US1903608A - Expansion joint, method and apparatus for the installation of the same - Google Patents

Description

April 11, 1933. C QLDER ,93,608 EXPANSION JOINT, METHOD AND APPARATUS FOR THE INSTALLATION OE THE SAME Filed Aug. 7, 1931 3 sheets-sheet 1 April 11, 1933. c. OLDE 1,903,608 EXPANSION JOINT, METHOD AND APPARATUS FOR THE INSTALLATION OF THE SAME Filed Aug. '7, 1931 5 Sheets-Sheet 2 20M 0 il] 22 i Ufff/5f f dffffdldef WMQQMJWI/S April 11,` 1933. Q OLDER I 1,903,668

EXPANSION JOINT, METHOD AND APPARATUS FOR THE INSTALLATION OF THE SAME Filed Aug. 7, 1931 3 Sheets-Sheet 3 xjgl.

4@ 75H @ifa wfg/ 20 Patented Apr. 11, 1933 UNITED STATES` PATENT OFFICE CLIFFORD OLDER, F WIIAMETTE, ILLINOIS EXPANSION JOINT, IIETHOD A ND APPARATUS FOR THE INSTALLATION OF THE SAME Application led August 7, 1.931. Serial No. 555,726.

concrete roads and the like.

The concrete pavements of the prior art are ordinarily constructed in a plurality of sections with cracks between the sections and with substantially larger expansion cracks located at regular intervals for the purpose of permitting the longitudinal expansion of the pavement under changes of temperature of the pavement. Expansion joints of this type may be installed to permit initial expansion or contraction depending upon the result desired.

When the separate sections of the pavement expand, there is a gradual sliding of the sections toward the expansion crack or 0 joint, but when the sections subsequently yso contract, they do not tend to return to their former position. This results in the disappearance of the relatively wide expansion` crack, and the space utilized by the wide expansion crack is soon divided into a plurality of cracks formed between adjacent sections of the pavement and it is practically impossible to prevent this action of the pavement sections in closing up the expansion joints.

The open expansion joints and cracks between adjacent sections soon become filled with dust, soil'and sand particles and as this material is generally incompressible it follows that when expansion again takes place, the joints cannot close between the adjacent sections and the whole series of sections-is pushed still further toward the expansion joint, until eventually all of the joints, including the expansion joint, have become filled with hard packed unyielding material. The purpose of the expansion joint is then defeated and further expansion of the concrete sets up compression stresses as great as there would be in oase no expansion joint had been provided in the lirst place.

Another diliculty encountered in providing expansion joints lies in the fact that the continuous expansion and contraction of the concrete permits the sand, `soil and other material to get in between the sections of concrete and the folds of the expansible metal joint. As the space between the concrete sections around the expansible metal becomes filled with hard packed material, the expansible, fold itself becomes compressed between the sections of concrete and hard packed material in the crack with the result that the easy curve, preferably provided between the folds of the expansible joint, becomes pressed to a sharp edge, thereby causing the expansible metal strip .to crack along the sharp edge between the sections of concrete. Unless provision is made for taking care of this tendency the fold in the expansible metal strip ultimately takes the form of a sharp bend, the metal then becomes pinched or creased and cracked and the purpose of the expansible joint is defeated.

One of the objects of the present invention is the elimination of the foregoing dihculties by the provision of an improved expansion joint of relatively simple and economical construction which is adapted to permit relative movement between adjacent sections of the pavement and to prevent the filling of the cracks between the sections with dirt or other foreign material. Another object of the invention is the provisin of a plurality of improved and simpliied forms of 'expansion joints adapted to positively prevent the formation of a sharp bend, fold or crease, and to prevent the pinching of the sheet metal ofy the joint by the foreign material filling the crack, so that the expansible metal joint will not be cracked or broken after a long period of service.

Another object of the invention is the provision of a plurality of forms of metal expansion joints for pavement, or the like,

which are not only adapted to secure the ad- -v minimum amount of labor after the concrete has been levelled off.

Another object of the invention is the provision of an improved template peculiarly adapted to install the expansion joints disclosed herein at a pre-determined height with respect to the'top of the concrete. Other objects and advantages of the invention will be apparent from the following description and rom the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings, of are three sheets;

Fig. 1 is a vertical sectional view of a portion of a concrete pavement, floor, sidewalk or the like, which is equipped with an expansion joint of the simplest type constructed according to the present invention;

Fig. 2 is a similar sectional view of the eX pansion joint just after it has been installed in the green concrete, showing one form of construction of the template.

