Finite Element Analysis of Shear Deficient Large Size Reinforced Concrete Beams

Abstract

The shear failure of reinforced concrete beams considered as a very complex fracture phenomenon for which a purely mathematical approach is not possible at present. However, detailed modeling of the fracture mechanism is not necessary for establishing the general form of the size effect. This paper reports the details of the finite element analysis using "ANSYS" program for eight large-size reinforced concrete beams. The beams were analyzed without web reinforcements to evaluate the nominal shear strength provided by the concrete. The main variables included in the study are the a/d, concrete compressive strength , and the type (conventional or high-strength steel) and amount of the longitudinal steel reinforcement. The finite element models are developed using a smeared cracking approach for reinforced concrete. The concrete is modeled using "SOLID65"eight node brick element, which is capable of simulating the cracking and crushing behavior of brittle materials. The steel reinforcement has been modeled discreetly using "LINK8" 3D spar element and it has two nodes. A comparison between the finite element analysis results, namely, loads, deflections and cracking behavior and the available experimental results were made and good agreement was obtained. Results show that the use of high strength steel as a longitudinal reinforcement improves the shear strength and post cracking tensile stiffness of the concrete.