US2334183A - Expansion joint - Google Patents

Description

mh E943.. A` c. FISCHER EXPANION JOINT Filed Nov. 29, 1938 3 Sheets-Sheet 1 :5 sheets-sheet 2 A. C. FISCHER EXPANSION JOINT Filed Nov. 29, 1938 Nav. 16, N43., A. c. FISCHER ZM EXPANSION JOINT FiledNov. 29, 195s s sheets-Sheet s Patented Nov. 16, 1943 `UNITEIZ STATES fPATENT OFFICE Emem Albert c. Fischer, chicago, nl.

Claims.

This invention relates to expansion joints for structural elements' such as pavement sections and more particularly to the llers disposed in said expansion joints.

It is the object of the present invention to provide expansion joints between pavement slabs possessing a predetermined inherent resilience which characteristic is availed of inthe repeated expansive and contractile movements of the slabs, and -in addition, which embodies extrusion chambers for receiving upon occasions the main body ofthe expansion joint material.

It is av further object of the present invention to provide a preformed expansion joint which may be produced' in a continuous extrusion process ready for placement in a construction project in association withA the other elements usually encountered in such constructions.

Other objects and purposes will appear from the more detailed -description of the invention following hereinafter taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a perspective view vof one form of an expansion jointhaving affixed to the opposite faces thereof preformed channels operating as extrusion chambers; p

Figures 2a, 2b, and 2c show lperspective views of different forms which I have designed for afxing the premolded extrusion chambers onto the faces of the expansion joints;

Figure 3 is a sectional view showing premolded extrusion chambers adjacent an expansion joint and retained in place by a metallic capping forming part of the joint;

Figure 4 is a perspective view of half of an expansion joint` in accordance with a different embodiment of the invention; y

Figure 5 is a transverse sectional view of a joint formed of two juxtaposed parts suchl as shown in Figure 4; and Y Figure 6 isa perspective view of an expansion joint made of twojuxtaposed parts constituting a different embodiment of the invention from that shown in .Figure 5.

Figures '7, 8, 9 and 10 are-sectional views showing the core constructions and their extrusion controlling 'and waterv sealing adjuncts of Figures 1, 5, 6 and 3, in the associations which they respectively assume with the, pavement sections when put into use.

In Figure 1 is shown an expansion joint core I made of material well known in the art embodying a binder and lling material with or without fibrous material. This core is disposed between adjacent structural sections or pavementslabs which may be cast upon the opposite sides thereof. In order to make provision .for the movement of this material upon the expansion of the pavement sections. extrusion chambers 3 are located on the opposite faces of the said core. These structural chambers may be formed `of the same material as is the core material I or may be formed of sponge or solid rubber which although self-sustaining is capable of movement. As shown in Figure 1, two' of such extrusion chambers are formed by preformed channels each comprising a back wall 3 and two side walls 6, the latter converging toward the open front of the channel and thus developing a fan-shaped section 'in the channel. Grooves 2 defined by confines extending longitudinally of the core are either molded or pressed in the faces of the core I and the longitudinal margins of the side Walls 6 of the channels are rabbeted to the confines of the grooves in order to make a tight joint between the side Walls of the channels and the faces of the expansion joint core. Suitable adhesive may be utilized in perfecting this joint between the channels and the faces of the expansion joint core.

An expansion joint as shown in Figure 1 permits a preformed assembly to be disposed in place by suitable aligning elements which may include dowel bars and the like, around which may be cast the concrete material. 'Ihe spaces formed on the inside of the channels operate as extrusion chambers to receive the core material receive and contain the plastic core material flowing under pressure ofthe pavingsections.

In Figures 2a, 2b, and2c are shown different joints which may be employed in afxingthe preformed channel receptacles to the sides of the expansion joint core. In'Figure 2a the groove I2 in\the face of the expansion joint is formed with trapezoidal sides tc receive the tapering side walls of the channels 3a.

In Figure'Zb, the groove '2 is formed With-rectangular sides in the same manner as shown in Figure 1 and against which nt rectangular extensions I6 at the inner margins of the side walls 6b of the channels 3b.

In l Figure 2c, the groove I4 is shown with curved sides in which are disposed curved rabbets at the inner margins -of the side walls 6c of the channel 3c corresponding. thereto.

The channel 3 may be molded or extruded from a plastic mass after which the same is permitted to harden prior to its afiixation to the 'sides oi' the plastic joint core. The material of this receptacle may be any material known in` the art -and may include rubber and asbestos cement 6 plastic compositions.

