Effects of High Temperature on Residual Punching Strength of Slab-Column Connections after Cooling and Enhanced Post-Punching Load Resistance
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Large-scale experiments were conducted on six isolated slab-column connection specimens. Each specimen contained a 300 mm square center column and a 150 mm thick slab. The objectives of the experiments were to study the effects of fire-induced high temperatures on the residual punching shear strength of reinforced concrete flat-plate structures after cooling and to examine the effectiveness of a detailing approach for enhancing the post-punching load-carrying capacity. Ceramic fiber heating panels were used to apply high temperatures to slab shear-critical regions at the compressive face. The test results indicate that the high temperatures up to 800 °C did not seriously impact connection punching shear strength. Moreover, the use of crossties can effectively engage slab tensile reinforcement in resisting post-punching loads with a loading capacity close to or even greater than the punching failure load. Complementary to experiments, finite element simulations were conducted. The numerical simulations predicted the punching failure load of slab-column connections at room temperature with a good accuracy; however, the simulations underestimated the post-heating punching strength of the cooled slab-column connections by up to 11%.
Flat plate; Flat slab; Fire; High temperature; Punching; Post-punching
Orton, S. L.
Effects of High Temperature on Residual Punching Strength of Slab-Column Connections after Cooling and Enhanced Post-Punching Load Resistance.
Engineering Structures, 199