US3880540A

US3880540A - Modular expansion joint

Info

Publication number: US3880540A
Application number: US358059A
Authority: US
Inventors: Michael C Rizza; Delmont D Brown
Original assignee: DS Brown Co Inc
Current assignee: DS Brown Co Inc
Priority date: 1971-03-08
Filing date: 1973-05-07
Publication date: 1975-04-29
Anticipated expiration: 1992-04-29

Abstract

Modular expansion joints made from aluminum extrusions providing longitudinal frames and longitudinal rails. The rails have an Ibeam-like structure with upwardly opening channels respectively receiving and interlocking therein deformable beads on the lower surface of an elastomer tread with hollow, V-sections deforming downwardly as the joint width becomes narrow. The elastomer tread completely covers and spans the joint. The longitudinal rails are supported by solid load-bearing beams having a greater width than depth, and coil springs are interposed between contiguous rails.

Description

United States Patent [191 Rina et al.

1 1 MODULAR EXPANSION JOINT [75] Inventors: Michael C. Rizza, Walnut Creek.

Calif; Belmont D. Brown, North Baltimore. Ohio [73} Assignee: The D. S. Brown Company, North Baltimore, Ohio 221 Filed: May 7,1973

21 Appl.No.:358.059

Related US. Application Data [63] Continuation-impart of Scr. No. 121.957. Feb. 8.

1971, Pat. No. 3.732.021.

[52] US. Cl. 404/69 [51] Int. Cl. E01c 11/02 [58] Field of Search 404/47, 48, 60, 68, 69,

[56] References Cited UNITED STATES PATENTS 1.977.496 10/1934 Snyder 404/47 X 2,043,571 6/1936 Bargrcen... 404/60 2.255.599 9/1941 Olmsted... 404/60 2.321.873 6/1943 404/47 X 2.494.869 1/1950 Godwin 404/60 Apr. 29, 1975 3.113.493 12/1963 Rinker 14/16 X 3.323.426 6/1967 Hahn 404/48 3.363.383 1/1968 La Barge 404/68 X 3.418.898 12/1968 Cimini 404/48 3.606.826 9/1971 Bowman 404/69 8 3.720.474 3/1973 Stog 14/16 X Primary ExaminerNile C. Byers. Jr. Almrney, Agent. or FirmJohnston. Keil, Thompson 8L Shurtleff [57] ABSTRACT Modular expansion joints made from aluminum extrusions providing longitudinal frames and longitudinal rails. The rails have an l-beam-like structure with upwardly opening channels respectively receiving and interlocking therein deformable beads on the lower surface of an elastomer tread with hollow. V-sections deforming downwardly as the joint width becomes narrow. The elastomer tread completely covers and spans the joint. The longitudinal rails are supported by solid load-bearing beams having a greater width than depth. and coil springs are interposed between contiguous rails.

12 Claims. 4 Drawing Figures whim 1 MODULAR EXPANSION JOINT RELATED APPLICATION This application is a continuation-in-part of our application Ser. No. 121.957. filed Mar. 8. I971 now US. Pat. No. 3.732.021.

INTRODUCTION The subject invention concerns improvements in expansion joint structures useful in the spanning of relatively wide joints in pavement surfaces. particularly joints in pavement decks of bridges. The latter joints have a relatively wide range of movement. i.e.. opening and closing. during expansion and contraction of sections of a bridge deck as the environmental temperature changes.

Expansion joints for bridges heretofore have involved heavy assemblies or subassemblies brought to the bridge site and mounted in the bridge joints by cranes or the like. One well known type of bridge expansion joint comprises a pair of heavy duty plates fixedly attached to opposite sides of the joint. The plates have projecting, interfitting fingers which span the joint and can move relative to each other if the joint opens or closes. Joints of this type cannot be effectively sealed against leakage of water from rain or melted ice or snow. The latter two in particular carry with them corrosive salts which. over a period of time. damage the superstructure of the bridge. its piers. and/or abutments.

