US3296638A

US3296638A - Bridge devices

Info

Publication number: US3296638A
Application number: US360654A
Authority: US
Inventors: Morlon Jean
Original assignee: Societe Commerciale Paulstra
Current assignee: Societe Commerciale Paulstra
Priority date: 1963-04-24
Filing date: 1964-04-17
Publication date: 1967-01-10
Anticipated expiration: 1984-01-10
Also published as: GB1067424A; FR1362639A

Description

Jan. 10, 1967 J. MORLON BRIDGE DEVICES 3 Sheets-Sheet 1 Filed April l7, 1964 J. MORLON BRIDGE DEVI 0133 Jan. 10, 1967 5 Sheets-Sheet 2 Filed April 17, 1964 J- MORLON BRIDGE DEVICES Jan. 10, 1967 5 Sheets-Sheet 5 Filed April 17, 1964 United States Patent 6 Claims. E01. 14-16) The present invention relates to devices for bridging the space between two piers.

The object of this invention is to provide a device of this kind which is better adapted to meet the requirements of practice than those existing up to this time, in particular in order to permit of keeping the bridge in working condition in case of relative movements of the ground portions on which are secured the bridge piers.

According to a feature of the present invention, the bridge device comprises at least one beam the respective ends of which are connected to the piers through bearings at least one of which cooperates with a pivoted link.

According to another feature of the present invention, the pivot connections between the beam and the piers include bushes of a resilient material, such for instance as rubber or an elastomer.

Preferred embodiments of the present invention will be hereinafter described with reference to the appended drawings, given merely by way of example, and in which:

FIG. 1 is a diagrammatical view showing in elevation the principle of the present invention;

FIG. 2 is a similar view illustrating the behaviour of the bridge device after a relative movement of the parts of the ground on which the two ends of the bridge are resting;

FIG. 3 is a plan view corresponding to FIGS. 1 and 2;

FIG. 4 is an elevational view showing an embodiment of the invention;

FIG. 5 is a similar view of another embodiment;

FIG. 6 is a cross sectional view of a bearing to be used according to the present invention;

FIG. 7 is a longitudinal view corresponding to FIG. 6;

FIG. 8 is an elevational view of a bridge made according to still another embodiment of the invention.

It will first be reminded that it has already been imagined to provide means for permitting relative displacements of the ends of a bridge with respect to the piers on which they are resting.

Such means generally consisted of metal rollers or rubber plates and served only to compensate for thermal expansion of the bridge elements. Such means permitted only movements of very small amplitude.

Now, it is often desirable to provide for much more important amplitudes of deformations, ranging up to several tens of centimeters for instance, as it may happen for bridges extending over mining exploitations capable of producing substantial ground deformations.

In order to permit deformations of such amplitudes, a bridge according to the present invention comprises at least one beam the respective ends of which are connected to the piers through bearings at least one of which cooperates with a pivoted link.

FIG. 1 shows an embodiment according to which each of the beams 1 of the bridge is connected to one pier A by being pivoted thereto about a bush 2, the other end of said beam 1 being connected to a pair B through a link 3 pivoted at 4 to beam 1 and at 5 to a bearing fixed to said pier B. The length of link 3 is chosen in accordance with the maximum amplitude of the ground displacement that can be foreseen.

If there is a relative movement between piers A and B it may be supposed that A remains stationary whereas B 3,296,638 Patented Jan. 10, 1967 has moved. Said pier B may have a vertical displacement, for instance as shown by arrow f (FIG. 2). This movement may occur without damage for the bridge by a rotation of link 3. In a likewise manner, if the displacement of the ground corresponds to a horizontal movement of pier, as illustrated by arrow f or by a pivoting movement, as illustrated by arrow 3, the whole corresponding to a displacement a of pivot 5, link 3 will come into an oblique position, as shown by FIG. 2, the obliquity being thus smaller as link 3 is longer.

If now it is supposed that the piers of the bridge have a relative movement in a direction transverse to the bridge, the device above described enables the bridge to accommodate itself to said deformations if there is provided a multiplicity of links or instance a number of links 3 equal to the number of beams 1. FIG. 3 shows a bridge including four beams 1a, 1b, 1c, and M. It is supposed in this view that pier B moves so as to become slightly oblique with respect to pier A with which it makes an angle 6. The relative displacements of the respective ends of the beams with respect to pier B have the respective values a, b, c and d. This is made possible by the different obliquities of the corresponding links, within relatively large limits, without involving non admissible torsional stresses, provided that links 3 have lengths corresponding, for instance, to at least ten times the maximum displacements such as d.

