US2608142A - Joint assembly for concrete pavements - Google Patents

Description

Aug. 26, 1952 J. H. JACOBSON 2,608,142

JOINT ASSEMBLY FOR CONCRETE PAVEMENTS filed April 7, 1947 2 SHEETS SHEET 1 1.75 far/2:59

A 1952 J. HLJACOBSON 2,608,142

JOINT ASSEMBLY FOR CONCRETE PAVEMENTS Filed April '7, 1947 2 SHEETSSHEET 2 IN VEN TOR.

vzrzzesjz fokwsazz Patented Aug. 26, 1952 UNITED STATES TENT OFFICE JOINT ASSEMBLY FOR CONCRETE PAVEMENTS 8 Claims.

This invention relates generally to improvements in Portland cement concrete pavement construction, and relates particularly to improvements in joints for such pavements where such joints are provided with mechanical load transfer devices for transferring wheel loads from one pavement panel to another.

It has been the practice in concrete pavement construction to employ expansion and contraction joints spaced at regular intervals, and it has been the design practice to specify means for maintaining the level of the top of the slabs and transferring loads from one panel on to the adjacent slab or panel. Generally, round dowels made of hot rolled steel, unreinforced at the face of the joint, have been specified for such load transfer.

In using such dowels, support must be provided at their ends, so that they are not disturbed or misaligned in the pouring of concrete at the joint. In some cases a stake pin driven into the subgrade has been provided at each end of the dowel. Whatever type of joint material has been specified, it has been necessary to support the joint material in a vertical plane, and it has been the common practice to support the joint material by pins driven into the subgrade on each side of the joint material.

More recent design practice has been to specify mechanical load transfer devices with means for supporting and reinforcing the dowels in bearing for at least a portion of their length, this reinforcement being provided particularly at the faces of each panel at the joint where the shear created by such loads is the greatest. Whatever means are specified for supporting and reinforcing the dowels in bearing, the means so specified must be firmly anchored in the face of each slab and the bearing load must be distributed through the concrete mass. Without the provision for distributing the shear load induced by the moving wheel loads the stress induced in the dowels is transmitted directly into the concrete. Without provision for distributing the bearing load at the face of the slab panel the stress transmitted by the unreinforced dowels may be so high as to cause the concrete to spall off, which action is progressive back from the face to create a condition known as funneling, until the dowels are no tlonger adequately supported within the concre e.

The requirement for support of the dowels or load transfer members at their extremities in order to prevent misalignment during the concreting operation, the requirement for means to support the dowels at the points where the shear load upon them is greatest in order to distribute the load into the concrete mass after it has set up, and the requirement for proper support of a vertical joint member all make for diflicult, expensive and cumbersome operations during the process of paving or laying down a concrete slab.

With the foregoing considerations in mind it is a principal object of this invention to provide a unitary assembly which will achieve all the de: sired functions discussed above and which can be positioned as a unit on the subgrade in advance of the paving operation.

Another object of the invention is to provide a simply constructed unit assembly which will support the extremities of the load transfermembers, which will support the members for distrib uting the stress on the load transfer members into the concrete mass, and which will support the joint or spacer member between two adjacent slabs or panels of concrete to the end that theentire assembly can be positioned upon the subgrade in advance of the concreting operation.

A yet further object is to provide a saddle or stirrup support which will springably engage the extremities of the load transfer members and which will springably engage the load distributing members with the joint member engaged .between the load distributing members whereby the entire assembly may be readily transported as a unit, or if desired, the units comprising the entire assembly may be shipped or transported in disassembled form prior to assembly at the con- :truction site well in advance of the paving operaion.

Still another object is to provide a basket consisting'of a plurality ofsaddles or stirrups spaced uniformly therein, the saddles or stirrups therein supporting load transfer members, load distribution members and the joint material.

Other objects and important features of the invention will become apparent from a study of the drawings taken together with this specification, which show a preferred embodiment of the invention. It is to be distinctly understood, how ever, that the invention isnot defined orlimited in terms of the embodiment here shown, nor otherwise than by the terms of the claims subjoined.

In the drawings which illustrate a-prefe rred embodiment of the invention: t

Figure 1 isanisometric view of a joint unit assembly according to the present invention;

Figure 2 is an end View of the joint unit assembly shown in Figure 1 showing the unit in place in a concrete slab;

Figure 3 is an end view of a basket employed in the joint unit assembly of Figures 1 and 2;

Figure 4 is a side view of a portion of the basket shown in Figure 3;

Figure 5 is an isometric view of another form of a joint unit assembly;

Figure 6 is an end view of the joint unit assembly shown in Figure 5, showing the unit in place in a concrete slab; and

Figure '7 is an end view of the assembly shown in Figure 6 looking from the left.

