WO1990006401A1

WO1990006401A1 - Enclosed prestressed concrete suspension bridge and method for constructing said bridge

Info

Publication number: WO1990006401A1
Application number: PCT/NO1988/000089
Authority: WO
Inventors: Odd Bernhard Torkildsen
Original assignee: Odd Bernhard Torkildsen
Priority date: 1987-06-05
Filing date: 1988-12-02
Publication date: 1990-06-14

Abstract

Enclosed suspension bridge, the interior of which is adapted for vehicle traffic and having ventilation means (11) and comprising at least four carrier cables (1-4), all which being secured in both ends, where inner annular reinforcements (5) being arranged inside the cables transversal to the longitudinal direction of the bridge, outer transversal annular reinforcements (7) being arranged outside the cables, cable reinforcements (6) connecting the cables, whereby all transversal reinforcements being arranged spaced along the entire length of the cables, longitudinal reinforcements connecting all transversal reinforcements and all transversal and longitudinal reinforcements as well as cables being confined by cast concrete thereby creating a hollow structure into which thereafter the ventilation means (11) and traffic adapted means being arranged, the bridge as such thereby comprising at least one such continous reinforced concrete structure.

Description

Enclosed prestresse concrete suspens on bridge and method for constructing said bridge

The present invention relates to an enclosed prestres¬ sed concrete suspension bridge and a method for constructing said bridge.

Bridges of a large variety of structural designs have been known for a long time to be arranged between bridge heads or as self supporting bridges, constructed of materials such as tree, stone, steel and concrete. Such bridges have been used to cross rivers, waters and valleys. To cross longer distances tunnels have been used or tunnels in combination with bridges. In the same way also floating bridges have been used, which however have their natural limitations.

It also is known to use "submerged bridges" or en- closed bridges arranged in water, in the shape of large pipes, arranged on the seabed. The only known bridge suspended in water, however, is a freely suspending portion of the Stockholm subway, bridging a distance of approximately 50 m. It furthermore is known to build roads on columns on land and as such also to build enclosed portions of roads on land. With the method and the bridge according to the pre¬ sent invention it is possible to build bridgeways for motor vehicles and railway with a long span between the supports on land, thereby being relatively independent of the natural formations in the terrain. Arranged in water such enclosed bridges may be maintained at a depth as is desired, based on considerations concerning other influences such as under¬ water currents, ship traffic and possible submarines, without need for preparing the sea bed as a support for the bridge or the tunnel.

With the method of the present invention it is pos¬ sible to construct bridges of the above described type more economically and within a shorter time than construction of conventional bridges or tunnels. Even in other connections the enclosed bridge according to the present invention will have advantages in relation to prior art, such as at offshore oil fields where the bridge may be combined with submarine oil pipes. Used on land, the bridge according to the present invention, supported on fundaments or columns, establishes a substantial simplification of road building in difficult terrains. By constructing a land based enclosed bridge accor¬ ding to the present invention it also is possible to arrange a highway on top of the bridge in addition to a bridgeway for motor vehicles and/or trains in the internal of the bridge tube, thereby increasing the capacity substantially.

The above mentioned advantages are achieved with the enclosed enclosed and the method for constructing the bridge according to the invention as defined in the claims.

The drawing discloses in Fig. 1-4 phases in construc¬ ting the iron reinforcement, seen in a cross section. Fig. 5 discloses a cross section through a single tube bridge. Fig. 6 discloses a cross section through a vertical double tube bridge. Fig. 7 and 8 disclose cross sections through horizontal triple bridges. Fig. 9-11 disclose different stages in the construction of a subsea bridge, and Fig. 12-14 dis¬ close views of the barge used for construction of a subsea bridge.

An essential feature of the bridge according to the present invention is the carrier cables 1, 2, 3 and 4 by which the bridge as such is suspended and which is anchored in fundaments on shore in the case of subsea bridges and on columns or fundaments correspondingly for bridges on land.

