US3828500A

US3828500A - Reinforced concrete construction

Info

Publication number: US3828500A
Application number: US00167623A
Authority: US
Inventors: L Ellis; J Chancey
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-07-30
Filing date: 1971-07-30
Publication date: 1974-08-13
Anticipated expiration: 1991-08-13

Abstract

An improved reinforced concrete construction is provided. The invention is concerned primarily with large, thick reinforced concrete structures of the type used for base slabs for reactors of nuclear power plants, which slabs may be in the order of six to fourteen feet in thickness and measure from one hundred to two hundred feet across. Such structures include mats of reinforcing bars extending thereacross with generally mutually perpendicular junctures, at both lower and upper portions thereof. The upper mat of reinforcing bars is carried on special supporting frames, including uprights and cross bars, which are used to support Ibeam stringers on which the upper reinforcing bars rest. The supporting frames are prefabricated and can be set up rapidly, thereby reducing construction time along with associated labor and other costs. The frames are also specially braced to enable them to be positioned in vertical planes through which the stringers extend.

Description

United States Patent 1191 Aug. 13, 1974 Chancey et a1.

REINFORCED CONCRETE [54] 3,650,081 3/1972 McCracken 52/650 X CONSTRUCTION 3,721,058 3/1973 Dewey, Jr. et a1 52/260 X [76] Inventors. finiesRg ihancefigolliuiy. .lfadies Primary Examiner prank L Abbott gg g i i Assistant Examiner-Carl D. Friedman Richmond Va 53223 Attorney, Agent, or Firm-Allen D. Gutchess, Jr.

[ PP -I 1 7,623 An improved reinforced concrete construction is provided. The invention is concerned primarily with 52 us. 01 52/292, 52/169, 52/648, large, thick reinforced eeherete Shuewree of the type 5 5 52/678, 52/414 used for base slabs for reactors of nuclear power 51 1111. C1 E02d 27/08, 1302a 27/32 Plants, Whieh Slabs may be In the Order of Six to four- [53] Field of Search 52 678, 646, 648, teen feet in thickness and measure from one hundred 52/650, 30, 82 260 600, 319, 3 77 to two hundred feet across. Such structures include 684486, 340, 414, 282, 284 383 mats of reinforcing bars extending thereacross with generally mutually perpendicular junctures, at both [56] References Cited lower and upper portions thereof. The upper mat of UNITED STATES PATENTS reinforcing bars is carried on special supporting frames, including uprights and cross bars, which are 1,115,387 10/1914 Brown 52/678 X used to support Lbeam stringers on which the upper 222;: 2 72 reinforcing bars rest. The supporting frames are pre- 25s9021 3/1952 ONeailll... IIIIIIIIII 52II69 x i be setupfapidly Fhereby reducing 3:O06:l 15 10/1961 Hillberg 52/678 cohstmchon along wlth assoclated labor and 3,233,374 2/1966 Micheels B131 52/650 x other eests- The frames are also Specially braced to 3,245,191 4/1966 Ernst 52/686 enable them to be p ioned in ertical planes 3,427,777 2/1969 Crowley 52/80 X through which the stringers extend. 3,564,803 2/1971 Breeze et al. 52/650 X 3,570,206 3/1971 Armistead 52/383 x 7 Clalms, 5 Drewmg Flglll'es ll/ s a? e *7 Z a k;

PAIENTEB NIB 1 31974 SHEEIIUFS mlil 'f FlCif) INVENTOR JAMES C. CHANCEV LEONA/PD C. ELL/5, BY JR...

ATTORNEY PAIENIEU ms 1 31924 SHEET 2 (If 3 INVENTOR JAMES C. CHANCEV LEONA/P0 C, E 5 d BY I :FIGZ- MBM L ATTORNEY PAIENTEBAIJBIIBIQH SHEEI 3 0F 3 g mv ow mm om ww om mm v INVENTOR JAMES C. CHANCEV EO/VAPD C. ELL/5,//a. wamh ATTORNEY REINFORCED CONCRETE CONSTRUCTION This invention relates to an improved concrete construction and particularly to a thick reinforced concrete slab.

