US3011413A - Paving joint constructions - Google Patents

Description

1961 E. s. MATHERS 3,011,413

' PAVING JOINT CONSTRUCTIONS Filed Feb. 3, 1959 2 Sheets-Sheet 1 INVENTOR ATTORNEYS Dec. 5, 1961 E. s. MATHERS 3,011,413

PAVING JOINT CONSTRUCTIONS Filed Feb. 5, 1959 2 Sheets-Sheet 2 if 79 5f i7- I=I=H if I I [I Z I Q 57 I k, al

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ATTORNEYS United States Patent I Maryland Filed Feb. 3, 1959, Ser. No. 790,897 4 Claims. (Cl. 94--8) This invention relates to concrete pavement construction and more particularly to contraction and expansion joint structures for curb-and-gutter work.

The general object of the invention is to provide novel and improved curb-and-gutter joint structures, embodying a joint strip supporting means with provisions for load transfer, which means is of relatively simple and economical construction, easy to install, and of sufficient sturdiness to effectively sustain the joint strips and load transfer dowels in place during the pouring of the slabs.

As is well known in the art, the laying of combined integral curb-and-gutter structures has become widespread practice, especially where the main portion of the roadbed or street is to be of macadam, black top, or asphalt, the curb-and-gutter structure providing not only drainage facility but also providing confining forms for the later applied road material by establishing both the boundaries of the road and the gradient, the road material being merely rolled level with the gutter surface and properly cambered.

The present invention in its preferred embodiments contemplates the provision of a joint structure which includes a looped rod bent to occupy a vertical plane largely within the confines of the gutter portion of the concrete structure, but provided with upwardly extending portions furnishing support for that part of the joint strip which separates the adjoining-curb-forming portions of the poured slabs.

Associated with these looped rods are appropriate chair structures which along with such rods form a basic structure for the proper support and positioning of the load transfer dowels.

Other objects and features of novelty, including the adaptation of the novel joint supporting structure for use either in contraction or expansion joints, will be apparent from the following specification when read in connection with the accompanying drawings in which certain embodiments of the invention are illustrated by way of example.

In the drawings:

FIGURE 1 is a view in elevation of a curb-and-gutter joint structure of the contraction joint type, looking in the direction longitudinally of the roadway to which it is to be applied;

FIGURE 2 is a view in side elevation of the structure of FIGURE 1 and taken at right angles to that figure;

FIGURE 3 is a view in perspective of the joint structure of FIGURES l and 2;

FIGURE 4 is a view similar to FIGURE 1 but showing a modified form of joint structure for use in connection with expansion joints;

FIGURE 5 is a view in side elevation of the joint structure of FIGURE 4; and

FIGURE 6 is a perspective view of the expansion joint structure of FIGURES 4 and 5.

The contraction joint structure peculiarly adapted for curb-and-gutter work and illustrated in FIGURES 1-3 of the drawings, is given the general designation 10. The structure comprises the contraction strip arrangement 11 which includes the transversely extending elongated strip portion 12 which extends through both the curb-andgutter portions of the poured concrete structure, and the upwardly extending curb strip portion 13 which may be secured to the strip 12 as by means of the welding 14.

Load transfer dowel members 15 extend transversely of the joint structure, portions of the dowels projecting through one of the adjoining slabs 16 as shown in FIG- URE 2 and the other end portions of the dowels entering the slab 17.

Supporting means for the separator strip 11 and the dowels 15 include the chairs 20, these chairs being provided at their rearward ends with upstanding flanges 21. These flanges 21 are surmounted by the spacer rod 23 which not only serve as tying means for the chairs but also as supports for the rear ends of the dowels 15. The dowels may be secured to the spacer rod 23 as by the welding shown at 24.

Adjacent the plane of separation of the slabs 16 and 17 effected by the joint strip 11, is the looped support rod 25, the lower reach 26 of which is adapted to rest upon the sub-grade 27 at the forward ends of the chairs 20 and in abutment with the latter. The rod 25 may be secured to the forward edge of the chairs 20 by means of the welding 28. The opposite ends ofthe looped rod structures 25 are return-bent and extended horizontally inwardly in parallelism with the bottom reach 26 as at 30. The extreme ends of the looped rod 25 are turned upwardly as at 31 and secured as by the welding 32 to the strip portion 12 at spaced points therealong. It will be noted that the dowels 15 adjacent the plane of the joint strip 11 rest upon the shoulders 30 of the looped rod structure 25 and may be welded thereto as indicated at 34.

In order to firmly secure the chairs 20 to the sub-grade during pouring of the curb-and-gutter slabs, anchor pins 35 are employed which pass through openings 36 in the base plates of the chairs 20. p

In FIGURES 4, 5 and 6 of the drawings there is illustrated an embodiment of the invention which is adapted for the construction of expansion joints wherein the dividing strips are made of somewhat thicker and more resilient material and which of necessity extend downwardly for the full extent of the height of the adjoining slabs. Whereas the metal contraction joint strips are applied to the upper portion of the slab separation zone and are readily we'ldable to the supporting structure, the expansion joint presents a'somewhat different problem. The material of which the joint strip is made comprises a softer non-metallic fabrication and is supported upon the sub-grade and braced in proper vertical position by more elaborate means associated with the supporting structure than in the case of the contraction joint.

