US20080092466A1

US20080092466A1 - Precast Concrete I-Beam Deck with Pre-Stressed Wire Strands as Reinforcing Material

Info

Publication number: US20080092466A1
Application number: US11/876,469
Authority: US
Inventors: Mark Zirbel; Bryant A. Zavitz
Original assignee: ZMZ PRECAST Inc
Current assignee: Metromont Corp
Priority date: 2006-10-20
Filing date: 2007-10-22
Publication date: 2008-04-24
Also published as: WO2008051923A2; WO2008051923A3

Abstract

A precast concrete I-deck is provided. The I-deck comprises a bottom slab member, or soffit, with a plurality of I-beams evenly spaced along the width of the soffit, the I-beams being parallel to each other along the length of the soffit. The I-deck has diaphragm members on either end, perpendicular to the I-beams Pre-stress wires are embedded in the soffit and I-beams between the diaphragms. The spaces between the I-beams may be used to run wiring, plumbing, or ducts, or they may be filled with a filling material. The I-deck may be used in bridging and support systems for roofing or flooring.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. Provisional Application 60/862,338, filed on Oct. 20, 2006, which is incorporated herein by reference.

BACKGROUND

1. Technical Field
This disclosure generally relates to reinforced pre-cast concrete I-beam decks, bridging and support systems that have pre-stressed steel wire strands as reinforcing material.
2. Description of the Related Art
Pre-cast concrete has many applications in the construction industry. Concrete that is precast tends to be of higher quality than concrete that is cast and cured on-site, as precasting may be done under controlled conditions. Pre-cast concrete slabs may be used in bridging and support systems, to support flooring or roofing in a building. Solid concrete slabs, or decks, used for this purpose may be heavy, making them difficult to handle or to lift up for installation on higher floors. Such decks may also exhibit poor sound and heat insulating qualities. Such slabs, or decks, may tend to crack over time and become weak or useless. Water may enter the cracks and damage any steel reinforcing material.

SUMMARY

I-beam decks (henceforth referred to as I-decks), systems using I-decks, and methods of forming I-decks are provided. In this regard, an exemplary embodiment of a light weight pre-cast concrete I-deck with pre-stressed wire strands comprises: a soffit with a bottom and a top surface with two ends and two sides, with a diaphragm on each end of the soffit that projects above the top surface of the soffit with an inside and outside surface, a plurality of spaced apart I-beams that are substantially parallel with each other projecting above the top surface of the soffit and extending between the diaphragms on each end, with an I-beam on each side serving as a side member, with the soffit and I-beams between the diaphragms having high tension steel wire strands embedded in the concrete that have been pre-stressed before the concrete is poured and kept pre-stressed until the concrete is cured. The concrete deck may have at least one load transfer member embedded in each diaphragm and extending outside of the diaphragm for extension onto a support structure for supporting the concrete deck.
If it is desired to place a top member, such as concrete slab, on top of the deck, the diaphragms and I-beams each need to have a top surface that is substantially in the same plane with each other.
An exemplary embodiment of a bridging and support system using an I-deck comprises: a plurality of light weight pre-cast reinforced concrete decks, each with a soffit with a bottom and a top surface with two ends and two sides, with a diaphragm on each end of the soffit that projects above the top surface of the soffit with an inside and outside surface, a plurality of spaced apart I-beams that are substantially parallel with each other projecting above the top surface of the soffit and extending between the diaphragms on each end, with an I-beam on each side of the soffit serving as a side members, with the soffit and I-beams between the diaphragms having high tension steel wire strands embedded in the concrete that have been pre-stressed before the concrete is poured and kept pre-stressed until the concrete is cured. Said deck may rest on the diaphragms on each end or they may have at least one load transfer member embedded in each diaphragm and extending outside of the diaphragm and resting on a support member in the structure. Each deck may have a top member placed on the top surfaces of the I-beams, side members and diaphragm, which may be a pre-cast concrete slab, flooring or a roof.
An exemplary method of forming an embodiment of an I-deck comprises: preparing a form for pre-casting concrete; placing the wire strands as reinforcing material in the form and stretching the wire strands under high tension; pouring sufficient concrete into the form to form the soffit; adding any filling material to the top of the soffit; and while the concrete has not cured, pouring the concrete for the I-beams and diaphragms into the form and finally cutting the wire strands and removing the deck from the form.
Constructing the deck by applying high tension to the steel wire strands before and during the curing of the concrete produces a monolithic structure of great strength and resistance to cracking. The high-tension steel wires help keep the concrete compressed throughout its life. These wires also reduce deflection for any length of span.
Other systems, methods, features, and/or advantages of this disclosure will be or may become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional system, methods, features and/or advantages be included within this description and be within the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 shows a cross-section of an embodiment of an I-deck.

