Abstract: A waterstop repair method and structure for use in both new and existing concrete structures in which a reinforced neoprene diaphragm is anchored to the concrete structure using corrosion-resistant anchors, fiberglass hold-down strips and polyester felt adhesive strips saturated with epoxy adhesive. The diaphragm is supported by a pressure injected hydrophylic urethane foam which is pumped beneath the diaphragm which thereby provides support for the diaphragm and fills the interstices of the existing concrete joint to prevent water leakage in and around a failed waterstop and to thereby form an integral, water-tight structure for new and existing concrete joints.

Abstract: Each of the recessed, confronting edges of adjacent concrete slabs in a roadway or the like has secured therein by a high density reinforced grout an elongated, rigid, prefabricated or precast edger strip, which also has an elongate recess in the edge thereof which faces on the space between the slabs. An elongate, semi-rigid, prefabricated cover member, which is generally T-shaped in cross section, has its upper, plate-shaped section positioned over the upper end of the space between the slabs so that opposite sides thereof project part way into the recesses in the edger strips, and has its downwardly projecting web section embedded in a sealing compound positioned between the confronting ends of the slabs. Remaining portions of the recesses in said edger strips are filled with a low modulus urethane compound.

Abstract: An expansion joint seal assembly comprising elastomeric face and back seals joined by a tear strip and mounted between abutting adjacent building surfaces by press-fitting holding arrows integrally formed with the face and back seals into corresponding receptacles in a retaining frame mounted to each of the building surfaces. The elastomeric face and back seals are provided with accordion-like surface contours that allow the space between the abutting building surfaces to expand and contract due to thermal expansion, wind drift, settling and seismic motions upon the building structure while maintaining an impervious seal. The elastomeric face and back seals and tear strip are produced from a single extrusion of a flexible material, and may be of a type susceptible of coloration.

Abstract: An expansion joint for use between adjacent sections of a roadway comprises a resilient seal for extending along the gap between the sections and two seal retainers adapted to be secured to the respective roadway sections on opposite sides of the gap. Each retainer has a cavity that opens towards the other retainer and internal shoulders on opposite sides of the opening. The seal has a V-shaped centre web and enlarged ears along opposite margins that fit into the retainer cavities. Each ear has two shoulders that abut against the shoulders in the cavity and prevent the ear being withdrawn from the cavity. The respective shoulders are carried by parts of the seal that have convex abutting faces, biassing the shoulders on the ear against the shoulders of the cavity.

Abstract: A joint covering has an elastic mat that is cast in situ and lies on rigid plates bridge the gap. The plates are controlled by providing the mat with elastomeric projections on its underside which engage the plates. The elastic behavior of the mat is not impaired in any way as a result.

Abstract: This invention provides an improvement in a road joint assembly wherein the amount of formwork required for installation of the joint is reduced, and wherein the joint assembly is particularly useful for installations where snow plows are utilized to clear snow from roads. In accordance with the invention, the road joint assembly comprises a pair of spaced-apart rail members which have a height at least two times their width. The rail members are provided with a plurality of spaced-apart anchoring members connected to the rear wall of the rail members. The anchoring members have a top surface which extends above the rear wall of the rail members and the rail members are recessed below the road surface, so that the top surface of the anchoring members is in substantially the same plane as the road surface.

Abstract: Elastomeric glands are disclosed provided with a laterally central chevron wall member which is carried in the gland, rearwardly to narrow and forwardly to widen, by front and back pairs of connecting wall means of the gland which apply thrust against the chevron wall member from relatively movable bodies during the rearward carry, and relieve thrust against the chevron wall member from the relatively movable bodies during the forward carry, under conditions of opposite lateral ends of the gland being supported relatively to move with the bodies and the gland being inside a movement tolerance space between the bodies. Gland and mount systems involving use of the elastomeric glands, and mounts for accommodating elastomeric glands such as of the character indicated and provided with anchors are also disclosed.

Abstract: An improved method and composition for repairing cementitious surfaces is provided. A polymerizable urethane composition having an excess of isocyanate groups to account for water present in the reaction environment is utilized. The method utilizes water, e.g. surface moisture, to foam the polymer and provide a long-lived repair of the surface. The method is particularly applicable in the repair of concrete roadways.