Thus, the stepped joint strip is formed with a lateral extension 51 separating the gutter portions of the two slabs 52 and 53 while the upward extension 55 separates the curb portions of these slabs. The bottom edge of the strip may be formed with a horizontal portion 57 and an inclined portion 58 which may follow any slight camber given the sub-grade 60 upon which the strip rests.

The dowels 62 are disposed through openings in the strip 50, the dowels themselves bridging the two adjoining slabs 52 and 53 and affording load transfer means in the known fashion. Sleeves or caps 63 are applied to the extending dowel ends as in the first embodiment.

The supporting structure for the strip 50 and dowels 62 comprises chairs 65 similar in construction and function to the chairs 20 of the previously described embodiment. Each chair 65 includes an upwardly extending flange 66 which supports the spacer rod 67 which in turn provides supporting means for the rearward ends of the dowels 62. These parts may be welded together as described in connection with the corresponding features of the first described embodiment.

Adjacent the junction between the two slabs S2 and 53 and disposed alongside of the expansion strip 59 is the looped supporting rod structure 70. The rod consists of the bottom reach 71 which extends approximately along the surface of the sub-grade and is supported thereby adjacent the front ends of the base flanges of the chairs 65, these edges preferably being welded to the bottom reach 71 of the looped rod 70 as at 73. At the left-hand end of the looped rod structure 7d as viewed in FIGURE 4 of the drawings the rod is given a return bend 74 and extends in a direction parallel to the reach 7-1 in the form of a bench portion '75 which serves to support the intermediate portions of the dowels 62, the dowels being welded to this stretch 75 of the rod for rigidly uniting the joint structure.

At the right-hand end of the structure as viewed in FIGURE 4 the rod is given a right-angled bend as at 77 and extends upwardly at 78 to a point adjacent the top of the curb portion 55 of the separator strip 50, whereupon it continues as a substantially horizontal portion 79 and then is bent downwardly to terminate in a vertical length 80 as shown.

In order to secure the expansion strip 50 in proper position prior to pouring the slabs, cap nails are driven through the slab at strategically spaced points and the ends of the nails clenched over the adjacent portions of the looped rod structure 70, as shown at 85.

In order to insure the proper positioning of the joint structure while the slabs are being poured, anchor pins 90 are employed, these pins passing through openings 91 provided in the base plate portions of the chairs 65 and entering the sub-grade 6G.

It will be understood that various changes and modifications may be made in the embodiments illustrated and described without departing from the scope of the in vention as defined by the following claims.

' Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. A load transfer and joint construction for adjoining sections of a concrete curb-and-gutter structure for roadways comprising, in combination, a stepped joint strip adapted to be vertically disposed at the junction of the Sections and comprising a substantially horizontally extending gutter portion and an upwardly projecting curb portion; dowels passing perpendicularly through the plane of said strip and positioned to be embedded in both concrete sections and provide load transfer means therefor; and a supporting structure for said strip and said dowels which comprises transversely spaced sheet metal chairs each having a base plate adapted to rest on the sub-grade and a vertical flange extending upwardly from the end of said base plate remote from said joint strip, a horizontal cross rod secured to said vertical flanges upwardly from the base plate and extending in a direction parallel to the plane of said strip, said dowels resting upon and secured tosaid cross rod, and a looped vertical planar rod structure disposed adjacent the joint strip, said looped rod structure including a base portion adapted to rest upon the sub-grade and extending substantially throughout the width of said joint strip, the rod bent upwardly at each end of said base portion, and the rod at one of said ends further bent inwardly to provide a bench portion substantially parallel to and spaced upwardly .from said base portion, a dowel resting on said bench portion and secured thereto, a portion of said rod at the other of said ends extending upwardly from said base portion beyond the level of said bench portion, and means securing said joint strip flatly against said looped rod structure.

The load transfer and joint construction set forth in claim 1 in which both end portions of the looped rod structure are return-bent at the ends of said base portion to provide two upwardly projecting bench portions,

one for the support and securement of each of a pair of said dowels, and both terminals of the bent rod structure projecting vertically upwardly in parallel relation and secured to the joint strip, one of said terminals constituting the aforementioned rod portion which extends upwardly beyond the level of the bench portion.

3. The load transfer and joint construction set forth in claim 2 in which said last named upwardly extending terminals are welded to the joint strip, which strip is a metal contraction joint strip.

4. The load transfer and joint construction set forth in claim 1 in which the bench portion extends approximately the width of said base portion, and the said portion of the red at the other of said ends extends upwardly from the base portion beyond the gutter level and.

further bent to provide a hook-shaped portion to back up the upwardly projecting curb portion of the strip.

References Cited in the file of this patent UNITED STATES PATENTS

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