Bridge designers and engineers have been giving more attention in recent years to use of bridge joints which are sealed against leakage of water and/or solids through the joint onto the underlying structure of the bridge. A relatively recent design for a sealed bridge joint embodies longitudinal. spaced rails resting on joint-spanning beams. Laterally compressible elastomer seals are compressed between the rails slightly below the upper surface thereof. The upper surfaces of the rails lie substantially in the plane ofthe bridge deck. The tires of automobiles crossing the joint run across these upper surfaces of the rails while the elastomer seals are recessed enough to avoid contact with the automobile tires.

These known expansion joints are manufactured and preassembled at an off-site facility. compressed to a width allowing them to be inserted in the joint. hauled to the bridge site and laid in the joint with heavy duty cranes. Once installed. they are difficult to repair. Repair or replacement of a component usually involves closing the entire bridge or several lanes thereof to traffic in order that heavy duty equipment may be brought to the joint site to raise the expansion joint. repair it. and replace it back in the joint.

THE INVENTION HEREIN This invention provides improvements in expansion joints having ranges of movement which are lesser than those attainable in the modular bridge joint of the aforesaid copending application. the latter having loadbearing beams which are segmentally interconnected to allow the beams to lengthen or shorten the movement of the joint. The improvements of the subject invention reside in modular expansion joints having a shallower overall depth attained through, inter alia. the use of load-bearing beams of solid material, e. g.. aluminum or steel, laid in the joint in a manner where the width exceeds the depth of the respective beams. Further improvements of the invention reside in the configuration of the seal and tread which spans and covers the entire joint. particularly in the provision of upper and lower V-shaped walls with a hollow space therebetween in the sections of the tread extending between respective longitudinal rails. Other improvements reside in the manner of mounting the outermost rails in the longitudinal frames on opposite sides of the joints.

The metal components of the joint include longitudinal frames mounted in stepped edges of a concrete pavement deck. such as the concrete pavement deck of a bridge. or in other concrete structures such as pavement sections adjoining or contiguous to bridges. The longitudinal rails extend longitudinally of the joint in substantially equally spaced relationship. These rails may be made in short sections and spliced together in end-to-end relationship in the manner shown in the aforesaid application.

The frames. rails and load-bearing beams preferably are fabricated as aluminum alloy extrusions. Each extrusion is relatively light in weight so that the joint can be assembled manually at the joint site without using heavy duty equipment. The rails are of relatively short lengths. e.g.. 12 feet. This feature allows the joint to be constructed or repaired on a one lane at a time basis. while keeping other lanes open to traffic flow during maintenance. The frame sections provided at each side of the joint also preferably are made in short sections and may have a gasket between abutting ends to seal the abutting ends against seepage of water at these points.

The joints of the invention are constructed in standard unit lengths and will span joints of medium width. e.g.. joints having a maximum opening of 8-l2 inches. The coil springs between the rails maintain substantially equal spacing therebetween regardless of joint width. The ends of the coil springs respectively are composed of horizontal legs which seat in a groove provided in the lower portion of the l-beamlike rails and a diagonal leg. the tip of which seats in an opposite groove of said rails.

The load-bearing beams or bars extend through aligned openings provided in the respective rails and span the entire joint between respective outer rails. The longitudinal frames at each side of the joint are provided with a recess segment into which the ends of the load-bearing beams or bars can project when the joint closes arid the ends of the load-bearing beams or bars begin to extend into the longitudinal frame members of the joint.

The frames at the edges of the joint are extrusions which may be placed at the time of the initial deck paving. Secure mounting of the frames in the deck pavement is accomplished by anchor bolts embedded in the concrete and tied to reinforcing steel in the deck pavement.

The elastomer seal and tread provides a continuous seal from curb to curb without joints subject to leakage. The seal has longitudinal beads which snap into channels on the upper edges of the rails thus making the seal easy to install'or replace. The seal covers all of the metal structure of the joint and is the only part which could be damaged by snowplows. The interlocking of the seal with the rails assures positive sealing in that the seal must move as the joint components move during thermal expansion or contraction of the joint.