Abstract: An expansion joint which provides a flexible seal between two spaced-apart confronting sections of similar structures such as roadway slabs or the like. The expansion joint includes at least one assembly adapted to be secured to each section of the structure. The assembly has an upper elongated beam portion and a lower elongate and fixed forming bar portion. The beam portion and the bar portion are spaced apart to provide an elongated channel. The channel defines has a mouth which opens towards the gap between opposing assemblies. The joint includes a sealing element for spanning the gap between the assemblies. The sealing element includes a flexible intermediate portion with two laterally extending elongate flanks. At least one clamp member lockingly engages the flanks to each of the confronting sections. The clamp member, together with the flanks, are insertable into a channel defined by the upper beams and lower forming bar.

Abstract: An expansion joint for a structure such as a bridge or roadway comprising a pair of elongate tubes 14, 16 each having a longitudinal slot 24, 26 and a relatively wider channel 32, 34 and a folded strip 22 of polymeric material. The tubes 14, 16 are fixed to the structure by means of anchors 18, 20. The strip has bulbous edge portions 36, 38 which are located in the channels 32, 34. The strip 22 and tubes 14, 16 are located below the level of the structure surface.

Abstract: An expansion joint for sealing the channel between two sections of roadway has a plug and a fluid-polymer poured into the joint and allowed to set in situ in the channel. Enclosed within the fluid is a core of a mastic material which is more plastic and less elastic than the fluid-polymer. The elasticity of the fluid-polymer allows the joint to accommodate changes in the size of the joint due to e.g. thermal expansion and contraction. Plastic flow of the core permits changes of shape of the joint to be absorbed without causing excessive stressing of the sides of the channel to which the fluid-polymer adheres.

Abstract: This invention provides a one-piece joining element of extruded material suitable for joining floor or similar sections together comprising a main body having opposed top and bottom surfaces, the body having a first side having an upper wall section and a spaced apart lower wall section, a first chamber in the body adapted to receive a portion of a sealing member and an opening extending between the upper and lower wall sections of the first side. The opening is in communication with the first chamber and a second side in generally opposed relationship to the first side, the body having a second retention chamber adapted to receive a joinder member in engaging relationship therewith, the second side having an opening therein in communication with the second retention chamber, the opening forming a restricted mouth with the second chamber.

Abstract: An expansion joint adapted for sealing an elongated gap formed between two adjacent road sections. The joint provides a continuous support for vehicles crossing the gap while enabling the desired temperature responsive movement of the slab road sections. A pair of non-metallic elongated mounting strips are secured to the adjacent road sections on either side of the gap. An elongated seal strip is mechanically and adhesively secured between the spaced mounting strips for straddling the gap to exclude entry of undesired matter into the gap. A curable epoxy cement is employed to form a smooth transition vehicle support surface between the road sections and the seal strip.

Abstract: An expansion joint system for functioning as an expansion joint between concrete sections of a roadway surface or the like. Such roadway surfaces are normally provided with a slot for accommodating thermal expansion and contraction of the concrete and a boxed-out zone for receiving the expansion joint system. The expansion joint system includes a plate and sealants. The plate is provided with a lower or interior resilient winged section inserted into the slot with wings extending exteriorly to frictionally engage the surfaces of the slot and thereby effect centering and preclude the raising of the plate from the slot. The plate is provided with an upper or exterior section including support surface for resting on the boxed-out surface of the cement segments to thereby preclude the plate from dropping into the slot. A stem couples the upper and lower sections of the plate. A sealant then covers the horizontal support and fills in the boxed-out zone of the concrete.

Abstract: The present invention relates to an improved expansion joint for bridging e space between structural components susceptable to relative movement. The joint construction presents an uninterrupted transition between the structural components and is capable of compensating for vertical as well as lateral displacement of the joined parts. The device is capable of withstanding high load forces due to a novel self centering reinforcing rail.

Abstract: An expansion joint for bridges and similar structures comprising an elastomeric sealing element, anchoring means gripping the sealing element and resin mortar connecting the anchoring means to the structure. The resin mortar is comprised of a mixture of ureide and epoxy resins and aggregate. The anchoring means has rods embedded in the resin mortar to distribute stresses therein.

Abstract: Expansion and cast-in retainer dams for sealing pavement joints against intrusion of water, dirt, etc., into the joint space, said dams utilizing a pair of extruded steel or aluminum frames on opposite sides of the joint and a continuous elastomer strip spanning the joint and interlocked along its opposite edges in slotted longitudinal openings in the frames by a bead of triangular cross-section on each edge of the strip, the frames each having elongated solid metal zones above and below the slotted openings.

