US2082805A - Expansion joint construction - Google Patents

Description

June 1937- c. L. METHVEN 2,082,805

EXPANSION JOINT CONSTRUCTION Filed May 10, 1933 2 Sheets-Sheet l l W L--";:,'--:--'-'-" 19 -1 54 22 I8 .20 F g 58 59 a3 19 67 67 65 2a 32 75 a7 v INVENTO CLYDE L...METHV Quid! June 8, 1937. c, METHVEN 2,082,805

EXPANS ION JOINT CONSTRUCTION Filed May 10, 1933 2 Sheets-Sheet 2 INVENTO CLf/DE L. METHV ATTORNEYS.

Patented June 8, 1937 UNITED STATES PATENT OFFICE 2,082,805 EXPANSION .rom'r coNsTn o'rIoN Clyde L. Methven, St. Paul, Minn. Application May 10,,1933, Serial No. 870,314

2 Claims.

This invention relates to improvementsin the joint space, and the poured type in which plastic bituminous material is poured into a molded joint space formed in the pavement.

er, infiltration of water frequently occurs at the joint, most of this water being surface water which finds its way through the joint to the subgrade below the pavement. In freezing temperatures this moisture freezes into ice lenses in the sub-soil which causes heaving of the pavement slabs at the joints. It is also to be noted that the shrinkage of the paving material and of the bi- V tuminous material is in opposite directions so that in cold weather the bond between the pavement and the bituminous material is broken thus forming crevices through which water finds its way to the soil below the pavement.

Thus far, the effort of engineers working in' this field has been directed to making the expansion joint as water-tight as possible at the top of the pavement. But the results attained have not been satisfactory because of the formation of crevices in cool weather herein referred to, re-

sulting in inevitable infiltration of surface water infiltration of water above the elevation; of the bottom of the slab. This water flows intothe I lower section of the joint and thus passes through into the sub-soil below. Hollow metal box types 45- permits the infiltration of water through the ends and thus through the corroded metal into the sub-soil below the pavement.

In addition to the heavingcaused by water freezing below the pavement in the cold climates, there is the disadvantage that in the warmer It is the primary object of the present invention to provide an expansion joint with a seal 60 at sub-grade elevation, which will positively ex;-

In-cool weather there is'also a crevice along I of expansion joints are not made with enduringmetal in their lower portions. In a comparatively few. years, disintegration of this portion climates the moisture seeping through the joint], produces an expansion of the sub-soils which may result in permanent deformation of the pavement} clude the passage bf the water through the joint into the sub-grade.

Another object of the invention is toprovide a water seal for expansion joints so constructed and arranged that it will expand and contract with movement of the adjacent pavement slabs. Another object istdfp'rovide a water seal for expansion joints of sirn e1 durable and inexpen sive construction andfwhich may be employed in connection .with anytype of expansion joint or so-called dummy contraction joint. Still another object of the invention is to pro- When pavements are contracted in c ld ath- I vide, in connection with the water seal herein referred to, a removable core mold for expansion joints for providing proper space between adjacent pavement slabs.

A further object of the invention is to provide a removable core mold for-producing expansion joint space in pavements which is of simple and durable construction and which may be applied and used in connection with the formation of any of the various designs of joint construction now generally employed.

In addition, the invention aims to provide numerous improvements in details of construction and use of apparatus for forming expansion joints in pavements and the like having many advantages from the standpoint of efiiciency in use, economy in cost and maintenance, and ease of assembly and installation.

Other objects of the invention and further advantages thereof will be more fully brought out as the description proceeds.

In the accompanying drawings I have shown several practical embodiments of my invention but it is to, be understood that these drawings are illustrative merely and I 'do not confine myself to the details of construction therein shown. It will be readily appreciated by those skilled in the art that my invention may beembodied in other forms without departing from the scope thereof or sacrificing any of its advantages.

