US2144814A - Road expansion joint - Google Patents

Description

Jan. 24, 1939. RR'ROBERTSON 7 2,144,814

m 0 PM WMM/ Patented Jan. 24, 1939 UNITED STATES ROAD EXPANSION JOINT Robert R. Robertson, Chicago, Ill., assignor to The Translode Joint Company, Chicago Heights, 111., a corporation of Illinois Application June 13, 1936, Serial No.'85,058

4 Claims.

The present invention relates to concrete construction joints, and more particularly to a road expansion joint disposed between adjacent concrete road slabs, with said joint including in combination, an assembled core unit or joint forming mechanism comprising pre-cast plastic filler boards, which are held in offset vertical planes by means of improved slidably interfitting load transmitting sections consisting of ofiset upper and lower plates or flanges, which are integrally connected by means of an S-shaped intermediate portion comprising channels or loops connected by means of a common plate of a width greater than the combined width of the two loop portions, for the purpose of bridging the space between the two offset portions of the load transmission joint, and furthermore separating overlapping portions of the road slabs formed on opposite sides of the joint mechanism to provide a road construction which will withstand greater stresses and strains than a road formed with load transmission joints, wherein the core boards are positioned above one another in substantially the same plane.

It is an object of this invention to provide an improved road expansion joint mechanism com prising an adjustable load transmission shield device consisting of slidably interfitting sections, which are so formed that they provide offset pockets projecting in opposite directions for the purpose of engaging over and holding joint core boards in oiiset vertical planes.

Another object of the invention is the provision of an improved road expansion joint forming device, including a shield device formed to provide ofiset upper and lower pockets for holding core boards in offset relation on opposite sides of the vertical center plane of the road expansion joint, and including slidably contacting plates which cross the center plane of the joint and separate overlapping portions of the concrete construction slabs between which the expansion joint is imbedded.

It is also an object of this invention to provide a concrete construction consisting of concrete slabs separated by means of an expansion joint mechanism, including interfitting metal supports having anchoring means formed thereon, and furthermore having oifset core board supports which are connected by plate members separating overlapping portions of. the road slabs at the center plane of the joint, providing an arrangement whereby stresses applied to one of the road slabs may be readily transmitted to an adjacent slab, with the receiving slab absorbing the greater.

part of .the load.

It is also an object of this invention to provide a road expansion joint forming device in the form of a unit adapted to be set up on a road subgrade for the separation of concrete road slabs, said device consisting of assembled preformed plastic core boards held'in offset relation by load transmission devices which interfit one another and are anchored in the adjacent road slabs, said load transmission devices adapted to be held in assembled relation with the core boards upon a road subgrade by means of a plurality of spaced holders which are staked in position in staggered relation on oppositesides of the joint forming mechanism, and include a base plate extending from the bottom of one road slab across the bottom of thejoint and beneath the opposite road slab.

It is an important object of this invention to provide a road expansion joint mechanism for imbedding between concrete road slabs, said mechanism consisting of either single or multiple sets of slidably interfitting core board supporting sections which are so arranged that the core boards are held in staggered or ofiset planes between the interfitting sections which are provided with anchoring means for anchoring the sections in the oppositely positioned road slabs, which also imbed holders for the load transmission mechanism during the pouring of the concrete slabs, said holders being constructed to conform to the shape of the joint and include base plates extending across the bottom of the joint beneath the two adjacent road slabs.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

The invention (in preferred forms) is illustrated in the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a fragmentary perspective view of an improved expansion joint forming mechanism embodying the principles of this invention, and having associated therewith improved holders for staking the joint forming mechanism in position upon a road subgrade preliminary to the pouring of concrete for forming the road slabs.

Figure 2 is a fragmentary vertical detailed section taken on substantially line IIII of Figure 1, and illustrating the load transmission joint forming mechanism imbedded in the concrete forming road slabs on opposite sides of the joint. Figure 3 is a' vertical detailed section of a modified form of load transmitting expansion another modified form of load transmitting expansion joint mechanism imbedded in the concrete forming opposite road slabs, separated by offset core boards held in position by means of the interfitting load transmitting shield sections, which are formed to hold the upper and lower core plates with the adjacent edges thereof slightly overlapping each other.

Figure 5 is a fragmentary vertical detailed section through another modified form of an expansion joint forming mechanism including a spring steel insert plate.

As shown on the drawings:

The road expansion joint, as illustrated in .Fig ures 1 and 2, is formed by .means of the joint forming unit illustratedin Figure .1 before being imbedded between concrete road slabs. The various members comprising the joint forming unit may be assembled and tied together and then shipped to locations ready to .be placed in position upon the road subgrade,or the various members forming the jointiorming-unitmay be assembled on a job andsecured in place to permit concrete to be poured on opposite sides-of the joint forming unit.

