US2698560A

US2698560A - Concrete expansion joint

Info

Publication number: US2698560A
Application number: US732170A
Authority: US
Inventors: The Union Savings Trus Company; Carl J Heltzel
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-03-04
Filing date: 1947-03-04
Publication date: 1955-01-04
Anticipated expiration: 1972-01-04

Description

J. N. HELTZEL CONCRETE EXPANSION JOINT Jan. 4, 1955 3 Sheets-Sheet l Filed March 4. 1947 Q. 6 h/N WV n. www f 4, J ./V E... .....A w.\...... L. u. n

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Jan. 4, 1955 J. N. HELTzEL 2,698,560

CONCRETE EXPANSION JOINT Filed March 4, 1947 3 Sheets-Sheet 2 Jan. 4, 1955 l 1 N HELTZEL 2,698,560

Y CONCRETE EXPANSION JOINT Filed March 4, 1947 3 Sheets-Sheet 3 2@ myn/fof?.

M J lv. Menzel.

United States Patent O CONCRETE EXPANSION JOINT John Nicholas Heltzel, Warren, Ohio; The Union Savings & Trust Company, Warren, Ohio, and Carl J. Heltzel, executors of John N. Heltzel, deceased Application March 4, 1947, Serial No. 732,170

Claims. (Cl. 94-18) This present invention relates to improvements in the so-called beamed expansion joint. According to this joint construction a sill or beam of suitable material, such as concrete, is embedded in the subgrade of a road or airport runway at a point predetermined by its location beneath a proposed expansion or contraction joint to be produced between a pair of concrete slabs. 'Ihe same are to be poured later or are to be placed over the beam.

The principal object of the invention is to provide a construction of the type characterized and including tension means connecting the beam to the slabs and permitting the latter to expand or contract in any direction but preventing the slab ends from moving up and down. This construction also includes moisture absorbent means for relieving the tension of the plastic mass represented by each slab.

Another object of the invention is to provide a construction as contemplated by the principal object of the invention and further characterized by tension means stressed during the expansion of the slabs and by virtue of such stress contributing towards the relief of the tension developing in the slabs during the contraction.

A further object of the invention is to provide, in a construction as characterized, drainage means conducting the Water from the joint to the subgrade.

Still another object of the invention is to provide, in a construction as characterized, a beam including a surface supporting a pair of slabs and also including adjacent said slab-supporting surface drainage means conducting the moisture to either side of the beam.

A still further object of the invention is to provide a contraction or dummy type joint.

With these and other objects in View which will become apparent as the invention is fully comprehended, the same resides in the novelty of construction, combination and arrangement of elements and method of constructing the combination of elements. Both the combination of elements and the method of constructing the combination will hereinafter be described in their specic details and are claimed in the subjoined claims.

The description should be read in connection with the accompanying drawings, forming part of the application and wherein:

Fig. l is a vertical section taken transversely of the joint structure forming the preferred embodiment of my invention;

Fig. lA is a fragmentary plan view of a portion of a highway or airport and illustrating the use of my slabsupporting beams below the joints of the highway;

Fig. 1B is a plan view of a slab-supporting beam incorporated in the invention;

Fig. 2 is a view similar to Fig. 1 of a modied form of my joint;

Fig. 3 is a perspective view of another modified form of a beam or sill submerged in the subgrade.

Referring specifically to the drawings and having particular reference to the form of invention disclosed in Figures l and 2, numeral 8 designates the joint space between the opposed slabs 9 of a roadway, airport or the like, which slabs are supported upon the subgrade 10.

The joint space 8 is provided between slabs to allow for expansion and contraction of same under diiferent atmospheric conditions, and as in my prior applications, identiiied earlier herein, I provide beam-like sills 11 which are disposed in the subgrade across the joint space at intervals, these sills 11 serving as the load-supporting elements of my expansion joint.

Nice

The sills or beams 11 are preferably made of reinforced concrete, bituminous or otherwise, and have their upper surfaces lying iiush with the surface of the subgrade so that road grading machinery such as rollers or the like may operate over them and eiect proper seating of same in the subgrade. Of course the beams or sills 11 may be made of other materials, and in the present instance they are preferably pre-formed in a factory or other place and hauled to the job.