In these drawings,

Fig. 1 is a fragmentary sectional view through a pavement joint showing the water seal of my invention;

Fig. 2 is a fragmentary sectional view through a pavement expansion joint showing a modification of my water seal;

Fig. 3 is a fragmentary perspective view, partly in section, showing the water 'seal construction illustrated in Fig. 2 in combination with a support for pre-molded joint material;

' Figs. 4 and 5 are fragmentary sectional views, similar to Figs. 1 and 2, showing modifications of "the water seal construction; a I

Figs. 6 and flare fragmentary sectional views through a pavement showing a so-called dummy contraction joint with a water seal of my inven- "tion applied thereto;

Fig. 8 is a fragmentary perspective view, partly in-section, showing a removable coremold of my invention in combination with my water seal construction; Fig. 9 is a vertical sectional view through the core mold and water seal shown in Fig. 8;

Fig. 10 is a sectional view taken on line lfl-lfl of Fig. 9;

Fig. 11 is a front view of a cover plate used in 10 connection with the core mold for covering the openings below the dowel bars;

Fig. 12 is a view, partly in section and partly in elevation showing a core mold support; and

Fig. 13 is a fragmentary sectional view show- 15 ing a means for interlocking the center section of the core mold with the acfiacent end sections. At the ofiset, it will be understood that the invention herein to be described and themodifications thereof may be applied to any type of pavement, bridge work, roofing and the like, re-

quiring expansion joints.

Referring now to the drawings, and particularly to Fig. 1, the reference numerals i5 and it indicate adjacent separated slabs of pavement made of concrete or any other suitable material which expands and contracts with temperature changes. The space between the adjacent edges of said slabs is usually filled with suitable bituminous material i? which is either poured into the space while in liquid condition or is occupied during construction as a pre-molded mixture of bituminous and fibrous substances. As will be seen from the said Fig. 1, said expansion joint material extends from the top of thepavement to a point substantially near the bottom of the said slabs.

flexible metallic member which extends along the joint from one longitudinal edge of the pavement to the other conforming to the cross-section design of the pavement and contour of the subgrade. The said metallic member is provided with laterally extending portions l8 and I9 which underlie the slabs I5 and Hi. The outer marginal edges of said portions l8 and it are bent upwardly to form flanges 20 and 2! which are embedded in the slabs l5 and is. At 'the center, the said metal member is bent to forma number of loops 22 which are provided for the purpose of permitting expansion and contraction of the metal member in accordance with movements of the adjacent slabs due to temperature changes.

Preferably these loops or bends will not be too sharp, thereby avoiding the danger that the continued flexing of the metal member over a period of years might cause rupture.

The member comprising the water seal may be made of any suitable metal but, preferably, the metal should be enduring and non-corrosive in order to increase the life of the joint and to eliminate, so far as possible, maintenance costs. Suitable metals such as copper and the like may be best used for this purpose. 9

While from practical considerations of installation and maintenance the water seal of my invention is preferably made of enduring metal, I wish it to be understood that I do not limit my inventionto use of such metal. Under cer tain conditions it will be quite possible to employ a fibrous material or fabriccoated with a suitable flexible substance to'make it water proof and sufllciently rigid to retain the shape of the bends and loops formed in the seal. Such ma- 75 terials as composition roofing and the like may The water seal of my invention comprises a I water seal.

aoeaeoe be employed for this purpose as well as the enduring metals referred to.

It will now be seen that because of the construction and arrangement of the water seal herein described it will be impossible for water to find its way through the joint into the .subsoil. Also, it would be impossible for moisture existing in the sub-soil, and the soil itself, to find its way into the joint. This is assured by reason of the fact that the laterally extending portions of the water seal underlie a substantial part of theadjacent pavement slabs. Additional assurance is afforded because of the marginal flanges which are embedded in the pavement slabs.

In order to prevent the entry of sub-grade soil into the loops of the water seal, I provide a shield 23 which underlies the water seal and which extends from one longitudinal edge of the pavement to the other. By this arrangement I prevent the possibility of the soil accumulating in the loops or bends of the water seal which would interfere with the free flexing movement of the said water seal.

