Proposed Residual Punching Strength-Temperature Relationships for High Strength Concrete Panels Exposed to Elevated Temperatures

This work studies the behavior of high strength concrete (HSC) slabs after exposure to high temperatures, and proposes punching strength-temperature relationship for HSC panels based on previous experimental work of the author, which tested reinforced HSC slab specimens subjected to four exposure levels. The HSC slabs have cube compressive strength of 94 MPa. The paper investigates the punching strength of HSC panels, load deflection behavior, crack patterns and failure modes and characteristics, as the temperature level of exposure is increased. The punching and compressive strengths reduced with the increase in the temperature of exposure. A parabolic equation is established that relates both strengths with the temperature of exposure. When temperature reaches 700 oC, the residual punching strength obtained was 54% of that at room temperature, and the type of failure was a flexural failure followed by punching shear failure