PRE-CAST MONOLITHIC CONCRETE STAIR WITH DUAL EDGE BEAMS, METHOD AND MOLD

摘要

Pre-cast concrete stairs, molds for making pre-cast concrete stairs, and methods of casting pre-cast concrete stairs are provided. The stair is constructed with two beams that are cast with the stair steps as an integral monolithic structure. One of the beams (integral down edge beam) projects below the steps on one side, and the other (integral up edge beam) projects above the steps on the other side. The weight of the stairs and the weight of traffic on the steps creates compression on the tops of the integral down edge beam and integral up edge beam, and tension on the bottoms of the integral down edge beam and integral up edge beam, which enhances the combined strength of the beams. The asymmetric orientation of the members creates a stronger cross-section than if the beams were in the same plane horizontally, allowing greater load handing capability. Lightweight steps are suspended between the two beams.