The beams 11 are reinforced by a plurality of transversely extending, laterally spaced rods 12 extending substantially the full width of the beams, which latter will preferably extend the full width of the two slabs 9 which they sustain; and in the case of a three-slab roadway, which is to say, one of three slab width, the beams 11 may extend the full width of all three slabs. Rods 12 are trussed or vertically oit-set as at 12a, for added strength and their ends are bent downwardly (12b) to form legs which serve as supports for the reinforcing assembly during the pouring of the concrete to form the beams 11.

Extending lengthwise of the beams or sills 11 are the reinforcing rods 13. These, by choice, are arranged in pairs laterally spaced adjacent opposite sides of the beam and although it is not absolutely necessary, l iind it desirable to weld rods 13, as at 13a, to the transverse reinforcing rods or members 12.

Figure l illustrates the reinforcing cross-rods 12 as having welded or otherwise secured to their under surfaces the medially apertured bearing plates 14. The welding referred to is indicated by reference character 14a. In the illustrated embodiment of the invention nuts 1S are welded or otherwise secured to the lower portions of the respective bearing plates 14, concentric with the apertures thereof, the welding being indicated by reference character 15a. However, it is to be understood that the bearing plates 14 and the nuts 15 may be made integral.

In carrying out the sill or beam reinforcement, I provide vertical tubular members 16 arranged in pairs at opposite ends of the beam 11 and concentric with openings in the bearing plates 14. It is also desirable that the flared lower ends 16a of the tubular members 16 be welded to the upper face of the bearing plates 14. The flared upper ends 16a of the tubular members 16 terminate flush or substantially flush with the top surface of the beams, as indicated in Fig. l. There should be provided a pair, or two tubular members 16 intermediate the ends of the beams or sills 11. The number of tubular members 16 used will, of course, depend upon the length of the sill or beam 11. The flaring of the upper and lower ends of the tubes, as indicated at 16a, serves to give same added strength and rigidity.

After the tubes 16 have been installed, the slab or sill 11 is poured and iinished, it being observed that the upper ends of the tube 16 will necessarily be temporarily plugged during the pouring of the sill. When the sill or beam 11 has properly set, it is installed in the subgrade as shown in Figure l, the various other elements shown associated with the sill being applied thereto later after the subgrade is iinished and is ready for the pouring of the slabs 9.

Figure l also illustrates vertically extending tension rods 17.

The upper ends of the vertically extending tension rods 17 are bent laterally inward as at 17h, the said ends of companion rods 17 being disposed in opposition to one another so as to engage and retain the U-shaped cap strip 20 which is seated over the usual joint strip 21 of compressible material. Thus, the tension rod ends 17b serve to align the joint strip 21 to retain it in vertical position during the pouring of the slabs 9.

It should here be observed that during the pouring and nishing of sill or beam 11, the vertical tension members 17 may be temporarily screwed into position so as to facilitate stabilization of the tubular members 16. This will assure accuracy of the centering of the tension members 17. Assuming that the tension members 17 have been used as above mentioned when sill 11 is poured, they are temporarily removed so as not to interfere with grading machinery, rollers and the like, used to prepare the subgrade l0 for the pouring of the slabs 9.

Figure l also illustrates that the lower end of the joint strip 21 is received in a U-shaped channel strip 21a. Both of the channel strips 20, 21a extend the full length of the joint strip 21. The channel strips-20, 21a, as previously intimated, serve to properly align the top and bottom edges of the joint strip 21.

After the sills or beams 11 have been properly positioned in the subgrade 10, and the latter has been rolled and otherwise prepared for the pouring of the slabs 9, the upper surface of each of the sills or beams 11 is covered with a layer of tar paper or the like 19, the ends 19a of which are inclined inwardly into the subgrade and covered so as to retain the tar paper in position.

The function of the tar paper covering 19 for the beams or sills 11 is to insure complete separation of the slabs 9 from the subgrade and beams or sills 11; and also to eliminate any possible resistance to the shifting of the slabs 9 on their supporting sills 11 during the expansion and contraction of the slabs under action of different atmospheric conditions. The tar paper sill covering 19 also assists in guarding against damage to the slabs 9 during the shrinking period of the plastic mass, there being also provided'means for relieving tension of the mass during the drying process, which means will be dealt with hereinafter.

Still referring to Figure l, it will be noted that I dispose upon the tar paper 19, above the sills 11, tubular members 18 whose ared bottom portions 18a are concentric with the tubular members 16 and rest upon the tar paper in alignment with the flared upper ends 16a of such tubular members 16. The upper ends of the upper tubular members 18 have frictionally or otherwise seated therein the inverted frusto-conical disks 1817 which are medially apertured for the tension rods 17 to extend therethrough. The tension rods 17 are, of course, screwed back into the nuts after the subgrade with the sill 11 embedded therein has been rolled and finished preparatory to pouring of the slabs 9. The upper ends of the upper tubular members 18 terminate substantially short of the inwardly bent portions 17b of the tension rods 17, as illustrated.