In Figure 3 is shown a metal capping disposed at the upper end of an expansion joint having channels I I formed at the bottom thereofl for receiving tightly the upper flanges 26 of rectan- 10 guiar channels I3 made of plastic compressible material and having its lower flanges 26 terminating adjacent to the faces of the core. These channels I3 serve the function of extrusion chambers in the same manner as explained in conjunction with the previously described embodiments.

The outside of the channels 3 may be covered with paper, felt, or fabric winch may or may not be Waterproofed depending upon the specific applications to which these articles may be put.

In Figures 4 and 5 is shown an expansion joint made up of two juxtaposed layers of mastic material 5I lined with paper, felt or fabric sheets 53 which may or may not be waterproofed, and 25 the resilience of which is enhanced by the inte7 gral formation therein of yielding channels 52, in the mastic, and 54 in the lining. In these figures, 5I represents the plastic elastic mass which is formed of straight portions 5I and deformed 30 channels 52 and their lining of paper or fabric material 53 have pockets 54 corresponding in depth to the deformations or channels 52 in the elastic layers.

l In Figure 5 is shown the preformed expansion 35 joint formed by the juxtaposition of two strips as shown in Figure 4 in juxtaposed relationship and the union of their opposed layers of fabric by suitable adhesive.

In lieu-of the formation of. the main bay of 4o the joint of a plastic elastic mastic material, sponge or solid rubber may be used. Such a structural arrangement is shown. in Figure 6 wherein the fabric layers are eliminated and in lieu thereof a mastic core 54 is disposed between 45 the rubber sides 5Ia, 5Ia. This construction results in. a thicker expansion joint and permits' the deformed sides 52a of the plastic and elastic mass to operate as extrusion chambers for the core material in substantially the same manner as disclosed in conjunction with the expansion joint described in Figures 1 and 3. The natural resilience of the extrusion chambers in the construction shown in Figure 6 assists the core material to be forced back into place following the 55 contraction of the pavement slabs. Furthermore, this arrangement in which exists the capability of the core, as well as of the sides, to expand and contract serves to maintain an integral joint between the parts at all times.

A, B, in Figure '7, A', B' in Figure 8, A2, B2 in Figure 9 and A3, B3 in Figure 10, represent the two sections of paving provided by pouring concrete against opposite sides of the cores and in enveloping or matrix forming relation to the water-stopping and extrusion receiving wings 3 (Fig. 1), 52 (Fig. 5), 52a (Fig. 6) and I3 (Fig. 3).' From the views of concretev enveloped wings may be gainedan appreciation of the effect of concrete pavement sections poured against core 70 members, having wing-like extensions that become embedded in the pouring, and when said extensions aremade of a plastically deformable mass as distinguished from sheet metal or other rigid structures and particularly when the ex- .the concrete is poured, it shrinks to an appreciable degree, varying according to the particular concrete in changing from the plastic to the crystalline or hardened structure. This shrinkageis resisted by an object embedded in tiie concrete. If the object be rigid and non-yielding and particularly when its section causes interlock and prevents deflection of the compressing faces of concrete, the contracting concrete may suffer rupture such as spaliing or cracking; but when the enveloped and interlocked structure is plastically deformable under the pressure of the contracting concrete, the eect will be merely to tighten the fit of the extension in the matrix that forms about it and the flowing of the mass from points of greatest pressure to any points of /of the wing- like projections 3, 52, 54 for instance,

accompanied by compression upon said wing-like projections, perpendicularly to the core; and contraction due to the outwardly flaring and interlocking form of the projections setting up substantial stresses of tension in said projections and through them in the core. Here again the deiormable or elastic nature of the material of which the projections are made lends peculiar advantage since, while maintaining the wing-like projections stretched, apron-like, in water stopping relation to any crack that may open between the retracting concrete and the core of the joint, elasticity of the core and wing material renders the water stop self arresting before rupture takes place; moreover` interengagement of the deformable wing further limits the distension to a point shortv of rupture ofthe water stop by the drawing of the -wing in the concrete matrix, from the broad to a transverselyrrestricted area of said matrix, permittedby transverse compressibility of the wing.

There is another serious\problem encountered with expansion joints of tle kind to which the present invention relates, namely, retention of eective form in the cores and adjunctive. elements of the joint under Vvrelative movement between the opposing ends of the paving sections in a vertical direction, as for instance when the footings of the sections become impaired as a result of water accumulating thereat. Under such circumstances it frequently occurs that the ends of the paving sections, under loads imposed by wheels passing along the surface of the roadway, undergo successive depression followed by recovery, which action aggravates the condition of impaired footing and imposed serious stresses of shear upon the embedded wings. This condition, in joints using sheet metal to denne extrusion recesses may defeat the functioning of the sheet metal structure, but with deformable Wings of the general nature herein shown, the wings yield and escape shear when subjected to such vertical stresses and escape impairment where the sheet metal, by. resisting, would invitedestruction. This yielding by the joint of the present invention will develop principally from plastic deformation of the dovetail wings in the matrices of theconcrete, but it may also arise in some degree from a bodily movement of the vertical walls along with the wings 52 (taking the form of Figure 8, for instance) and this latter condition is favored by the multiple ply construction of the core made'up. as it is, from the middle layer and the two outer layers of material.