A land based version may cross terrain formations having large variations and may also be constructed like a suspension bridge as such or including fundaments or columns spaced along the bridge. After constructing the fundaments from which at least four cables are set under tension between fundaments to a desired tensioning, a vehicle build of units to be separated for transportation, is used for arranging iron reinforcement followed by casting of the concrete portion of the bridge. This vehicle is adapted to be displaced in the terraine by means of wheels on huge hydraulic cylinders thereby following the progress of the construction works. In areas with bed ground, the ground may be frozen in the period where the vehicle is passing. In cases where the bridge • is buildt substantially like a suspension bridge, the carrier cables 1-4 first are anchored in both ends, set under tension to a desired value and the vehicle which may be special adap¬ ted for this purpose, is brought to drive on the cables during construction of the bridge.

In cases where the bridge according to the invention is used as a subsea bridge, a barge 12, preferably design as a catamaran, is used as the construction site. An anchoring fundament 13 is arranged on shore on one side of the river or sea and the cables 1-4 are connected with the fundament and held under tension by the barge 12. The construction of the enclosed bridge is thereby performed on board the barge whereby the bridge is suspended into the water to a desired depth and thereafter anchored to a corresponding fundament on the other shore.

Principally the bridge is constructed in the same way if crossing land or being submerged in water. The vehicle or barge respectively, both have facilities for producing prestressed concrete structures continously whereby inner iron reinforcement 5 first is arranged between the lower carrier cables 1 and 2 and the upper carrier cables 3 and 4. The cables are connected with inner reinforcements 6 and an outer reinforcement 7 is arranged outside the cables as well known in the art. The reinforcements are arranged trans- versially as well as longitudinally as disclosed in Figs. 1-4. Depending on the shape of the bridge, if a single, double or triple structure is desired as disclosed in Figs. 5-8, reinforcements are arranged between adjacent sets of carrier cables and between reinforcements for each set.

A bridge design for land crossing may be of the type disclosed in Fig. 5 comprising facilities for transportation, motor vehicles of railways or a combination of such, and ventilation facilities 11 as well. In a subsea embodiment as disclosed in Figs. 6-8 at least one ballast facility 10 is required, the buoyancy of the bridge continously is moni¬ tored and ballast is removed or added according to the condi¬ tions existing, such as tide and traffic.

Fig. 7 discloses one embodiment where an enclosed bridge is arranged between two ballast facilities 10 and opposite Fig. 8 discloses one embodiment having a ballast facility 10 arranged in the middle between two enclosed brid¬ ges for traffic, one for motor vehicles and one for trains. For building a subsea bridge, the barge 12 is equipped with a dock 15 arranged between the two hulls of the catamaran. The actual construction work is performed on this dock which is displaceable within the barge, in the longitudinal direc¬ tion and to a certain extend, also in the vertical direction as can be seen in Fig. 10. The dock 15 is used separately at the beginning of the bridge as disclosed in Fig. 9 and as well during the finishing of the construction as disclosed in Fig. 11.

First of all the lower carrier cables 1 and 2 are fixed to a fundament 13 on shore, and continously kept under tension by means of appropriate devices on board the dock, possibly also by means of the barge 12. Thereafter the inner iron reinforcements 5 are arranged on the cables as reinforce¬ ment sections , the upper carrier cables 3 and 4 also are maintained under tension and fixed to the inner reinforcement 5, whereafter the cable reinforcement 6 is fixed to the cables and the outer reinforcement 7 arranged around the structur.

Appropriate form works are arranged around the outer reinforcement 7. An inner form work may be arranged within the reinforcements or a net may be fixed to the inner rein¬ forcement 5 whereafter quickly curing concrete is fixed to the net which thereafter is used as form work. The outer form work 16 may be in segments of for example 5 m and con¬ structed to be used for lifting the portion of the bridge. The conditions in the dock 15 are arranged optimally for the works to be performed. Subsequent to curing the concrete the finished portion of the bridge is lifted out of the dock and the next portion of the bridge is constructed. During construction progress the dock is adjusted according to the desired direction of the bridge, as disclosed in Fig. 10.

