US2775924A

US2775924A - Pavement joint

Info

Publication number: US2775924A
Application number: US292697A
Authority: US
Inventors: Alan E Brickman
Original assignee: Acme Highway Products Corp
Current assignee: Acme Highway Products Corp
Priority date: 1952-06-10
Filing date: 1952-06-10
Publication date: 1957-01-01
Anticipated expiration: 1974-01-01

Description

Jan. 1, 1957 A. E. BRICKMAN 2,775,924

PAVEMENT JOINT Filed June l0, 1952 2 Sheets-Sheet 1 Imh @n E @y '777 nl '1 lll 72 76 Jam 1, 1957 A. E. BRICKMAN 2,775,924

PAVEMENT JOINT Filed June 10, 1952 2 Sheets-Sheet 2 78 24- j/Z'g. 6.

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United States Patent O PAVEMENT JOINT Alan E. Brickman, Buffalo, N. Y., assignor to Acme Highway Products Corporation, Buffalo, N. Y.

Application June 10, 1952, Serial No. 292,697

Claims. (Cl. 94-17) This vinvention relates to improvements in pavement joints of the type used to connect adjacent slabs of cement concrete pavements, and particularly to joints of this type which compensate for contraction of such pavements. Portland cement concrete pavements are subject to expansion and contraction due to reactions caused by initial setting, thermal coefficient of expansion, moisture absorption and aging.

Expansion joints in a pavement usually include a compressible filler placed between abutting ends of pavement slabs. The expansion of a pavement compresses this joint ller material without appreciable increase in the stresses in the pavements. Contraction joints on the other hand provide for thermal or other contraction of a pavement, which generally shows up as an opening between the slabs when a cut joint has been provided between slabs, or in one or more cracks when no cut joint has been provided. Due to low tensile strength of cement concrete, relief of contraction stresses is nearly always in the form of crack openings intermediate of the ends of the labs, which tend to reduce the loadcarrying capacity of the pavement.

One of the objects of this invention is to provide a contraction joint of new and improved construction between pavement slabs.

A further object is to provide new and improved load transfer members for use in connection with pavement joints of this type.

It is also an object of this invention to provide a load transfer contraction joint including longitudinally extending` plates arranged in vertical and horizontal directions and connected with each other by means of load transfer members.

Another object is to provide load transfer members with means of improved construction for securing the longitudinally extending plates thereto.

Other objects and advantages will be apparent from the following description of some embodiments of the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawings:

Fig. l is a fragmentary top plan view of a contraction joint embodying this invention.

Fig. 2 is a fragmentary elevation thereof.

Fig. 3 is a transverse sectional elevation thereof on an enlarged scale on line 3 3, Fig. 1.

Figs. 4 and 5 are respectively horizontal sections on lines 4-4 and 5-5, Fig. 3.

Fig. 6 is a sectional elevation thereof on line 6 6, Fig. 3.

Fig. 7 is a side elevation of a load transfer member as originally formed by casting.

The drawings illustrate by way of example one embodiment of this invention, and in these drawings are shown load transfer members designated generally at 10. These load transfer members are mounted on the plane of weakness plate, 11, which is supported by the load Patented Jan. l, 1957 ICC transfer members in a substantially upright plane, and a base plate 12 is secured to the lower parts of the load transfer members. The two plates may be made of any substantially rigid material, relatively thin steel being preferably employed.

The load transfer members each include a base portion 15 which has a at, lower face formed to rest on the subgrade of pavement. This base member may be of any suitable or desired shape, that shown being substantially segmental in cross section and provided with acurved upper surface 16. The load transfer member also includes a pair of upright parts 17 formed integral with the base 15 and spaced apart in positions to receive between them the upright plane of weakness plate 11. The upper ends of these upright parts 17 terminate in substantially horizontal, extending anchor members 18 which extend in spaced relation above the base member 15 and are to be embedded in adjacent slabs of concrete. These anchor members may terminate in enlarged ends 19 which serve to cause the anchoring members to become more securely bonded to the concrete slabs. The anchoring members may be of any other suitable or desired form, and the upright parts 17 are preferably provided with substantially flat surfaces formed to bear against the plane of weakness plate 11.

In order to ensure the desired positioning of the load transfer members lengthwise of the upright plate 11, this plate is provided at intervals lengthwise thereof with suitable means for locating the load transfer members thereon, such for example as notches or recesses 21 extending into the plate from an edge thereof, and at least one of the upright parts 17 is provided with a boss or projection 22 of approximately the same shape as the notches 21, and extending into the space between the two parts 17. Consequently, when the upright parts 17 are in the positions shown in Fig. 3 and the upright plate 11 is correctly inserted between the upright parts 17, the notches 21 in this plate will cooperate with the projections 22 in such a manner that the projections extend into the notches. l

At least one of the upright parts 17 is also provided near the upper end thereof with a tooth or projection 24 which, as shown in Fig. 3, extends partly across the space between the two upright parts 17. Since these upright parts are somewhat exible, the upright plate 11 may be forced past the tooth or projection 24, and thus passed into the space between the two upright parts 17. To facilitate the insertion of a plate between the upright parts 17, each tooth or projection 24 may also be provided with an upper, inclined or bevelled face 25. Consequently, the projecting parts 22 serve not only to locate the load transfer members lengthwise of the upright plate 11, but also limit the extent to which this plate may be moved downwardly relative to a load transfer member, and the tooth 24 serves to prevent the load transfer member from moving downwardly relatively to the upright plate 11 so that the load transfer members are held in fixed positions to the upright plate 11. Any other suitable means for correctly positioning the load transfer members on the upright plate 11 may be provided.

