US2176574A - Parting strip for roadways or the like - Google Patents

Description

Oct. 17, 1939.- J. H. JACOBSON PARTING STRIP FOR ROADWAYS OR THE LIKE Filed Feb. 10; 1934 Patented Oct. 17, 1939 UNITED STATES PATENT OFFICE James H. Jacobson, Chicago, Ill., assignor to Cal 0. Chambers and Robert S. Bradshaw, Jr., St. Louis, Mo., as joint tenants Application February 10, 1934, Serial No. 710,686

7 Claims.

In monolithic pavements, such as concrete, it is well known that the pavement as such moves across and in respect in the sub-grade, this movement being occasioned by various factors ,5 such as temperature change and moisture content, impact, etc.

In the contraction of the pavement, the concrete is put under tension and drawn across the surface of the sub-grade-friction is created called skin friction and When this friction exceeds ultimate strength of the concrete, the slab will crack or rupture. Usually this is a transverse, irregular rupture consisting of a number of irregular cracks.

To overcome this objectionable feature, a parting strip to predetermine and control this cracking is interposed at definite intervals throughout the pavement commonly used in combination with expansion joints.

This invention relates to such a parting strip, or joint and particularly to that type adapted to be embedded in the pavement of a roadway or the like to control or confine cracking or separation of the paving material along a definite line, and thus in this manner reduce the occurrence of detrimental breaks or cracks in the pavement.

One of the principal objects of the invention is the provision of a simple, substantial joint capable of performing the above and other advantages, having means whereby the joint may be arranged upon the sub-grade and positioned thereupon with a portion arranged substantially perpendicular to the plane of the sub-grade and in which position it is maintained against displacement by the action of the aggregate or other paving material, during the pouring or application of the latter to the sub-grade.

Another object of the invention is to construct the joint in a manner to provide means whereby road load is transmitted from one pavement slab section to an adjacent pavement slab section; further to provide a joint which also functions to distribute the load lengthwise of the separation or crack and transverse to the line of travel on the pavement.

A further object of the invention is to provide a joint for controlling cracking or separation of a slab section along a definite line, having means whereby road load when applied to one section, is transmitted to said joint and carried therethrough to means coupling the separated slab sections with each other.

It is also an object of the invention to provide a joint capable of performing the above and other objects, having a seal combined therewith for sealing a crack occurring in the pavement and thus prevent the infiltration of water and other foreign matter into the space produced by separation of the pavement, the seal also providing ,5 means compensating for the relative movement of the slab sections due to temperature change and/ or other cause.

It is an additional object to produce the joint from a strip of relatively heavy metal fashioned to provide a vertical leg or strip, the strip having one edge formed to produce foot pieces which extend in opposite directions from the leg and thus provide a substantial base or support for the joint; and

A still further object is to fashion the joint from a strip of material and to cut or otherwise deform the strip at intervals of the length thereof to provide spaced, longitudinally arranged feet located upon opposite sides of the strip to form a base for the joint, the top or uppermost edge of the vertical leg being provided with a cushion which separates the seal from the leg.

The invention has these and other objects, all of which will be explained in detail and more readily understood when read in conjunction with the accompanying drawing in which,

Figure 1 is a perspective view of a fragment of a parting strip or joint constructed according to one embodiment of which my invention is susceptible, and

Figure 2 is a sectional view of a fragment of pavement showing the device illustrated in Fig. 1, cast into the pavement and supported by the sub-grade of the roadway. 35

The structure illustrated primarily comprises a parting strip and a seal, the parting strip is formed of a single piece of material fashioned to provide a vertical leg l0, having the lower edge thereof, such as H, fashioned to provide oppositely extending foot pieces, respectively designated I2 and I3. These foot pieces are formed by cutting or otherwise separating the material at intervals of the length of the strip ID, as designated I4 and IE, to thus form portions which may be bent to provide a base comprised of these foot pieces, l2 and I3. The foot pieces l2 and I3 are arranged longitudinally of the parting element I 0 and in spaced relation to each other, and are disposed on opposite sides of the leg I0. It is believed evident, by referring to Fig. 2, that these foot pieces provide a substantial base which will maintain the joint in a position perpendicular to the surface of the sub-grade, and will maintain the leg 10, which provides the parting element, in its proper position during the pouring of the surfacing material It.

The leg It, which forms the parting element, extends from the sub-grade to adjacent the upper surface of the paving material it; however, this leg does not extend entirely through the pavement and will, therefore, provide an area ill in the pavement, above the parting element, which area will break upon the initial set of the concrete slab and cause separation of the surfacing material along a definite line, defined by the parting element Ill.

The seal, generally designated i8, is mounted upon the upper edge of the parting element Hi. This seal in the present instance, is formed of a piece of suitable material which is bent upon itself, as indicated at 19, to produce spaced parallel walls 20 and 2!. The material forming the walls 20 and 2| is bent at an angle to said walls, to thus provide longitudinally extending flanges 22 and 23, which flanges 22 and 23 are each provided with a plurality of openings 24, which are employed to cause a bond to be formed between the paving material and the seal. Thus, when the paving material becomes cracked or separated along the upper edge of the element ll? due to the initial set of the concrete, temperature change or other factors, the separated sections or slabs of the paving material thus formed will move relatively to each other in a direction transverse to the element ID.

A rod or cushion 25 is arranged in the bend L) of the seal, between said bend and the upper edge of the element ill to thus prevent crushing or otherwise injuring the material of the seal at the bend. As when the slabs A and B contract, they move away from one another, which movement draws the copper seal downward upon the top edge of the leg of the joint in a shearing action. The openings 24 provided in the flanges 22 and 23, also provide means through which support ing stakes 26 and 2? may be passed, so that these may be driven into and sub-grade to temporarily support the device during the pouring of the pavement material. As before stated, the material of which the parting strip is formed, is preferable of a substantial thickness or weight.