Referring now to the drawings, in Figure 1 there is shown a joint assembly for concrete pavements indicated generally by the ordinal Hi. The joint In is adapted to lie between two adjacent concrete panels when poured, and to transfer the load from one panel to another, and comprises a spacer member l2, which in Figure 1 is shown as being of the expansion type, which is deformable upon expansion of the panels and may if desired be of the kind which recovers its former d 31 1 911 sub equent w li 'ailtion 0f the panels. The spacer member I; may also be a thin plate of steel if the joint it! is of the contraction t pe. s show in. Fi ure 1 th spac r m mb r I2 may be pro ct d or r inforced on its pp r d by a channel strip 14 nd a on its bottom edge by a channel strip l6.

Load transfer members 1.8 are provided which pass throu h apertures in the spacer member 12 and which are embedded in the concrete panels when poured. In order to provide for movement of the load transfer members I 8 within the panels upon contraction and expansion of the panels one end .of each load transfer member I8 is provided with a cap ivin end clearance to the load transfer member. As is known to those skilled in the art the portion of the load transfer member I8 carrying the cap 20 is greased or oiled to break the bond with the concrete in which the member 8 is edded. while th portio of the load transfer member, not carrying the cap 2.0, is bonded to the concrete.

Means are provided to furnish bearing for the load transfer member at the point of greatest shear u d by l d on h con rete panels on ea h side of the joint 10. To his end on each side of t e spa er member 12 are lo ated bearin pl es 22 and 23 wh ch are apertured at .24 to receive the load transfer member l8 which has a earin fit with the bearing plates 22 and 23,. ref rably, the plate 23 h s a tight fit with the member l8, and .the plate 22 has a close sliding bearing fit with the member Ill.

The plates 2 and 23 are pro ded with W n s 25 wh ch are bent. out of t e plane of the plat 22 and 23 and which project back into the concrete panels.

By the arrangement thus far described shear ad up h l ad transfer membe s 18 at th .1

face of the concrete panels immediately adjacent the spacer member I2, where the shear loads are greatest, are transferred into the plates 22 and Z3 and distributed by means of the wings 25 into the concrete slab or Panel. 7

Means are provided for supporting or maintaining the spacer member l2, the channel strip I6, and the plates 22 and 23 together as a unit, with the load transfer members l8 held by the plates, at the same time providing for support of the extremities of the load transfer members I8 so that they will not be misaligned during the concreting operation. To this end there is provided a basket, indicated generally by the ordinal 28. consisting of a pair of stringers 28, one each side of the spacer member [2, and spaced therefrom, to which are secured a plurality of stirrups 30, substantially of an inverted W configuration. The stirrups are preferably welded to the stringers 28, and include a pair of upstanding legs 32 and 34, which are adapted to springably engage the plates 22 and 23 with the channel strip l6 and the spacer member I2 held therebetween.

The stringers 28 also have connected thereto. preferably by welding, saddles 36 which are formed of a pair of connected legs which are so formed, as at 38, to springably engage the extremities of the load transfer members l8. It is obvious, of course, that the load transfer members I8 may have any desired cross-section and that the saddle 36 may be suitably formed at 38 to springably engage the members I 8.

From the foregoing description it will be apparent that there has been provided a unitary assembly for a joint to be used in concrete construction. The structure according to the present in vention can be readily shipped disassembled, and easily assembled prior to placing on a subgrade prior to concreting therearound or prior to incorporating the joint assembly in any concrete structure. The placement 01 the bearing plates, which distributes the bearing stress on the load transfer members into the concrete insures against funneling or spalling of the concrete at the faces of the joint. While a plate type of structure has been shown other types are adaptable, as lon as they serve to distribute the bearing stress into the slab.

Referring now to Figures 5, 6 and 7, there is shown a modification of the unit assembly described with reference to Figures 1 to 4 inclusive. The assembly shown in Figures 5, 6 and 7 is for a contraction joint and comprises a thin spacer member 4.0, made generally of some type of premolded bituminous material, or of a thin plate of steel. The spacer member 40 is protected along its upper edge by means of a channel strip 42 and alon its bottom edge by a similar channel strip 44. Load transfer members 46 extend through openin s in the spacer member 40 to provide load transfer from a concrete panel on one side of the spacer member to a panel on the other side of the spacer member 40.

