Abstract: An inclined pair of stringer beams carries a plurality of transverse steps supported on saddles secured to the stringers. The upper tread surfaces of the steps are planar whereas the lower surfaces are arcuate, with a predetermined radius of curvature matching the corresponding arcuate shape of the subjacent supporting saddles.By angularly tipping each of the steps to or fro in the respective pair of saddles, the upper tread surface of the steps can be leveled despite variations in the angle of inclination of the stringers.The step is ordinarily constructed of precast concrete and includes metal reinforcements as well as metal inserts affording anchor points for attachment to the saddle, as by threaded fastenings or by welding.