Fig. 3 is a similar view showing another form of construction of the template.

- Fig. 4 is a similar sectional view of another form of template.

Figure 5 is a. transverse sectional view of the concrete pavement at the expansion oint showing a side elevation of the template and metal expansion strip.

Fig. 6 is a view similar to Fig. 1 of an* other form of expansion joint just after the edges of the concrete sections have been finished olf at the surface.

Fig. 7 is a similar view of the same joint after the cap has been removed and the joint filled with a suitable plastic filler. l

Fig. 8 is a similar view of another form of expansion joint peculiarly adapted to prevent the formation of a sharp crease at the fold between the parts of the metal strip.

Fig. 9 is a similar view of another improved expansion joint having a different form of division plate. i

Fig. 10 is a similar view of another form of expansion joint provided with means of preventing the concrete fillingthe space between the folds of the expansion strip.

Fig. l1 is another similar sectional view of a modification.

Fig. 12 is a similar view of another modifiL cation.

Fig. 13 is a similar view of a modified form of installation having an expansion strip at the top and bottom and Fig. 14 is a similar view of another modification.l

Referring to Fig. 1, the numerals 2d and which there `21 indicate the adjacent concrete sections of the pavement ywhich are separated by the crack 22, which is formed as the natural result of the contraction of the concrete as the concrete dries or contracts. The forml of eX- pansion strip shown in Fig. 1 is indicated in its entirety by the numeral 23 and it preferably consists of an eXpansible member or strip of non-corrodable sheet metal such as brass, bronze or the like, if desired. Ordi nary sheet steel may also be employed. The expansion strip 23 preferably includes a centrally located expansible portion comprising a downwardly extending V-shaped part formed by the flanges 24 and 25, and the downwardly extending side flanges 26 and 27.

The bends at 28, 29 and 30, between the flanges 24-27 inclusive are preferably easy bends, being slightly rounded to prevent the breaking of the metal or creasing of the metal at these points and the flanges 24-27 are adapted to flex resiliently to permit move ment between the adjacent sections 20-21 of concrete.

The expansible portion of the present strip is, therefore, substantially M-shaped in cross section and the downwardly extending flanges 26 and 27 are provided with laterally projecting parts 30, 31 and 32 extending into the concrete 20 and 21. The laterally projecting flanges 31 and 32 are preferably bent downward as at 33 to provide an anchoring formation in the concrete or they may be provided with backwardly bent flanges 34, which provide a support for a downwardly extending integral sheet metal division plate 35.

The division plate 35 extends sufficiently into the concrete body so that the concrete is weakened at 22 between the sections 2O and 2l and the crack 22 naturally results.

Between the flanges 32 and 34 the expan sion strip is preferably formed with an enlarged bead 36, which also provides an anchoring formation for this side of the expansion strip in the concrete section 2l. The4 strip is preferably installed between sections 2O and 21, substantially below the surface of the concrete, leaving spaces 37 and 38 at each side between the flanges 26, 27 and the adjacent concrete. These spaces are preferably filled with plastic filler 39, such as some asphaltum compound, adapted to fill these spaces and prevent dirt from getting in between the sections of concrete. The adj accnt corners 40 and 41 of the concrete sections 2O and 21 are preferably rounded off and when the expansion is so installed it is adapted to permit relative movement between the concrete sections 2O and 21 without permitting the dirt or foreign material to enter the crack 22. f

It should be noted that between the flanges 24, 26 and 25-27, there are open spaces 42-43, and that as the concrete section 21 spreads from section 20 the V- shaped portion 24, 25, 30 tends to lift up from the adjacent concrete. This lifting tendency of the expansion strip tends to permit the plastic filler l 39 to spread out to cover the space between the concrete sections 20, 21 more effectively. Referring to Fig. 2, this is an illustration of the same type of expansion joint with improved template adapted to be used to install these expansion strips. The template is indicated in its entirety by the numeral 44, and it 'preferably consists of a long strip of lumber or metal having sufficient flexibility to adapt itself to the natural crown of the pavement without being so flexible as to permit it to sag.