Before the slabs 9 are poured, reinforcing rods 22 are suitably positioned and supported temporarily by any convenient means from the subgrade, the position of said rods being in the bend between the inturned end 17b and the vertical portions of the tension rods 17. This, when the slabs 9 have been poured, the tension rods 17 in effect connect the upper area of the slab with the subjacent joint spanning supporting beam or sill 11.

Previous reference has already been made to means for relieving the tension of the plastic mass comprising each slab during the setting or drying out process, and, as shown in Figure l, this takes the form of a wooden bar 23 kwhich is co-extensive in length with the joint 8 between slabs 9. The wooden bar 23 as shown is square or rectangular in cross section and rests upon the tar paper 19 centrally of the joint space 8. The bar 23 has been stated as being of wood but the primary or essential characteristic of the bar 23 is that it must be highly absorbent so as to expand under the action of moisture and contract as it dries out.

The wooden bar 23 has disposed on either side the angle bars 24, the vertical flanges of the angle bars engaging said wooden bar 23, while the base flanges 24 thereof rest upon the tar paper covering 19 of the sill 11. The angle bars 24 may, and preferably do, extend the full width of the associated slab and are pressure absorbing elements, to reinforce the bottom portion of the slab 9 adjacent the tubular members 18.

Brace members 25, in the form of rods having laterally bent lower end portions 25h, engaging the angle bars 24 at the intersection of their flanges', extend diagonally upward into the associated slab 9, and have their outer ends bent laterally, as at 25a, to effect an anchoring bond in the slab. The angle bars 24 and brace members 25 are, of course, located in the positions illustrated in Figure l, and are suitably retained in place during the pouring of the slabs 9.

In order to hold the moisture-absorbent wooden or other bar Z3 in place, during the pouring of the concrete to produce the slabs 9, I provide wires 26, whose inner terminals are nailed as at 27, to the absorbent bar 23, and have their outer ends provided with loops 26a extending around the upper tubular members 18, all as shown in Figure 1. It is desirable that a compressible strip 28 be disposed on top of the wooden or other expansible bar 23, as shown in Figure 1. 28 may be of material such as asphalt or it may be of fibrous moisture absorbing material such as the composition commercially known as Celotex. The function of compressible strip 28 is to act as a cushion to at least partially absorb upward expansion of the wooden bar 23 which would tend to elevate the slabs 9.

It will be understood that during the pouring of the slabs 9, the upper tubular members 18 are sustained by the tension rods 17 extending through the apertured medial portions of the inverted frusto-conical top-closures 18b of said tubular members. Thus, there will be no lateral shifting of the tension rods 17 in said tubular menbers during the pouring of the concrete to produce sla s 9.

Figure l also illustrates that the upper and lower tubular members 18, 16, are filled with sealing filler 29. This ller material 29 is preferably resilient, rubber being a Very satisfactory material to use for this purpose. The lling material 29 serves to prevent infiltration of foreign matter into the tubular members while permitting universal lateral tlexation of the tension rods 17 within the contines of tubular members 16, 18.

After the road or airport has been placed in service, the tension members 17 will connect the slabs 9 to the joint spanning beams or sills 11 thereby preventing the slab ends from moving up and down but permitting movement of the slabs 9 in all directions due to expansion and contraction.

When the slabs 9 are being poured, it will be obvious that the Wooden or other absorbent material bar 23 will absorb moisture and expand, forcing the lower ends of said slabs 9 outwardly as they shrink in the drying out process. This avoids the formation of fissures or the creation of any weakened areas in the slabs as the result of tension as the slabs shrink in the drying out process. It is to be understood that the joint strip 21, particularly after the road has been in service for some time, provides a very imperfect seal of the joint against moisture so that when there is rainfall a substantial amount of water will reach the wooden bar or the equivalent 23. Then, of course, after the road or airport is in service and the slabs expand in dry hot weather, the wooden or other moisture absorbing bar 23 will contract to cornpensate for such slab expansion. By the same token, in wet weather the bar 23 expands assisting the normal tendency of the slabs' to shrink and produce a widening of the joint space 8. The beam 11 has a plurality of central drip passages 11b disposed under the bar 23, detailed reference to which will be made in the description of Fig. 2.

