Structural Behavior of Waffle-Shaped Precast Concrete Panels for Floor Systems

Abstract

A waffle-shaped precast concrete panel named WAS has been newly developed as a floor system. Compared to the conventional double tee (DT), the WAS has a more spacious connection area between the panels while having a shallower depth, which possibly results in an enhanced performance of the connection. Experimental studies were performed to examine the flexural behavior of the WAS according to several primary parameters: the panel types, prestress levels applied to the panels, panel sizes, and the existence of steel ties. Connection tests were also performed on the short and long edges of each panel against out-of-plane shear. The test results showed that the WAS panels yields satisfactory flexural capacity similar to the DT up to ultimate state, and they satisfy the deflection limit for serviceability while their stiffnesses were less than those of DT panels. It was also found that the ultimate flexural strength of the WAS panel increases as the applied prestress increases, and that the connections can undertake the applied bending moment and properly transfer the developed shear force between WAS panels. The enhanced performance of the WAS connection makes it possible to efficiently design the panels addressing the moment distribution, and to enhance the serviceability (less deflection and cracking) and structural continuity/integrity of the WAS system while still being able to reduce its depth.