THE DRAWINGS A preferred embodiment of the invention is illustrated in the drawings. wherein:

FIG. 1 is a vertical section of an expansion joint with the concrete segments of the joint shown in fragment;

FIG. 2 is a section view taken on section plane 22 of FIG. 1 without the elastomer tread;

FIG. 3 is a fragmentary. bottom plan view of abutting sections of an end frame member of the joint; and

FIG. 4 is a fragmentary detail in side elevation of the bracket and bolt connection for the abutting sections.

Referring to the drawings. the modular expansion joint spans a space 14 between adjacent sections 11 and 12 of a concrete bridge deck. The sections 11 and 12 each have a step 13 on which the longitudinal end frames 14 and 15 are seated and held in place by conventional J-bolts or other type of anchor bolts 16 or like holding devices The anchor bolts have treaded shanks which tread into nuts 17 seated in

longitudinal slots

18 and 19 which extend the length of the

frame sections

14 and 15. The nuts 17 are placed in the slots 18 at any desired longitudinal spacing. The J-bolts may then be treaded into the nuts until the bolt and nut bind in the

respective slots

18 and 19. This mounting of the nuts in the slots has proven very advantageous in installation or mounting of the frame sections on the bridge structure. The nuts may be positioned anywhere in the slots and thus can be located on thejob site to allow the anchor blots to interfit with or avoid interfering contact with other components of the bridge deck or its understructure.

The longitudinal end frames preferably are aluminum extrusions having an upper. rearwardly projecting lip 20 forming an undercut 21 beneath which concrete can flow. The

frames

14 and 15 preferably also have a small forward lip 22 adapted to overlie the respective ends of the eiastomer tread 23. The lip 22 helps provide a seal against intrusion of sand and other incompressibles between the seal and the frame and also aids in holding the respective ends of the elastorner tread in position in the respective end frames 14 and 15.

The lower portion of the end frames 14 and 15 includes a rearwardly directed wall 24 joined to the bottom wall 25 by a connecting wall 26 which flares in an upward direction to accommodate the longitudinal slot 18. A chamber 27 is provided between the upper and

lower walls

24 and 25. which chambers will receive and accommodate the ends of the load-bearing beams or bars 28 when the joint 10 closes to its minimum or near minimum width.

The lower wall 25 of the end frame includes an enlarged segment to accommodate the longitudinal slot 19 and further form a seat 30 for the lower wall 31 of the respective end rails 32. which are mounted on the respective end frames.

The intermediary rails 33 are of the same cross section as the outermost rails 32. Their lower walls 39 with upturned ends 34 provide longitudinal rigidity for the rails and forming grooves 48, later described. Their upper ends have wall segments 35 like the bottom wall 39 and further include U-channels 36 with inwardly directed lips 37 for receiving deformable. dovetailed tongues 38.

The elastomer tread 23 may be made in sections which fit side-by-side across the width of the joint. Each section includes an end wall 40 having a sawtoothed or serrated upper side edge 41. The latter interlock and form a seal against intrusion of water between abutting faces of the tread sections. The contacting faces of the end walls 40 are positively sealed against water leakage therebetween by tight-fit and compression of the portions of tongues 38 which seat between the neck formed by the opposed. inwardly directed lips 37. The side-byside. lower portions of the abutting edges together form as a composite dovetailed tongues 38a.

The remainder of the elastomer tread may include one or more solid elastorner segments 42 between the end walls 40, each solid segment being located above a U-channel 36 with a dovetailed tongue 38 depending therefrom. The intermediary portions of the tread sections between the respective rails are composed of a shallow, V-shaped upper wall 43 and a shallow, V- shaped lower wall 44 with a hollow space 45 therebetween. As the joint closes and the elastomer tread is pushed inwardly from its respective ends. the shallow. V-shaped walls 43 and 44 assume a deeper. V- configuration. Only the upper wall 43 is essential to make the seal waterproof. However. the lower wall 44 gives symmetric stability to the tread sections and serves as a second sealing surface. should the upper wall 43 become punctured or torn.