Abstract: A deflector comprising a stem portion and a deflecting body portion for protecting a roadway expansion joint. The stem portion anchors the deflector in an operating position in which the body portion deflects snow plow blades and the like upwardly away from the expansion joint.

Abstract: An expansion joint sealing assembly of the type employing a flexible membrane extending between two relatively rigid elongated elastomeric pads is adapted to seal the gap in the area where a curb and roadway portion of the deck intersect. The assembly is especially useful in situations where the gap extends at a skew angle across the roadway, so that the line of intersection between the curb and roadway portions of the deck, along which the sealing assembly must be bent, is not perpendicular to the longitudinal dimension of the sealing assembly. This creates a complex bending angle for the flexible membrane portion of the seal. In brief terms, the problem is solved by providing laterally extending convolutions in the side edge portions of the membrane and a locking rib on the top of each convolution which fits into an appropriate slot in the elastomeric pad to which each side edge portion of the membrane is connected.

Abstract: A composite expansion joint assembly having a pair of edge members, a plurality of elongated resiliently yieldable sealing elements, rigid structural members interposed between adjacent sealing elements and laterally spaced support bars for the structural members. Equalizing springs acting directly upon the structural members independently of the support bars are compressed by movement of the structural members away from each other and from the edge members as the sealing members open, providing equalizing forces to maintain equidistant spacing between the structural members whether they are laterally slidable on the support bars in a single support bar system or are fixed to the support bars in a multiple support bar system.

Abstract: A roadway expansion joint and seal is provided which comprises a pair of parallel metal side rails having a flexible membrane secured therebetween. The membrane includes enlarged opposite side edge portions which are mounted within respective C-shaped sockets in the side rails, and the side edge portions of the membrane each include a cavity which permits the side edges to be assembled in the sockets by initially compressing each side edge portion so as to collapse the cavity, while laterally forcing the same into the socket. Once in position, a relatively incompressible material is injected into the cavities of the side edge portions so as to substantially fill the cavities and thereby resist the withdrawal of the side edge portions from the sockets.

Abstract: An expansion joint cover comprises a pair of elongated rigid frame members, each of which includes a generally vertical, longitudinally continuous wall portion and a multiplicity of longitudinally spaced-apart, substantially horizontal plate-like tongues supported in cantilevered relation from the vertical wall portion at locations spaced from the upper edge of the wall portion and in longitudinal alignment. The longitudinal spacings between adjacent tongues of each frame member are not less than the widths of the tongues of the other frame member such that in the cover as installed in the expansion gap the tongues of each frame member project into the spaces between the tongues of the other frame member, and a generally longitudinally continuous bridge is formed by an intervening of the tongues of each of the frame members between the tongues of the other.

Abstract: A prefabricated expansion joint element for forming a surface joint between two concrete construction parts (1,2). The joint element has a central, resilient member (4) and anchoring members (5,6) connected to each side thereof. According to the invention the anchoring members are formed by profile elements (5,6) of epoxy plastic with at least one reinforcing layer (7) cast thereinto, said layer also extending through the intermediate resilient member. The external surface of the central resilient member (4) is connected to and aligned with the external surface of the profile elements (5,6). The profile elements (5,6) are securably by adhesion directly onto the edge portions of the concrete construction parts (1,2), so as to provide easy mounting, long life and resistance to severe climatic conditions and heavy loads.

Abstract: Expansion and cast-in retainer dam for sealing pavement joints against intrusion of water, dirt, etc., into the joint space, said dams utilizing a pair of rolled steel frames on opposite sides of the joint and a continuous elastomer strip spanning the joint and interlocked along its opposite edges in slotted openings in the frames by a bead of triangular cross-section on each edge of the strip.

Abstract: An expansion joint cover comprises at least one elongated frame assembly which includes a base member having a bridge-supporting rib adjacent the gap and a cover-supporting flange spaced laterally outwardly from the rib, the cover-supporting flange having an upwardly open groove and an abutment located laterally outwardly from the groove, relative to the expansion gap. A cover member having, in cross-section, a web portion, a bridge-supported flange extending down from the underside of the web portion adjacent to the gap and generally vertically above the rib of the base member and a retainer rib extending down from the underside of the web portion, is fastened to the base member of the frame assembly by longitudinally spaced-apart, generally U-shaped spring clips received on the retainer rib of the cover member and in the groove of the base member.

