Prefabricated structure and method of construction

Abstract

Disclosed is a monolithic prefabricated structure that is wind and impact resistant. This special pre-cast lightweight concrete structure is a blend of special aggregates and additives combined to resist the impacts of flying debris and extremes of weather. The curved exterior surface minimizes wind friction and deflects debris. The circular structure has a low center of gravity and firm attachment to a floor made of concrete. It has protected ventilation openings, viewing ports and a strong smooth-fitting door.

What is claimed is:  
     
         1 . A prefabricated monolithic impact and wind resistant structure with a smooth dome-like shape and a low center of gravity, said structure being capable of remaining in place and providing a safe environment to occupants during the most severe weather.  
     
     
         2 . The provisions of  claim 1 , wherein the structure is constructed of concrete containing by volume 7 parts polystyrene aggregates of varied sizes smaller than ⅝ inch cubed, 3 parts Portland cement, polyacrylonitrile homopolymer or other fibers, acrylic, ethylene vinyl acetate terpolymer, styrene butadiene or other polymers, minor amounts of other additives such as fly ash and silica fume and water to allow workability.  
     
     
         3 . The provisions of  claim 2 , wherein the structure is molded by placing fluid concrete in a bowl-shaped mold and a second smaller mold being forced downward into the first mold to a controlled point of descent, said process forcing sufficient fluid concrete into the spaces between the two molds to fill the spaces and after curing complete the formation of the monolithic structure.  
     
     
         4 . The provisions of  claim 2 , wherein the structure is molded by filling a space defined by spacer blocks made of the lightweight concrete by pumping, pouring, injecting or otherwise filling the space between 2 molds and defining the shape of the structure.  
     
     
         5 . The provisions of  claim 2 , wherein the concrete is molded into a monolithic shell being six inches thick and not less than 6 feet in diameter, with the height not exceeding the base diameter.  
     
     
         6 . The provisions of  claim 2 , wherein the structure is enlarged, with uniform or non uniform thickening of the concrete in accordance with engineering calculations that determine thickness required to support increased loads imposed by increased spanned distances.  
     
     
         7 . The provisions of  claim 1 , wherein the structure with a base diameter or 8 feet or less can be easily transported and installed on reasonably level ground without site grading.  
     
     
         8 . The provisions of  claim 1 , wherein the structure is provided with a ventilation system, said system consisting of a plurality of small diameter pipes capable of transferring sufficient fresh air to sustain healthy interior conditions for the maximum number of shelter occupants during sustained occupancy and said ventilation system being capable of equalizing interior and exterior atmospheric pressures while preventing the entrance of wind blown objects.  
     
     
         9 . The provisions of  claim 1 , wherein the monolithic structure has a plurality of viewing ports consisting of solid transparent plastic or glass fitting into holes in the structure walls so as to allow viewing in at least 4 directions while protecting the viewers from flying objects.  
     
     
         10 . The provisions of  claim 1  wherein the structure has a doorway cut out of the wall material, said cut doorway being tapered to provide firm seating when closed into its original position in the wall, and said door being sealed with gaskets to prevent water intrusion and latched to resist severe wind pressures and impact loads when closed.  
     
     
         11 . The provisions of  claim 10 , wherein the door opens toward the inside and closes toward the outside by use of an inside track mechanism that supports and guides the door, said mechanism consisting of interior overhead and bottom track assemblies equipped with ball bearing rollers.  
     
     
         12 . The provisions of  claim 10 , wherein the door opens toward the outside and closes toward the inside by use of an outside track mechanism that supports and guides the door, said mechanism consisting of exterior overhead and bottom track assemblies equipped with ball bearing rollers, and said track mechanism being supported by 2 columns inside the structure, said columns being made of materials that do not conduct electricity.  
     
     
         13 . The provisions of  claim 1  wherein the structure has a tie-down method comprising a plurality of holes near the base, said holes allowing the insertion of horizontal anchor bolts from the inside to the outside prior to pouring of the concrete floor, and said bolts penetrating through the wall a sufficient distance to accept a washer and a fully threaded nut.  
     
     
         14 . The provisions of  claim 1  wherein the structure is tied down by use of anchor bolts set vertically in the wet concrete floor, said vertical bolts extending through a slotted steel angle plate, and said plate receiving a second horizontal bolt penetrating the structure near the base, and washers and tamper proof nuts being installed on the horizontal bolts.  
     
     
         15 . The provisions of  claim 1 , wherein the structure is held down by being placed a minimum of four inches above the bottom of a circular trench that is at least 12 inches deep and 18 inches wide at the top, and the lower base of the structure being fully embedded in the wet concrete on both the interior and exterior sides by filling the trench with concrete, said method eliminating anchor bolts.  
     
     
         16 . The provisions of  claim 1 , wherein the structure withstands impact loads such as lumber driven by wind at the velocity of 150 miles per hour.  
     
     
         17 . The provisions of  claim 2 , wherein the polystyrene aggregates consist of recycled waste.