This application is a National Stage Application of International Application No. PCT/IB2014/001342, filed on Jun. 6, 2014, which is hereby incorporated by reference in its entirety for all purposes as if fully set forth herein.
The invention relates to a method for building a bridge and a bridge-building apparatus.
Bridges typically comprise a substructure in the form of piers which are laid out vertically and are inserted in the ground, and a superstructure which comprises a deck which extends between the piers and defines a path for effectively crossing the bridge.
The construction of such bridges potentially relies on the use of a girder to be cantilevered relative to a constructed zone of the bridge, and on which two or more movable lifting devices circulate so as to pick up and transfer bridge elements between the constructed zone of the bridge and a construction zone located in the vicinity of the cantilevered end of the girder.
However, it has been found that the known methods for building such bridges have drawbacks. In fact, for the most part, the building of the piers and the building of the deck are generally planned as two separate tasks to each of which one of the lifting devices is assigned. These two devices are then mostly used in a sequential manner, which translates into a substantial overall building duration.
It is an object of the present invention to solve the above-described problem and to provide an improved method for building a bridge and an improved apparatus for building a bridge.
The invention relates to a method for building a bridge, said bridge comprising piers and at least one deck, the method comprising:
This translates into a minimized time window during which the lifting devices operate sequentially, and therefore tends to minimize the duration of the building process as a whole.
According to another aspect of the invention, the construction step comprises the installation of part of the deck elements via the first lifting device and, at the same time, the installation of part of the pier elements via the second lifting device.
In another embodiment, construction tools are moved along the girder by a movable rack mounted movable on the girder.
Yet, according to another aspect of the invention, the method also comprises:
A bearing system configured to monitor and adjust the geometrical and/or the load configuration of the interface between the girder and said cofferdam may be arranged between the cofferdam and the girder for the construction of said pier.
In one aspect of the invention, during at least part of the installation of the cofferdam, the second lifting device is located at the first end of the girder and the first lifting device is located at the second end of the girder, and, during at least part of the construction of said pier, the second lifting device is located at the second end of the girder and the first lifting device is located at the first end of the girder.
The invention also relates to a bridge-building apparatus, said bridge comprising piers and at least one deck, said apparatus comprising:
The guides may comprise a set of rails defining at least two independent running tracks between the first and second ends of the girder.
In accordance with another aspect of the invention, the girder comprises a storage rack, the storage rack being independent of the lifting devices and movable along the girder, said storage rack being adapted to move construction tools along the girder.
In particular embodiments, the girder has a length corresponding to substantially three times the distance between two consecutive piers of the bridge.
The girder may comprise at least one guiding frame for the vertical guiding of pier elements, said guiding frame being located at the second end of the girder.
The girder may comprise a front support adapted to rest on a cofferdam in the construction zone, the front support comprising a bearing system configured to monitor and adjust the geometrical and/or the load configuration of the interface between the girder and said cofferdam.
In other embodiments, the method and apparatus comprise one or more of the above features, whether considered alone or according to any possible combination.
In particular, the invention also relates to a method for building a bridge, said bridge comprising piers and at least one deck, the method comprising:
In fact, the sole use of the movable rack single-handedly contributes to solving the above-problem.
In addition, the invention relates to a bridge-building apparatus, said bridge comprising piers and at least one deck, said apparatus comprising:
Further features and advantages of the invention will become more apparent by reading the following detailed description of the embodiments, which are given by way of non-limiting examples with reference to the appended drawings, in which:
Each pier is made of pier elements. For instance, in view of
The pile 6A and the pile cap 6B form the foundations of the pier 6. Alternatively, a pier 6 may comprise a plurality of piles 6A, the pile cap 6B being therefore connected to all of the piles 6A.