The improved joint forming uni-tillustrated in Figures 1 and 2 :comprises a pre-iormed compressible bottom filler or core board 1 and an upper filler or core board 2 adapted to be constructed of asphalt, sponge-rubbencork or any other suitable compressible :material, such for example as thecompressible .mater-ial known to the trade as Flexceli. The-two filler or core boards 1 and -2 are positioned -at difierentlevels, and are furthermore disposedin difierent vertical planes in an offset relation. The two core boards i and 2 are held in oifset or staggered :relation with respect to one another, by means vof .improved load transmission devices comprising two reversed identically'constructed sections formed out of sheet metal. Each of .the .metal sections comprises plates or flangesBFa-nd .4, each of which has struck outwardly therefrom tapered anchoring blades or wings .5. The outer ends of the anchoring blades 5 are wider than theinner ends toserve as wedge or anchoringimeans when .the expansion joint device is imbedded in concrete. The anchoring blades of one of the sections are staggered with respect to the anchoring blades of the opposite section. v

The section plates or flanges 3 and 4 are'held in spaced offset relation with respect to one another by the middle portion of the section, which isalso constructed of sheet metal bent or formed to provide an intermediate S-section of alarge loop or channel 6 and a smaller or thinner loop or channel 'l, which project outwardlyawayfrom one another in opposite directions. One margin of the plate or flange 3 is integrally connected with the margin of one of the platesforming the loop'portion 6, while the plate or flange 4 is integrally connected with one margin ofone ofthe plates forming a part of the thinner loop 1. The two remaining plates of theloop portions'li and I are integrally connected by a transverse connecting plate 8, which is of such a width that the flanges 3 and 4 are held in spaced-or'offsetparallel planes,

As clearly illustrated in Figure l, the two metal sections are reversed with respect to one another, with the narrow channel or loop I of one of the sections slidably interfitting into the wider channel or loop 6 of the adjacent section. This slidable interfitting relation of the metal sections positions the connecting plates 8 in slidable contacting engagement with one another, providing a double thickness of themetal in-the space separating the two core board holders which are formed by the flanges 3 and 4 of the interfitting sections.

It will .be noted that the formation of the core board holders is such that the holders project in opposite directions from the contacting plates 8, and serve to hold the core boards or fillers in offset spaced relation in substantially parallel planes.

For the purpose of holding the expansion joint forming mechanism in position upon a road subgrade, a plurality of holding brackets are :positioned in staggered interfitting relation on :opposite sides of the joint mechanism and are staked in position. Each of'the expansion joint holders comprises-a base plate9, one end of which is bent upwardly and back'over the top of the base plate to form an upper base plate It]. Integrally formed on the inner edge of the top base plate 10 is an upright supporting wall or plate H, which has integrally formed on the upper margin thereof an outwardly projecting upper loop portion [2, into which one set of the interfitting loop portions -6 and 1 are adapted to project, as clearly illustrated :in Figure 1. The

inner end of the top plate of the top loop I2 is bent upwardly to provide a top flange or wall 13, which is deflected at 1-4 to fit around the flange 3 of one of the interfitting'sections, thereby permitting the upper margin'of theplate 13 to fit or seat against one side of the top filler or core board 2. The-top loop 12-01 the holderis provided withopenings I 5, while'the base plate9 andthe upper base plate 10 are provided with registering openings Hi to permit a tapered channel :peg or stake H to be-projected downwardly through the apertured loop portions of the holder for the purpose of staking one-side of theholder to'the subgrade, Struck outwardly from the intermediate plate of the channel stake H is a finger or lug l8, which is adapted to seat against the top plate of the loop portion I2 to limit the projection of the'stake 'l I through the apertured p'ortion'of the holder, The base plate 9 on the opposite side of the lower core board I is also provided with an opening Hi to permit another channel stake H to be driven through the base plate '9 and into the road subgrade, until the projecting finger or lug l8 seats against the top of the loop portion 6 on that side of the joint mechanism. It will thus be seen that the holders staked in position, as illustrated in Figure 1, serve to hold the joint forming mechanism properly positioned upon the road subgrade to permit the pouring of concrete on opposite sides of the joint forming mechanism to form the road slabs l9 and 2!]. Asillustrated in Figure l, the major portion of the joint forming mechanism holder is engaged on one side of said mechanism with the base plate 9 projecting from beneath the slab on one side of the joint beneath the slab on the opposite side. It is intended to position the holdersin staggered reversed position on opposite sides of the joint forming mechanism at spaced intervals, depending upon the length of the expansion joint.

As clearly illustrated in Figure 2, it will be noted that the formation of the expansion joint causes a peculiar formation of the road slabs l9 and 20, in whichthe road slab I9 has a portion thereof adjacent the upper core board 2 which overlaps or overhangs the portion of the road slab 20 which contacts one side of the lower core board I. It will thLLS be seen that the two overlapping portions of the slabs l9 and 20 are separated by the slidable contacting plates 8, which connect the two core board holders forming part of the road joint forming mechanism. The anchor blades or wings of the interfitting sections are imbedded in the respective slabs I9 and 20, to permit loads to be transmitted from one road slab to an adjacent road slab through the overlapping portions of the slabs to provide a road construction of materially greater strength, and able to withstand greater shocks and strains before cracking of the road slabs takes place. The arrangement of the anchoring blades 5, as well as the offset relation of the core boards I and 2, provides for reinforcement of the road slabs l9 and 20 on opposite sides of the joint for considerable distances away from the joint.