The foregoing description will make clear a practical embodiment of my invention. It is obvious, however, that the water seal of my invention is susceptible of embodiment in a great variety of other forms and I- have chosen to illustrate several such modifications herein.

In Fig. 2 there is shown a modification in which the waterseal is provided with laterally extending portions 25 and 26 which underlie adjacent slabs 2? and 28 of the pavement. In this case,

as in the structure shown in Fig. 1,, the said latterally extending portions are provided with flanges 29 and 3B which are embedded in the adjacent slabs. However, in this form, the water seal is provided with but one loop or bend 3! which is formed centrally of the metal member comprising the water seal and which extends upwardly into the space between the adjacent slabs. Under ordinary conditions this single loop of the water seal will be sufllcient to provide for freedom of flexure due to the movement of the adjacent slabs. In this figure, I have shown a portion of a removable core mold 32 which rests on the portions 25 and 26 of the water seal. This structure will be more fully described in connection with description of Figs. 8 and 9. In this case also I have provided a shield 33 which prevents movement of a sub-soil into the loop of the water seal which is locatcd in the space between the adjacent slabs.

In Fig. 3 I have shown the same water seal as that illustrated in Fig. 2. In this case I have indicated a manner of supporting upon the saidseal a block or strip of pre-miolded bituminous material. Reference numeral 35 indicates a strip of such material which will ,flll the space between adjacent slabs of the pavement. This. pre-molded bituminous material may be supported by means of metal plates 36 which rest upon the water seal and exclude concrete from bonding to and preventing free fiexure of said loop 3|. The said plates 36 may be provided with punched out tongues 31 which are embedded in the strip 35 so as to securely fasten the same.

It will be noted that the block 35 of bituminous material does not extend to the bottom of the space between the slabs but that it terminates and rests upon the top of the loop 3| of the This results in a considerable saving of bituminous material in the installation of pre-molded joints.

In Fig. 4 I have shown ,a further modification of mywater seal. In this case the water seal comprises a metal member having a centrally formed loop-or bend 40 which is located in the space between adjacent slabs 4| and 42 of the pavement. This water seal is provided with laterally extending portions 48 and 44 which are bent upwardly and embedded in the adjacent slabs. This type of structure will also form an 0 efiective seal against the passage of moisture through the joint into the sub-soil. Here, also I have provided a shield 45 which prevents the sub-soil from entering into the loop 40, thus assuring free flexing movement of the seal.

Fig. 5 shows a further modification of the water seal. In this case I have provided a metal member having a centrally formed loop or bend 41 provided with marginal portions 48 and 49 which extend upwardly into the space between the adjacent slabs of the pavement and which are provided at their upper edges with marginal flanges 58 and 5| which are embedded in the said pavement slabs. This structure also forms a seal against the passage of moisture through the joint into the sub-grade.

Here, again, I have provided a shield52 for preventing movement of the 'sub-soil into the loop of the water seal.

In Fig. 6 I have shown a so-called dummy contraction joint to which the water seal of my invention has been applied. A dummy joint is merely a crevice formed in the pavement to establish a weakened plane which will predetermine the location of a contraction crack or joint. In the said Fig. 6, reference numeral 55 indicates a section of a pavement in which there is a contraction crack or crevice 55 extending from the upper surface to the lower surface of the pavement. At and near the upper surface,

the crevice is filled with suitable bituminous material 51. v

In the case of the structure shown in Fig. 6, I also employ a water seal extending along the joint from one longitudinal edge of the pavement to the other which will prevent the passage of water through the dummy joint into the subsoil. The water seal proper comprises a corrugated metal plate 58 extending under the dummy joint and under the adjacent parts of the slab for some appreciable distance on each side of the possible location of a crack. This water seal is corrugated so as toprovide for flexing movement occasioned by any movement of the adjacent sections of the pavement. The water seal is protected by a shield 58 which underlies the same and prevents the sub-soil from packing into the corrugations of the seal which would result in destroying its free flexing movement. To prevent the entry of the paving ma- 60 terial into the upper part of the corrugations in the seal, I employ an upper shield 68 which rests upon the water seal 58 in the manner shown. The said water seal 58 is provided with marginal flanges BI and 62 which are bent upwardly and 65 embedded in the pavement. It will be seen that this structure provides an effective seal against the entry of water into the sub-soil through the crack or crevice 56.

