A stair tread pan includes a plurality of stair risers, each of the plurality of stair risers comprising a uniform depth and width, whereby the stair tread pan consistently satisfies code requirements. The stair tread pan further comprising predetermined assembly tolerances are less than approximately inch for drainage of the stair tread pan in an exterior use. The stair tread pan comprises at least one tread nosing formed into the stair tread pan for yielding a uniform for reliable and durable tread nosing. The stair tread pan further comprising a poor stop at a top end of the stair tread pan for receiving poured concrete, thereby illuminating the need for tea-bars or other concrete containing structures for forming a top landing on the stair tread pan. The the stair tread maybe read a leap replaced without disturbing the structured integrity outside stair tread pan in a building environment.

A spiral staircase comprises a mounting column extending along a longitudinal axis. A plurality of tread assemblies each having a tread portion attached to a mounting plate is also provided. The tread assemblies are axially and angularly offset from an adjacent tread assemblies along the mounting column. In this aspect, each mounting plate has a first face that engages a corresponding portion of an outer surface of the mounting column and a second face from which the tread portion extends. Each of the tread assemblies further have attachment hardware that secures the mounting plate to the mounting column. Prior to attachment to the mounting column and in an unstressed state, the mounting plate has a first radius of curvature and the corresponding portion of the outer surface of the mounting column has a second radius of curvature. The first radius of curvature is less than the second radius of curvature so that when the mounting plate is secured to the column with the attachment hardware and the second face of the mounting plate substantially engages the mounting column, the mounting plate is in an elastically deformed state applying tension to the attachment hardware to inhibit loosening thereof.

A modular stair system comprises a plurality of modular stair units. Each of the plurality of modular stair units are associated with a single story of a construction. An upper, rectangular landing comprises a pair of long members connected at each end to a pair of short members. A mid-level, rectangular landing comprises a first pair of members and a second pair of members interconnected at their ends. A first and second plurality of corner brackets interconnects an end of the members with an end of the members of the upper and mid-level landings. The first and second plurality of corner brackets have the variable size depending on the number of the plurality of modular stair units to be stacked in the stairwell. A plurality of corner support columns support the upper, rectangular landing at a top portion thereof and the mid-level, rectangular landing at a mid-portion thereof and removably connected to the upper, rectangular landing and the mid-level, rectangular landing. The plurality of corner support columns have a second variable size depending on the number of the plurality of modular stair units to be stacked in the stairwell. A first stair runner removably connects to the mid-level landing and connects a bottom level to the mid-level landing. A second stair runner removably connects to the mid-level, rectangular landing and the upper, rectangular landing to connect the mid-level, rectangular landing to the upper, rectangular landing. Each of the plurality of modular stair units are organized such that a bottom modular stair unit is placed on a foundation and each successive modular stair unit of the plurality of modular stair units are stacked on top of and connected to a lower modular stair unit.

A modular platform system utilizing a number of components including a platform. The platform is configured so that each of the components may interchangeably connect to any side of the platform. The components include, for example, handrails and stairways, as well as other platforms. The platform and most of the components are formed from single, continuous pieces of metal.

A modular stair system comprises a plurality of modular stair units. Each of the plurality of modular stair units are associated with a single story of a construction. An upper, rectangular landing comprises a pair of long members connected at each end to a pair of short members. A mid-level, rectangular landing comprises a first pair of members and a second pair of members interconnected at their ends. A first and second plurality of corner brackets interconnects an end of the members with an end of the members of the upper and mid-level landings. The first and second plurality of corner brackets have the variable size depending on the number of the plurality of modular stair units to be stacked in the stairwell. A plurality of corner support columns support the upper, rectangular landing at a top portion thereof and the mid-level, rectangular landing at a mid-portion thereof and removably connected to the upper, rectangular landing and the mid-level, rectangular landing. The plurality of corner support columns have a second variable size depending on the number of the plurality of modular stair units to be stacked in the stairwell. A first stair runner removably connects to the mid-level landing and connects a bottom level to the mid-level landing. A second stair runner removably connects to the mid-level, rectangular landing and the upper, rectangular landing to connect the mid-level, rectangular landing to the upper, rectangular landing. Each of the plurality of modular stair units are organized such that a bottom modular stair unit is placed on a foundation and each successive modular stair unit of the plurality of modular stair units are stacked on top of and connected to a lower modular stair unit.

A curved pathway including a double helix form with no center support column includes a plurality of segments, wherein each of the segments is formed from a plurality of rods coupled to a plurality of connecting nodes. The plurality of rods are arranged in a skewed tetrahedral geometry, which causes the plurality of stair segments to form a helical structure when the plurality of segments are coupled together. The plurality of rods form a spine on an underside of the plurality of stair segments. A pathway surface is coupled to each of the segments. In alternate embodiments, the curved pathway may be formed from sheet metal creased to form a plurality of linear support locations and connecting nodes.

A pre-cast concrete stair tread is provided where the stair tread has reinforced corrugated metal embedded within the core of the concrete stair tread. The corrugations are lined up along the elongated direction of the stair tread. Concrete is poured and cured over at least one side of the corrugated metal. Additionally, the pre-cast concrete stair tread may have one or more metal straps fixed on the reinforced corrugated metal in a direction perpendicular to the corrugations and the elongated direction.

An open staircase is provided comprising a flight of stair treads and an uncut stringer. The treads have free opposing ends positioned on the stringer in a stepped apart relationship relative to one another and each are fixed to the uncut stringer at a position along the horizontal length of the tread such that the tread is cantilevered from the stringer.

A curved pathway including a double helix form with no center support column includes a plurality of segments, wherein each of the segments is formed from a plurality of rods coupled to a plurality of connecting nodes. The plurality of rods are arranged in a skewed tetrahedral geometry, which causes the plurality of stair segments to form a helical structure when the plurality of segments are coupled together. The plurality of rods form a spine on an underside of the plurality of stair segments. A pathway surface is coupled to each of the segments. In alternate embodiments, the curved pathway may be formed from sheet metal creased to form a plurality of linear support locations and connecting nodes.

A curved staircase including a double helix form with no center support column includes a plurality of stair segments, wherein each of the stair segments is formed from a plurality of rods coupled to a plurality of connecting nodes. The plurality of rods are arranged in a skewed tetrahedral geometry, which causes the plurality of stair segments to form a helical structure when the plurality of stair segments are coupled together. The plurality of rods form a spine on an underside of the plurality of stair segments. A tread is coupled to each of the stair segments. In alternate embodiments, the curved staircase may be formed from sheet metal creased to form a plurality of linear support locations and connecting nodes.