Precast concrete modular stairwell tower

Abstract

A multi-story building is constructed by first erecting at least one modular stairwell tower on a concrete base pad. The tower includes a number of horizontally alternating precast concrete modular stairwell units arranged in a stack and corresponding to twice the number of floors in the building. Each stairwell unit includes a precast reinforced concrete tower section having opposite side walls and opposite end walls defining an open top and an open bottom and a height generally equal to one half the vertical distance between two adjacent floors. An inclined stairway and a horizontal landing platform are formed within each tower section and are rigidly connected to the walls. Anchor members are embedded in the base pad and in upper and lower portions of the walls of each tower section, and adjacent anchor members are connected by weld plates. Each stairwell unit has a handrail supported by the corresponding stairway.

1 . A modular stairwell tower for use in the construction of a multi-story building having a number of floors, said tower comprising
 a series of precast concrete stairwell units arranged in a stack with the number of stairwell units corresponding to twice said number of floors in said building,   each of said stairwell units including a precast reinforced concrete tower section having vertical opposite side walls and vertical opposite end walls defining an open bottom and an open top,   said walls of each of said tower sections having a vertical height generally equal to one half a vertical distance between two successive floors of said building,   an inclined stairway in each of said tower sections and connected to one of said side walls with each stairway having a series of steps,   a horizontal platform located adjacent an upper end of said stairway in each said tower section and connected to said side walls and one of said end walls of said tower section to form a horizontal landing,   each of said stairwell units being horizontally oriented one hundred eighty degrees relative to each adjacent said stairwell unit,   at least one of said walls of each of alternate said tower sections in said stack defining a doorway opening,   anchor members projecting into and embedded in upper and lower portions of said walls of each of said tower sections, and   said anchor members in said upper portions of said walls of said tower sections rigidly connected to said anchor members in said lower portions of said walls of the adjacent said tower section thereabove.   
   
   
       2 . A stairwell tower as defined in  claim 1  wherein at least one of said walls of at least one of said tower sections defines a partial doorway opening vertically aligned with said doorway opening in the adjacent said tower section therebelow. 
   
   
       3 . A stairwell tower as defined in  claim 1  and including a poured reinforced concrete floor pad supporting said stairwell tower, a set of metal anchor members embedded in said floor pad adjacent said walls of a bottom said stairwell unit, and metal connector members welded to said anchor members in said floor pad and to corresponding adjacent said anchor members in said lower portions of said walls of said bottom stairwell unit. 
   
   
       4 . A stairwell tower as defined in  claim 1  wherein said stairway in each of said stairwell units supports an inclined handrail, and U-shaped handrail sections above said platforms in said stairwell units and rigidly connecting said inclined handrail in each said stairwell unit to said inclined handrail of the adjacent said stairwell unit thereabove. 
   
   
       5 . A stairwell tower as defined in  claim 1  and including spaced horizontal reinforcing bars having end portions projecting into and secured to said one side wall of each said tower section, and said reinforcing bars extend into the corresponding precast concrete said inclined stairway in said tower section. 
   
   
       6 . A stairwell tower as defined in  claim 1  and including spaced horizontal reinforcing bars having end portions projecting into and secured to said one end wall of each said tower section and extending into the corresponding precast concrete said platform. 
   
   
       7 . A stairwell tower as defined in  claim 1  wherein said building is adapted to receive an erected steel frame, and said walls of said precast stairwell units of said stairwell tower have embedded anchor members for rigidly connecting subsequently erected steel frame members for said building. 
   
   
       8 . A stairwell tower as defined in  claim 1  wherein each of said tower sections has an overall length within the range eighteen feet to twenty five feet and an overall width within the range of nine feet to twelve feet. 
   
   
       9 . A first transportable precast concrete stairwell unit for use in erecting a modular stairwell tower in a building having multiple floors, said first stairwell unit comprising
 a precast reinforced concrete tower section having vertical opposite side walls and vertical opposite end walls defining an open bottom and an open top,   said walls of said tower section having a vertical height generally equal to one half a vertical distance between two successive floors of the building,   a preformed inclined stairway connected to one of said side walls and including a series of steps,   a horizontal platform located adjacent an upper end of said stairway and connected to said side walls and one of said end walls to form a horizontal landing, and   anchor members projecting into and embedded in upper and lower portions of said walls of said tower section.   
   
   
       10 . A stairwell unit as defined in  claim 9  in combination with a second said stairwell unit including said tower section, said stairway, said platform and said anchor members,
 said walls of said second stairwell unit stacked on and supported by corresponding said walls of said first stairwell unit,   said second stairwell unit being rotated one hundred eighty degrees relative to said first stairwell unit, and   said anchor members in said lower portions of said walls of said second stairwell unit rigidly connected to said anchor members in said upper portions of said walls of said first stairwell unit.   
   
   
       11 . A stairwell unit as defined in  claim 10  wherein at least one of said walls of said tower section of said first stairwell unit defines a doorway opening. 
   
   
       12 . A stairwell unit as defined in  claim 11  wherein at least one of said walls of said tower section of said second stairwell unit defines a partial doorway opening vertically aligned with said doorway opening in said first stairwell unit. 
   
   
       13 . A stairwell unit as defined in  claim 11  and including a poured reinforced concrete floor pad supporting said first stairwell unit, a set of metal anchor members embedded in said floor pad adjacent said walls of said first stairwell unit, and metal connector members welded to said anchor members in said floor pad and to corresponding adjacent said anchor members in said lower portions of said walls of said first stairwell unit. 
   