In Fig. 7 I have shown a modification of my 70 invention as applied to a so-called dummy contraction Joint. In this figure, reference numeral 65 indicates a section of pavement which is provided with crevice 66 which forms a so-called dummy joint. At and near. the upper surface of 75 the pavement, the said crevice is filled with suitable bituminous material 81. In this figure I have also provided a water seal comprising a looped member 68 having laterally extending flanges 88-which underlie adjacent sections of the pavement and which are provided with m'arginal flanges I0 which are bent upwardly and embedded in the pavement. The water seal is protected at the bottom by a suitable shield II. To prevent movement of the paving material into contact with the loop of the seal, I have provided a shield 12 which surrounds the said loop, as clearly shown in Fig. 7. Thus, by this arrangement there will be no interference with the free flexing movement of the water seal on account of the impacting of the paving material or the sub-soil- The arrangement shown in this, figure is such that the space around the loop 88 predetermines the weakest cross-section of the pavement, thereby assuring the location of the eventual contraction crack or crevice; For example, if the crevice be somewhat misplaced as shown in dotted lines at 56a and 61a in. said Fig. 7, the contraction crack or crevice will nevertheless flnd its place to the seal because the seal locates the weakest cross-section of the pavement.

The foregoing description is directed particularly to various forms of construction of the water seal of my invention. I will now describe how the said seal is arranged in combination with a removable core mold which provides space between adjacent pavement slabs i'or the formation of an expansion joint.

In Fig. 8 I have shown in perspective and in section an arrangement of a removable core -mold in combination with one of the forms of water seal heretofore described. The core mold comprises an inverted U-shaped metal structure of box-like form made up in a pair of end sections 15 and a removable center section 16. The said center section 18 may be secured to the end sections 15 by a, suitable interlocking fastening having an extending tenon from the side section into and within the center section permitting upward withdrawal of said center section. When required the center section 18 is provided in its top edge with a substantially V-shaped notch for thepurpose of constructing a longitudinal dummy joint in the center of thepavement, usually filled with bituminous material and serving as a traffic lane division mark.

.Each of the end sections I5 carries a plurality of dowel bars 18 having sockets 18 at one end thereof. These dowel bars, as is well understood, are left embedded in the pavement and, hence, the core mold must be so constructed as to permit removal of the core while the bars are left in place. To this end, the side walls of the end sections are provided with openings 88 which 7 are covered by plates 8|. have openings 82 therein which are of a diameter slightly less than the diameter of the dowel bars. The edges of said openings are provided The said plates 8| with incuts so that when the bars are passed through the said plates they will be held by fricgrade.

of inexpensive construction nothing substantial is added to the cost of making the joint.

.In order to support the core mold in vertical position during the laying of the pavement and the first striking ofi operation, I provide a number of braces for each of the end sections 55. These braces comprise a yoke shaped member d5 having a supporting bar 86 which is notched at its outer extremity and rests against a stake ,8? driven into the sub-grade. By this arrangement, the core mold is adequately supported in vertical position during the times heretofore stated. After the paving material has been poured, and puddled into place and the prelimimay strike 015: and finishingoperations completed, the support may be pulled out, leaving the stake ti embedded in the sub-grade. This is a very simple operation and is inexpensive because the only material expended is that used in the formation of the stakes 87.

I also provide a means for supporting the core mold at its ends, that is to say at the end adjacent the longitudinal edge of the pavement. In Fig. 8, reference numeral 88 indicates the side form or support for the pavement. as indicates an end support for the core mold comprising a plate provided at its edges with stakes at welded or fastened securely to said plate and which are adapted to be driven into the sub- In part these stakes support the plate 89 in vertical position, but are particularly intended to resist displacement along the face of the side form during the placement and the striking ofi/of the pavement material.