Adjacent one side of each load-bearing beam or bar 28 there is provided a coil spring 46 between each rail. The respective rails have opposed upper and

lower grooves

47 and 48 on each side thereof. The lower groove 48 on each rail receives a horizontal leg 49 at each end of the coil spring while the upper groove 47 receives the end 50 ofa diagonal leg 51 extending from one end of the respective legs 49. These diagonal legs provide a useful function in holding the coil springs 46 in place under vibrations imparted to the joint by traffic passing thereover. Springs without such diagonal legs and mounted only by the horizontal legs 49 have been found. on occasion. to work loose as a result of the vibrations imparted on the joint by traffic moving thereover.

The

outer rails

31 and 32 are held in position on the longitudinal

end frame members

14 and 15 by a T-bar 52, the cross leg of which is seated in opposed grooves 53 and 54 of the frame. The other leg 55 is connected by bolt 56 to a T-bar 57 having edge portions seated in the opposed grooves 58 and 59 of the outermost rails. One or both of the parallel legs of the T-bars may have a slot allowing for adjustable positioning of the respective bars in the end frames and the outermost rails.

The load-bearing beams or bars 28 have attached at opposite ends thereof by bolts 60 or other suitable means. a plate 61 whose length is greater than the width of the load-bearing beams or bars 28. The respective plates 62 serve as stops to prevent either end ofthe beams or bars 28 from passing through the

outermost rails

31 and 32.

The half tongues 38b of the elastorner tread are seated in end frames by providing an inverted L-leg 62 spaced from and directed toward the wall portion 63 of the end frames. The horizontal lip of the half tongues 38b lies beneath the horizontal leg of the inverted L-leg 62 continually along the longitudinal dimension of the joint. The vertical leg of the half tongues 38b are compressed between the end of the L-leg and the opposing face of wall portion 63 to make a constant. water-tight seal. This interlocking. coupled with the lips 22 overlying the upper side of the outer edge of the tread section. hold the tread section firmly in place in the respective end frames. Further. the upper portion of the wall 63 may be provided with serrations 64 to match and receive the serrated side portion 4] of the outer most wall of the seal section forming the tread. This further aids in preventing seepage of moisture and incompressibles between the contacting faces of the side walls 40 of the outermost seal and the face of the wall 63 of the frame.

Preferably the rectangular opening 65 in the interme diary rails 33 and outermost rails 32 are lined with a wear-resistant bushing 66. e.g., a gasket-like lining of Adiprene.

In preferred forms of the invention. the

rails

33 and 32 and the end frames l4 and are aluminum extrusions approximately l2 feet in length. which length corresponds to one lane of a dual line or multilane highway or bridge. The abutting ends of the

rails

32 and 33 are spliced together by elongated plates of the type shown in our application aforesaid. which splicing plates are seated in the

opposed grooves

47 and 48 on each side of the respective rails at the point or points of splicing. By using lengths corresponding substantially to lane widths of the highways or bridges. it is possible to repair or inspect or conduct periodic maintenance of the joint by closing off only one late at any given time in the performance of the aforesaid functions.

The invention thus provides a modular joint structure utilizing a pair of elongated, longitudinal frames mounted firmly in concrete or other paving material on steps at the respective edges of the joint. A plurality of elongated, longitudinal rails span the joint in parallel. spaced relationship to each other. These rails respec tively have rectangular openings therein disposed at longitudinal intervals along the rails. The openings are aligned in a plurality of transverse rows through which joint-spanning. load-bearing beams of rectangular cross section extend through at least some. and usually all. of the rows of rectangular openings. The respective rails. excepting the two outermost rails. rest individually and independently slidable on the rectangular load-bearing beams.

To maintain substantially equal spacing between the respective rails. the modular joint structure utilizes a plurality of coil springs mounted between respective rails and preferably in an arrangement providing a plurality of longitudinally spaced. transverse rows close to but spaced from one side of the load-bearing beam.

