Shear Crack and Tensile shear Stirrup Dowel Action of HSC After Elevated Temperatures

Abstract:

In order to study the shear crack and the tensile shear stirrup dowel action of high strength concrete (HSC) after elevated temperatures, two Z shaped HSC specimens were cast. After being exposed to 200°C, 400°C and 800°C, the push off tests of specimens were conducted to study the effect of the elevated temperature and the concrete strength on the shear crack. The dowel action model was developed based on the beam on elastic foundation theory, and the dowel shear stress between HSC and stirrup after elevated temperatures was calculated in combination with the measured crack width and crack slip. The results show that except for an exposed temperature of 200°C, the crack peak deformation (crack peak width and crack peak slip) increases with the increase of temperature. As the strength of concrete (at any temperature) increases, the peak crack deformation decreases. The dowel shear stress of the stirrup exhibits a linear relationship with the crack slip, and the dowel shear stiffness reduces as the exposed temperature rises and increases as the concrete strength increases. The dowel shear stress increases as the exposed temperature rises and reduces as the concrete strength increases.