Abstract: An improved sealing assembly for sealing the expansion gap between adjacent sections of a structure has elongated elastomeric pads laid end to end along the length of the gap with a groove in at least one of the end surfaces of each pad for containing a flowable sealant.The groove has an inlet port at the top edge of the end surface through which the flowable sealant may be injected, an intermediate sealing portion for housing the sealant to prevent debris and liquid from passing between the end faces, and a vent portion communicating between the intermediate sealing portion and the top edge of the end surface, so that sealant emerging from the top of the vent portion will indicate that the intermediate sealing portion has been filled.

Abstract: A sealing system and method for sealing an expansion joint in a roadway gap. Channel-shaped members are mounted at each side of the joint. A seal having a bead at each side is sealingly clamped by a retainer bar against the channel member to provide a seal across the roadway gap. The retainer bar is maintained in a clamping position against the seal bead by retainer plates and by a keeper pin which overlies the bar. The bar is forced downwardly into sealing engagement with the bead to permit positioning of the keeper pin over the retainer bar to hold it in clamping and sealing engagement.

Abstract: An elongated elastomeric strip has means along the longitudinal edge for fastening to a receiving element secured in a roadbed. The fastening element comprises at least one set of retaining members, each having a head portion at least in part embedded and bonded securely in the elastomeric strip and a projecting portion depending from the strip. The retaining members are arranged so that the projecting ends of some of them face oppositely to the projecting ends of the others of them, thereby being relatively movable toward and away from each other under deformation of said strip and cooperate to resiliently clamp onto the receiving element. The projecting ends of the retaining members are preferably claw-like.

Abstract: An expansion joint seal for use in roadways, bridges and the like adapted for use with a pair of elongated, parallel spaced-apart edge members defining a gap therebetween and each of the edge members having a generally C-shaped cavity opening towards said gap. The seal includes mounting beads on each of its longitudinal edges for reception within the aforesaid edge member cavities and a double walled, resilient web construction spanning the aforesaid gap and being attached to the mounting beads. The double walls of the web are disposed in an upper and lower relative relationship to one another and are connected to the mounting beads at correspondindly upper and lower portions thereon. The upper and lower web walls fold downwardly upon movement of the edge members towards one another and corresponding reduction in width of the gap.

Abstract: An expansion joint seal for use preferably in walkways and the like having a pair of elongated, parallel spaced-apart slab members defining a gap therebetween with each of the slab members having a generally C-shaped cavity opening toward said gap. The seal includes mounting beads on each of its longitudinal edges for assembly within the aforesaid slab cavities and an intermediate section spanning the aforesaid gap and being attached to the mounting beads. Each mounting bead is of tubular construction and includes an outer wall surface configuration generally adapted for matching engagement with said cavity. The radius of curvature of each mounting bead outer wall portion in an unstressed, disassembled condition is less than the radius of curvature of the corresponding cavity so that upon assembly of the mounting bead within the cavity the outer wall portion is forced to assume the curvature of the cavity resulting in a highly effective mounting of the bead.

Abstract: Two concrete slabs separated by a gap are interconnected by a molded expansion joint formed by a pair of composite marginal bodies formed of metal and elastomeric material which are disposed on opposite sides of the gap. Each marginal body includes a groove with an aperture which is open in the direction of the gap. An elastomeric sealing means is disposed to span the gap and be received through the marginal body apertures for mounting in the grooves thereof wherein each marginal body includes a metal mounting plate embedded in the elastomeric material thereof which overlies the groove associated therewith. Anchor means secure each of the marginal bodies against the slabs whereby the mounting plates therein reinforceably urge the longitudinal edges of the sealing means into a firm engagement against the slabs.

Abstract: Means are provided for reducing or eliminating leakage of water around rubber cushion expansion joints in highway and bridge pavements. Molded rubber cushion joint sections which are typically 4 to 6 feet long are spaced from each other, end-to-end and a flexible membrane is fitted between the facing ends to absorb shearing stresses between adjoining sections and seal the end-to-end connections. In addition, a hollow rubber tube is compressed between the sections and the pavement to seal against leakage around the joint sections.