The modular joint is sealed over its entire width and length by providing an upper. elastomer tread having solid elastomer segments above and supported on the upper portions of the respective rails. preferably by deformable beads or tongues interlocked in channelforming members on the upper surface ofthe rails. The intermediary portions of the treads between the rails preferably comprise upper and lower. vertically spaced, shallow V-shaped walls with a hollow space therebetween. As the joint closes. these upper and lower walls deform into a deeper V-configuration.

The tread preferably is composed of a series of sideby-side elastomer segments made from low crystallization neoprene formulations. The abutting edges of the treads with the sides of the longitudinal end frames and with another side of an adjacent tread segment for a water-tight seal. ln the illustrated embodiment. the tread sections comprise three sideby-side sections 67,

Lit

68 and 69 of identical cross section and a section 70 which is one-half the width of the tread sections 67-69. If desired. the tread sections may comprise three or more integrally formed sections. each of which corresponds in cross section to section 70 in the same manner as sections 67-69 comprise the equivalent of two sections 70. By such dimensions and geometry of the tread sections. they can be used to span joints of vary ing width dimension through appropriate selection of the tread section widths needed to span the particular joint between the longitudinal end frames 14 and IS.

The sections of the longitudinal end frames 14 and 15 preferably are also sealed at their junctures by an elastomer gasket. Referring to FIGS. 3 and 4, the end portions ofthe longitudinal slots or grooves 19 of abutting frame sections 14a and 14b have placed therein a nut 71. An L-bracket 72 is fixedly attached to the underside of the bottom wall 25 of each frame section. the horizontal leg 73 of which is held by a bolt 74. The shank of the bolt projects through a hole or slot (not shown) in the leg 73 and is threaded into the nut 71 to hold L-bracket 72 fixedly on the bottom wall.

The vertical leg 75 of each L-bracket has a boltreceiving hole through which the shank 76 of bolt 77 extends. An elastomer gasket 78 conforming to the cross section of the frame 14 is placed between the frame sections 14a and 14b and is compressed therebetween by drawing up tightly the bolt 77 and its nut 79.

Similar bracket and bolt means may be mounted in the longitudinal slots or grooves 18 to draw the abutting frame sections together and give a more uniform compression of the gasket 78.

lt is through that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form. construction and arrangement of the several parts without departing from the spirit or scope of the invention. or sacrificing any of its attendant advantages. the form herein disclosed being a preferred embodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

I. A shallow modular joint structure useful for spanning joints comprising a pair of elongated longitudinal frames adapted to be mounted at the respective edges of the joint. a plurality of elongated. longitudinal rails spanning the joint in parallel. spaced relationship to each other. said rails respectively having openings therein at longitudinally spaced intervals. said openings further being aligned in a plurality of transverse rows. said openings being of rectangular cross section and having a horizontal width greater than the vertical depth. and a plurality of joint-spanning load-bearing beams of rectangular cross section with a horizontal width greater than the respective vertical depth of each beam and extending through at least some of said rows of rectangular openings with said rails resting slidably thereon.

2. A joint structure as claimed in claim 1. said rails having mounted therebetween a plurality ofcoil springs arranged in a plurality of longitudinally spaced. transverse rows.

3. A joint structure useful for spanning joints com prising a pair of elongated longitudinal frames adapted to be mounted at the respective edges of the joint. a plurality of elongated. longitudinal rails spanning the joint in parallel. spaced relationship to each other. said rails respectively having openings therein at longitudinally spaced intervals. said openings further being aligned in a plurality of transverse rows. said openings being of rectangular cross section and having a width greater than the depth. and a plurality ofjoint-spanning load-bearing beams of rectangular cross section with a width greater than the respective depth of each beam and extending through at least some of said rows of rectangular openings with said rails having mounted therebetween a plurality of coil springs arranged in a plurality of longitudinally spaced. transverse rows. said springs balancing the spacing between respective rails at the joint structure widens or narrows. said spring members each having horizontal legs at opposite ends thereof seated in leg'receiving groove means in respective rails and diagonal end portions extending from said legs with the tip portions of the diagonal end portions seated in opposed groove means in respective rails.

