Experimental study and finite element analysis on shear performance of high strength steel reinforced ultra-high performance concrete beam

This paper investigates the shear performance of high strength steel reinforced ultra-high (HSSUHPC). Test were carried out on seven beam specimens with the different parameters of web steel ratio, shear-to-span ratio, and steel fibres content in volume. The failure patterns and load-displacement curves were obtained. The bearing capacity, deformation capacity and strain variation laws of UHPC, steel web, stirrups, tensile longitudinal reinforcement and tensile flange of steel were analyzed. The experimental study established the finite element model of the shear performance of HSSRUHPC beams. The results of finite element fit well with the experimental results. Then parametric analysis was carried out. The results showed two shear failure patterns for the HSSRUHPC beam: shear diagonal compression failure and shear-compression failure. The mechanical process of the HSSRUHPC beam could be divided into four stages: the elastic stage, cracking stage, strengthening stage, and failure stage. There were two peak loads for the loaddisplacement curves. As the steel ratio of the steel web and yield strength of steel increased, the bearing capacity and deformation capacity of the HSSRUHPC beam increased. The shear-tospan ratio had a significant influence on the failure pattern of HSSRUHPC beam, and with the increase of the shear-to-span ratio, the bearing capacity of the HSSRUHPC beam decreased, but the deformation capacity increased. As fibre content increased, the crack resistance and deformation capacity of the HSSRUHPC beam were improved. With the increasing width ratio between the steel flange and beam, the bearing capacity of HSSRUHPC beam increased, but the change range decreased, so it is suggested that the width ratio between the steel flange and beam should not be larger than 0.6. As the stirrup ratio increased, the bearing capacity of the HSSRUHPC beam increased, but the availability of stirrups decreased, so it is suggested the stirrup ratio should not be over 3 %.