FIG. 2 shows a perspective cut-away section of an embodiment of an I-deck from one corner of a deck adjoining another deck.

FIG. 3 is a plan view of four I-decks, which have intermediate diaphragms surrounding an aperture.

FIG. 4 a cross-section of a portion of an I-beam of a deck with a support attached to a wall.

DETAILED DESCRIPTION

I-decks, systems using I-decks, and methods of forming I-decks are provided, and several exemplary embodiments will be discussed in detail. Embodiments of an I-deck are relatively lightweight, making them easy to handle and install when used in building construction. They may also have enhanced sound and heat insulating properties. Other embodiments may provide a low-cost alternative to solid concrete slabs or pre-cast deck systems. The pre-cast I-decks of this invention have greatly improved strength because the high tension steel wires are stressed under high tension while the concrete is being poured and cured which greatly helps to keep the deck as a monolithic structure. This prevents cracking because the high-tension wires compress the concrete between the two ends of the deck.
Constructing the deck by applying high tension to the steel wire strands produces a monolithic structure of great strength and resistance to cracking. The high-tension steel wires help keep the concrete compressed throughout its life. These wires also reduce deflection for any length of span.
FIG. 1 shows a cross-section of an I-deck 101. The I-deck comprises a solid concrete bottom slab member, or soffit, 102, having I-beams 103 spaced evenly across its width. Each I-beams comprises a web 104 and flange 105 at the top. The I-beams 103 are parallel to each other extending across the length of the soffit 102. Four I-beams 103 are shown as an example; the number may vary based on the size of the I-deck and the application for which it is used. The soffit and I-beams are preferably made out of precast self-compacting or semi self-compacting concrete. The wide top surfaces of the flanges 105 provide structural support for flooring or roofing material 106. This floor or roofing material 106 may comprise any material appropriate for a flooring or roofing application, including but not limited to, cast-in-place concrete, wood, wire mesh, or metal. The spaces 107 between the I-beams 103 may be used for running utilities, such as plumbing, electrical wiring, or ducts; or the spaces 107 may be filled with a filling material. This material may be chosen to decrease the weight and production cost of the slab, while increasing its sound and heat insulating properties; polystyrene and fiberglass are useful materials.
In some embodiments, a support for the installation of a fixture, such as a chandelier, may be cast into the bottom of the soffit 102. A plate can be cast in the concrete for the support, or lag screws can be turned into the concrete. In such embodiments, the webs 105 support roofing or flooring material for an upper floor, while the bottom of soffit 102 can be used to support a fixture.
Because of the strength of the deck, provision may be made for supporting a heavy fixture from the deck. For example, a heavy fixture may be supported by putting a beam across the top of the I-beams with a cable to support a fixture below the soffit.
FIG. 2 shows a perspective cut-away section of an embodiment of an I-deck from one corner of the deck. The pre-cast concrete I-deck 201 is reinforced along its length by high tension steel wire strands 202 that have been pre-stressed before the concrete is poured and are kept that way until the concrete has cured.
The hollow sections 203 between the I-beams 210 of I-deck 201 may be used for running of utilities, such as ducts, electrical wiring or plumbing; or they may be filled with a filling material. The filling material 209 may be an inexpensive, lightweight material with good insulating properties, such as polystyrene or fiberglass. I-deck 201 has two integral transverse end diaphragm members 204, one on either end, perpendicular to the I-beams 210. The end diaphragms basically support the I-deck and provide increased shear capability and load distribution between the I-beams.
For use in areas that have significant seismic activity, one or more additional diaphragms 212 may be placed parallel to the end diaphragms along the length of the I-deck, resulting in a stronger I-deck. This transverse diaphragm can provide additional strength to allow the span of the deck to be longer or for other reasons. One or more transverse diaphragms 212 will permit the inclusion of a large opening, such as for an elevator shaft.
A load transfer device 205 connects I-deck 201 to structural support 206, which may be part of a wall, a beam, or a foundation of a building. The load transfer device may be a hollow steel tube. Alternatively, the deck may be supported by resting the diaphragms 204 directly on a support in place of using a load transfer device 205.
Reinforcing material 213 may be embedded in the length of the diaphragm to increase the strength of the deck. Reinforcing material may be embedded across the width of the soffit to increase strength and for handling increased loads produced by seismic activity (not shown).
Flooring or roofing material 208 is laid on top of the I- decks 201 and 207. This material 208 may be any material that is appropriate for a flooring or roofing application, including but not limited to metal, wood, wire mesh, or cast-in-place concrete.
A shear transfer channel 240 extends along the side member I-beam 210 A and provides for transfer of shearing forces between I- decks 201 and 207. A key 241 is shown for inserting in the channel 240.
An exemplary embodiment of a bridging and support system using an I-deck has a plurality of lightweight pre-cast reinforced concrete decks. FIG. 3 is a plan view of four decks with intermediate transverse I-beams on the decks to form a large opening in the floor This deck structure 310 is composed of four decks 312, 314, 316, and 318. An aperture 320 is formed by including intermediate transverse beams 322, 324, 326 and 328. Intermediate longitudinal beams 330 and 332 are used to complete the formation of the aperture 320. The use of these intermediate transverse and longitudinal beams provides good support for the decks. The pre-stressed wiring in the soffits and I-beams is also essential for supporting the deck structure 310.
The strength of the I-deck of this invention is sufficient to help support a wall as shown in FIG. 4 because of the pre-stressed wire strands. I-beam 103A abuts wall 120, with a support angle iron 122 attached to the wall 120 and I-beam 103 by fasteners 124.
In some embodiments, the I-deck may be formed as follows: first, a form for pre-casting concrete is prepared. Second, reinforcing material is placed in the form; this reinforcing material is a preferably high-tension steel wire strand. These strands are stretched and put and kept under a pre-determined load while the cement is poured and cures. Third, sufficient concrete is poured into the bottom of the form to make the soffit. Fourth, any filling material desired is placed on top of the soffit. Last, concrete is poured into the form to form the I-beams and diaphragms. The concrete for the I-beams and diaphragms is poured before the concrete in the soffit has cured, so that the I-deck will cure and set into a single mass. The wire strands are cut and the deck removed from the form.
It should be emphasized that the above-described embodiments are merely possible examples of implementations set forth for a clear understanding of the principles of this disclosure. Many variations and modifications may be made to the above-described embodiments without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the accompanying claims.

