US3114161A

US3114161A - Suspended girder the horizontal projection of which is incurved

Info

Publication number: US3114161A
Application number: US102685A
Authority: US
Inventors: Colombot Yves
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-04-26
Filing date: 1961-04-13
Publication date: 1963-12-17
Anticipated expiration: 1980-12-17

Description

Dec. 17, 1963- Y. coLoMBo'r 3,114,161

SUSPENDED GIRDER THE uoazzonm. PROJECTION OF WHICH IS INCURVED Filed April 13, 1961 United States Patent 3,114,161 SUSPENDED QIRDER THE HURIZGNTAL PR9- .iEiITl -UN (9F WHIQH ES WCURVED Yves Colomhot, Saint-Cloud, France, assignor to Bandin- Chateauneuf, Chateauneuf sur-hoire, Loiret, France, a

French company Filed Apr. 13, 1%1, Ser. No. 102,685 Claims priority, application France Apr. 26, 196i) 6 Claims. (Cl. 14-18) The present invention concerns a suspended girder which is curved in a horizontal plane. Such a suspended girder may serve particular for suspended railways so as to allow the latter to pass over large spans under excellent conditions for the connection of the track sections, which is a particularly diflicult matter by reason of the high speed reached by trains on such tracks.

Briefly the invention includes a girder which is curved in a horizontal plane and is carried by cables supported by towers. Each carrier cable whose projection on a vertical plane is approximately a parabola, is developed on a warped surface passing through supporting points constituted by the upper ends of the corresponding towers and through the middle of the curved line defined by the girder. Means are provided for balancing thrusts arisin opposite directions in said girders under the action of the horizontal components of the forces to be considered.

This structure satisfies the object obtaining an incurved suspended girder provided, on the one hand, with the advantages of conventional suspended girders and on the other hand, with the further advantage of simplifying the connection between the two ends of the girder in different directions.

The invention has also for its object embodiments incorporating at least one of the following features:

Means adapted to balance the thrusts produced along the incurved girder, constituted by the actual natural resistance of the latter against fiexion which is taken into account.

Abutment blocks anchored in the g ound which serve as bearings for the two ends of the incurved girder and form means for balancing the horizontal thrusts produced in the girder.

The means for balancing the thrusts produced inside the incurved girder are constituted by one or more lies connecting the ends of the girder with each other.

Each tie is rectilinear and is carried, at intervals, by slings secured to the corresponding carrier cable.

The terminal towers slope upwardly and inwardly of the curve formed by the girder.

The connection between the suspension cabl and the incurved girder is ensured by slings arranged normally to the girder and by a rigid connection in the middle of said girder.

According to a modification of the invention, the connection between the cable and the girder is ensured by slings which are oblique with reference to the longitudinal component of the girder with which they are connected.

The invention will be better understood by a reading of the follow-mg description, reference being made to the accompanying drawings showing by way of example, and by no means in a limiting sense, various embodiments of the invention. in said drawings,

FIG. 1 illustrates diagrammatically and in perspective view, a suspended bridge including several bays of which one has an incurved shape on a horizontal projection,

FIG. 2 is a detm'led plan view of a modified embodiment of the incurved bay of FIG. 1,

FIG. 3 is a cross section through line lIIIII of FIG. 2,

FIG. 4 is a side view of a further embodiment of the invention incorporating the modification shown in FIG. 2 for a single bay structure.

FIG. 5 illustrates a modification of FIG. 4.

The suspended bridge illustrated in FIG. 1 includes an incurved bay designated, as a whole, by the reference number )1. The other bays 2, 3 and 4 are, for instance, bays having a rectilinear horizontal projection.

The incurved bay 1 forms an example of a suspended girder the horizontal projection of which is incurved according to the invention.

The girder is illustrated diagrammatically as comp-rising two curved beam members 3 and 9 as shown also in FIG. 2, while the carrier cables corresponding thereto re shown at 11 and 12.. The curved beams are connected by horizontal bracings l d and 19 to form the girder.

Each carrier cable, for example, cable 12, is connected between the upper

corresponding ends

14a and 15a of the towers l4 and 15 and the middle of the shaped member 9' carried thereby. The upper ends of the towers are located inwardly of the base of the tower whereby the towers will slope upwardly and inwardly of the curved girder which can best be seen in FIGS. 2 and 3. The cable 11 is similarly associated with the towers l0 and 17 and shaped member 3. The

cables

11 and 12 are curved and lie in warped surfaces passing through the corresponding upper ends of the towers and the middle of the associated shaped member. The cables have a projection in a vertical plane which is approximately or parabolic shape, as can be seen in FIGS. 4 and 5.