Huge, thick reinforced concrete slabs are used for bases of nuclear reactors at nuclear power plants. A typical slab of this nature is circular'in shape, measures 175 feet in diameter and is feet thick. Such slabs require heavy reinforcement to maintain stability and prevent cracking in the case of earthquakes, etc. Heretofore, the reinforcementfor such a slab has consisted of a mat of reinforcing bars in several criss-crossing layers located near the supporting surface on which the slab is poured, along with an upper mat of reinforcing bars spaced from the firstand locatednear the upper surface of the slab. The upper reinforcing bars have been supported heretofore by a network of steel beams cut to length and welded at the job site to maintain them in their predetermined spaced relationship with respect to the lower reinforcing bars-prior to the pourin g of the concrete. This construction has required considerable labor costs. and a substantial amount of construction time which also adds to the overall cost of construction, including increased financing costs, etc.

In accordance'with the'invention, special prefabricated supporting frames, including adjustments for levelling the supported reinforcing members, position the,

upper reinforcing bars .and specifically stringers upon which they rest at predetermined positions. In a particular form, the stringers extend radially from a central portion of theslab toward the periphery thereof. The frames for supporting the stringers are positioned in vertical planes extending parallelly tothestringers with adjustable jacks located on the frames to engage and support spaced portions of the corresponding stringers. Diagonal braces connect pairs of the frameswith the braces being of 'special'length to enable the braced frames to be positioned in a diverging relationship corresponding to that of the supported stringers.

It is, therefore,.a principal object of the invention to provide an improved reinforced concrete construction.

Another object of theinvention is to provide a reinforcing structure for concrete, which structure includes prefabricated, adjustable supports for upper reinforcing members of the structure.

Still another object of the invention is to provide an improved reinforced concrete structure which can be fabricated more rapidly and with less cost than heretofore.

Other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings, in which:

FIG. 1 is a somewhat schematic view in perspective of a reinforced concrete structure in the process of construction at a plant site;

FIG. 2 is an enlarged, schematic, fragmentary, plan view of the structureof FIG. 1;

FIG. 3 is a view in elevation taken along the line 3-3 of FIG. 2;

FIG. 4 is a view in perspective of braced supporting frames used to support some of the reinforcing members of the reinforced concrete structure; and

FIG. 5 is an enlarged, fragmentary view taken along the line 5-5 of FIG. 4.

Referring to FIG. 1, a job site indicated generally at 10 can be the site of a nuclear power plant, by way of example. It is essential at such plants that maximum support be provided for the nuclear reactor containment, particularly to minimize shock or vibration and to prevent possible damage to the reactor and subsequent emission leakage in the event of an earthquake. It is common practice to excavate the site down to a firm foundation, with the diameter of the. excavation exceeding the ultimate diameter of the slab to be constructed for the reactor. A supporting surface 12 is then established either by levelling the ground at the desired depth or bypouring a layer of concrete on the ground to provide, in either event, a relatively smooth or level, firm supporting surface. A slab or concrete reinforcement generally indicated at 14 is subsequently fabricated on the surface 12.

Referring particularly to FIG. 3, the concrete reinforcement 14 includes a lower mat or network 16 of lower reinforcing bars supported on or near the surface 12 and an upper mat or network 18 of upper reinforcing bars supported above the mat 16 near the upper level of concrete 20 which is subsequently poured over the entire reinforcing structure 14 to provide a large r reinforced concrete slab or base 22.

' The lower. mat 16 of reinforcing bars includes a lower layer of bars 24 which are supported directly on the surface- 12 or may be supported off the surface 12 slightly by chairs. These bars are disposed in circular patterns concentric with the slab 22. Bars 26 of a second layer extend radially and are generally perpendicular to the bars 24 at their junctures. Bars 28 of a third layer also extend circularly and concentrically with the slab, with the radial bars 26 being between the

bars

24 and 28. The particular number of layers, disposition,

and size. of the reinforcing bars in the lower mat 16 will depend on the size and physical characteristics desired for the particular reinforced structure 22 being made,-

and are subject to wide variation.

. way of example. These are at different levels in order to accommodate different numbers of layers of the upper reinforcing bars. On the outer stringers 30, all of which extend radially, there are fourlayers of reinforcing bars including a lower layer of bars 38 extending in a circular pattern, another layer of bars 40 extending radially, an additional layer of bars 42 extending circularly, and an upper layer of bars 44 again extending radially. The bars 40 and 44, in this instance, have outer down-turned end portions extending adjacent an outer peripheral wall 46 built of concrete block.