In order to distribute the stress in the concrete induced by loads transmitted by the load transfer members 46, the members are provided with load distributing means 48, which distribute the shear load on the load transfer members at the face of a concrete panel back in the concrete panel. The load distributing means 48 comprises a sleeve 50 surrounding the load transfer member 46 which ha e ending erefrom a pair of wings 52 which lie in the face of the concrete panel adjacent the spacer member 40. The sleeve 5015 also provided with a downstanding leg 54 which is adapted to lie in the face of the concrete panel when poured and against the spacer member 40, the downstanding leg 54 being notched at 56 to accommodate the reinforcing strip 44. The sleeve 50 is also provided at the end remote from the spacer member 40 with oppositely disposed flanges 58, whereby with the wings 52 and the flanges 58 the sleeve 50 and the downstanding leg 54 may be securely anchored into the concrete.

One end of the load transfer member 46 may be provided with a loose fitting cap 60 to break the bond. between the load transfer member 46 and the concrete, and o provide for movement of the member 46 upon expansion or contraction of the of the concrete.

Means are provided for holding the spacer member 46, the reinforcing strips 42 and 44, the load distributing means and the load transfer member 46 together as a unit for shipping and for location on the sub-grade prior to the concreting operation. To this end there is provided a basket indicated generally by the ordinal 62 which includes a pair of stringers 64 spaced from the spacer member and parallel thereto. Secured as by welding to the stringers 64 and connecting the stringers 64 transversely thereof is a stirrup 66 substantially of an inverted W configuration and including a pair of upstanding legs 63 which are adapted to springably engage the downstanding legs 54 of the load distributing means 48 with the spacer member 46 therebetween. Secured also as by'welding to the stringers 64 are saddles 10 formed of a pair of connected legs bent to the configuration shown at 12 to springably engage the extremities of the load transfer member 48.

From the foregoing description it will be apparent that there has been provided a unitary assembly for a joint to be used in concrete construction. The structure just described can be readily shipped disassembled and easily assembled to place on a sub-grade prior to the concrete operation. The placement of the load distribut- 1 ing means which distributes a bearing stress on the load transfer means, particularly at the joint faces insures against funneling at the faces of the joint.

While the invention has been disclosed and described in terms of a preferred embodiment thereof, its scope is to be limited only by terms of the claims here appended.

This application is a continuation in part of Jacobson application, Serial No. 716,329, Joint Assembly for Concrete Pavements, filed December 14, 1946, since abandoned.

I claim:

1. A joint assembly for concrete pavement construction adapted to be placed as a unit on the subgrade in advance of the pouring operation comprising a spacer member for separating adjacent concrete panels, means extending through said spacer member and in substantially perpendicular relation thereto for transferring loads from one concrete panel to an adjacent concrete panel, spaced means havin bearings receiving the load transfer means, each of said spaced means being adapted to be embedded in the face of an adjacent concrete panel when poured, and

interconnected means comprising a stirrup member having a U-shaped portion engaging the spacer member and the spaced supporting means and also a pair of saddle members each having a U-shaped portion springably engaging the extremities of the load transfer means and maintaining the spacer member, the load transfer means and the spaced supporting means as a single upright self-supporting unit when the assembly is placed on a subgrade in advance of the concrete pouring operation.

2. A joint assembly for concrete paving or the like adapted to be placed as a unit in advance of the pouring operation comprisin a spacer member for separating adjacent concrete panels, load transfer means passing through the spacer member and spanning the space between adjacent panels when poured, means providin bearing support for the load transfer means comprising plates located at opposite sides of the spacer 6, member and having anchors and bearing openings for the load transfer means and arranged to be embedded in the facesof adjacent concrete panels for distributing the stress in the load transfer means, a stirrup member having a U-shaped portion engaging said platesand said spacer member and means operatively connected with the stirrup member and'including U-shaped portions springably engaging the extremities of the load transfer means to maintain the entire assembly as a single upright self-supporting unit when the same is placed upon a subgrade in advance of the concrete pouring operation.

3. A joint assembly for concrete paving or the like adapted to be placed as a unit in advanc of the pouring operation comprising a spacer member for separating adjacent concrete panels, a load transfer member passing through thespacer member and spanning th space between adjacent panels when poured, means providing bearing support for the load transfer member comprising plates located at opposite sides of the spacer member and having anchors and bearing openings for the load transfer member and arranged to be embedded in the faces of adjacent concrete panels fordistributing the stress in the load transfer member, and a basket supporting said spacer member, said load transfer member and said bearing supports comprising a stirrup member having a U-shaped portion springably engaging the bearing supports and clamping the same against the spacer member and saddle members interconnected with the stirrup member and including U-shaped portions supporting and clamping the extremities of the load transfer member, said basket maintaining the entire assembly as a single upright self-supporting unit when the same is placed upon a subgrade in advance of the concrete pouring operation.