It should be noted that, in order to permit relative displacements such as illustrated by FIG. 3, the joints at the ends of the links should be swivel joints. But cylindrical trunnions cooperating with cylindrical bearings (or half bearings) with a suflicient play permit of obtaining equivalent results.

However, such articulations, in view of the amplitude of the movement, should generally be made of cast iron or steel, expensive to manufacture and difiicult to fit in position. On the other hand, their lubrication and their upkeep might easily become defective due to the unavoidable action of intemperies. The device might be improved by the use of bearings provided with self lubricating bushes (impregnated metal, polyurethane).

Therefore, it will be advantageous, according to another feature of the present invention, to make use of articulations of the resilient type, wherein the relative movements of the parts connected together by the articulation produce deformation of a resilient material such as natural or synthetic rubber.

Any known arrangements used in such resilient articulations may be adopted, and in particular arrangements according to which there is a greater resiliency in some preferential directions.

According to a first embodiment, use is made of articulations of a conventional type consisting of a rubber ring mounted between two concentric metallic rings. Every beam is then arranged, as shown by FIG. 4 in longitudinal section, in a manner very analogous to the device commonly used for the main blade of a spring for an automobile vehicle. A fixed point is provided on one of the piers A and a double articulation is provided on the other pier B.

In view of the important loads that are brought into play, such an articulation will be of great dimension. It may commonly exceed 500 mm. in length and in diameter and similar proportions apply to bearings 6, stirrups 7 and spindles 8, which are metallic.

It will be noted that, in arrangements such as that of FIG. 4, the loads that are applied at the hinges are always substantially vertical and always applied downwardly, whereby it does not seem necessary to use complete cylindrical bearings. In the embodiment of FIG. 5, use is made of semi-cylindrical bearings according to a simple and advantageous arrangement.

Bushings

4 and 5 in bearings 6, which cooperate with the respective ends 12 of rigid link 3, have their concavities turned respectively downwardly and upwardly. The bushing 2 in a bearing 6 that cooperates with rigid part Z at the other end of beam 1 has its concavity turned upwardly.

In the construction illustrated by FIG. 8, which will be hereinafter examined, where all the bearings have their concavity upwardly, the rigid links have a male end and a female end. When the parts are assembled together and before the load is applied, they therefore remain in position under the action of their own weight.

It will be of interest, in order to limit the rubber flow under the action of the stresses, to reinforce the rubber elements by means of metallic parts. Thus, as shown by FIGS. 6 and 7, there may be provided successive relatively thin layers 9 of a resilient material between which are provided semi-cylindrical metal shells 10, the rubber being or not fixed to the metal. Anyway in view of the radial loads that are applied, there is not risk of the rubber parts slipping either along the metal of the shells or along the surfaces applied to the inside and the outside of the bush. Bearings 6, thus cooperating only with male elements 7, may be advantageously and economically made of reinforced concrete.

Finally, concerning the manner in which the resilient articulations according to the invention will be mounted, all possible steps will be taken for preserving the clearances necessary to the introduction of the bearing elements of said articulations.

' For this purpose for instance, as shown by FIG. 8, the

beam 1 of the bridge is first temporarily mounted on parts 11 and the male articulation elements 7 are mounted.

The bearings 6 are then secured on the piers in respective recesses made for this purpose and they are provided with their

bushes

2 and 5. Beams 1 are then lifted by means of jacks 14, and rigid link 3 provided with its bush 4 is placed in position and kept vertical through suitable means.

The bridge formed by beams 1 is then allowed to move down slowly by operating the jacks, the bearings 6 being fixed in position by means of adjustment shims 13 so that all the parts arein correct position when the load is wholly supported by the bearings. The packs can then be removed. Of course the mounting must be such that, at this time, the ends of the bridge do not any longer bear on the temporary supports, a clearance sufficient to take into account possible deformations of the material being provided.

The device above described has the advantage of permitting relative movements of very great amplitude of the bridge ends with respect to the piers. Furthermore it involves only simple means easily and quickly assembled together.

In a general manner, while the above description discloses what are deemed to be practical and efiicient embodiments of the present invention, said invention is not limited thereto as there might be changes made in the arrangement, disposition and form of the parts Without departing from the principle of the invention as comprehended within the scope of the appended claims.