Atan intermediate portion of the slab, the stringers 32 are at a slightly higher level to support only three layers of thereinforcing bars, including a lower circular layer of bars48, a layer of radially extending bars 50, and an upper layer of circular bars 52. The stringers 34 are at still a higher level and support only two layers of reinforcing bars, a lower one including circular bars 54, and an upper one consisting of radially extending bars 56. Stringers 36 are intermediate the stringers 30 and are at the same level as the stringers 30 to aid in supporting the outer four layers of reinforcing bars. By varying the levels of the stringers 30-34, the upper layers of reinforcing bars in each instance will be at the same level and at a given distance below the upper surface of the concrete slab 22, even though different number of layers of the bars are used at different portions of the slab.

Central stringers 58 also support two layers of bars 59 and 60, in this instance, these bars being disposed in a generally square pattern in-the central portion of the slab 22.

It is to be understood that the reinforcing bar construction discussed above is only illustrative, although fairly typical, of an average nuclear plant slab base installation. Each site may have its own special design depending on the width and thickness of the slab as well as other geological and physical characteristics of the specific location. Also, details of the construction such as the location of expansion joints and the specific construction of the central portion of the slab are not discussed.

Referring to FIG. 4, the stringers or reinforcing members 30-36 are supported in predetermined, spaced relationship to the lower reinforcing members 24-28 by a multiplicity of supporting frames indicated at 62. The frames 62 are preferably located in vertical planes in which the stringers 30-34 also are located so that each frame supports its corresponding stringer at spaced points or locations. Some of the frames may support one end portion of one stringer and another end portion of an aligned stringer, as shown in FIG. 3.

Each of the supporting frames 62 includes uprights or legs 64 and 66 connected by cross bars 68 and 70. The lower portions of the legs 64 and 66 are strengthened or stiffened against bending movement by curved bars 72 and struts 74. Also, vertical struts 76 are affixed between the cross bars 68 and 70. Each of the frames 62 is prefabricated with the aid of a jig with the various elements of the frame precut and welded in the jig prior to being brought to the job site.

Each of the legs 64 and 66 is supported on a pedestal 78 having a central stud or projection (not shown) fitting into the lower end of the tubular leg. At the upper end of each of the legs 64 and 66 is an adjustable jack 80 (see also FIG. 5) comprising a threaded shaft 82 of a diameter to fit inside the upper end of the corresponding leg 64 or 66. A leveling nut and handle 84 has a central portion threaded on the shaft82 and, in turn, is supported on the upper end of the leg 64 or 66. On the upper end of the shaft 82 is affixed a supporting head 86 which has flanges extending up and around the lower flange of the corresponding stringer 30-36 to help support and position it. The handle 84 is turned downwardly on the'shaft 82 to raise it and the head 86, and is turned upwardly on the shaft to lower it into the leg and lower the head 86. This adjustable feature of the frame 62 is important to enable the various stringers to be supported at predetermined levels so that a predetermined number of layers of reinforcing bars supported above the stringers will always be at the same upper level so as to be a given distance under the upper surface of the concrete 20. Also, the adjustable frames enable the stringers to be supported in a truly horizontal position even though the supporting surface 12 may not be level.

It is necessary that each of the spaced frames 62 be connected to at least one adjacent frame in order to provide lateral stability for the supporting network of the frames 62. For this purpose, the legs 64 and 66 have appropriately spaced studs or pins 88 (FIG. 5) affixed thereto and extending from the leg in the plane of the frame, either inwardly or outwardly, extending inwardly as shown, each of the pins 88 having a gravityoperated latch 90. Pairs 92 of

diagonal braces

94 and 96 extend between the corresponding legs 66 of two of the spaced frames 62, with the ends of the braces being flattened and having holes punched therein to enable them'to be fitted over and received on the pins 88. The latches yield to enable the brace ends to be slid thereover but then drop down by gravity to prevent unwanted removal of the brace ends. Pairs 98 of braces 100 and 102 also extend between the corresponding legs 64 in a manner similar to the pairs 92. The number of the

pairs

92 or 98 of the

diagonal braces

94, 96, or 100, 102 will depend, to a substantial extent, on the height of the legs 64 and 66. However, in any instance, at least one of the pairs of braces will be employed and, further, the braces are always employed in pairs affixed to the corresponding legsat the same corresponding height. Substantially the entire height of each of the legs should be braced, leaving at the most only short distances at the ends which are not braced.