The template body 45 is preferably provided with plow handles 46 at each end to permit the handling of the template. In some embodiments of the invention the tem'- plate may be supported by stirrups and cables in such manner that it may be made more flexible, since it can be supported at its half and quarter points. The template is preferably as long as the expansion strip intended to be installed, or as long as the width of the strip of concrete in which the expansion joint is being installed. The surface of the concrete is preferablyvfinished to final form prior to the installation of the joints and the template ,should therefore be sufficiently flexible in alengthwise drection so that when the flat surface 47 rests on the concrete, the template will conform to the actual crown of the concrete, rather than to the theoretical curve. It is generally impossible to obtain exactly the theoretical curve desired and by having the template adjust itself to the actual curve of the concrete the. expansion strip will be located at a proper elevation relative to the actual concrete surface.

The template is preferably provided with a plurality of transversely extending vertical bores 48, adapted to serve as guides for the securing rods 49. Each of the securing rods 49 extends through bores 48 and is provided with a bent end or handle 50 at the top as well as a bent end 51 at the bottom for engaging the expansion strip 23. Each of the rods 49 is urged upward by-helical s ring 52, which engages the upper surface o the template body and also engages washer 53 below the handle 50. The spring 52 tends to pull the rod 49 upward to maintain it in engagement with the expansion strip 23. Y

The lower bent end 51 is preferably provided with a notch 54 for engaging the edge of the flange 35. The body of the template may be provided witha groove 55 for rece1ving a channeled metal member 56, which-1s secured in-the groove by a plurality of screws 57. The channeled metal member 56 has, 'a pair of downwardly extending flanges 58 and 59, spaced apart sulllciently to receive the cap strip 60.. The cap strip 60 may consist of a channeled metal member having downwardly extending parallel flanges 61 and 62, spaced sufficiently so as to receive the expansion strip 23 between them. The ends of thev flanges 61 and 62 engage the laterally extending flanges 31 and 32 of theexpansion strip 23, and the expansionstrip may be secured to 'the template 44 by pushing the rods 49 downward and rotating them until the grooves 54 register with division strip 35. Upon releas.

ing the handle 50, the rod 49 will be forced into engagement with the edge of division strip 35 by the spring 52 and the expansion strip 23 will be clamped between the channeled cap member 60 and the bent ends 5l of the rods 49. The template and expansion strip may then be lifted as an'entirety by means of the plow handle 46 and the template with the expansion strip may be placed on top of the green concrete. The weight of the template, together with tapping or pressure exerted on the template will cause the expansion strip to be embedded into the concrete as shown in F ig. 2 and the expansion strip will be located at a predetermined depth below the surface ofthe concrete by reason of the fact that the flexible template conforms to the crown of the concrete when the surface 47 engages the top of the concrete. The rods 49 may then be pushed downward and rotated to release the division strip 35 and upon lifting the template the channeled member 56 will leave the cap strip 60 and expansion strip 23 embedded in the concrete.

The cap strip 60.may then be used as a guide in employing edging tools to finish the adjacent edges 40 and 41 of the concrete sections 2() and 21, after which the cap strip 60 may also be removed and used over again for subsequent joints.

Referring to Fig. 3, this is a modified form of template in which the template body 45 has been made thinner and more flexible and the body has been provided with metal guides 63 for the rods 64 and 65. The cap strip 60 has been permanently secured to the automobile body 45 in this modification and is adapted to be remov'ed with the template. The rod 64 for holding the expansion strip 23 may be of substantially the same construction as the rod 49 previously described, except for the provision of vthe metal guide 63. The rod 65 may also be of the same construction except that it is shorter and is provided with a groove 66 for engaging the downwardly bent flange 33 on the other side of the expansion strip 23. In this modification the template is adapted to hold the ex fied form of template, having a flexible metal body 67, provided with a simple cap strip 60, having downwardly extending flanges 61 and 62. The template body 67 carries a channel 68, one flange of which is secured to the body 67 and the other flange of which carries a metal lplate 69. The metal plate 69 and the templa-tebody 67 are provided with 4bores 70 and 71 adapted Ito act as guides for l sections 20 and 21.

the rods 49. The rods 49 in every one of the templates are preferably located at-each end Lof the template and at regularly spaced points longitudinally of the template.

Fig. 5 is an elevational view showing the side elevation of the template as it extends across the pavement conforming to the actual crown of the concrete.