From the foregoing it will be seen that the present invention contemplates a novel structural organization comprising a-corecapable of f (cement) pavement section, the walls of this recess become hermetically anchored in the masonry; that/since the walls of this recess and the should beunderstood than: r de not uma my lnvention thereto, since various modications will suggest themselves to those skilled in the art without departing from the spirit of my'invention, the scope of which is set forth in the annexed claims.

What I claimis:

1. In an expansion joint for use( between expanding and contracting sections oi poured` masonry.- a compressible core constructed of cold iiow' plastic material and comprising a pair of outer'core members arranged face to face and having between them an intervening web-like means which separates said core membersand leaves them free to act independently of each other; said core members being provided with confines ,of the matrix to which it Igives being are convergent tension imposed upon these walls serves tovtighten the anchorage. However, ccmpressibility of the particular material of which the walls of this extrusion recess are made converts thisanchorage into a yielding engagement so that excessive tension will not disrupt the connection but will cause lost motion to take place between the masonry and theV connection which ties it to the core. I

Finally the invention contemplates, as a function inherent in the several forms illustrated in Figures 1 to 5 and Figure 6, the maintenance of a complete and effective waterstop across the joint, at all times and under allconditions of expansion and contraction of the joint. Thus, referring to Figure 6 for instance, and starting with the hermetic anchorage of members 52 in the masonry which automatically enters the organization as the joint goes into use, the side walls of element 52 extend to the core member Bia, thence to middle layer 54a, and thence to members 5in. and 52a and to the masonry that will envelope 52a, on the'opposite side. This makes a complete and hermetic waterstop for the joint, so that when the masonry sections separate by contraction andmembers 52 partake of the movement freedom of deformation as by buckling or straightening of sidewalls of 52 permitted by the rubber of which said members 52 are made, will compensate any crack or opening that will occur and maintain a complete watershed at all times; and this will be true even if fiat core-layery 5I should partially separate from the layer 54a on either side of the extrusion recess. Finally, if the distance of retracting movement between the masonry sections should overstrain the watershedding parts and their connections, the dovetailed box 52a would be drawn by the excessive tension, toward the narrow end vof the matrix,I

submitting to transverse compression by movement toward the bottleneck and thus, without specific manner for purposes of i1lustrationit outwardly ared hollow projections defined by walls of plasticallydeformable material mounted upon and in tension transmitting union with said core-members at points that cause saidl projections-to form conforming matrices in and become anchored to masonry sections poured around the projections; the plastically deformable walls ofv said projections being movable into and compressibie byk dimensionally restricted portions of the matrices when the masonry sections draw from the core members; and said intermediate weblike means being constructed with web-portions and portions deflected from said web-portions and entering the hollow projection of the outer core-members and, by the exure of their said deected portions, removing restraint of flow upon the core-members.

2. In an expansion joint for use between expanding and contracting sections of poured masonry. a compressible core comprising a pair of core members constructed of cold ilow plastic material and assembled with major faces opposed, each of said core members being provided onits outer surface with a flared hollow projection ldefined by walls of plastically deformable material mounted upon and in tension transmitting union with said core-members at points that` cause said projections to form conforming matrices in and become anchored to masonry sections poured around the projections; the plastically deformable walls of said projections being movable into and compressible by dimensionaily restricted portions of kthe matrices when the masonryy sections draw from the core members; said core members being constructed of resilient plastic material and having between them a third core member constructed of cold owing mastic material.

3. In an expansion joint for use between exi `of cold owing mastic material, each of said outer core members being provided with an outwardly flared hollow projection dened by walls of plastically deformable material mounted upon and in tension transmitting union with said coremembers at points that cause said projections to form conforming matrices in and become anchored to masonry sections poured around the projections; the plastically deformable walls of said projections qbeing movable into and compressible by dimensionally restricted portions f the matrices when the masonry sections draw from the core members; and each of said outer core members having an opening therethrough that y 2,884,188 vmaintains access 'to its interior by the intermerices in and become anchored to masonryl sections poured around the projections; the plasj tically deformable walls of said projections being movable into and compressible by dimensionally restricted portions ci' the matrices when the masonry sections draw fromvthe core member.

l/ 5. In a device as set forth in claim 4 wherein at least the walls of the flared hollow projections are of rubber.

ALBERT C. FISCHER.

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