Simplified precast concrete system with rapid assembly formwork

Abstract

The disclosed system divides the precast and cast-in-place construction into vertical and horizontal components. The vertical components are precast, permitting rapid vertical building construction without a delay for concrete to set. The three primary precast components are a column, a horizontal slab, and a central panel placed diagonally between the slabs. By separating the columns from the horizontal slabs, the molds required to precast are simplified and transportation of the precast elements is streamlined. The resulting precast components are also of a weight and size that is readily manageable using a standard construction crane. The horizontal components are a combination of cast-in-place, and precast components. The result creates a continuous unitary floor structure that carries larger loads with less thickness that purely simple span pre-cast construction.

Claims

1. A method of erecting a multi-story structure, the method comprising the steps of: excavating a building site to create an excavated surface; placing one or more base members against the excavated surface, each base member comprising: a horizontal slab; placing a precast column atop each of the one or more base members, each precast column comprising: a column portion; and one or more upwardly-protruding rebar; placing a precast slab atop each precast column, each precast slab comprising: a horizontal slab; a column foot protruding from a top of the horizontal slab, one or more foot risers protruding from a top of the column foot; placing a precast spanning member, the precast spanning member resting atop the horizontal slabs of two or more precast slabs, each spanning member comprised of: a perimeter wall; a multiplicity of individual cavities; one or more formwork support rods affixed to a base of the precast spanning member; affixing a rotating formwork panel to the one or more formwork support rods of the precast spanning member, each rotating formwork panel comprised of: a solid panel; fixed hooks adapted to rotate around the formwork support rods of the spanning member; slideable hooks to affix to formwork support rods after rotation of the panel into place; pouring concrete on top of the rotating formwork panels; pouring concrete across the precast slabs and precast spanning members; repeating steps placing a precast column through placing a precast spanning member, each time completing a floor of the multi-story structure, stopping when the multi-story structure is the desired number of floors.

2. The method of erecting a multi-story structure of claim 1, wherein: the base member further comprises: a shear key receiving cavity located on top of the vertical column; and a vertical column extending from the horizontal slab; the precast column further comprises; a shear key located beneath the column portion; wherein the shear key interfaces with the shear key receiving cavity when the precast column is placed atop the base member.

3. The method of erecting a multi-story structure of claim 1, wherein the spanning member further comprises: a continuous central member upper rebar that includes a portion within the spanning member and a portion that extends beyond the spanning member; and a continuous central member lower rebar that includes a portion within the spanning member and a portion that extends beyond the spanning member.

4. The method of erecting a multi-story structure of claim 1, wherein the multiplicity of individual cavities of the spanning member further comprise: a lightweight fill material that substantially fills the individual cavities.

5. A hybrid precast and cast-in-place concrete building system comprising: an upper precast column and a lower precast column, each comprising: a column portion; one or more upwardly-protruding rebar; a bottom-mounted metal connection plate with penetrations; and a precast slab comprising: a horizontal slab; a column foot protruding from a top of the horizontal slab; one or more foot risers protruding from a top of the column foot, thus creating space for the later placement of rebar; each of the one of more foot risers surrounding a riser penetration; whereby, during assembly the precast slab is placed on top of the lower precast column, the upwardly-protruding rebar of the lower precast column passing through the riser penetrations, and through the bottom-mounted metal connection plate of the upper precast column, after which concrete is poured on top of the precast slab, thereby creating a hybrid precast and cast-in-place structure.

6. The system of claim 5, wherein the upwardly-protruding rebar of the upper precast column and lower precast column is threaded, thereby permitting the use of nuts to mechanically connect the upper precast column to the lower precast column.

7. The system of claim 5, further comprising: a precast spanning member comprising: a multiplicity of individual cavities; a perimeter wall surrounding the individual cavities; a projection extending from the perimeter wall; whereby the precast spanning member rests upon two or more precast slabs, the projection interlocking with the horizontal slab to support the precast spanning member, and following placement, concrete is poured on top of the precast spanning member and precast slabs, thereby creating the hybrid precast and cast-in-place structure.

8. The system of claim 6, wherein the precast spanning member further comprises: a lightweight fill material that substantially fills the multiplicity of individual cavities.