Because the stringers 30-34 extend radially outwardly from the central portion of the slab 22, the adjacent, braced pairs of frames 62 also must be positioned in a non-parallel manner relative to one another so that they can lie in vertical planes through which the stringers 30-34 extend. To achieve this, the braces of the

pair

92 or 98 are of different lengths, the pairs 98, in this case being shorter, to achieve the converging position of the frames 62 toward the central portion of the slab or the diverging position in a direction toward the periphery.

The braces must be supplied in a manner of lengths, not only to provide the divergent or convergent relationship of the brace frames 62, but also to accommodate the different spacing of the stringers as they extend away from the central portion, as shown schematically in FIG. 2. As is also shown there, the outer supporting frames are used to support the adjacent stringers whereas toward the center of the structure, the frames support alternate stringers in some instances. Inner ends of some of the stringers 34, as shown in FIG. 3, are supported on single adjustable supporting posts 104. Also in some instances, as schematically represented in FIG. 2, three adjacent frames may be braced together, rather than being braced in pairs.

With the reinforced construction shown, after the lower mat 16 of reinforcing bars 2-28 is fabricated on or near the surface 12, the frames 62 are positioned with the pedestals 78 located in spaces between the reinforcing bars 24-28 on the surface 12. The frames 62 for each of the stringers are arranged in vertical, radially-extending planes in positions corresponding to the stringers. With the frames 62 erected and the appropriate length braces 92 and 98 installed, the stringers can then be positioned on the supporting heads 86 and the upper reinforcingbars placed thereover. With this arrangement, the overall fabrication or construction time for the reinforced structure is much shorter than otherwise possible, resulting in a substantial savingsin labor Various modifications of the above described embodiment of the invention will be apparent to those skilled in the art and it is to be understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

We claim:

1. In combination, means forming a firm supporting surface, a lower multiplicity of reinforcing members located in predetermined positions above and near said supporting surface, an upper multiplicity of reinforcing members, said upper multiplicity of reinforcing members including lower reinforcing members and upper reinforcing members supported on said lower ones, at least some of the lower ones of the upper multiplicity of reinforcing-members extending in a diverging manner from a commmon location, means'supporting the upper multiplicity of reinforcing members in predetermined locations spaced above the supporting surface, said supporting means comprising a plurality of frames, each having two spaced, parallel uprights and cross bars affixed to and connecting said uprights, adjustable means supported on the upper ends of said uprights and having means to engage some of said upper multiplicity of reinforcing members with the supporting frame corresponding to one of said diverging members bieng located in a vertical plane parallel thereto, with the supporting frame for another one of said diverging members being located in a vertical plane parallel thereto and spaced from the other frame, diagonal braces extending between corresponding uprights of the spaced frames with the diagonal braces extending between two of the corresponding uprights of the spaced frames.

being shorter than the diagonal braces extending between the other two corresponding uprights of the spaced frames, means for removably attaching said diagonal braces to said uprights, and concrete embedding all of said members, frames, adjustable means, braces, and attaching means and extending from the supporting surface to a level above said upper multiplicity of reinforcing members.

2. The combination according to claim 1 characterized by said removable attaching means comprises projections extending from said uprights and holes in the ends of said cross braces receiving said projections.

3. The combination according to claim 1 characterized by the lower ones of the upper multiplicity of reinforcing members extend generally radially from a central area and terminate in a circular periphery.

4. The combination according to claim 3 characterized by said lower members which extend radially are positioned and supported by said frames at a lower level toward the periphery than near the central area.

.plicity of reinforcing members.