In order to facilitate the production of the load transfer members during molding, these members are preferably molded int-o the form shown in Fig. 7, with the upright parts 17 diverging upwardly from the base 15. Since Ithese load transfer members are preferably made of malleable castings, the upright parts 17 can readily be bent toward each other after removal of the same from the molds to lie in substantially parallel relation, as shown in Fig. 3. Malleable metal also has limited resilient properties giving flexibility of springiness to the upright parts as heretofore stated. By casting the upright parts as shown in Fig. 7,

the space between the upright parts, after they are benty into substantiallyparallel relation -to each other, maybe very small, just sufficient to receive a relatively thin steel plate, and lby casting the load transfer devices in this manner, expensivefcoring is` avoided andthe iling,lgrinding and inspection of the inner faces of the upright parts isl facilitated.` This manner of castingthe load transfer devices .also makes it possible .tot easily form the boss or;V

projection 22 on the inner face of an upright part 17. By spacing the upright parts 17 closely together, the load transfer devices have a higher loadtransfer value as compared with similar constructions of equal cross section in which the uprightparts 17 are spaced farther apart.

Ay base plate 12 may be secured to the loadtransfer member in any sui-table or desired manner. Intheconstruction illustrated byA Way of example, the .base portion 15 ofgeachload transfermember is provided on the lower face ythereof' with a recess 27 ofV such size and shape that the base plate 12 'may readily lit into Vthe same. The base of theload transfer member is also provided with a downwardly extending, short stud 28,l preferably formed integral therewith, and the base plate vis provided at intervals withholes or openings `through which the studs-28 of the load transfermembers may be inserted. These studs, after passingthrough the holes in the base plate, may then be riveted or burred over so that the base plate will be rmly lsecured to the load transfer members.

In order to facilitate the assembly of the load transfer members Vand the

plates

11 and 12, the plate 11 is preferably temporarily held in inverted position. The load transfer members are then pushed downwardly in to correct relation to the notches 21 until the teeth 24S-snap across the opposite edge of the plate 11. The 'base plate is then placed into position to enter the recess 27 in the bases of `the load transfer devices with the studs ZS passing through the holes in the base plate, whereupon the outer ends of the studs may be riveted or burred over to secure the bottom plate in place,

When the load transfer members fare secured to `the uprigh-t plate 11 and the base plate 12, an assembled unit is formed which is then ready `to be placed on the subgrade of a pavement without requiring any further work thereon. The construction of the joint connection described has'the advantage that the assembled units have the two

plates

11 and 12 arranged in T-formation so that the. assembled unitstcan be readily handled for shipping and positioning on the subgrade and will not readily ex or bend v in lany direction.

In `order tol support this unit incorrect position an-d prevent displacement of the same when the cement concrete is poured,- the base plate is preferably provided at intervals -with holes 30,Fig. l, through which spikes or stakes 31, Fig. 2, may pass. These stakes are then driven intothe -subgrade Preferably the 'holes 30 Yare lalternately arranged at opposite sides 4of the center of the base plate 12 'and the stakes 31 are preferably long enough to extend upwardly from the base plate after being driven into the subgrade along opposite sides-.of the upright plate 11, so that this plate willbeheld incorrect position-by" these stakes as-well asby` the bases'of the load transfer members.V

In the use of these lcontraction joints, the `assembled units, .including the load transfer members, the-upright plates 11 andthev base plates 12, are properly positioned on the prepared subgrade-betweenfthe lusual road forms 29, Pigs. l and 2, and 4secured in place on the subgrade by means of the stakes 31. The wet'cement concrete is then poured between the forms over and around the assembled units in an amount sufficient to screeding or leveling olf t a level slightly above the uppery ends of. the. load transfer, members, whereupon the usual reinforcing bars 32 are placed, onthescreeded top. surface of they cement concrete. complete .the slabs.

endsnof KVthe upright plates-11 in such manner that` the Additional cement concreteis then poured toV Before lthe, last mass .oflpwetfcement,A concrete is poured,l locating pins 33 are; appliedto the;

upperendsthereof. will ,be ator slightly .abovetthelfinal upper surface of the pavement. These locating pins may be of any suitable construction, those shown being in the form of plates bent into substantially U-shaped cross sectional form so that they may grip or clamp themselves to the ends of the upright plates 11. These locating pins are desirable for the reason'that they serve to indicate the position of the joint member, and particularly of the upright plate 11 when the same is covered with concrete.

