Abstract: A staircase construction is disclosed in which a plurality of identical riser units are bolted together in series, each riser unit comprising a tread member in the form of a flat slab, and two bracket members each supporting a respective end of the tread member.Each bracket member is formed from metal strip bent to shape in one plane and welded as and where appropriate and has a first horizontal planar part supporting the respective tread member and a second horizontal planar part spaced above the first part by the unit riser height and supporting a rear part of the first horizontal planar part of the next higher bracket member on the same side of the staircase, the last mentioned bracket member being set forward with respect to the bracket member being set forward with respect to the bracket member which supports it.

Abstract: A double helical earthquake and fire escape structure for multiple story buildings formed mainly of a plurality of prefabricated section of precast concrete. Two identically formed upper sectional units and two identically formed lower units are arranged in facing relationship to each other for each floor of the building. Complementary portions of the assembled units combine to form a pair of oppositely disposed entrances on each floor leading to two separate helical slides arranged about a separately formed central circular smokestack. The units are provided with steel members adjacent their edges which are connected together and secured to a surrounding supporting steel framework. Two additional smokestacks formed within the corners of the assembled units may also be used as shoe drops.

Abstract: A wooden spiral staircase with a central column and treads and riser members disposed spirally around said column. The risers have the shape of an asymmetric "T" and are let into a subjacent tread, a superjacent tread, and the central column, thereby serving to support the treads, which are not directly connected to the central column, but are each additionally connected to a superjacent tread and a subjacent tread at their ends remote from the central column.