Claims

1. A light weight pre-cast reinforced concrete deck for installation as a floor or roof in a structure with support members for supporting the deck, comprising:

a soffit with a bottom and a top surface with two ends and two sides, with a diaphragm with a length on each end of the soffit that projects above the top surface of the soffit with an inside and outside surface, a plurality of spaced apart internal I-beams that are substantially parallel with each other projecting above the top surface of the soffit and extending between the diaphragms on each end, with an I-beam on each side of the soffit serving as a side beam, with the soffit and I-beams having a plurality of pre-stressed wire strands as reinforcing material embedded in the concrete extending between the diaphragms.

2. The concrete deck of claim 1 in which each internal I-beam consists of a web extending from top surface of the soffit and having a width, and a flange as a top member, with the flange extending beyond the width of the web, with the flanges and diaphragms having top surfaces which are in substantially the same plane with each other, said deck having a top member supported by the I-beams and diaphragms.

3. The concrete deck of claim 1 in which at least one load transfer member is embedded in each diaphragm which extends outside of the diaphragm for supporting the deck on a support structure.

4. The concrete deck of claim 1, further comprising a lightweight filling material located between the top surface of the soffit and the flanges of the I-beams.

5. The concrete deck of claim 4, wherein the filling material is polystyrene.

6. The concrete deck of claim 4, wherein the filling material is fiberglass.

7. The concrete deck of claim 1 in which the diaphragms have reinforcing material and the soffit has reinforcing material extending between the sides.