In Figure 2, illustrating a modified form of my invention, numeral 8 denotes the space between adjacent ends of slabs 9a supported by a subgrade 10 in which the sill or beam 11a is submerged. The sill or beam 11a extends longitudinally and on either side of the space 8 and transversely of the road or airport runway.

In the beam 11a is formed a desired plurality of drip or drainage passages such as 11b for water which might enter at the top of the expansion joint or at the top surface of the slab. During the winter months and when the temperature is low the water inltrates through the joint formed by space 8 and is trapped in that position. This fact justifies the location of the drainage passages 11b directly under the joint.

The water passing through the passage 11b filters into the subgrade or the underpassage drain 11C, which extends throughout the entire length of the sill or beam 11a.

The underdrain 11e may also be useful for a purpose other than the one stated and affords a means whereby a beam 11a that has become depressed in the subgrade may be elevated by forcing ballast beneath the beam. This is carried out by pneumatic rams operated from the edges of the roadway and taking the place of the mud-jack, well known in the art.

Lengthwise of each beam 11a extend, in spaced relation, a plurality of horizontal reinforcing rods 13.

The medially apertured bearing plates 14 are arranged in pairs and the underside of each plate 14 is welded to the upper end of a nut 15 and is also welded or otherwise secured to the bottom end of the aring lower portion 16a of a tubular member 16. An apertured rubber or other compressible material plug or disk 16x closes the lower ared tube portion 16a and the adjacent tube part.

This' compressible strip L The upper end 16a of each tube 16 is likewise flared as at 16a and is also closed by a similar apertured plug 16x. The tubes or sleeves 16', 18 are encased in the beam 11a.

A pair of vertical tubes 1S in spaced relation are each arranged in a slab and have a lower flaring end 18a in substantial alignment with one of the lower tubes 16'. The upper tubes 18 have their upper ends plugged by apertured plugs 18b.

ln this connection the question might be raised as to Whether it is possible to entirely eliminate the so-called pumping of the subgrade. However, constructing the sills or beams 11a as submerged in the subgrade and the provision of passage 11e will do away with most of the pumping tendency owing to the fact that a cushion member 19, having its end portions 19a embedded in the subgrade, is laid across the top of the beam 11a.

This cushion member 19 may consist of asphalt composition and will, therefore, reduce the friction between the bottom of the slabs 9a and top of the beam 11a. Figure 2 shows the cushion member crimped at an intermediate zone 19b, owing to the approaching or expanding movement of the slabs 9a. The cushion member 19 absorbs the shocks of traic passing over the joint. Thus, pumping of the subgrade is minimized and slab curling prevented. Experts in the art realize that pumping is due to Vibration of the slab 9a at the joints. By my construction. such vibration is largely eliminated.

The joint space 8 is occupied by an expansion joint strip 21' which. as illustrated in Figure 2, has been compressed by the approaching expanding movement of the slabs 9a. (ln Figure l the slabs 9, on the contrary, are shown contracted and the expansion joint strip 21 uncompressed.)

A pair of horizontal reinforcing rods 22 are suitably positioned prior to the pouring of slabs 9a and supported temporarily by any available means from the subgrade and each located in the bend between the inturned portion 30b and the vertical part of a tension rod 36. The inturned portion 30b of each tension rod 30 has a free beveled end engaging the vertical side of the joint strip 21'.

Tension rods 30 are of standard reinforcing steel and may also be galvanized or made otherwise rust-proof. Fig. 2 indicates deformations on the rods 30, each of which extends near its lower end through the aperture of a bearing plate 14 and is threaded at such end for connection to a nut 15. The reinforcing steel for the rods 30 may be high carbon rerolled material of a very high tensile strength.

The use of deformed material for rods 30 will provide anchorage in the top portion of the slab. The unusual rigidity of this high carbon material insures corresponding resistance to bending.

31 denotes one of a desired plurality of reinforcing cross rods embedded in spaced relation and horizontal position in the beam 11a and extending substantially the full width thereof.

Each cross rod 31 is secured by welding or otherwise at points spaced on its underside to the tops of the bearing plates 14 and supports the same and the structure resting upon said plates 14. The end portions of rod 31 comprise vertical legs 31a. preferably formed by bending, and they terminate in horizontal feet 3111 bent laterally of the legs and in the vertical plane of the latter and of the horizontal part of rod 31. Preferably, each rod 31 is welded or otherwise secured on its upper surface to the lower surfaces of rods 13.