9. A method of erecting a multi-story structure, the method comprising the steps of: excavating a building site to create an excavated surface; placing one or more base members against the excavated surface, each base member comprised of: a horizontal slab; a vertical column extended from the horizontal slab; placing a precast column atop each vertical column of each of the one or more base members, each precast column comprising: a column portion; and one or more upwardly-protruding rebar; placing a precast slab atop each precast column, each precast slab comprising: a horizontal slab; a column foot protruding from a top of the horizontal slab; one or more foot risers protruding from a top of the column foot; placing a precast spanning member, the precast spanning member resting atop the horizontal slabs of two or more precast slabs, each spanning member comprised of: a perimeter wall; a multiplicity of individual cavities; one or more formwork support rods affixed to a base of the precast spanning member; hanging a rotating formwork panel from one formwork support rods of the spanning member, each rotating formwork panel comprised of: a solid panel; fixed hooks adapted to rotate around the formwork support rods of the spanning member; slideable hooks to affix to formwork support rods after rotation of the panel into place; lifting the rotating formwork panel into a horizontal position; sliding the slideable hooks of the rotating formwork panel into an adjacent formwork support rod; pouring concrete on top of the rotating formwork panels, thereby filling the spaces between the precast slabs and precast spanning member; pouring concrete into the multiplicity of individual cavities of the precast spanning member, thereby filling the individual cavities; repeating the steps of placing a precast column through pouring concrete into the multiplicity of individual cavities each time completing a floor of the multi-story structure, stopping when the multi-story structure is the desired number of floors.

10. The method of erecting a multi-story structure of claim 9, wherein: the base member further comprises: a shear key receiving cavity located on top of the vertical column; and the precast column further comprises; a shear key located beneath the column portion; wherein the shear key interfaces with the shear key receiving cavity when the central member is placed atop the base member.

11. The method of erecting a multi-story structure of claim 9, wherein the spanning member further comprises: a continuous central member upper rebar that includes a portion within the spanning member and a portion that extends beyond the spanning member; and a continuous central member lower rebar that includes a portion within the spanning member and a portion that extends beyond the spanning member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which:

(2) FIG. 1 illustrates a view of an embodiment of the central member.

(3) FIG. 2 illustrates a view of an embodiment of the central member placed atop a base member.

(4) FIG. 3 illustrates an embodiment of a base member.

(5) FIG. 4 illustrates an embodiment of a spanning member.

(6) FIG. 5 illustrates an embodiment of a collapsible tower placed between base members.

(7) FIG. 6 illustrates an embodiment supporting a spanning member.

(8) FIG. 7 illustrates the locating pins of the collapsible tower penetrating a spanning member.

(9) FIG. 8 illustrates an embodiment of the rotating formwork, hanging from a spanning member.

(10) FIG. 9 illustrates an embodiment of the rotating formwork, hanging between spanning members.

(11) FIG. 10 illustrates an embodiment of the support trusses used to hold the position of the temporary formwork along the outer edges.

(12) FIG. 11 illustrates the placement of a collapsible tower atop a spanning member, with a lower collapsible tower supporting the spanning member from below.

(13) FIG. 12 illustrates a second embodiment of the precast column and slab using a nut.

(14) FIG. 13 illustrates a second embodiment of the precast column and slab using a threaded coupling.

(15) FIG. 14 illustrates a second embodiment of the precast spanning member installed between the precast column and slab, prior to pouring the cast-in-place concrete.

(16) FIG. 15 illustrates a cross-sectional view of the second embodiment of the precast column, precast slab, and precast spanning member.

(17) FIG. 16 illustrates a second cross-sectional view of the second embodiment of the precast column, precast slab, and precast spanning member.

(18) FIG. 17 illustrates a cross-sectional view of a third embodiment of the precast column, precast slab, and precast spanning member.

(19) FIG. 18 illustrates a top-view of an optional temporary support structure.

(20) FIG. 19 illustrates a side-view of an optional temporary support structure.

DETAILED DESCRIPTION

(21) Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numerals refer to the same elements in all figures.

(22) Referring to FIG. 1, a view of an embodiment of the central member is shown. The central member 30 is formed from an upper column portion 32 and a lower column portion 34, with a dividing slab 36 placed between.

(23) A perimeter notch 38 follows the edge of the dividing slab 36. Protruding from the edge of the dividing slab 36 are continuous central member upper rebar 40 and continuous central member lower rebar 42.

(24) Hidden is the shear key 48 used to connect the central member 30 to the columns above or below itself.

(25) Along the bottom and top corners are the corner connection cutouts 50, which make room for the column vertical rods 52. Their use is discussed further below.

(26) The dividing slab 36 may be located at other positions with respect to the central member 30, and thus need not be centered top-to-bottom. The building design may necessitate placement of the dividing slab 36 at points such as the bottom of the central member 30, top of the central member 30, or at other locations between.

(27) Referring to FIG. 2, a view of an embodiment of the central member placed atop a base member is shown.