What I claim is:

1. A device for bridging the space between a first and a second pier comprising:

(a) a beam located above the piers and having a longitudinal axis extending between the said two piers,

(b) a first bearing member fixed to the first pier and having an at least partially cylindrical portion, a first rigid member fixed to the beam above the bearing and having an at least partially cylindrical portion matable with and resting upon the said at least partially cylindrical portionof the first bearing, and an at least partially cylindrical resilient bushing mounted between the said at least partially cylindrical portion of the bearing and the matable portion of the said first rigid member, g

(c) a second bearing member fixed to the second pier and a third bearing member fixed to the beam above the second bearing member, said second and third bearing members having at least partially cylindrical portions,

(d) a rigid link having at least partially cylindrical upper and lower ends located between and matable with the at least partially cylindrical portions of the third bearing member and the second bearing member respectively, and an at least partially cylindrical resilient bushing mounted between each of said at least partially cylindrical portion of the second and third bearings and the respective corresponding mating end of the rigid link,

wherein the axes of the at least partially cylindrical portions, members and bushings are substantially perpendicular to the said longitudinal axis in the absence of a force applied to displace one pier relative to the other, whereby when one pier moves obliquely in horizontal plane relative to the other pier the said at least partially cylindrical portion of the first rigid member and the said ends of the link turn relative to the adjacent coresponding resilient bushings and bearings to compress opposite sides of the said resilient bushings against opposite sides of the adjacent corresponding bearings, thereby providing limited freedom of horizontal oblique movement of the first pier with respect to the second pier.

2. A device as claimed in claim 1 wherein the said at least partially cylindrical portions, members and bushings are semi-cylindrical.

3. A device as claimed in claim 2 wherein the said at least partially cylindrical members, portions and bearings are completely cylindrical.

4. A device according to claim 1 wherein said three bearings are female bearings, said first and second bearings having their concavities turned upwardly and said third bearing has its concavity turned downwardly, both ends of said link being convex.

5. A device according to claim 1 wherein said first and second bearings are female bearings having their concavities turned upwardly and said third bearing is a male bearing having its convexity turned downwardly, the lower end of said link being convex and its upper end being concave.

6. A device according to claim 1 wherein said bushes comprise at least partially cylindrical layers of metal alterating with at least partially cylindrical layers of a resilient material.

References Cited by the Examiner UNITED STATES PATENTS 480,863 8/1892 Westwood et al 1416 2,680,259 6/1954 Milk 14-16 2,953,797 9/1960 Dodds 14l6 3,151,015 9/1964 Griffith 308238 X 3,188,152 6/1965 Miller 308238 X FOREIGN PATENTS 235,498 9/1961 Australia.

22,262 11/ 1898 Great Britain.

CHARLES E. OCONNELL, Primary Examiner, N. C. BYERS, Assistant Examiner.

Claims

1. A DEVICE FOR BRIDGING THE SPACE BETWEEN A FIRST AND A SECOND PIER COMPRISING: (A) A BEAM LOCATED ABOVE THE PIERS AND HAVING A LONGITUDINAL AXIS EXTENDING BETWEEN THE SAID TWO PIERS, (B) A FIRST BEARING MEMBER FIXED TO THE FIRST PIER AND HAVING AN AT LEAST PARTIALLY CYLINDRICAL PORTION, A FIRST RIGID MEMBER FIXED TO THE BEAM ABOVE THE BEARING AND HAVING AN AT LEAST PARTIALLY CYLINDRICAL PORTION MATABLE WITH AND RESTING UPON THE SAID AT LEAST PARTIALLY CYLINDRICAL PORTION OF THE FIRST BEARING, AND AN AT LEAST PARTIALLY CYLINDRICAL RESILIENT BUSHING MOUNTED BETWEEN THE SAID AT LEAST PARTIALLY CYLINDRICAL PORTION OF THE BEARING AND THE MATABLE PORTION OF THE SAID FIRST RIGID MEMBER, (C) A SECOND BEARING MEMBER FIXED TO THE SECOND PIER AND A THIRD BEARING MEMBER FIXED TO THE BEAM ABOVE THE SECOND BEARING MEMBER, SAID SECOND AND THIRD BEARING MEMBERS HAVING AT LEAST PARTIALLY CYLINDRICAL PORTIONS, (D) A RIGID LINK HAVING AT LEAST PARTIALLY CYLINDRICAL UPPER AND LOWER ENDS LOCATED BETWEEN AND MATABLE WITH THE AT LEAST PARTIALLY CYLINDRICAL PORTIONS OF THE THIRD BEARING MEMBER AND THE SECOND BEARING MEMBER RESPECTIVELY, AND AN AT LEAST PARTIALLY CYLINDRICAL