The lower edge portion of the joint strip 21 is seated in a recess 32a extending longitudinally of, and in the ton portion of, a wooden bar 32 which is thus held in alignment by the joint strip. Wooden bar 32 is shown in a compressed condition brought about by a previous movement of the slabs 9a toward one another. (ln Figure l, for contrast, the corresponding wooden bar 23 is shown as uncompressed.)

The lower edge of wooden bar 32 is formed with a lineal recess or groove 3217 which receives the crimped zone 19b of the cushion member 19, when, as shown, the slabs are expanded.

The major lower portions of the vertical sides of the wooden bar 32 are each engaged by the vertical flange 33a of a cover plate 33 whose plane horizontal portion closes the top opening of a sleeve 16. Each cover plate 33 has its plane horizontal portion provided with an opening 33e for passage of a tension rod 30.

Each cover plate 33 terminates in outer upwardly rising terminal portions 33b with an anchoring hole 33c for the concrete.

As will be apparent, the cover plates 33 act through their vertical anges 33a to properly position the wooden bar 32 under the joint space while slabs 9a are being poured.

During the expansion of the slabs 9a the latter exert an inwardly diverted force against the vertical flanges 33a of cover plates 33 with the result that the opening 33e thereof engages its rod 30 at a point remote from the joint and ilexes said rod 30 inwardly as shown in dotted lines in Figure 2.

The tension members or rods 30 tend to resist the movement of the slabs 9a toward one another. The bending stress to which the rods 30 have been subjected urges the slabs 9a to move apart and away from the joint 8. This relieves the concrete slabs 9a from tension during contraction.

So that cover plates 33 may be made of lighter gauge material than would otherwise be possible, a deformation 33d is pressed in adjacent portions of the horizontal part and vertical llange portion intermediate the sides of said plate. (See left hand plate 33 as viewed in Figure 2; and also dotted lines in right hand plate 33 in Figure 2.)

One of the great difficulties in connection with structures of the type described is the accumulation of moisture in the joint 8 and beneath the slabs 9a and about parts, such as 33, 18, etc., which are submerged in the concrete. This moisture becomes especially detrimental to the structure when the moisture is trapped and freezes.

The drainage of the moisture is accomplished by the provision of a tubular member 35 which, at its ends, communicates with the tubes 16 and includes sloping portions emptying the drainage into the passage 11b and from there to the drain 11C.

The casting of the beam and slab is done in a manner similar to the one outlined in the description of the preferred embodiment.

During the contraction of the slabs excessive stresses may develop which are, however, relieved by the resistances of the joint strip 21', and the wooden bar 32 and the bending stress prevailing in the vertical portions of rods 30.

Figure 3 shows a modified form of sill or beam 41 submerged in the subgrade 42. Preferably, this beam extends completely across the roadway and below the joint space 43 between adjacent ends of the slabs 44. A beam extending completely across a multiple slab width roadway would undoubtedly, as a practical proposition, have to be poured on the job. However, a plurality of sills or beams laid end to end and possibly precast and hauled to the place, could replace the single beam.

instead of relying on the structural rigidity of the sill or beam to carry a load, it may appear desirable to reinforce the beam by rigid steel members 45 embedded therein and extending transversely thereof or longitudinally of the roadway. The members 45 may have spaced holes 45a through which the concrete exgelnds and which thus provide an anchorage in the beam Angle irons or channels could be the form taken by members 45 which preferably are reinforced and supported at their ends by spacer members 46. Said spacer members 46 are each welded to an upturned end portion 47a of a subjacent reinforcing member 47 disposed transversely of the joint.

Anchorage terminal members 48 are each seated in sockets 49 and covered by covers 50 and each of said terminal members 48 have in their lower portion a notch 51 receiving a rib 52 forming on the interior of the cover 50 and holding the terminal member 48 against rotation. The covers 50 are water-tight and are filled with a supply of lubricant. The terminal members 48 are threaded at their upper ends projecting through the sockets for grgagement by threaded end parts of tension members The lower part of each tension member 53 is surrounded by a tube 54 bearing with its lower end against the upper side of the adjacent socket 49 and with its upper flared end against the upper ange of the beamreinforcing member 45, which ange is apertured for theA passage of the tension members 53.