Figure 3 illustrates a modified form of the load transmission joint imbedded between concrete road slabs 2| and 22, and consisting of a compressible core comprising a lower filler or core board 23, an intermediate filler or core board 24, and an upper filler or core board 25. The three core boards are separated by two sets of the interfitting metal holder sections, which are substantially the same as the sections illustrated and described in connection with Figures 1 and 2, with the exception that the cross plates 8 are not as wide as the plates=8 illustrated in Figure 1, but are of sufficient width to permit the interfitting holder sections to position the intermediate core board 24 in offset relation with respect to the lower and upper core boards 23 and 25 to afford an arrangement where the middle portion of one side of the road slab 2| projects between the two sets of interfitting load transmission holder sections and between the lower and upper core boards 23 and 25s The arrangement illustrated in Figure 3 also permits upper and lower portions of the road slab 22 to project above and below the intermediate core board 24. This arrangement also provides a road construction of greater strength, inasmuch as the slabs 2| and 22 on opposite sides of the joint forming mechanism tend to reinforce the slabs for considerable distances away from the joint so that the road is adapted to withstand greater loads.

In the arrangement illustrated in Figure 3 it will be noted that the core boards 23, 24, and 25 are so positioned in offset relation with respect to one another, that one side of the intermediate core board 24 is substantially in the plane of one side of the lower and upper core boards 23 and 25, respectively.

Figure 4 illustrates another modified form of load transmission joint, in which the mechanisms forming the joint are substantially the same as those described in connection with Figures 1 and 2, with the exception that in this case the connecting plates 8 of the core board supporting sections are of a width permitting the lower core board 26 and the upper core board 2'. to be offset with respect to one another substantially half of the thickness of the core boards. This permits portions of the road slabs 28 and 29 adjacent the joint, to overlap portions of the core boards 26 and 21, thereby providing a road construction adapted to withstand greater loads and providing a plurality of metal plates between the concrete road slabs at the portion of the joint where the core board holding interfitting sections engage one another. This'modified form of the joint also reinforces the concrete slabs on opposite sides of the joint fora considerable distance away from each side of the joint.

Figure 5 illustrates a fragmentary sectional view of another modified form of an expansion joint forming mechanism substantially the same as the filler board holding units illustrated in Figures 1 to 4, inclusive. The similar parts are designated by corresponding reference numerals. In this modified form of the mechanism the modification consists of the use of a spring steel plate 30 which rests upon the upper common plate 8 of one of the holder sections and projects into the loop portion 1 which is disposed directly beneath the upper filler board 2. The use of the spring steel plate 30 reinforces the twointerfitting holder sections and serves to strengthen the middle portion of the joint.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention, and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. An expansion joint forming mechanism including in combination, a plurality of pre-formed plastic filler boards, load transmitting members formed for holding the filler boards in offset planes, and holders for supporting the filler boards and said members in position on a road subgrade to be imbedded between concrete road slabs, each of said holders comprising a pair of loop sections, a wall connecting the same, a flange formed on one of said loop sections, and a base plate formed by an extension of the bottom plate of the other of said loop sections, said base plate extending from beneath one of said road slabs across the bottom of the expansion joint and beneath the opposite road slab.

2, An expansion joint forming mechanism including in combination, a plurality of filler boards, load transmitting members formed for holding the filler boards in ofiset parallel planes, holders for supporting the filler boards and said members in position on a road subgrade to be imbedded between concrete road slabs, each of said holders comprising a pair of apertured loop sections, a wall integrally connecting the same, a flange formed on one of said loop sections, an apertured base plate formed by the extension of the bottom plate of the other of said loop sections, said base plate extending from beneath one of said road slabs across the bottom of the expansion joint and beneath the opposite road slab, and stake members engaged through the apertured loop sections and through the base plate and extending into the road subgrade.

3. In an expansion joint for imbedding between adjacent concrete road slabs, a plurality of preformed compressible filler boards, slidably interfitting load transmitting sections constructed to hold the filler boards in offset parallel planes and including superimposed plates spanning the space between the offset filler boards, and a spring steel insert plate for reinforcing the transverse interfitting portions of said sections and interfitting with one of said load transmitting sections and resting upon said superimposed spanning plates.

4. The combination with adjacent concrete road slabs having a plurality of filler boards therebetween, of load transmitting means anchored in the slabs onopposite sides of the filler boards and holding said boards in oifset re1ation,and a spring steel insert plate projecting transversely between the slabs and between adjacent edges of the filler boards and supported on the load transmitting means.

ROBERT R. ROBERTSON.

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