Referring to Fig. 6, this is a similar view of an expansion joint of simple shape except that the flanges 26 and 27 of the expansion strip 23 are joined by a semi-circular curved portion 72 making an expansible portion of a substantially inverted U-shape. The expansion joint is illustrated with the cap strip in place, just after the corners 4.0 and 4:1 have been rounded off with edging tools. The same form of expansion strip` is shown in Fi ure 7 after the joint has been completed and t e space around expansion strip 23 has been covered with a plastic filler 39. The expansion joint shown in Fi 7, however, has its flange 34 shorter than anger 32, so that the concrete may extend across at 73 below the space 7 4, which may be filled with yielding material 75, such as sponge rubber, plastic asphalt, corrugated paper, etc. The concrete at 73 is thus adapted to prevent the falling out or escaping of the filler 75 into the crack 22 when the sections 2O and 21 contract, as shown in Fig. 7. In Fig. 6 the space 74 is left vacant in order that the flexible part 26, 27 and 72 of the expansion strip 23 may move downward as the concrete contracts and pulls the flanges 26 and 27 apart.

Referring to Fig. 8, this is a modified form of expansion joint, with an improved form of expansion strip 23, shown with the cap strip in place as in Fig. 6. The expansion strip 23 of this figure is provided with a substantially circular bead 76, the edges of which are attached to the parallel flanges 77 and 78, which extend downwardly from the bead 76 in contact engagement with each other. The flanges 77 and 78 are adapted to resiliently engage and hold a division plate 79, which may consist oa plane strip of sheet metal and the division strip 79 is thus located immediately below the expansible portion 76 of the expansion strip 73.

The flanges 77 and 78 are bent laterally at 79 and 80, forming the flanges 81 and 82, which extend into the body of the concrete The edges 'of flanges 81 and 82 are preferably bent downward or upward to provide anchoring formations 83 in the concrete and `tongues 84 may be bent upward out of the body of flanges 81 and 82 for engaging the sides 'of the cap strip 60. The diameter of the circular bead 76 should preferably be such that the circular partr 7 8 engages the inside of the cap strip 60* and the present expansion strip 23 may thus bev installed by the same form of template, provided the rods are made sufficiently short to engage the edges 83.

Referring to Fig. 9, this is another modification comprising expansion strip 23 of the same form shown in Fig. 8 except that the division plate 35 is of the form illustrated in Fig. 1. The circular bead 76 in both of these modifications is adapted to effectively prevent the formation of a sharp crease at the upper edge of the expansible strip 23 even after the space around the strip has been filled with relatively hard and incompressible material. r[he dirt or other incom ressible material may engage the flanges 7 and 78 as'the concrete sections expand against the expansible metal strip without damaging the strip.

Referring to Fig. 10, this is another modified form of strip, the anchoring formation and division plate of which are similar to those shown in Fig. 1. rlhe expansible part consists of the inverted U-shaped portion formed by the flanges 26 and 27 and the curve 72, similar to Fig. 6. In this embodiment, however, provision has been made to fill the curved portion 72 of the expansion strip 23 by providing a metal wire 85, which is carried by the curled edge 86 of a filler strip 87. The curved upper portion of the expansion strip 23 being filled by the wire 85 and bead 86, it is practically impossible for the curved portion 72 to be forced into a sharp crease, and the present type of expansion joint is adapted to be opened and closed over long periods of time without the possibility of the joint being damaged by dirt or other incompressible material which might gather around the joint. The filler strip 87 preferably extends diagonally across the space 88 between the flanges 26 and 27, and is formed with a transversely extending flange 89, which is slidably received between the flanges 32 and 34. The transverse flange 89 closes the lower opening of the space 88, and prevents the concrete from entering the space 88 as the expansion strip is pressed into place in the green concrete.

Referring to Fig. 11, this is a modified expansion joint with expansion strip 23 of substantially the same form as that shown in Fig. 8, but the circular bead 76 has been filled with a coiled sheet metal member 90. The division plate 79 is carried in the same manner as shown in Fig. 8, and the division plate 79 prevents the coiled filler 90 from falling out of the bead 76 as the opening at the crack 22 increases.