The members of the Figure 3 disclosure so far described form part of the beam 41 structure and may be encased with either concrete or bituminous material. If the rigidity of member 45 is ample, the same may be encased in bituminous material for protection against 1'11St.

The use of bituminous material as a rust-induced deterioration preventer, as stated for member 45, makes it possible in many instances to dispense with the spacing and reinforcing means 46 and 47. Such would be the case where means 46 and 47 were used in conjunction with 45 to supply strength to supplement that of 45 when partially rusted away. However, similar means could be used for supporting members 45 in position during the application of the bituminous material. The use of concrete in the formation of beam 45 will make it possible to use a lighter member 45 than would be the case otherwise.

It may prove practical to position the beam 45 elements so far described on the subgrade, and to then pour the concrete and surface it so that the resulting beam has a top bearing portion flush with the subgrade. Care should be taken to prevent the infiltration of any concrete into a tubular member 54, since such concrete might interfere with the insertion and proper subsequent swinging operation of the tension member 53 upon expansion and contraction of slabs 44.

After the beam 41 has been placed in proper position, an asphalt or other cover strip 56 is placed over the structure to promote relative freedom of movement of slabs 44 on beam 41.

Then the expansion or joint strip 57 and the supporting members 58 are mounted on the cover strip 56 so that the vertical portions of the former hold the joint strip 57 in a vertical position during the pouring of the slabs. The bottom portions 58h of members 58 function as slides or skids during the expansion or contraction of the slabs 44.

58e denotes lineally extending reinforcing ribs pressed into members 58 intermediate its ends to rigidify the same and enable me to use lighter gauge material than would otherwise be possible. The upper and lower angularly directed ends of members 58 are provided with holes 58d for anchoring purposes.

The slide or base portion 58b of each member 58 is provided with an opening 58e registering with an opening in the horizontal ange or web member 45. Each tension member 53 is inserted through these openings in the members 45 and 58 and is surrounded by a tubular 1 member 62 preventing the infiltration of foreign matter.

The upper end of each tension member 53 is formed by a knob-like terminal member 63 capable of universal movement in socket 64 resting on top of the tube 62 and covered by cap or cover 65. The terminal member 63 has on its upper side a notch 63a for the insertion of a wrench-like implement whereby the tension rod 53 may be turned and threaded into or out of the part 48. The insertion of the wrench must, of course, be preceded by the removal of the cap 65 which, in its operative position, prevents the entry of foreign matter.

In order to properly space rigid members 45, spacers 67 extending longitudinally of the beams 41 are provided and secured to the former.

Drainage and friction are important factors in expansion joints. In order to reduce the friction on the top surface of the sill on which the slabs bear, and at the same time to provide for drainage, the top of the sill is provided with corrugations 68 spaced from one another by drain channels 69 sloping downward from the bottom of the expansion joint.

The asphalt cover 56 is positioned between the top surfaces of the corrugations 68 and the bottom surfaces of the slabs 44 and facilitates the shifting of the latter on the former. In addition, a lubricant may be applied to the asphalt cover 56.

Moisture, having infiltrated through the expansion joint or otherwise, will be diverted to the drain channels 69. This drainage also relieves the tension members 53 of excessive strains otherwise imposed on them by the freezing of the moisture.

The top surfaces of the corrugations 68 are level and lie ush, or in plane with, the subgrade of the roadway. The tension members 53 are anchored in the corrulgatiogns 68 and do not project through the drain channe s I desire it to be understood that the corrugated (68) basey or beam 41 proposition with the drainage channels 59 may be used in connection with contraction joints, also called dummy-type joints.

While I have hereinbefore described the specic details of various embodiments of my invention illustrated in the accompanying drawings, I desire it to be understood that changes or modifications of these details, falling within the scope of the appended claims, may be resorted to without departing from the spirit or scope of the invention.

What I claim is as follows:

1. In a roadway or runway construction, a subgrade, a beam submerged in said subgrade, an upwardly extending bar secured in said beam at opposite sides of its lineal center, each bar having its major portion disposed above the beam and universally movable in lateral directions, tube means secured in said beam inwardly from the top surface of the latter and ush therewith,

said tube means spacedly surrounding the beam-carriedl end of said bar, a pair of slabs supported by said beam on opposite sides of the lineal center thereof and spaced from one another to provide a joint space, each of said slabs anchoring the other end of one of said beam-carried bars, inwardly extending tubes carried by said slabs and spacedly surrounding said bars, said respective slab and beam-carried tubes being aligned with one another, an absorbent moisture expandable bar interposed in said joint space, a slab-carried reinforcement member for each slab and bearing against said absorbent bar, and each slab-carried reinforcement member having a portion embracing the related beam and slab connecting bar whereby expansion of said absorbent bar applies force to said slab and beam connecting bars.

