Abstract: 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.

Abstract: A precast concrete I-deck is provided. The I-deck comprises a bottom slab member, or soffit, with a plurality of I-beams evenly spaced along the width of the soffit, the I-beams being parallel to each other along the length of the soffit. The I-deck has diaphragm members on either end, perpendicular to the I-beams Pre-stress wires are embedded in the soffit and I-beams between the diaphragms. The spaces between the I-beams may be used to run wiring, plumbing, or ducts, or they may be filled with a filling material. The I-deck may be used in bridging and support systems for roofing or flooring.