Abstract: An apparatus for collecting fluid seepage in a building structure or the like wherein the structure is constructed with generally horizontal slabs having separations therein, such as expansion joints and/or shrinkage cracks, settlement cracks, stress cracks or the like. The apparatus includes first and second elongate barrier strips operably positionable along opposite sides of the separation. A flexible collection sheet is hung from mounting channels on the outer edges of the barrier strips. Drip contour lips are fashioned upon the inner edges of the barrier strips and serve to direct fluid seepage passing through the expansion joint, stress crack, or the like, into the collection sheet.

Abstract: An expansion joint for mounting in the gap left between roadway sections, e.g. sections of a roadway bridge structure, to accommodate thermal expansion of the sections, is provided with at least one intermediate beam member extending in the gap across the width of the roadway and sealing strips of elastomeric material fitted between the roadway section edge structures and the intermediate beam. The joint has a plurality of units spaced apart across the width of the roadway, each unit comprising a lazy tong link arrangement pivotally mounted to the edge structures of the two roadway sections and to the intermediate beam members and extending across the gap, so as to ensure that any expansion or contraction of the gap between the roadway sections is equally distributed among the various parts of the gap on each side of and between the intermediate beam or beams.

Abstract: Pavement joint structures utilizing laterally spaced, elongated metal frames with a four-sided, compartmented, elongated, elastomer seal locked in the frames and spanning the space, the seal having a double arch, nadir-to-apex internal web structure.

Abstract: A sealing system for roadway expansion joint gaps and the like. A continuous seal is provided comprising an elongated central arched segment, a pair of longitudinally extending legs, and a protrusion extending upwardly from each of the legs. The seal embeds at least one fabric reinforcement layer to stiffen, rigidify and strengthen the seal means and the protrusions. The seal is secured to each roadway slab between a horizontal surface and a retainer which defines an elongated recess for sealingly receiving, engaging and compressing a protrusion. A limiter is provided for limiting the compression of the protrusions, and a retainer lip is provided for visually indicating that sealing of a protrusion has been effected.

Abstract: A seal assembly for expansion joint gaps in which a sealing member having a gap spanning portion and side walls is sealingly attached to abutments on respective sides of said gap by a clamping plate adjustably adapted to squeeze the sealing member side wall against a flange of said abutment.

Abstract: A large motion expansion joint having a plurality of parallel load-carrying modules which are disposed transverse to the direction of the roadway. The load-carrying modules generally span the expansion gap between adjacent structural members to support vehicular traffic thereon and include a first end module mounted to an edge of one of the structural members, a second end module mounted to an edge of the other structural member and at least one intermediate module. The intermediate modules carry a plurality of spaced sleeve-like beam guides which are aligned with spaced elongated sleeve-like support beam housings secured to the second end module. A plurality of support beams are fixed to the first end module and slide into the beam guides and housings generally in the direction of the roadway so as to support the intermediate load-carrying modules.

Abstract: A method and gap sealing assembly for sealing adjacent roadway slabs at the gap. Gap sealing members bridging the gap are positioned in end-to-end array. A resistance heater is positioned adjacent elastomeric end surfaces of the members and a rubber-like heat activatable bonding agent is positioned between the end surfaces. When the heater is energized, the end surfaces are bonded to each other to form a seal in situ.

Abstract: Sealing apparatus for joints in roadways which comprises elongated anchor pads secured by studs and nuts to the surfaces of concrete slabs on opposite sides of a gap therebetween and a flexible, resilient, elongated, sealing member extending between and integral with said pads, said pads preferably being formed of a relatively hard elastomeric material having rock fragments embedded therein and reinforced by longitudinally extending metal plates therein. Means is provided for connecting sections of said sealing apparatus end-to-end and preventing leakage at their contacting ends.

Abstract: A device for bridging expansion joints in roadways, comprising edge plates anchored in the edges of the roadway to be joined together, an intermediate plate between the edge plates, a resilient seal between the intermediate plate and each edge plate, and flexible lateral supports depending from the intermediate and edge plates and connected together at their ends remote from the plates.

Abstract: A composite expansion joint assembly of alternating elastic sealing elements and rigid structural members mounted on transversely extending support bars by mounting means restricting vertical and horizontal translational displacement of the structural members. The mounting means comprises two embossments disposed between a structural member and support bar with a pinned connection extending between the embossments so as to allow relative rotational movement between the structural member and support bar. Each support bar has mounted thereon only one structural member with each structural member being supported at each of its ends.