5. A reinforced concrete structure which is generally circular in horizontal cross section comprising means forming a level surface on which the structure is located, a multiplicity of elongate reinforcing members, said members comprising a plurality of elongate reinforcing members extending generally radially from a central portion of said structure toward the periphery thereof, means supporting said plurality of reinforcing members in the predetermined positions spaced above the surface, said supporting means comprising a plurality of frames, each including two spaced, parallel uprights and connecting cross bars affixed to said uprights, adjustable jacks supported on the upper ends of said uprights and having means engaging portions of said plurality of elongate reinforcing members, at least one of said frames being positioned so that the adjustable jacks supported on the upper ends of the two uprightsengage and support the same radially-extending elongate supporting member at spaced points, at least another one of said frames including two uprights positioned so that the adjustable jacks supported on the upper ends of these two uprights engage and support another radially-extending elongate supporting member at spaced points corresponding generally to the spaced points of the first radially-extending elongate supporting member, two diagonal braces extending between the two uprights of the two frames which are closer to the central portion of said structure, said diagonal braces being connected by removable attaching means to the corresponding uprights,-and two diagonal braces extending between the two uprights of the two frames which are closer to the periphery of said structure, the latter two diagonal braces being connected by removable attaching means to the corresponding two uprights, the latter two braces being longer than the first two braces, and concrete embedding all of said members, uprights, bars, jacks, and braces and extending from the level surface to a level above said multi- 6. A reinforced structure according to claim 5 characterized by said removable attaching means comprises projections extending from said uprights and holes in the ends of said cross braces receiving said projections.

ing lower flanges of said stringers.

Claims

1. In combination, means forming a firm supporting surface, a lower multiplicity of reinforcing members located in predetermined positions above and near said supporting surface, an upper multiplicity of reinforcing members, said upper multiplicity of reinforcing members including lower reinforcing members and upper reinforcing members supported on said lower ones, at least some of the lower ones of the upper multiplicity of reinforcing members extending in a diverging manner from a commmon location, means supporting the upper multiplicity of reinforcing members in predetermined locations spaced above the supporting surface, said supporting means comprising a plurality of frames, each having two spaced, parallel uprights and cross bars affixed to and connecting said uprights, adjustable means supported on the upper ends of said uprights and having means to engage some of said upper multiplicity of reinforcing members with the supporting frame corresponding to one of said diverging members bieng located in a vertical plane parallel thereto, with the supporting frame for another one of said diverging members being located in a vertical plane parallel thereto and spaced from the other frame, diagonal braces extending between corresponding uprights of the spaced frames with the diagonal braces extending between two of the corresponding uprights of the spaced frames being shorter than the diagonal braces extending between the other two corresponding uprights of the spaced frames, means for removably attaching said diagonal braces to said uprights, and concrete embedding all of said members, frames, adjustable means, braces, and attaching means and extending from the supporting surface to a level above said upper multiplicity of reinforcing members.

5. A reinforced concrete structure which is generally circular in horizontal cross section comprising means forming a level surface on which the structure is located, a multiplicity of elongate reinforcing members, said members comprising a plurality of elongate reinforcing members extending generally radially from a central portion of said structure toward the periphery thereof, means supporting said plurality of reinforcing members in the predetermined positions spaced above the surface, said supporting means comprising a plurality of frames, each including two spaced, parallel uprights and connecting cross bars affixed to said uprights, adjustable jacks supported on the upper ends of said uprights and having means engaging portions of said plurality of elongate reinforcing members, at least one of said frames being positioned so that the adjustable jacks supported on the upper ends of the two uprights engage and support the same radially-extending elongate supporting member at spaced points, at least another one of said frames including two uprights positioned so that the adjustable jacks supported on the upper ends of these two uprights engage and support another radially-extending elongate supporting member at spaced points corresponding generally to the spaced points of the first radially-extending elongate supporting member, two diagonal braces extending between the two uprights of the two frames which are closer to the central portion of sAid structure, said diagonal braces being connected by removable attaching means to the corresponding uprights, and two diagonal braces extending between the two uprights of the two frames which are closer to the periphery of said structure, the latter two diagonal braces being connected by removable attaching means to the corresponding two uprights, the latter two braces being longer than the first two braces, and concrete embedding all of said members, uprights, bars, jacks, and braces and extending from the level surface to a level above said multiplicity of reinforcing members.

6. A reinforced structure according to claim 5 characterized by said removable attaching means comprises projections extending from said uprights and holes in the ends of said cross braces receiving said projections.

7. A reinforced concrete structure according to claim 5 characterized by said uprights being tubular and said adjustable jacks including threaded shafts extending inside the upper ends of said uprights, and threaded nuts engaged on said shaft and supported on the upper ends of said uprights, lower ones of said multiplicity of reinforcing members being I-beam stringers, and said threaded shafts have generally U-shaped heads engaging lower flanges of said stringers.