(28) A central member 30 is shown placed atop a base member 10, which is formed from a base slab 12 and vertical base rectangular column 14. The column vertical rods 52 are connected to each other, locking the lower column portion 34 to the base rectangular column 14 to prevent uplift.

(29) Referring to FIG. 3, an embodiment of a base member is shown.

(30) The base member 10 includes a base slab 12 and base rectangular column 14. A corner threaded rod 16 is placed on the corners of the base rectangular column.

(31) One or more shear key receiving cavities 18 aid in placement of upper columns and help to prevent twisting.

(32) Referring to FIG. 4, an embodiment of a spanning member is shown.

(33) The spanning member 60 includes a perimeter wall 62 that bounds a central cavity 70. The central cavity 70 is divided into a multiplicity of individual cavities 72 that are later filled with concrete.

(34) The individual cavities 72 are optionally filled with a plug of lightweight material before being covered with concrete. For example, an expanded foam may be used, then covered with a concrete layer. Or a concrete that is lightweight, either by using a lightweight mix or a novel type of concrete, such as autoclaved aerated concrete, may be used. The result is a lightweight spanning member 60 that maintains the majority of its strength.

(35) Continuous spanning member upper rebar 66 and continuous spanning member lower rebar 68 are shown protruding above and below the inverted perimeter notch 74.

(36) A central supporting face 76 is pre-formed, later used to support a collapsible tower (not shown). The pin penetrations 78 will interface with locating pins of the collapsible tower to aid in proper placement of the spanning member 60.

(37) Referring to FIG. 5, an embodiment of a collapsible tower placed between base members is shown.

(38) The collapsible tower 100 is preferably formed from four posts 102, held in position by cross braces 104 and horizontal braces 106. At the bottom of each post 102 is a base plate 108. At the upper end of each post 102 is a top plate 109. Protruding beyond the top plate 109 is a locating pin 110, which will interface with the pin penetrations 78 of the spanning member 60 (not shown).

(39) Referring to FIG. 6, an embodiment supporting a spanning member is shown.

(40) The spanning member 60 is shown placed atop a collapsible tower 100. Along each edge is a formwork support rods 130, held to the spanning member by fasteners 132.

(41) Referring to FIG. 7, the locating pins of the collapsible tower penetrating a spanning member is shown.

(42) This topside view of the spanning member 60 shows the locating pins 110 protruding through the pin penetrations 78, aiding placement of the spanning member 60. Furthermore, the subsequent collapsible tower 100 (not shown) is placed on top of the locating pins 110 to maintain alignment as the structure grows higher.

(43) Referring to FIG. 8, an embodiment of the rotating formwork, hanging from a spanning member, is shown.

(44) A rotating formwork panel 120 is shown with its fixed hooks 122 rotating above the formwork support rod 130 attached to the spanning member 60. The solid panel 121 will support the concrete that will be poured above. One or more optional stiffeners 126 increase the rigidity of the rotating formwork panel 120 to support the weight of the concrete. The slideable hooks 124 are shown hanging from the rotating formwork panel 120, not yet in a position to provide support.

(45) Referring to FIG. 9, an embodiment of the rotating formwork, hanging between spanning members, is shown.

(46) The rotating formwork panel 120 is now supported along both edges, with the fixed hooks 122 providing support along one edge, and the slideable hooks 124 inserted between the spanning member 60 and formwork support rod 130. The formwork panel 120 is now ready to support pour concrete.

(47) Referring to FIG. 10, an embodiment of the support trusses used to hold the position of the temporary formwork along the outer edges is shown.

(48) The trusses 134 support the rotating formwork panels 120 along their outer edge. The trusses are affixed to the dividing slabs 36 using fasteners 132.

(49) Referring to FIG. 11, the placement of a collapsible tower atop a spanning member, with a lower collapsible tower supporting the spanning member from below, is shown.

(50) The collapsible tower 100 is in position to support a subsequently placed spanning member 60, and so construction proceeds.

(51) Referring to FIG. 12, a second embodiment of the precast column and slab using a nut is shown.

(52) The precast column 230 ends at the top with threaded rebar 234, and the bottom with plate 232.

(53) The precast slab 240, primary formed from horizontal slab 245, includes an upwardly-protruding column foot 246 with multiple foot risers 248. The threaded rebar 234 of the precast column 230 below protrudes through the riser penetrations 250 (see FIG. 14), affixing to the precast column 230 above at the plate 232 using nuts 236.

(54) The precast lower rebar 242 is placed during factory casting of the precast slab 240. The laid-in upper rebar 241 is installed after placement of the precast members, placed between the foot risers 248 and affixed to the protruding precast stirrups 244.