In the following description, the piers 6 are referred to by an integer. The bridge 4 thus presents a constructed zone 12 which extends, or spans, up to a pier P(N) (left hand side of
The apparatus 2 is adapted for building bridges over land as well as over water, whether shallow or deep. In particular, the apparatus 2 is adapted to build multi-span bridges, or the multi-span portions of bridges, these spans being roughly identical. In addition, as will become apparent, the apparatus is particularly adapted for building bridges made of precast or premade elements to be assembled together.
The bridge-building apparatus 2 comprises a girder 16, a first lifting device 18, a second lifting device 20 and a cofferdam 22.
The girder 16 forms the main structure of the apparatus 2. The girder is also known as a launching girder. The girder 16 extends along the axis of the bridge. The girder 16 presents a length which corresponds substantially to three times the distance between two consecutive piers of the bridge. That distance is also known as a span of the bridge. The girder is therefore shorter, less bulky and easier to manipulate than those of typical bridge-building systems which span over four bridge-spans. The girder 16 presents a first end 24 overhanging the constructed zone 12 or the bank from which the bridge 4 extends, and a second end 26 overhanging the construction zone 14. The first end 24 may be understood as the entire portion of the girder that is located above the constructed zone 12. The second end 26 may be understood as the entire portion of the girder overhanging the construction zone 14.
The girder 16 comprises support bearings. More precisely, the girder 16 comprises rear support bearings 28, 29 resting on the constructed zone 12 of the bridge, and an intermediate support bearing 30 either resting on an erected pier in the construction zone 14 or also resting on the constructed zone 12. For example, the rear and intermediate support bearings 28, 29, 30 are identical and in the form of beams. These bearing are configured to be selectively secured or detached from the girder 16, for instance for their moving to another position in the constructed zone 12 or in the construction zone 14. In addition, while secured to the girder 16, the rear and intermediate bearings 28, 29, 30 are movable relative to the girder. In other words, the girder 16 is movable relative to its rear and intermediate support bearings. As will be seen later, this allows for the launching of the girder over the construction zone so that the extremity of its second end 26 may be brought above the area in which a new pier is to be erected.
The girder 16 further comprises a front support 32 configured to serve as a support for the girder either on the cofferdam or on installed pier elements. The front support 32 is located beneath the extremity of the second end 26 of the girder 16. In view of
In reference to
In addition, the front support 32 comprises a bracket 37 configured to be connected to pier elements so as to allow the girder to rest on pier elements. The bracket 37 is located beneath the floor plate 34. For instance, the bracket 37 comprises deployable frame elements supporting an attachment mechanism configured to be secured to pier elements, in particular to pier columns.
As illustrated by
According to one aspect of the invention, the girder 16 further comprises guides 40 extending between the first 24 and second ends 26 of the girder 16 and along which the lifting devices 18, 20 are movable. The guides 40 are configured to allow the lifting devices 18 and 20 to cross one another along the girder 16. This configuration allows for an enhanced freedom of movement of the two lifting devices 18, 20 along the girder 16. More specifically, while in operation, this configuration greatly reduces the need for downtimes associated with having to clear one of the lifting device out of the way of the other lifting device. This translates into a reduced building duration overall.
The guides 34 comprise a set of rails 42 that defines two independent running tracks 44, 46 which each extend between the first and second ends of the girder 16. More precisely, these two tracks extend between the extremities of the girder 16. Each track is respectively associated with one of the lifting devices 18, 20. The running tracks 44, 46 are both located on top of the girder. Alternatively, the running track 44 of the first lifting device 18 is located beneath the running track of the second lifting device.