Referring to Fig. 12, this is a modified form of the same expansion strip in which th'e circular bead 76 has been filled with a Wire 90, the wire being carried by the curled edge 91 of a filler plate 92, in order toinsure the maintenance of the filler plate in proper form. It is provided with a laterally extending flange 93, located between the flanges kform described with respect to Fig. 8, but

they are preferably lled with wires 94 at the beads 76, to insure the maintenance of these beads in circular form. The division plate 95 is preferably formed with a laterally extending trough 96, so as to provide the section of concrete with a lug 97, slidably engaging the trough 96 in section 21 to maintain the alignment of the concrete sections.

It will thus be observed that the present expansion joints may be utilized with a number of different forms of division plates, and both surfaces of the concrete may be protected, if desired. v

Referring to Fig. 14, this is a modified form utilizing a similar type of expansion strip 23, but the division plate 98 is provided with a curled upper edge 99, curled about a wire 100. The wire and curled edge 99 and 100.v Being located in' the bead 76, there is no possibility of the wire dropping and the division plate 98 is also positively held in proper position. It will thus be observed that I have invented a plurality of improved forms of expansion joints, expansion strips and division plates -which are capable of permitting movement between adjacent sections of concrete. My expansion strips have their expansible portions so formed and arranged that it is practically impossible for the adjacent sections of concrete to crush the expansion strip and form a crease. The tendency toward creasing or cracking has thus been eliminated, and one of the most important defects of the expansion strips of the prior art is hereby eliminated. y

The present apparatus for installing these expansion strips is adapted to permit their installation with a minimum amount of labor and at a predetermined height with respect to the surface of the concrete, so that it is unnecessary to fasten the expansion strips or division plates to the ground prior to the installation of the concrete. This leaves space open for the installation of the concrete and for the operation of concrete machinery without interfering with the previously installed division plates or the like and greatly expedites the installation of the pavement.

While I have illustrated and described a preferred embodiment of my invention,

many modifications may be made without departing fromthe spirit of the invention,l

sire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent of the United States is:

l. A template for installing expansion strips comprising the combination of a iexible body adapted to conform to the surface of the concrete pavement, with means for engaging an expansion strip in predetermined vposition with respect to said template, and detachable fastening devices for releasably holding said expansion strip and said template whereby said expansion strip may be released from said'template after it has been located in the concrete by means of said tem=` plate.

2. A template for installing expansion strips, comprising the combination of a iiexible body adapted to conform to the surface of the concrete pavement, with means for engaging an expansion strip in -predetermined position with respect to said template,

detachable fastening devices for releasably holding said expansion strip and said template whereby said expansion strip may be released from said tem late after it has been located in the concrete y means of said template, and a substantially flat auge surface on said template for engaging t e upper surface of the concrete and determining the final position of said expansion strip with respect to the surface of the concrete.

3. A template for installing expansion wstrips comprising the combination of a. flexible body adapted to conform to the surface of the concrete pavement, with means for holding an expansion strip in predetermined position with respect'to said template, comprising a plurality of spring pressed plungers adapted to be rotated into engagement with said expansion strip to hold the strip on said template.

4. A template for installing A expansion strips comprising an elongated iexible strip with a lower flat'gauge surface, adapted to conform substantially to the crown of the concrete pavement, a channeled metal member carried by said gauge surface and adapted to telescopically receive an expansion strip and means for detachably holding said expansion strip in said channeled member.

5. A template for installing expansion strips comprising an elongated exible strip with a lower fiat gauge surface, adapted to conform substantially to the crown of the concrete pavement, a channeled metal member carried by said gauge surface and adapted to telescopically receive an expansion strip and means for detachably holding said expansion strip in said channeled member, comprising a plurality of spring pressed plungers carried by said body, said plungers having laterally extending ends for engaging below said expansion strip and having springs for urging said plungers into engagement with said expansion strip.

6. A template for installing expansion strips comprising an elongated flexible body with a lower flat gauge surface, adapted-to conform substantially to the crown of the concrete pavement, a channeled metal member carried by said gauge surface and adapted to telescopically receive an expansion strip, means for detachably holding said expansion strip in said channeled member, comprising a plurality of spring pressed plungers carried by said body of said plungers having laterally extending ends for engaging below said extension strip and having springs for urging said plungers into engagement with said expansion strip and a plurality of handles carried by said template.