Substantially centrally of the said plate dd I have provided an open bottom inverted U- shaped housing 9! which is also open at its front so that the end of the core mold section l5 may be .inserted therein and held rigidly in vertical position. The plate $9 is provided with suitable openings 92 into which a tool or the fingers of an operator may be inserted when the plate 88 is to be removed. In order-to prevent the end plate 89 from overturning in extremely soft sub-grade soil I provide a number of Scrap metal plates 33 which when slipped under the edge of plate 89 and the bottom of the side form, provides any needed bearing area for support.

It will be understood by those skilled in the art that the core mold of my invention will be assembled in sections before it is laid down in position to form the space required for the expansion joint in the pavement. Each of the end sections-15 is assembled with its dowel bars and cover plates 8i in place and the water seal secured thereto by means of suitable tie wires 94. The end plates 89 are driven into place between'the end of the core mold and the face of the side form and thereupon the end sections 15 of the core mold are positioned within the housing or flanges ill of the said end plates. Then the center section 16' is slipped into place interlocking the adjacent end sections.

In- Fig. 13 I have shown a means for interlocking the center section with the end sections of the core mold. The end sections 15 are provided with a casting 95 inserted in the end thereof and held in place by any suitable means. The casting 35 has a tongue 96 and an aperture 91. The metal sides of the center section 16 forms a recess or loop, into which the tolfguest is adapted to fit. The casting 98 is provided with a lug I00 which is adapted to seat in the aperture 91 in the casting 95. This forms a simple means for locking the sections of the core mold 1 together. Also the parts may be readily separated when the core mold is to be removed.

This being accomplished, the braces 85 are positioned with the extremities of the brace bars 86 resting on the sub-grade. Stakes M are then placed in the notches provided in the extremities of the brace bars and driven into the sub-grade. When the, concrete or other paving material has been puddled into place and the preliminary strike ofi and finishing operations completed and while it is still soft, the braces 85 and end plate supports 89 are removed. During all construction operations up to this point, which includes all of the major puddling and casting movements of the paving material with the incidental displacement strains and stresses, the core mold has been rigidly supported in a vertical plane against overturning or displacement from position. After the removable joint brace's dd and end supports 89 are withdrawn, only a surface finishing operation remains, which of itself cannot deform the position of the core mold.

After the initial set of the concrete has occurred the core mold assembly is removed. The center interlocking section it is first removed after which the end sections are raised and partially removed.

While in this raised position any required edging of the adjacent slabends is done using the sides of the core mold for a guide. After the edging operations the sections are entirely removed which completes the construction of the expansion joint space or opening. Filling this space with bituminous or other materials follows later.

It will be understood that during the pouring of the paving material, the cover plates ti prevent the passage of any of this paving material through the openings 88 into theinterior of the core mold.

-These plates are left in place embedded and bonded to the concrete.

The dowel bars are left in place in their proper positions to function in the customary manner. ,The water seal'band is left in its proper position with its edges sealed into the adjacent concrete slabs and providing a bend or loop of the seal band, free of any bond or restraining contact with said adjacent slabs, capable of absorbing such pavement movement as the design of the joint interval and space requires.

It will be understood that with very'little modir fication the removable joint braces 85 and end supports 89 may be applied to the installation of any types of pavement joint assembly or material, such use of these devices being covered by this invention.

I claim as my invention:

1. In combination with adjacent slabs of a pavement separated by a joint space, a water seal adjacent the bottom of the joint space comprising a member of flexible material having a bending loop and provided with sharply upturned flanges imbedded in the adjacent slabs of the pavement, and a sealing member underlying the adjacent slabs of said pavement and also said flexible member.

2. In combination with a joint space in pavements formed by the cracking of the pavement to produce separated slab portions, a water seal adjacent the bottom of the pavement comprising a flex ble member adapted to yield with movements of the pavement slabs, said member having sharply upturned flanges imbedded in the pavement on each side=of the joint space, and a shield underlying the pavementand said member.

- CLYDE L. ME'I'HVEN.

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