The set of rails 42 thus comprises a first pair of rails 48 and a second pair of rails 50 that form running track 44, respectively running track 46. These pairs of rails 48, 50 are laid out in parallel on the beams 38. Each beam 38 supports one rail from the first pair 48 and one rail from the second pair 50. The two rails of the first pair 48 are located internally relative to the two rails of the second pair 50. The first lifting device 18 is movable along the first pair 48, while the second lifting device 20 is movable along the second pair of rails 50. As a consequence, the first and second lifting devices 18, 20 can cross each other at any point along the girder 16. In addition, when the lifting devices 18, 20 cross each other, the first lifting device 18 passes underneath the second lifting device 20 (
The girder 16 further comprises a movable storage rack 52 provided to move construction tools between the constructed zone 12 and the construction zone 14. The rack 52 is mounted on the girder 16 and is movable along the girder 16. For instance, the construction tools comprise a vibro-hammer configured to help bury the cofferdam and the steel piles in the soil in the construction zone 14, a grab adapted to remove soil material from inside the cofferdam, and a lifting frame configured to extract the cofferdam from the seabed. The presence of this movable rack allows for minimized movements of the lifting devices whenever they are due to pick up something from the rack as the rack can be moved to meet the lifting devices, thereby reducing the overall bridge-building duration. In addition, the rack 52 can serve as an adjustable counterweight, and be moved along the girder 16 whenever required. Moreover, its impact on the movements of the lifting devices 18, 20 is minimal. In addition, as it does not need to be stored at a particular point along the girder, the movable rack allows for a reduced length of the girder 16, which can therefore be reduced to a length of three spans. Preferably, the rack 52 is in the form of a cradle. In other words, the rack 52 presents both lateral and transverse walls that can be laid out so as to define between them a compartment only accessible from atop. This particular form helps prevent the inadvertent fall of objects the rack may contain while moving.
The rack 52 is independent of the lifting devices, i.e. the rack can be moved along the girder 16 regardless of the lifting devices' configuration. To that end, the rack is provided with wheels or rollers 54 movable along a separate track 56 which extends along the girder between the first end 24 and the second end 26 of the girder 16. For instance, the separate track 56 is distributed between the two beams 38 and is located below the tracks of the lifting devices 18, 20 (
The girder 16 further comprises one or more guiding frames 58 (
The first and second lifting devices 18, 20 are configured to move the deck segments 10 and the pier elements between the constructed zone 12 and the construction zone 14. In particular, they are adapted to pick up bridge elements on the constructed zone 12 of the bridge, lift these elements and then move them to their destination along the girder 16. The lifting devices 18, 20 comprise one or more engines adapted to move the associated lifting device relative to the girder 16. The lifting devices 18, 20 also comprise a lifting mechanism, such as one or more winch. Preferably, the lifting devices 18, 20 are both gantry cranes with different respective sizes. For instance, the first lifting device 18 presents a box shape made of frames defining see-through sides. For instance, the second lifting device 20 presents two triangle-shaped sides connected to each other by a top frame. As indicated above, the first device 18 moves along the internal track 44 whereas the second device 20 moves along the external track 46. The first lifting device 18 is smaller than the second lifting device 20. The lifting devices 18, 20 have dimensions adapted to allow the first lifting device 18 to pass beneath the second device 20 between the sides, i.e. between the legs, of the second lifting device 20 when the two devices move along their respective track 44, 46.
The first lifting device 18 is more precisely adapted to:
The second lifting device is more precisely adapted to:
Preferably, the apparatus 2 only comprises the first and second lifting devices 18, 20, and does not include any other lifting device, such as another small gantry crane, or another big gantry crane. The overall bulkiness and cost of the apparatus 2 are therefore minimized.
The cofferdam 22 is adapted to be partly inserted in the soil or seabed in the construction zone 14 and define a dry enclosure within which the installation of pier elements, such as the pile 6A, is carried out. In addition, the cofferdam 22 is adapted to be attached to the girder 16 and serve as a support for the girder 16. To that end, the cofferdam 22 comprises a watertight casing having a cylindrical shape. For instance, the casing is made of a single metal sheet. This further increases the tightness of the cofferdam 22 as well as its sturdiness. In addition, the cofferdam 22 presents a locking mechanism 62 located on its top and adapted to cooperate with the bearing system 36. The locking mechanism 62 comprises a circumferential sleeve flange located near the top of the cofferdam 22. As indicated above, the sleeve flange is adapted to be grabbed by the bearing system 36. In some embodiments, the cofferdam 22 further comprises structural reinforcement components, such as vertical and/or circumferential reinforcing beams 63. These components strengthen the cofferdam 22 and help reduce deformations that may occur while it is used as a support for the girder 16.