Abstract: An apparatus for the working of materials in a vacuum by means of an electron beam. A vacuum machining facility incorporating a first chamber which includes a longitudinal gap which determines a vacuum tight area around the machining line of the parts to be machined, a flexible sealing strip to plug the gap and a second leakproof chamber which houses an electron gun. The second chamber abutting the first chamber, includes an orifice located close to the gap through which the electron beam passes. The second chamber is movable on the first chamber along the gap. An apparatus is included which moves the plugging strip out of and to the side of the gap in the proximity of the orifice, the plugging strip being fully housed inside the gap except in the region close to the orifice.

Abstract: An expansion joint strip seal for use in roadways, bridges, buildings, and the like adapted for use with a pair of elongated, parallel, spaced apart edge members defining a gap therebetween and each of the edge members having a generally C-shaped cavity opening toward said gap. The seal includes mounting beads on each of its longitudinal edges for mounting within the aforesaid edge member cavities and a downwardly folding resilient web member spanning the aforesaid gap and being attached to the mounting beads. Each mounting bead is of tubular construction and includes an outer wall surface configuration adapted for engagement in said cavity.

Abstract: An expansion joint seal assembly for sealing the gap between adjacent sections of a deck structure, such as a highway bridge or parking deck. The assembly includes an elongated body of elastomeric material that has two elongated compression pads extending along each side, and a flexible sealing section joining the two pads together. The compression pads are secured to the roadbed sections on opposite sides of the gap by means of metal cover plates that extend over ribs on the top of each compression pad, and fasteners such as anchor bolts that are secured to the deck sections at points in between the ribs of the compression pads. The anchor bolts extend up through the cover plates, and the heads of the anchor bolts are tightened down against the cover plates to press them against the compression pads and secure the compression pads in firm sealing engagement with the deck sections.

Abstract: An expansion joint with an elastomer seal having longitudinal frames made from aluminum extrusions extending longitudinally of an expansion joint for pavements and bridge decks. The longitudinal frames are mounted by anchor bolts in the pavement or bridge deck concrete, which pavement or bridge deck has a concrete or asphaltic wear surface. The elastomer seal is fixedly held in the longitudinal frames by elongated tongue and groove means, and the joint space is spanned by at least one shallow, V-shaped elastomer wall which deforms downwardly as the joint width becomes narrower. The longitudinal frames are held in position in steps in the concrete adjacent to the joint by the anchor bolts, which have threaded ends projecting upwardly into an upwardly facing longitudinal channel and the hollow space of a hollow segment of substantially square cross section in the respective longitudinal frames.

Abstract: A composite expansion joint assembly of alternating elastic sealing elements and rigid structural members slidably mounted on transversely extending support bars with uplift restraint assemblies associated therewith restricting vertical displacement of the structural members.

Abstract: An assembly for sealing the intersection of curb and gutter portions of adjacent roadway slabs, including side pads joined by an upstanding joint membrane and a sealing flap extending away from them. The sealing flap is more flexible than the joint membrane, but has a relatively rigid zone positioned to promote folding of the flap between the side pads and below the joint membrane when the side pads are secured to the curb portions. The folding takes place without bunching and wrinkling to provide a smooth and neat transition from the curb to the gutter portions to promote effective sealing. A method of installing that assembly is also disclosed.

Abstract: An improved modular expansion joint having proportioning bars to provide support for and to center the beams which run longitudinally in the gap being joined. The proportioning bars extend across the gap under and at an angle to the beams. The ends of the bars slide in channels formed in the ends of the pavement sections being joined. As the gap narrows, the angle between the bars and the beams becomes more acute. Each beam is connected to at least a pair of bars and its position in the gap is thereby controlled. Removable caps are provided on each beam to accommodate replacement of the resilient seals between the beams.

Abstract: A seal and cover for expansion joints in roadways and bridges comprised of a block of elastomer having grooves extending downwardly from its top surface to allow for expansion and contraction. A metal plate is secured to the top of the elastomer block to protect the block and help carry the weight of vehicles over the joint. The plate may also have grooves in its top surface to reduce the likelihood of vehicles skidding as they cross the joint.