By employing a joint of this character, the parting element functions to assist in transmitting road load lengthwise of the strip, and in addition, provides means which will assist to transmit the load from one slab or road section to another. To assist in accomplishing this last mentioned advantage, dowel or shear bars 28 are employed, which are passed through suitable apertures such as 29, formed in the vertical member of the parting strip.

The dowel bars may, as illustrated, be welded or otherwise secured to the vertical leg or portion l6 of the strip, as indicated at 36, so that the dowel or shear bars form an integral part of the structure. This arrangement increases the dowel in bearing.

The above arrangement will transmit road load applied to one slab section such as A, lengthwise of the strip 10 to an adjacent dowel bar. In addition it will prevent channelling or breaking of the pavement occasioned by the bending of the bar and the consequent action of the bar upon the pavement in which the bar is embedded.

The structure also provides means whereby a portion of the road load is applied to the foot pieces such as i2, from which the load is transmitted to the vertical leg It, to the dowel bars. The reciprocal of this same action will take place upon the application of road load to the slab section. It is, of course, understood that road load may be transmitted from one slag section to the other through the dowel bars when the dowels are employed, in which case, one end of the dowel bars, such as 28, may be provided with a cap or slip socket 3|, it being understood that the cap fits loosely upon the end of the bar 28, which will compensate for the linear movement of the slab sections, such as A and B.

From the foregoing description of the joint, it is believed manifest that a simple, substantial structure is provided which will control and confine the cracking of pavement material along a certain or definite line, and thus assist in preventing the occurrence of intermediate cracks or breakage of the pavement in other directions. It is further believed, that the combination of a seal with the parting strip structure will allow relative movement to occur between the slab sections A and B, and in addition, will prevent the infiltration of water, dirt, etc. into the space between the sections, and thus protect the pavement against disintegration.

It is further evident that the joint provides a structure which may be mounted perpendicularly to the surface of the subgrade and that the structure will be maintained in this position against displacement by the paving material during the pouring thereof.

It may also be perceived that by welding or otherwise permanently securing the dowel or shear bars, such as 28, to the vertical leg ll] of the structure, that this structure provides means whereby road load is distributed lengthwise of the parting strip.

In addition to the above it is believed that the structure including the laterally disposed, longitudinally extending foot pieces I2 and I3 will function to transmit the road load applied to the slab section, such as A and B through the vertical leg H], to the dowel bars. Manifestly, the device provides a substantial structure which Will prevent relative vertical movement of the slab sections.

Having thus described my invention, what I claim as new and desire to cover by Letters Patent is:

1. A parting strip for joining adjacent sections I of concrete road or the like comprising a stool and a seal capping an edge thereof, the stool consisting of a stiff structure girder in the form of an inverted T-section, the stem of the T-section being of relatively thick cross-section and having a top surface of substantial width, and the seal being fashioned from flexible metal of relatively thin cross-section and having depending portions lying against the upper margin of the stool, anchors extending therefrom and into engagement with the adjacent sections of concrete, the top surface of said stool being spaced from the seal to provide a cushion there-between, a spacing member positioned there-within, and a plurality of dowel members passing through the stem of the T-section and rigidly secured thereto.

2. A parting strip for joining adjacent sections of concrete road or the like comprising a stool and a seal capping an edge thereof, the stool consisting of an inverted T-section, the stem of v and the elements upon the opposite side of the stem being arranged opposite the space provided between said first mentioned elements, and the seal being fashioned from flexible metal of relatively thin cross-section and having portions engaging the adjacent sections of concrete.

3. A parting strip for joining adjacent sections of concrete road or the like comprising a stool and a seal capping an edge thereof, the stool consisting of a stiff structural girder in the form of an inverted T-section having a stem and a base, the seal being fashioned from flexible material and having portions engaging the stem of the T, a member positioned between the top surface of the stem of the T-section and the seal providing a cushion for the seal between a portion of the seal and the stool, and dowels affixed to the stem of the T projecting laterally therefrom and adapted to extend into the adjacent concrete.

4. A parting strip for joining adjacent slab ends in concrete pavement or the like and providing means for transferring road load in both directions of vehicular travel and which consists of a stool and a seal capping an edge thereof, the stool consisting of a stiff structural girder comprising a stern and a base, the ratio of stem height to thickness being relatively small to develop column stiffness and provide beam action to stiffen the structure against lateral distortion,

and a series of load transfer members spanning the space between the adjoining sections of concrete, said members being fixedly attached to the stool whereby a portion of the load applied to one is carried laterally by the stool for distribution to the remaining load transfer members.

5. A joint of the character described comprising a stiff structural girder, a seal enclosing an edge thereof, and dowels rigidly and permanently affixed to the girder and projecting laterally therefrom and adapted to project into and move within the adjacent concrete sections.

6. A joint of the character described comprising a stiff structural girder of a T section, a seal enclosing the top of the stem of the T section, and dowels rigidly and permanently aflixed to the stem of the T and projecting laterally therefrom and adapted to project into and move within the adjacent concrete.

7. A joint of the character described comprising a stiff structural girder in the form of a T having a stem and a, flange, a seal enclosing the top of the stem, and dowels rigidly and permanently secured thereto and projecting laterally therefrom and adapted to project into and move within the adjacent concrete, said dowels passing thru the stem of the T and having bearing therein.

JAMES H. JACOBSON.

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