US 4,076,777 A · Method and apparatus for forming a concrete roof

Abstract

Each one of a plurality of sector-shaped form members for a reinforced concrete or postensioned roof supported by a circumscribing wall, footing, columns or the like of a large building structure has an eyebolt located near its center of gravity to permit raising and lowering the form. The forms are lifted by this eye and successively positioned with their wide ends supported by brackets fastened to the circumscribing walls, footings, or columns and supported near their narrow ends by a central staging structure. If the building structure has circular walls or columns for supporting the roof, a pivoted station at the wide end of each form member provides a work platform for access to the bracket fastening means. When all of the forms are in place, their narrower ends define an opening which is centrally located. The forms are then covered by a layer of reinforced concrete. Holes are left in the roof at each eyebolt. An access opening of predetermined size is left in the center of the roof above the opening defined by the narrower ends of the forms. After the concrete has cured, the forms are each secured to the roof by the eyebolt which extends through the rod. A metal plate coupled to the eyebolt and engaging the upper surface of the rod enables the newly made roof to carry the forms. The staging is then removed through the access opening. The cable of a crane is then connected to the eyebolt of a given form. When the cable is tensioned, the load of the form is transferred from the roof to the cable and this enables the metal plate to be released from the eyebolt. The wide end of each form is then disengaged from the circumscribing wall, and each form is lowered to the bottom of the structure by the cable attached to the lifting eye. During lowering, the eyebolt and cable pass through the hole in the roof. After lowering, some or all of the forms, a lifting line is attached to each form near its narrow end such that the form will hang suspended from the lifting line with the wide end beneath the narrow end. In this position the form is hoisted by the lifting line through the access opening in the roof. The forms are then available to be placed on the wall or footing of the next structure when a plurality of structures are to be erected at a common site. If simply a single roof is being built, the forms can be reused with some modification on another project. The roof is completed by filling the holes for the eyebolts and by providing a closure for the access opening.

A method of constructing a concrete roof on top of a large structure having an open interior with the aid of a plurality of prefabricated elongated sector-shaped form members, each sector-shaped form member having a wide end and a narrow end with each being disposed at a different opposite end portion of the length thereof, each form member having a sector-shaped upper surface for receiving and supporting a layer of reinforced concrete and an integral supporting beam extending below the upper surface between the ends thereof to enable the form to resist bending mounts applied thereto either by the weight of the form when the form is suspending from a single suspension point disposed intermediate with respect of its ends or by the weight of a layer of concrete on the top surface of the form when the form member is supported only at its ends, the method including the steps of:

erecting a staging extending vertically to a predetermined height above the structure in the center of the interior of the structure, the staging being self-supporting and independent of the structure;
successively positioning each sector-shaped form member with its wide end being supportably engaged by the upper portion of the structure and with the under side of each form member adjacent its narrow end being supportably engaged by the erected staging, such that the upper sector-shaped surface of each form member extends inwardly and upwardly from the structure and is adapted to receive and support a layer of reinforced concrete, each form member being otherwise unsupported, and each form member being flanked by adjacent form members to provide a substantially continuous upper surface having a centrally disposed access opening therein which is substantially in alignment with the narrow ends of the form members;
covering the upper surfaces of the form members with a layer of reinforced concrete to form a roof having an opening corresponding to the access opening in the continuous upper surface provided by the form members and that is large enough to permit removal of each form member intact through said opening;
suspending each of the form members at said single suspension point from the roof after the concrete has cured to a predetermined strength, thereby enabling the roof to carry up to all the weight of each form member that was heretofore carried by the structure and the erected staging;
removing the staging from engagement with the form members and from the interior of the structure through the opening in the roof, the suspending of each form from the roof supporting each form member upon the removing of the staging;
applying a lifting force to a form member at said suspension point thereof to remove the load of the form member at said suspension point away from the roof;
disengaging from the structure the wide end of the form member to which the lifting force is applied;
reducing the lifting force on the form member to which the lifting force is applied to lower the form member out of engagement with the inner surface of the roof;
repeating the steps of applying a lifting force, disengaging the wide end, and lowering for each of the form members;
and
removing each form member intact through said opening in the roof.

8 more elements

Facts

Application

05/769,399Filed 16 Feb 1977 · continuation

Priority

12 Jun 1975

Granted

28 Feb 1978

Term ends

Not estimatedThe source records don’t support an estimate.

Classification6 codes

E04G 11/04
Forms, shutterings, or falsework for making walls, floors, ceilings, or roofs: for structures of spherical, spheroid or similar shape, or for…
E04B 1/166
Structures made from masses, e.g. of concrete, cast or similarly formed in situ with or without making use of additional elements, such as…: with…
Y10S 425/126
Plastic article or earthenware shaping or treating: apparatus: silo mold
E04G
Scaffolding

Method and apparatus for forming a concrete roof

Life of this patent

Method and apparatus for forming a concrete roof

Life of this patent

Abstract

Claims14