4. A joint structure as claimed in claim I. said longi tudinal frames having formed therein longitudinally extending cavities into which the ends of the jointspanning. load-bearing beams can extend as the joint approaches its narrowest spacing.

5. A modular joint structure useful for spanning joints comprising a pair of elongated, longitudinal frames adapted to be mounted on respective sides of the joint. a plurality of elongated. longitudinal rails spanning the joint in parallel relationship to each other. plurality of joint-spanning. load-bearing beams extending transversely across the joint and supporting the respective rails. an elastomer tread composed of one or more tread sections. means supporting said tread on the upper portion of each rail with a solid elastomer strip portion of the tread above and supported by each rail. and said solid portions being connected by at least one shallow V-shaped wall connecting respective upper corner portions of said solid portions of said tread.

6. A joint structure as claimed in claim 5. said tread also having a lower. shallow V-shaped wall below and spaced from said first-mentioned wall and defining a hollow space between said walls and solid portions.

7. A joint structure as claimed in claim wherein said tread sections have dformable members depending from said solid portions and interlocking in channelforming means extending along the upper sides of respective rails.

8. A joint structure as claimed in claim 5. said longitudinal frames having longitudinal groove means for receiving an interlocking member depending from the end wall of said tread mounted on said frame. and said frame further having an elongated lip overlying the upper corner of said tread.

9. A joint structure as claimed in claim 5. said tread comprising a plurality of side-by-side sections extending longitudinally of the joint and interlocking serrations formed in the contiguous. abutting side walls of respective tread sections.

10. A modular joint structure useful for spanning joints comprising a pair of elongated, longitudinal frames adapted to be mounted on respective sides of the joint. a plurality of elongated. longitudinal rails spanning the joint in parallel relationship to each other. a plurality of joint-spanning. load-bearing beams extending transversely across the joint and supporting the respective rails. said frames having one or more downwardly facing. longitudinal slots. nuts slidably positionable at any desired point in said slot or slots. and an chor bolts having threaded ends threaded into said nuts until the nuts and bolts bind in the slot or slots. the shanks of said bolts projecting from the frame for M choring in pavement poured adjacent and beneath said frames.

ll. A modular joint structure useful for spanning joints comprising a pair of elongated. longitudinal frames adapted to be mounted on respective sides of the joint. a plurality of elongated. longitudinal rails spanning the joint in parallel relationship to each other. a plurality of joint-spanning. load-bearing beams extending transversely across the joint and supporting the rails. said frames being composed of aligned sections. a gasket between abutting ends of said section. said sections each having a downwardly facing longitudinal slot portion near respective abutting ends. a nut slidably adjustably seated in each slot portion. a bracket mounted on the inside of each section adjacent respective abutting ends by a bolt threaded into a respective nut in each slot portion and bolts connecting respective pairs of brackets of respective abutting ends for drawing said ends together and compressing therebetween said gasket.

12. A modular joint structure as claimed in claim 11. said bolts having threaded ends threaded into said nuts until the nuts and bolts bind in said respective slots.

* l t i

Claims

1. A shallow modular joint structure useful for spanning joints comprising a pair of elongated longitudinal frames adapted to be mounted at the respective edges of the joint, a plurality of elongated, longitudinal rails spanning the joint in parallel, spaced relationship to each other, said rails respectively having openings therein at longitudinally spaced intervals, said openings further being aligned in a plurality of transverse rows, said openings being of rectangular cross section and having a horizontal width greater than the vertical depth, and a plurality of joint-spanning load-bearing beams of rectangular cross section with a horizontal width greater than the respective vertical depth of each beam and extending through at least some of said rows of rectangular openings with said rails resting slidably thereon.

2. A joint structure as claimed in claim 1, said rails having mounted therebetween a plurality of coil springs arranged in a plurality of longitudinally spaced, transverse rows.