   
       14 . A stairwell unit as defined in  claim 13  wherein said stairway in each of said first and second stairwell units supports an inclined handrail, and
 a U-shaped handrail section above said platform of said first stairwell unit and rigidly connecting said inclined handrail of said first stairwell unit to said inclined handrail of said second stairwell unit.   
   
   
       15 . A stairwell unit as defined in  claim 9  and including spaced horizontal reinforcing bars having end portions projecting into and secured to said one side wall, and said reinforcing bars extend into a precast concrete said inclined stairway of said stairwell unit. 
   
   
       16 . A stairwell unit as defined in  claim 9  and including spaced horizontal reinforcing bars having end portions projecting into and secured to said one end wall of said stairwell unit and extending into a precast concrete said platform. 
   
   
       17 . A series of said precast stairwell units as defined in  claim 9  for use in a multi-story building having a number of floors, said stairwell units arranged in a stack with the number of stairwell units corresponding to twice said number of floors in said building and forming a stairwell tower,
 each of said stairwell units in said stairwell tower including said tower section, said stairway, said platform and said anchor members,   said walls of each said stairwell unit above a bottom said stairwell unit supported by said walls of the adjacent said stairwell unit therebelow, and   said anchor members in said walls of said stairwell units being rigidly secured to said anchor members in said walls of adjacent said stairwell units.   
   
   
       18 . A stairwell unit as defined in  claim 17  wherein said building is adapted to receive an erected steel frame, and said walls of said precast stairwell units of said stairwell tower have embedded anchor members for rigidly connecting subsequently erected steel frame members for said building. 
   
   
       19 . A modular tower for use in the construction of a multi-story building having a number of floors, said tower comprising
 a series of precast concrete tower units arranged in a stack with the number of tower units corresponding to twice said number of floors in said building,   each of said tower units including vertical opposite side walls and vertical opposite end walls defining an open bottom and an open top,   said walls of each of said tower sections having a vertical height generally equal to one half a vertical distance between two successive floors of said building,   at least one of said walls of each of alternate said tower units in said stack defining a doorway opening,   anchor members projecting into and embedded in upper and lower portions of said walls of each of said tower units, and   said anchor members in said upper portions of said walls of said tower units rigidly connected to said anchor members in said lower portions of said walls of the adjacent said tower unit thereabove.   
   
   
       20 . A modular tower as defined in  claim 19  and including a poured reinforced concrete floor pad supporting said tower, a set of metal anchor members embedded in said floor pad adjacent said walls of a bottom said tower unit, and metal connector members welded to said anchor members in said floor pad and to corresponding adjacent said anchor members in said lower portions of said walls of said bottom tower unit. 
   
   
       21 . A modular tower as defined in  claim 19  wherein said building is adapted to receive an erected steel frame, and said walls of said precast tower units have embedded anchor members for rigidly connecting subsequently erected steel frame members for said building. 
   
   
       22 . A method of constructing a modular stairwell tower for a multi-story building having a steel frame and a plurality of floors, said method comprising the steps of
 forming a support base for the stairwell tower,   precasting a series of reinforced concrete stairwell tower sections each having opposite side walls and opposite end walls and with the height of the side and end walls generally equal to one half the vertical distance between two adjacent floors,   forming a doorway opening within at least one wall of alternate said tower sections,   forming within each stairwell tower section an incline stairway having steps and extending to a horizontal platform forming a landing at an upper end of the stairway,   rigidly connecting each stairway and landing to the walls of the corresponding tower section to form a series of modular stairwell units,   positioning a first stairwell unit on the support base and anchoring the first stairwell unit to the support base,   successively stacking a series of the stairwell units on top of the first stairwell unit with alternate stairwell units being horizontally oriented one hundred eighty degrees relative to each adjacent stairwell unit, and   anchoring the walls of each stairwell unit to the walls of adjacent stairwell units to form a precast concrete stairwell tower.   
   
   
       23 . A method as defined in  claim 22  and including the step of forming the inclined stairway and landing of each stairwell unit with precast concrete, and providing each stairway and horizontal platform with horizontal reinforcing rods projecting into and secured to adjacent walls of the corresponding precast concrete stairwell unit. 
   
   
       24 . A method as defined in  claim 22  and including the step of erecting a steel frame for the building around the stairwell tower, and rigidly connecting steel frame members to the stairwell tower. 
   
   
       25 . A method as defined in  claim 22  wherein each of the tower sections is formed with an overall length within the range of eighteen feet to twenty five feet and an overall width within the range of nine feet to twelve feet. 
   
   
       26 . A method as defined in  claim 22  and including the steps of mounting an inclined handrail on the stairway of each stairwell unit prior to stacking the stairwell units. 
   
   
       27 . A method of constructing a modular concrete tower for a multi-story building having a steel frame and a plurality of floors, said method comprising the steps of
 forming a support base for the modular tower,   precasting a series of reinforced concrete tower units each having opposite side walls and opposite end walls and with the height of the side and end walls generally equal to one half the vertical distance between two adjacent floors,   forming a doorway opening within at least one wall of alternate said tower units,   positioning a first tower unit on the support base and anchoring the first tower unit to the support base,   successively stacking a series of the tower units on top of the first tower unit, and   anchoring the walls of each tower unit to the walls of each adjacent tower units to form a precast concrete modular tower.   
   
   
       28 . A method as defined in  claim 27  and including the step of erecting a steel frame for the building around the tower, and rigidly connecting steel frame members to the tower units. 
   
   
       29 . A method as defined in  claim 27  wherein each of the tower units is formed with an overall length within the range of eighteen feet to twenty five feet and an overall width within the range of nine feet to twelve feet.