The shape of the first portion of the bridge is de¬ pending on the depth on which the bridge should be arranged, which could be such as 200 m. As the weight of such a bridge may be 70000 tons, appropriate buoyancy tanks are fixed to the bridge until the bridge itself achieves buoyancy from its interior.

The barge 12 comprises all facilities necessary for manufacturing concrete, iron reinforcements, handling form works, accurate positioning and displacement, monitoring all operations workshops and so on. On board the barge, road segments are arranged in the bridge continously as the con¬ struction proceeds.

It may be unnecessary to anchor shorter bridges as very large forces are necessary to move such profiles and furthermore a certain movement of the bridge may be accepted. It is, however, necessary to consider the possibility of collisions between ships and especially submarines, and the bridge. By the design of the bridge according to Fig. 7 this possibility has been taken into account and the section com¬ prising traffic of motor vehicles or possibly trains, is arranged in the middle between two structures for ballasting purposes. In areas where such danger does not exist, the design according to Fig. 8 may be used, having only one sec¬ tion 10 for ballasting and two sections 9 for traffic pur¬ poses . Bridges of a certain length usually are anchored to the seabed at spaced intervals, or a combination of ballasting special intervals, or a combination of ballasting special adapted structures and anchoring may be used.

Claims

P a t e n t C l a i m s

1. Enclosed suspension bridge, the interior of which is adapted for vehicle traffic and having ventilation means (11) and comprising at least four carrier cables (1-4), all which being secured in both ends, CHARACTERIZED IN inner annular reinforcements (5) being arranged inside the cables transversal to the longitudinal direction of the bridge, outer transversal annular reinforcements (7) being arranged outside the cables, cable reinforcements (6) connecting the cables , whereby all transversal reinforcements being arranged spaced along the entire length of the cables, longitudinal reinforcements connecting all transversal reinforcements and all transversal and longitudinal reinforcements as well as cables being confined by cast concrete thereby creating a hollow structure into which thereafter the ventilation means (11) and traffic adapted means being arranged, the bridge as such thereby comprising at least one such continous reinforced concrete structure.

2. Bridge according to claim 1, CHARACTERIZED IN the bridge comprising at least one continous structures of which at least one is used for traffic purposes, the bridge thereby being submerged into water and the cables being an¬ chored to fundaments on shore, which fundaments thereby are constituting the structure outlets.

3. Bridge according to claim 2, CHARACTERIZED IN the bridge being anchored to the seabed.

4. Bridge according to claim 2, CHARACTERIZED IN the bridge comprises at least one structure for ballast pur¬ poses.

5. Bridge according to claim 1, CHARACTERIZED IN the continous concrete structure being arranged over land and resting on columns or fundaments to which the carrier cables are anchored.

6. Method for constructing an enclosed suspension bridge according to claim 1- , CHARACTERIZED IN securing at least ^'four carrier cables (1, 2, 3, 4) to fundaments, tensioning the cables to a desired stress value, arranging inner transversal annular reinforcements (5) within the cables as well as outer transversal annular reinforcements (7) out¬ side the cables and cable reinforcements (6) connecting the cables and the transversal reinforcements, of which all rein¬ forcements are arranging at spaced intervals along a section of the cables arranged on a production unit (12), arranging inner and outer longitudinal reinforcements between the trans¬ versal reinforcements which longitudinal reinforcements are tensioned to provide a prestressed concrete structure en- capsuling all reinforcements and cables by means of internal and external frame works and thereafter displacing the erected section of the structure resting on the production unit to construct the next section connected with the preceding sec¬ tion thereby providing a continous enclosed bridge.

7. Method according to claim 6, CHARACTERIZED IN using a catamaran type barge as the production unit and a dock (15) between the catamaran hulls on which dock the con¬ struction work is performed.

8. Method according to claim 6, CHARACTERIZED IN using as a production unit a construction unit adapted for displacement on land thereby to provide an enclosed bridge crossing a landscape as a suspension bridge between columns or fundaments .

9. Method according to claim 8, CHARACTERIZED IN the production unit being adapted for displacement along the cables .