Performance of Composite Plate Shear Walls (SpeedCore) Under Fire Loading: An Experimental Investigation

Composite-Plate Shear Walls/Concrete Filled (C-PSW/CF), also known as SpeedCore walls, are being used in the construction of mid- and high-rise buildings. The cross-section of C-PSW/CF consists of concrete infill sandwiched by steel plates, steel tie bars, and shear studs. Fire incidents may occur in buildings and the structural components including C-PSW/CF may be exposed to elevated temperatures. The mechanical properties of the materials in the cross-section of C-PSW/CF will degrade due to elevated temperatures during a fire incident. This phenomenon may result in the collapse of walls under combined fire and gravity loading. Thus, there is a need to evaluate the fire performance of C-PSW/CF. Five scaled C-PSW/CF specimens with a wall thickness of 229 mm were tested under combined fire and gravity loading. The experiments evaluated the effect of steel plate slenderness ratio, axial load ratio, use of shear studs, and fire scenario (uniform and non-uniform heating) on the behavior of C-PSW/CF under fire loading. For uniform fire exposure, the specimens meeting the design and detailing requirements of current U.S. specifications resisted the fire loading for more than 150 min without the application of any fireproofing. Thermal expansion of the specimens was observed in the initial stages of fire exposure, followed by the buckling of steel plates. No weld or tie bar fractures were observed for the specimens. The specimen subjected to non-uniform fire exposure satisfied the thermal barrier criteria for a fire duration of 140 min. Global out-of-plane bending of the wall was observed due to non-uniform fire exposure. For all specimens, water and steam emanated through the provided steam vent holes.