8. The concrete deck of claim 3 in which each diaphragm has at least two load transfer members, with said members being constructed from steel.

9. The concrete deck of claim 1, further comprising utilities for the structure which are at least partially located between the I-beams.

10. The concrete deck of claim 1, further comprising the inclusion of a support member embedded in the soffit for supporting a fixture hanging from the soffit.

11. The concrete deck of claim 1, further comprising a support attached to an I-beam for attaching to a wall for support of the wall.

12. The concrete deck of claim 1, further comprising a support resting on the top of at least one I-beam for supporting a fixture below the bottom of the soffit.

13. The concrete deck of claim 1, further comprising a top member placed on the top surfaces of the I-beams and diaphragm.

14. The concrete deck of claim 13, where the top member is cast-in-place concrete.

15. The concrete deck of claim 1, further comprising at least one additional diaphragm extending above the top surface of the soffit and extending between the two sides of the soffit.

16. The concrete deck of claim 1, further comprising that each of the diaphragms extending between the two sides of the soffit has at least one load transfer member constructed from steel.

17. The concrete deck of claim 1 in which each side I-beam has an outside surface in which a sheer transfer key is formed in the outside surface extending from one diaphragm to the other.

18. A bridging and support system in a structure comprising:

a. a plurality of light weight pre-cast reinforced concrete decks, each with a soffit with a bottom and a top surface with two ends and two sides, with a diaphragm with a length on each end of the soffit that projects above the top surface of the soffit with an inside and outside surface, a plurality of spaced apart internal I-beams that are substantially parallel with each other projecting above the top surface of the soffit and extending between the diaphragms on each end, with an I-beam on each side of the soffit serving as a side beam, with the soffit and I-beams having a plurality of pre-stressed wire strands as reinforcing material embedded in the concrete extending between the diaphragms; and

b. a plurality of support members in the structure with the deck resting between two support members on the diaphragms on each end.

19. The bridging and support system of claim 18, wherein each diaphragm has at least one load transfer member constructed from steel embedded in each diaphragm which extends outside of the diaphragm for supporting the deck on a support structure.

20. The bridging and support system of claim 18, in which each internal I-beam consists of a web extending from top surface of the soffit and having a width, and a flange as a top member, with the flange extending beyond the width of the web, with at least some of those flanges and diaphragms having top surfaces which are in substantially the same plane with each other, said deck having a top member supported by those I-beams and diaphragms where their top surfaces are in the same plane.

21. The bridging and support system of claim 18 in which each I-beam has a flange on the top of I-beam with a filling material located between the top surface of the soffit and the flanges of the I-beams.

22. A method of forming a light weight pre-cast reinforced concrete deck for installation as a floor or roof in a structure with support members for supporting the deck, which has a soffit with a bottom and a top surface with two ends and two sides, with a diaphragm with a length on each end of the soffit that projects above the top surface of the soffit with an inside and outside surface, a plurality of spaced apart internal I-beams that are substantially parallel with each other projecting above the top surface of the soffit and extending between the diaphragms on each end, with an I-beam on each side of the soffit serving as a side beam, with the soffit and I-beams having a plurality of pre-stressed wire strands as reinforcing material embedded in the concrete extending between the diaphragms, comprising:

a. preparing a form for pre-casting concrete;

b. placing the wire strands as reinforcing material in selected locations in the form and stretching the strands to predetermined load to pre-stress them;

c. pouring sufficient concrete into the form to form the soffit;

d. while the concrete poured in step (c) has not yet cured, pouring the concrete for the I-beams and diaphragms into the form and allowing the concrete to cure; and

e. cutting the wire strands and removing the concrete deck from the form.

23. The method of claim 22, in which filling material is added to the top of the soffit after step (c).

24. The concrete deck of claim 1, wherein the pre-cast concrete is self-compacting concrete.

25. The concrete deck of claim 1, wherein the pre-cast concrete is semi self-compacting concrete.

26. The concrete deck of claim 1, further comprising at least one additional diaphragm intermediate the diaphragms on each end of the soffit.

27. The bridging and support system of claim 18, further comprising an aperture surrounded by I-decks with intermediate diaphragms.