4. A joint assembly for concrete paving or the like comprising a spacer member, a load transfer member passing through said spacer member, bearing supports for the load transfer member positioned on opposite sides of the spacer member and having anchors and adapted to distribute the stress in said load transfer member into the concrete when poured, and a basket supporting said spacer member, said load transfer member and said bearing supports as a unit comprising stringers extending one each lengthwise of the spacer member, a stirrup member connecting the stringers and having a U'-shaped portion springably engaging said bearing supports and clamp--' ing the same against the spacer member therebetween, and saddles connected to the stringers and having U-shaped portions springably engaging the extremities of said load transfer member, said basket uniting the entire assembly in a single upright self-supporting unit adapted to be placed on a subgrade in advance of the concrete pouring operation.

5. A joint assembly for concrete paving or the like comprising a spacer member, a load transfer member passin through said spacer member, bearing supports for the load transfer member positioned on opposite sides of the spacer member and having anchors and adapted to distribute the stress in said load transfer member into the concrete when poured, and a basket supporting said spacer member, said load transfer member and said bearing supports and comprising stringers extending one each lengthwise of the spacer member and spaced therefrom, a stirrup connecting said stringers and having a pair of upstanding legs springably engaging said bearing supports and clamping the same against the spacer member, and saddles connected to said stringers and having U-shaped portions springably engaging the extremities of said load transfer member, said :basket uniting the entire assembly in a single upright self-supporting unit adapted to be placed on a subgrade in advance of the concrete pouring operation.

.6. A joint assembly for concrete paving or the like comprising a spacer member, a load transfermember passing through .said spacer member, two separate means providing bearing supports for the load transfer member and having anchors and arranged to be embedded in adjacent concrete panels when poured 'for distributing the stress in the load transfer member into the concrete, a sleeve surrounding one'end portion of the load transfer member and spaced from the spacer member, and a basket supporting said spacer member, the load transfer member and said bearing support means, comprising stringers extending one each lengthwise of the spacer member and spaced therefrom, stirrups connecting said stringers and having a pair of upstanding legs springably engaging said separate bearing support means and maintaining the same in engagement with the spacer member, and saddles connected to said stringers and located at the extremities of said load transfer member and engaging one end of the same and the sleeve at the other end thereof, said basket uniting the entire assembly in a single upright self-supporting unit adapted to be placed on a subgrade in advance of the concrete pouring operation.

7. A joint assembly for concrete paving or the like comprising a spacer member, spaced load transfer members passing through said spacer member, means providing bearing support for the load transfer members and having anchors and distributing the stress in said load transfer members into the concrete when poured and ing a downstanding leg lying along each. side of said spacer member, a sleeve surrounding one end of each of the load transfer members and positioned on each side of said spacermember, and a basket positioned at each load transfer member and supporting the same and the spacer member and said bearing support means, comprising stringers extending one each lengthwise of the spacer member and spaced therefrom, a

stirrup connecting said stringers and having a pair of upstanding legs springably engaging said doivnstanding legs and clamping the same against the spacer member with the spacer member therebetween, and saddles connected to said stringers and provided with resilient clamping portions in clamping engagement with the extremities of the associated load transfer members, said basket uniting the entire assembly in a single upright self-supporting unit adapted to be placed on a subgrade in advance of the concrete pouring operation.

8. A joint assembly for concrete paving or the like comprising a spacer member for separating adjacent concrete panels, a load transfer member passing through said spacer member and extending from opposite sides thereof, bearing plates located at opposite sides of the spacer member and having bearing openings receiving the load transfer member, said bearing plates extending downwardly and terminating adjacent the lower edge of the spacer member and having anchors and distributing the stress in the load transfer member into the concrete when poured, and a basket comprising stringers extending one each lengthwise of the spacer member and spaced therefrom, a stirrup connecting said stringers and having a pair of upstanding legs springably engaging said bearing plates and clamping the same against the bearing plates with the spacer member therebetween, and saddles connected to said stringers and composed of legs extending upwardly therefrom to the extremities of the load transfer member and provided thereat with means springably engaging said load transfer member, and said basket uniting the entire assembly in a single upright self-supporting unit adapted to be placed on a subgrade in advance of the concrete pouring operation.

JAMES H. JACOBSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS slumber Name Date 2,133,553 Lord Oct. 18, 1938 2,154,748 I-Iillberg Apr. 18, 1939 2,178,119 Jacobson Oct. 31, 1939 2,256,930 Willard Sept. 23, 1941 2,282,335 Methven -1 May 12, 1942 2,321,087 Jacobson June 8, 1943 2,365,550 Heltzel Dec. 19, 1944 2,417,824 Jacobson Mar. 25, 19 17 2,419,022 Heltzel -1 Apr. 15, 1947

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