3. A joint structure useful for spanning joints comprising a pair of elongated longitudinal frames adapted to be mounted at the respective edges of the joint, a plurality of elongated, longitudinal rails spanning the joint in parallel, spaced relationship to each other, said rails respectively having openings therein at longitudinally spaced intervals, said openings further being aligned in a plurality of transverse rows, said openings being of rectangular cross section and having a width greater than the depth, and a plurality of joint-spanning load-bearing beams of rectangular cross section with a width greater than the respective depth of each beam and extending through at least some of said rows of rectangular openings with said rails having mounted therebetween a plurality of coil springs arranged in a plurality of longitudinally spaced, transverse rows, said springs balancing the spacing between respective rails at the joint structure widens or narrows, said spring members each having horizontal legs at opposite ends thereof seated in leg-receiving groove means in respective rails and diagonal end portions extending from said legs with the tip portions of the diagonal end portions seated in opposed groove means in respective rails.

4. A joint structure as claimed in claim 1, said longitudinal frames having formed therein longitudinally extending cavities into which the ends of the joint-spanning, load-bearing beams can extend as the joint approaches its narrowest spacing.

5. A modular joint structure useful for spanning joints comprising a pair of elongated, longitudinal frames adapted to be mounted on respective sides of the joint, a plurality of elongated, longitudinal rails spanning the joint in parallel relationship to each other, plurality of joint-spanning, load-bearing beams extending transversely across the joint and supporting the respective rails, an elastomer tread composed of one or more tread sections, means supporting said tread on the upper portion of each rail with a solid elastomer strip portion of the tread above and supported by each rail, and said solid portions being connected by at least one shallow V-shaped wall connecting respective upper corner portions of said solid portions of said tread.

6. A joinT structure as claimed in claim 5, said tread also having a lower, shallow V-shaped wall below and spaced from said first-mentioned wall and defining a hollow space between said walls and solid portions.

7. A joint structure as claimed in claim 5 wherein said tread sections have dformable members depending from said solid portions and interlocking in channel-forming means extending along the upper sides of respective rails.

8. A joint structure as claimed in claim 5, said longitudinal frames having longitudinal groove means for receiving an interlocking member depending from the end wall of said tread mounted on said frame, and said frame further having an elongated lip overlying the upper corner of said tread.

9. A joint structure as claimed in claim 5, said tread comprising a plurality of side-by-side sections extending longitudinally of the joint and interlocking serrations formed in the contiguous, abutting side walls of respective tread sections.

10. A modular joint structure useful for spanning joints comprising a pair of elongated, longitudinal frames adapted to be mounted on respective sides of the joint, a plurality of elongated, longitudinal rails spanning the joint in parallel relationship to each other, a plurality of joint-spanning, load-bearing beams extending transversely across the joint and supporting the respective rails, said frames having one or more downwardly facing, longitudinal slots, nuts slidably positionable at any desired point in said slot or slots, and anchor bolts having threaded ends threaded into said nuts until the nuts and bolts bind in the slot or slots, the shanks of said bolts projecting from the frame for anchoring in pavement poured adjacent and beneath said frames.

11. A modular joint structure useful for spanning joints comprising a pair of elongated, longitudinal frames adapted to be mounted on respective sides of the joint, a plurality of elongated, longitudinal rails spanning the joint in parallel relationship to each other, a plurality of joint-spanning, load-bearing beams extending transversely across the joint and supporting the rails, said frames being composed of aligned sections, a gasket between abutting ends of said section, said sections each having a downwardly facing longitudinal slot portion near respective abutting ends, a nut slidably adjustably seated in each slot portion, a bracket mounted on the inside of each section adjacent respective abutting ends by a bolt threaded into a respective nut in each slot portion and bolts connecting respective pairs of brackets of respective abutting ends for drawing said ends together and compressing therebetween said gasket.

12. A modular joint structure as claimed in claim 11, said bolts having threaded ends threaded into said nuts until the nuts and bolts bind in said respective slots.