2. In a roadway or runway construction, a subgrade, a beam submerged in said subgrade, tension means anchored in said beam, tubes in said beam opening from the top surface thereof and enclosing said tension means in spaced relation, a pair of slabs supported by said beam and including end portions adjacent to and spaced from one another, said tension means being also anchored in said slabs, other tubes in the slabs opening from the bottom surfaces thereof and enclosing said tension means in spaced relation, said tension means permitting relative horizontal movement of said slabs on said beam, means connecting said other tubes and preventing outward movement thereof, angles slidable on said beam and engaged by said slab ends, brace members each engaging an angle and anchored in said slabs, and an absorbent moistureexpandable bar between said slab ends and angles.

3. In a roadway or runway construction a subgrade, a beam submerged in said subgrade, tension means anchored in said beam, tubes opening from the top surface of said beam and surrounding said tension means in spaced relation, a pair of slabs supported by said beam and including end portion adjacent to and spaced from one another, said tension means being also anchored in said slabs, other tubes in the slabs opening from the bottom surfaces thereof and surrounding said tension means in spaced relation, an absorbent moistureexpandable bar between said slab end portions and supported by said beam, and drainage means in said beam below said absorbent bar in communication therewith and connected to and communicating into said first tubes.

4. In a roadway or runway construction a subgrade, a beam submerged in said subgrade, tension means anchored in said beam, tubes opening from the top surface of said beam and surrounding said tension means in spaced relation, a pair of slabs supported by said beam and including end portions adjacent to and spaced from one another, said tension means being also anchored in said slabs, other tubes surrounding said tension means in spaced relation in said slabs opening from the bottom surfaces thereof, said tension means permitting relative horizontal movement of said slabs on said beam, cushion means between said beam and slabs and first and second tubes, an absorbent moisture-expendable bar between said slab end portions and supported by said beam, said bar having a recess for a zone of the cushion means crimped during expansion of the slabs, and drainage means in said beam below said absorbent bar and communicating therewith.

5. In a roadway or runway construction a subgrade, a beam submerged in said subgrade, tension means anchored in said beam, tubes opening from the top surface of said beam and surrounding said tension means in spaced relation, a pair of slabs supported by said beam and including end portions adjacent to and spaced from one another, a moisture-expandable bar in the space between said slabs, said tension means being also anchored in said slabs, other tubes surrounding said tension means in spaced relation in said slabs and opening from the bottom surfaces thereof, said tension means permitting relative horizontal movement of said slabs on said beam, slab-carried reinforcement means engaging said tension means between said iirst and second tubes and stressing said tension means during expansion and contraction of said slabs, and said bar engaging said slab-carried reinforcement means for stressing said tension means.

6. In a road or airport runway construction or the like including subgrade-supported slab members spaced from one another to provide an expansion joint therebetween, and a beam member embedded in the subgrade below and paralleling the joint between the slab members; the combination of an absorbent, moisture-expandable bar supported on said beam member at the site of said expansion joint and extending lengthwise of the latter, said bar being of a width exceeding the maximum width of said expansion joint and of a thickness materially less than the thickness of said slab members, said slab members having opposed bar-receiving bottom recesses at the site of said joint and providing shoulders overlying portions of the bar top, at opposite sides of the joint, the bottom of said bar lying substantially ush with the bottom surfaces of said slab members, said beam member having drainage means extending therethrough from its top surface and located below said joint, the top of the beam member lying substantially flush with the bottoms of the slab members and bar, and upstanding relative horizontal movement-permitting tie means connecting said beam and slab members at opposite sides of said expansion joint, there being a yieldpermitting relief area surrounding each of said tie means and extending into at least one of said slab and beam members, whereby the tie members maintain the beam member in contact with the under surface of said expandable bar and slab members at opposite sides of said expansion joint so as to assure of drainage from the joint and expandable bar reaching the drainage means of said beam member.