(55) Referring to FIG. 13, a second embodiment of the precast column and slab using a threaded coupling is shown.

(56) Rather than using a nut 236 as shown in FIG. 12, a threaded coupling 238 connects the threaded rebar 234 of the precast columns 230.

(57) Referring to FIG. 14, a second embodiment of the precast spanning member installed between the precast column and slab, prior to pouring the cast-in-place concrete is shown.

(58) The projection 264 formed from the perimeter wall 262 of the precast spanning member 260 rests on the corners of the precast slabs 240, thereby supporting the precast spanning member 260. Within the precast spanning member 260 are a plurality of individual cavities 272 that are optionally filled with a lightweight material or poured concrete.

(59) The spanning member upper rebar 266 protrudes above the projection 264, with the spanning member lower rebar 268 protruding below the projection 264. As discussed above, this rebar will be overlapped and tied with rebar placed during construction and prior to pouring concrete.

(60) The spanning member lower rebar 268 is optionally installed after placement of the precast spanning member 260.

(61) Also shown are the components of the precast slab 240 that support the precast columns 230 (see FIG. 12), including the horizontal slab 245, precast stirrups 244, column foot 246, foot risers 248, and riser penetrations 250.

(62) The rotating formwork panels 120 are visible between the precast slabs 240.

(63) Referring to FIG. 15, a cross-sectional view of the second embodiment of the precast column, precast slab, and precast spanning member is shown.

(64) During construction, the precast slab 240 is installed over a precast column 230, with the threaded rebar 234 sliding through the riser penetrations 250. The next-higher precast column 230 rests on the foot risers 248 of the column foot 246.

(65) The nuts 236 hold the threaded rebar 234 to the plate 232, which is in turn welded to the internal rebar of the next-higher precast column 230.

(66) The precast spanning member 260 is placed atop the precast slab 240, with the projection 264 of the perimeter wall 262 resting on top. A notch 265 creates space for the overlap.

(67) The precast lower rebar 242 is visible within the horizontal slab 245.

(68) The laid-in upper rebar 241 and spanning member upper rebar 266 are then placed, optionally tied to the precast stirrups 244 and spanning member stirrups 280.

(69) In some embodiments, the precast spanning member 260 includes penetrations for rebar installation 282, through which the spanning member lower rebar 268 is installed and then grouted into place.

(70) The multiple individual cavities 272 of the precast spanning member 260 preferably include foam cavity fillers 271 that block the flow of concrete while reducing weight.

(71) After assembly, cast-in-place concrete 290 is poured to join the precast into a unitary structure.

(72) Referring to FIG. 16, a second cross-sectional view of the second embodiment of the precast column, precast slab, and precast spanning member is shown.

(73) This cross-section is through the center of the precast spanning member 260.

(74) Again shown are the individual cavities 272 with foam cavity fillers 271. The spanning member upper rebar 266 and spanning member lower rebar 268 are seen, with spanning member stirrups 280 tying the precast spanning member 260 to the cast-in-place concrete 290.

(75) Note that the cast-in-place concrete 290 beyond the precast spanning member 260 is full thickness because it is poured on top of the rotating formwork panel 120 (see FIG. 8) used during construction.

(76) Referring to FIG. 17, a cross-sectional view of an alternative second embodiment of the precast column, precast slab, and precast spanning member is shown.

(77) This embodiment is a hybrid of the first and second embodiments. The precast column 330 and precast slab 340 are a single piece, but with a rebar gap 349 for placement of the laid-in upper rebar 241.

(78) This design reduces the number of pre-cast elements that must be placed during construction, but still permits the use of long spans of rebar.

(79) Each precast column 330 includes a plate 332 and nut 336 to aid in attachment elements above and below the column 330.

(80) Referring to FIG. 18, top-view of an optional temporary support structure is shown.

(81) The precast spanning member 260 is shown affixed to the precast slab 240 using a metal support box 350. The metal support box 350 is connected to the precast spanning member 260 and precast slab using bolts 352.

(82) A precast column 230 is shown above and below the precast spanning member 260.

(83) Referring to FIG. 19, a side-view of an optional temporary support structure is shown.

(84) The temporary support structure is optionally used during construction, before the concrete has been poured.

(85) The precast spanning member 260 is again shown affixed to the precast slab 240 using a metal support box 350, held in place using bolts 352.

(86) An additional angled metal support 354 optionally supports the metal support box 350 by bracing against the precast column 230. Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result.

(87) It is believed that the system and method as described and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.