INVESTIGATING THE BEHAVIOR OF REINFORCED CONCRETE HORIZONTALLY CURVED BEAM SUBJECTED TO COMBINED SHEAR AND TORSION USING FINITE ELEMENT ANALYSIS

Abstract

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This study deals with investigating the behavior and performance of reinforced concrete horizontally curved beam and subjected to combined shear and torsion by using three dimensional nonlinear finite element models. The commercial software package tool ABAQUS 6.14-2 is used to model the beams. Concrete damage plasticity model was employed to model the concrete material and the reinforcing bars were modeled as axial truss member embedded in the concrete element. Strong bond between reinforcing steel bars and concrete is assumed. The numerical simulation model was carried out to investigate the performance of horizontally curved reinforced concrete beam by using finite element analysis and validated with the experimental studies from the literature. In general, very approximate agreement was seen between finite element analyses and experimental results with difference of 2.3% with respect to ultimate load. Therefore the proposed numerical model has capacity to fully represent the behavior and performance of reinforced concrete horizontally curved beam. Then parametric study was carried out to investigate the influence of radius of curvature, shear length to depth ratio, amount of transverse reinforcement, boundary condition and compressive strength of concrete on the ultimate load capacity of horizontally curved beam. The numerical results for the analyzed beams shows that, for the same length of beam, the ultimate load increased about (72%, 128%, 167%) when radius of curvature decreases from (0.94) to (0.48, 0.33 and 0.25) rad respectively. When compared to horizontally curved beam, the ultimate load of conventional beam with the same length is increased about (255%). The effects of Shear span to depth ratio of curved beam on its ultimate load capacity were investigated and it is found that, the ultimate load increase from (19%-40%) when shear span to ratio decreases from (3.92 to 1.8). Also the amount of transverse reinforcement has a significant effect on the performance of curved beam and it reveals that up to 10.6% enhancement of the performance of curved beam has seen when diameter of transverse reinforcement vary from 6mm to 10mm. The boundary condition of the beam has significant effect on both horizontally curved and conventional beam. About 210% increases of ultimate load on curved beam when changing the support condition from simply support to fixed support while 56% increase in conventional beam. Also due to releasing the torsional restraint of curved beam at one end decreases the ultimate load by 32.4%