7. In a road or airport runway construction or the like including subgrade-supported slab members spaced from one another to provide an expansion joint therebetween, and a beam member embedded in the subgrade below and paralleling the joint between the slab members; the combination of an absorbent moisture-expendable bar supported on said beam member at the site of said expansion joint and extending lengthwise of the latter, said bar being of a width exceeding the maximum Width of said expansion joint and of a thickness materially less than the thickness of said slab members, said slab members having opposed bar-receiving bottom recesses at the site of said joint and providing shoulders overlying portions of the bar top, at opposite sides of the joint, the bottom of said bar lying substantially ush with the bottom surfaces of said slab members, the top of the beam member lying substantially ush with the bottoms of the slab members and bar, and upstanding relative horizontal movement-perrnitting tie means connecting said beam and slab members at opposite sides of said expansion joint, and there being a yield-permitting relief area surrounding each of said tie means and extending into at least one of said slab and beam members, whereby the tie members maintain the beam member in contact with the under surface of said expandable bar and slab members at opposite sides of said expansion joint.

8. In a road or airport runway construction or the like including subgrade-supported slab members spaced from one another to provide an expansion joint therebetween, and a beam member embedded in the subgrade below and paralleling the joint between the slab members; the combination of an absorbent, moisture-expandable bar supported on said beam member at the site of said expansion joint and extending lengthwise of the latter, said bar being of a width exceeding the maximum width of said expansion joint and of a thickness materially less than the thickness of said slab members, said slab members having opposed bar-receiving bottom recesses at the site of said joint and providing shoulders overlying portions of the bar top at opposite sides of the joint, a compressible pad means interposed between said bar and shoulders, the bottom of said bar lying substantially ush with the bottom surfaces of said slab members, the top of the beam member lying substantially ush with the bottoms of the slab members and bar, and upstanding relative horizontal movement-permitting tie means connecting said beam and slab members at opposite sides of said expansion joint, and there being a yield-permitting relief area surrounding each of said tie means and extending into at least one of said slab and beam members, whereby the tie members maintain the beam member in contact with the under surface of said expandable bar and slab members at opposite sides of said expansion joint.

9. In a road or airport runway construction or the like including subgrade-supported slab members spaced from one another to provide an expansion joint therebetween, and a beam member embedded in the subgrade below and paralleling the joint between the slab members; the combination of an absorbent, moisture-expandable bar supported on said beam member at the site of said expansion joint and extending lenghwise of the latter, said bar being of a width exceeding the maximum width of said expansion joint and of a thickness materially less than the thickness of said slab members, said slab members having opposed bar-receiving bottom recesses at the site of said joint and providing shoulders overlying portions of the bar top at opposite sides of the joint, a compressible pad means interposed between said bar and shoulders, the bottom of said bar lying substantially lush with the bottom surfaces of said slab members, said beam member having drainage means extending therethrough from its top surface and located below said joint, the top of the beam member lying substantially ush with the bottoms of the slab members and bar, and upstanding relative horizontal movement-permitting tie means connecting said beam and slab members at opposite sides of said expansion joint, there being a yield permitting relief area surrounding each of said tie means and extending into at least one of said slab and beam members, whereby the tie members maintain the beam member in contact with the under surface of said expandable bar and slab members at opposite sides of said expansion joint so as to assure of drainage from the joint and expandable bar reaching the drainage means of said beam member.

10. ln a roadway or runway construction, a subgrade, a beam submerged in said subgrade, tension means anchored in said beam, tubes opening from the top surface of said beam and surrounding said tension means in spaced relation, a pair of slabs supported by said beam and including end portions adjacent to and spaced from one another, said tension means being also anchored in said slabs, other tubes surrounding said tension means in spaced relation in said slabs and opening from the bottom surfaces thereof, said tension means permitting relative horizontal movement of said slabs on said beam, cushion means between said beam and slabs and irst and second tubes, an absorbent moisture-expandable bar between said slab end portions and supported by said beam, and said bar having a recess for a zone of the cushion means crimped during expansion of the slabs.

References Cited in the le of this patent UNITED STATES PATENTS 1,739,102 Strauss Dec. 10, 1929 2,050,290 Earley et al Aug. 11, 1936 2,072,381 Post Mar. 2, 1937 2,148,773 Ozias Feb. 28, 1939 2,201,824 Brickman et al. May 21, 1940 2,244,315 Ridgeway June 3, 1941 2,254,885 Carswell et al. Sept. 2, 1941 2,319,049 Fischer May 11, 1943 2,330,213 Heltzel Sept. 28, 1943 2,342,181 Crom Feb. 22, 1944 2,479,434 Van London Aug. 16, 1949 FOREIGN PATENTS 321,495 Great Britain of 1929 562,495 Germany of 1932