In the example illustrated in FIG. 1, the shaped member 9 is supported by the carrier cable 12, through the agency of slings such as 16 which are normal to a tangent to the shaped member with which they are connected. Since the projection of the upper ends of the tower in the plane of the girder are oifset from the curved members and 9 (see FIG. 2) this will cause the slings lid to slope upwardly and inwardly of the curved members 3 and 9 of the shaped member 9.

FIG. 2 shows the transverse elements 18 extending normally to the shaped members 8 and g and diagonal elements 19 extending betwen adjacent transverse elemen-ts.

In the embodiment illustrated in FIG. 1, the actual resistance of the incurved shaped members t5 and 9 against fiexion is sutiioient alone for the balancing and compensation of the horizontal thrusts appearing in the girder under the action of the resultant of the forces to which said girder is subjected.

In another embodiment, there are provided one or more ties such as 21 (FIGS. 2, 3 and 4) interconnecting the two ends of the incurved girder 9. Said tie is rectilinear and extends in the horizontal plane of the girder. It is carried by slings such as 22 connecting it with the corresponding carrier cable, 12 for instance.

The arrows fl of FIG. 4 show by way of example tensile stresses exerted by the tie 21 for compensating for the thrusts arising in the incurved girder.

The arrows such as f2 show the resultant of the vertical forces absorbed by the terminal bearing

parts

24 and 25 of the Igirder. Lastly the arrows such as if} show the tensile stresses exerted by the carrier cables ll and 12 on the

anchoring blocks

27 and 28.

In the modification illustrated in FIG. 5, the thrusts exerted along the incurved girder are balanceld by the resistance affiorded by the two

anchoring blocks

31 and 32 which serve both as supports and abutments her the ends of the girder. The resultant of the vertical forces is again illustrated by the arrows f2, while the thrusts along the incurved girder which are balanced by the stops'or abutments considered are indicated by the arrows f4. The anchoring blocks for the carrier cables are shown, as above at 27 and 23.

By way of a modification also, whereas the slings 15 connecting the carrier cables ill and 12- with the

sha ed members

8 and 9 of FIG. 1 are directed normally to the corresponding member forming part of the girder while the middle of the carrier ca le is secured to the middle of the corresponding shaped member, in contradistinction, in the case of FIGS. 4 and 5, the slings 33 are oblique with reference to the cable Without the middle of the carrier cable being necessarily secured to the gh'der.

Obviously, the invention is not limited to the embodiments described and illustrated by way of example, and various modifications may be brought thereto Without unduly Widening the scope of the invention as defined in the accompanying claims.

I claim:

1. A suspension bridge comprising a supporting girder curved in a horizontal plane, end tower-s angularly disposed relative to each other in a horizontal plane, spaced carrier cables extending between said towers and having points of connection to said towers which are spaced laterally of the sides of the girder in a direction inwardly O f the curve of the girder, and spaced slings connecting said carrier cables to said curved girder, the carrier cables having a parabolic projection in a vertical plane and said slings being inc-lined vupwardly and inwardly from said girder.

2. A suspension as claimed in claim 1 wherein the slings lie in planes perpendicular to the tangent to the girder at the point of connection between the slings and the girder.

3. A suspension as claimed in claim 1 wherein the slings lie in planes which are obliquely inclined to the tangent to the girder at the point of connection between the slings and the girder, in a direction towards the center of curvature of the girder.

4. A suspension as claimed in claim 1 comprising anchoring block means supporting each of the ends of the girder and including thrust surfaces for resisting forces developed by the carrier cables in both a horizontal and a vertical direction.

5. A suspension as claimed in claim 1 comprising a straight tie member extending in the plane of the girder between the opposite ends thereof and connected thereto, and spaced. slings connected between one of said cables and tie member.

6. A suspension as claimed in claim 5 comprising anchoring block means at both ends of the girder support ing the same.

References (Ziteii in the file of this patent UNITED STATES PATENTS Kenan Dec. 8, 1953 Stoltenburg Novv 22, 1960

Claims

1. A SUSPENSION BRIDGE COMPRISING A SUPPORTING GIRDER CURVED IN A HORIZONTAL PLANE, END TOWERS ANGULARLY DISPOSED RELATIVE TO EACH OTHER IN A HORIZONTAL PLANE, SPACED CARRIER CABLES EXTENDING BETWEEN SAID TOWERS AND HAVING POINTS OF CONNECTION TO SAID TOWERS WHICH ARE SPACED LATERALLY OF THE SIDES OF THE GIRDER IN A DIRECTION INWARDLY OF THE CURVE OF THE GIRDER, AND SPACED SLINGS CONNECTING SAID CARRIER CABLES TO SAID CURVED GIRDER, THE CARRIER CABLES HAVING A PARABOLIC PROJECTION IN A VERTICAL PLANE AND SAID SLINGS BEING INCLINED UPWARDLY AND INWARDLY FROM SAID GIRDER.