A method for building a bridge 2 will now be described in view of the Figures.
Initially, at step 64 (
At step 66, the supporting arrangement of the girder 16 is modified. More specifically, the first lifting device 18 picks up one of the rear support bearings, for instance second rear bearing 29, rotates it then moves it to the second end 26 of the girder 16 by following its track 44, then lowers it on top of pier P(N+1) which is located underneath the second end 26 of the girder. While doing so, the first lifting device 18 crosses the second lifting device 20, and passes underneath the latter, as explained above. The second end 26 of the girder 16 is then laid to rest on bearing 29. The first lifting device 18 is then moved back to its former position over the constructed zone 12.
At step 68, the girder 16 is cantilevered, or “launched”. In other words, the girder 16 is moved relative to its bearings 28, 29, 30, the second end 26 being moved towards the area where pier P(N+2) is to be erected. To that end, the first lifting device 28 is attached to the constructed zone 12 over pier P(N−1) and is connected to the support bearing located on top of pier P(N−1), that is support bearing 28 on
At step 70, still in reference to
In view of
These above steps are then repeated until completion of the bridge 2.
The apparatus and method according to the invention present several advantages, some of which have been mentioned above. In particular, the general configuration of the apparatus, and in particular the use of a girder overhanging the construction zone 14 to move the bridge elements between the constructed zone and the construction zone prevents any undesired harm that may be caused to the flora or fauna harbored in the construction zone, as the apparatus does not rely on ships which usually damage the seabed especially in shallow waters. In addition, the apparatus allows for a simpler and more efficient way of building bridges, as it exhibits two lifting devices whose freedom of movement relative to the other lifting device is enhanced by the presence of independent tracks 44, 46. This aspect is particularly visible during the construction step, during which the lifting devices switch from a configuration in which the first device is at the second end of the girder above the construction zone and the second device is at the first end of the girder above the constructed zone of the bridge, to a reverse configuration in which the second lifting device is at the second end of the girder above the construction zone whereas the first device is at the first end of the girder in the constructed zone.
Moreover, the bridge-building apparatus is thus adapted for carrying out both the pier works and the deck works, and therefore suppresses the need for two separate systems each dedicated to one of these aspects.
In addition, the presence of the movable rack 52 yields several positive effects, as it can be moved towards the lifting device which needs to access its content and thereby minimizes the overall movements of the lifting devices 18, 20 along the girder 16. In addition, the impact of the rack on the movements of the lifting devices is in turn reduced, as it can be moved around to free up space, for instance for the picking up of the cofferdam from the seabed. Moreover, it can be used as an additional counterweight whose position along the girder is adjustable, thereby limiting the structural constraints on the girder and on its balance properties. In particular, the overall length of the girder can be reduced. The use of the cofferdam as a support for the girder then increases the stability properties of the girder without requiring the use of additional support bearings laid out on the constructed elements of the bridge. The use of the bracket 37 whenever using the cofferdam as a support is not possible also improves the overall stability of the girder 16. In addition, the presence of the bearing system 36 increases the reliability of using the cofferdam as a support, in particular during construction phases during which the second lifting device is above the construction zone and carries heavy pieces of equipment such as a steel pile or carries out pile driving tasks with a hydro-hammer of a vibro-hammer.
Many modifications and variations of the present invention are made possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
Filing Document | Filing Date | Country | Kind |
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PCT/IB2014/001342 | 6/6/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2015/185959 | 12/10/2015 | WO | A |
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