Atthe prescribed time, after finishing therupper surface ofthe low tensile strength of cement concrete,` cracking of -the pavement -will occur, and these cracks; because ofthe plane of weakness plate 11 and thegroove 35, willloccur, in the space between this `plate'and the grooveand Vin a substantially verticalfplaneat one or both` sidesof the upright plate 11. Cement concrete willlnotad-l here with much tenacity to metal-surfaces of 'the -plates or load transfer members and, consequently, the crackin the pavement may readily separate one or bothfslabs from the upright plate 11.

to cracking in approximately the plate of the plate 11, and when a crack occurs in the pavementslab along the pavement joint, the :elastic sealing compositioneinthe groovef35 will merely be stretched and thus continue-to f keep moisture and foreign material out of the crack. The

base plate 12 serves a similar purposez of preventing such foreign material from entering into the part-v of thecrack below the upright plate 11.` When these' cracks occur' in the pavement at the juncture of two'adjacent slabs, no damage to the pavement-will result, and thetload transfer members will keep the adjacent edges of theV two slabsin alinement and prevent damage to the pavement: These' loadtransfer meansY or devices provide for surface alinement of adjacent ends of-.slabsat a joint and are of def signed strength and principal as-necessaryl tomaintainthis alinement under the stressesapplied bypassing wheel' loads over the joint, and internal stresses of the concrete;`

Whenthe pavement-contracts sufficiently to formcracksi between adjacent slabs, the slabs will move away from the ends of the base 15 and from-the lower portions of the upright parts 17. Since the anchor members 18 are embedded in theopposite slabs, the Yseparation'ofthe slabs will cause the Vupright parts 17 to bend or ex'to a slight-extent relatively to the-base 15," but-thisflexing isH very slight and will not result in breaking of the upright parts. The anchor members lcooperating with the bases 1S of the load transfer devices will hold the adjacent ends'.

of the pravement in alinenztentandvwillv transfer` wheel. loads from one pavement-slab'to an Yadjacentv one.`

It willbeunderstood that 'various changes inthe `details, materials and arrangements of partsrwhich have been hereindescribed and illustrated 'in order to explain the nature of the invention may bemade by'those skilled`` in the art withinthe yprinciplel and vscope 'of-the' invention as expressed in the appended claims.

I claim:

1. A pavement contractionjointcomprising ra plurality of load transfer members each having aibase, a pair of flexible Vuprightv partsv formed integral with said *baselv and in closely spaced relation-.to each other, anchor members;

extending outwardly in oppositefdirections from` the upper ends of said upright'partsand lintegral` therewith; a tooth There Vis only Aa relatively small,` vertical space between the groove 35 and the plane of'- weaknessv plate 11, and anotherA small space of this typel exists below -the plate of weaknessplate.. Consequently, theV cement concrete pavement has the minimum resistance on one of said upright parts extending into proximity to the other upright part, an elongate upright plate carried by said load transfer members, said upright plate having a minimum thickness greater than the minimum distance between the outer portions of said tooth and said other upright part, whereby said upright plate is snap held by said upright parts upon being passed between the upper ends of said upright parts, and past said tooth, and means for locating said load transfer members in spaced relationship to each other along said upright plate.

2. A pavement contraction joint as in claim l, and wherein said locating means comprises a notch on said upright plate, and a projection on the inside of one of said upright parts extending toward the other of said upright parts cooperating with said notch.

3. A pavement contraction joint as in claim 1, and having a horizontal plate underlying said upright plate and secured to the bases of said load transfer members.

4. A pavement joint as in claim 1, said bases of said load transfer members being recessed7 a horizontal plate underlying said upright plate and seated in said recesses and secured to said bases, and wherein said locating means comprises a notch on said upright plate, a projection on the inside of one of said upright parts extending toward the other of said upright parts cooperating with said notch, said projection being arranged in vertical alinement with said tooth.

5. A load transfer member of malleable metal for pavement contraction joints comprising a base, the bot tom of said base being recessed for receipt of a flat hori- Zontal plate, a stud in said recess for locking said horizontal plate in position, a pair of flexible upright parts formed integral with said base and in closely spaced relation to each other, anchor members extending outwardly in opposite directions from the upper ends of said upright parts and integral therewith, a projection spaced above said base on the inside of said upright parts and extending toward the other of said upright parts for cooperation with a notch in an elongated upright plate thereby locating said load transfer member on said elongated upright plate, a second projection on the upper end of one of said upright parts above said rst mentioned projection extending toward the upper end of the other of said upright parts, said rst and second projections providing locking means, whereby an elongated upright plate when inserted between said second projection on the one of said upright parts and the inside upper end of the other of said upright parts, causes said upright parts to ex away from each other until said upright plate clears said second projection whereupon said upright parts snap back to lock said upright plate in position.

References Cited in the le of this patent UNITED STATES PATENTS 1,298,018 Davis Mar. 25, 1919 1,753,316 Robertson Apr. 8, 1930 2,064,528 Fischer Dec. l5, 1936 2,207,168 Thomas July 9, 1940 2,309,538 Robertson Jan. 26, 1.943 2,319,972 Brickman May 25, 1943 2,441,903 Robertson May 18, 1948 2,589,815 Jacobson Mar. 18, 1952