7. In a device for installing metal expansion joints the combination of a channeled metal member with a flat flexible supporting body, an expansion strip having an expansiblo portion adapted to be received in said channeled member, having downwardly extending flanges and a plurality of plungers adapted to resiliently engage said downwardly extending flanges and retain said expansion strip in said channeled member.

8. In an expansion joint, the combination of a pair of concrete sections located adjacent each other, with a metal expansion strip having a pair of anchoring formations embedded in said concrete sections, upwardly extending flanges carried by said anchoring portions and located in an open space between said sections, and a pair of downwardly extending diagonal flanges joined together to form an expansible portion, one ofsaid anchoring portions comprising a substantially circular bead and an integral division plate carried by said bead and extending downward between said concrete sections to form a crack at a predetermined oint.

9. An expansion joint the combination of a channeled cap strip, having a pair of parallel, downwardly extending flanges with an ex ansion strip having a substantially circu ar bead, located inside said channeled cap strip, said expansion strip having a pair of downwardly extending adjacent flanges, each joined to laterally extending flanges, having anchoring flanges embeddedin the concrete.

l0. In an expansion joint the combination of a channeled cap strip, having a pair of parallel, downwardly extending flanges, with an expansion strip having a substantially circular bead, located inside said channeled cap strip, said expansion strip having a pair of downwardly extending adjacent flanges, each joined to laterally extending flanges, having anchoring flanges embedded in the concrete, and a division strip slidably mounted between said downwardly extending flanges and resiliently gripped thereby for forming a crack between sections of concrete at said expansion strip.

11. An expansion joint the combination of a channeled cap strip, having a pair of parallel, downwardly extending flanges with an expansion strip having a substantially circular bead, located in said channeled cap strip, said expansion strip having a pair of downwardly extending adjacent flanges, each joined to laterally extending flanges, having anchoring flanges embedded in the concrete, and an integral downwardly extending division plate carried by said expansion strip.

l2. An expansion joint the combination of a channeled cap strip, having a pair of parallel, downwardly extending flanges with an expansion strip having a substantially circular bead, located in said channeled cap strip, said expansion strip having a pair of downwardly extending adjacent flanges, each joined to laterally extending flanges, having anchoring flanges embedded in the concrete, and an integral downwardly extending division plate carried by said expansion strip, said division plate being offset from the axis of said expansion member, to cause the concrete to close the opening below the said expansion member.

13. An expansion strip comprising a resilient sheet metal member formed with a pair of laterally extending flanges, each having anchoring formations for securement in adjacent sections of concrete, a pair of upwardly extending resilient flanges jointed by a substantially cylindrical curved portion and a filler of circular form adapted to prevent the crushing of said cylindrical portion of said expansible member to prevent the cracking of said expansible member.

14. An expansion strip comprising a resilient sheet metal member formed with a pair of laterally extending flanges, each having anchoring formations for securement in kadjacent sections of concrete, a pair of upwardly extending resilient flanges joined by a substantially cylindrical curved portion and a filler of circular form adapted to pre- Lvent the crushing of said cylindrical portion of said expansible member to prevent the cracking of said expansible member, said filler comprising a sheet metal member having its edge curled ,about a wire, and said sheet metal member having a laterally extending flange for preventing entrance of concrete between said upwardly extending flanges.

l5. Anexpansion strip comprising a resilient sheet metal member formed with a pair of laterally extending flanges, each having anchoring formations for securement in adjacent sections of concrete, a pair of upwardly extendingresilient flanges jointed by a substantially cylindrical curved portion and a filler of circular form adapted to prevent the crushing of said cylindrical porvtion of said expansible member to prevent the cracking of said expansible member, said filler having a divison plate having its edge curled about a wire and said wire being l0- cated in said cylindrical portion of said expansible member.

16. In an expansion joint for concrete pavements or the like, the combination of a pair of concrete sections located adjacent each other, with a metal expansion strip, said metal expansion strip having an extensible medial portion, downwardly extending flanges on each side of said medial portion,

a laterally projecting flange having an anchoring formation for securement in one of said concrete sections, a laterally projecting flange formed with a bead for securement in the other of said concrete sections, and a downwardly extending dividing strip adapted to form a crack in the pavement below said expansion joint.

In witness whereof, I hereunto subscribe my name this 24th day of July, 1931.

CLIFFORD OLDER.

Images