element model with non-linear analysis has been employed using ABAQUS software to simulate the behavior of fifteen square slabs with varying fiber volume ratios and reinforcement bar sizes. The analysis has assessed the torsional properties, including cracking moment, yielding moment, ultimate moment, and stiffness.

The results have indicated that using steel fibers could enhance the torsional cracking, yielding, and ultimate moments. The torsional ultimate moment has increased between 3% to 4% by using fibers with a volume ratio of 0.5%, but it has increased between 106% to 148% by using fibers with a volume ratio of 2%. The study has concluded the proper volume ratio of fibers to improve the torsional ultimate moment to be between 1% to 2%. Moreover, an increase in reinforcement bar size has led to a higher torsional ultimate moment.

The torsional stiffness of slabs in uncracked phases has been found to be about 14.4-30.9 times the stiffness in the cracked phase. Fiber reinforcement has been found to lead to an increase in the stiffness of the cracked phase.