Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
  • E01D15/00—Movable or portable bridges; Floating bridges
  • E01D15/14—Floating bridges, e.g. pontoon bridges

Definitions

• the present invention relates to a pontoon bridge system. More particularly, the invention relates to an anchor system for holding floating pontoons in a pontoon bridge in a fixed relative position.
• Pontoon bridges are previously known, such as for example the bridge systems from US 1 934 286; US 3 685 074; and GB 2 344 370. Pontoon bridges are designed for use in areas where the water is too deep to build static, stationary bridges. In such a system, the bridge towers are supported by floating pontoons. The roadway can thereby be arranged between the bridge towers for example as a suspension bridge. Common for these systems is that the pontoons must be anchored to prevent currents or wind from driving them out of the desired relative position.
• Both US 1 934 286 and US 3 685 074 employ a cable or chain anchored to the sea floor to anchor the pontoons against sideways movement caused by current or wind.
• US 1 934 286 also employs a chain arranged between the pontoons to prevent relative movement in the bridge's lengthwise direction.
• This solution is however inadequate for use in very deep water such as fjords, which can have a depth of over 1000 m.
• fjords In the first place it is difficult to install a stationary anchor point in extremely deep water.
• a single cable with extreme length will have top much slack to withstand the effects of current or wind.
• US 1 934 286 discloses that the cable can be attached to a winch in order to take up the slack, however such an arrangement is naturally prone technical interruptions, which creates a large safety risk.
• GB 2 344 370 employs a different system for anchoring the pontoons. Instead of a cable attached to the sea floor, the system takes advantage of the inherent stiffness from several cables that are stretched in a spiral between the pontoons in order to hold these in a fixed relative position. The system is too complicated to have any practical application. It is also doubtful that the stiffness would be adequate to withstand strong angular-forces from currents or wind.
• the present invention has the object of avoiding the above named disadvantages with known anchoring systems.
• the invention is characterized in that the pontoons are anchored with the help of cables or chains that are attached to the shore.
• each of the pontoons is attached to the shore with the help of one or more cables that form a fan-shaped pattern.
• only the first few pontoons at each end of the bridge are anchored by cables that form a fan- shaped pattern, while the intermediate pontoons are permitted to a certain degree to drift with the current.
• the pontoons are anchored with the help of perpendicular cables that are attached to curved stabilizing lines that extend in the entire length of the bridge on each side of the bridge.
• Fig's la and lb show respectively a side view and top view of a first embodiment of the invention with anchor cables attached to each pontoon.
• Fig's 2a and 2b show respectively a side view and a top view of the first embodiment, but with more pontoons than shown in figs la and lb.
• Fig's 3a and 3b show respectively a side view and a top view of the first embodiment, but with anchor cables attached in addition to the top of the towers.
• Fig' s 4a and 4b show respectively a side view and a top view of a second embodiment of the invention, with anchor lines attached only to the first few pontoons at each end of the bridge.
• Fig's 5a and 5b show respectively a side view and a top view of a third embodiment of the invention, with pontoons attached with perpendicular lines to two curved, adjacent anchor cables.
• a typical pontoon bridge comprises one or two bridge towers 1 mounted on the land, and a plurality of bridge towers 2 mounted on pontoons 3.
• the pontoons are attached to each other in the bridge's lengthwise direction with essentially horizontal anchor lines 4, that lie under the water surface 5 at a depth that does not hinder boat traffic.
• a roadway 6 is constructed between the towers, for example in the form of a suspension bridge.
• the pontoons are stabilized against sideways movement according to the invention by the help of several stabilizing lines that are attached to the pontoons, and that have at least one end attached to land.
• a plurality of stabilizing lines 7 are attached to each pontoon.
• One end of stabilizing lines 7 is attached to land at an angle in relation to the bridge's longitudinal axis, such that the anchor lines 7 form a fan-shaped pattern.
• Anchor lines 7 are preferably arranged at the same depth as anchor lines 4.
• the bridge can comprise several pontoon elements.
• anchor lines 7 are attached to each pontoon and tightened, such that all the pontoons are held in a fixed relative position. Because there can nonetheless be a certain amount of movement of the pontoons, each of the towers can be equipped with means that permits a certain degree of rotation.
• the tops of the towers can also be stabilized with upper stabilizing lines 8, which form a similar fan-shaped pattern, as shown in figures 3a and 3b.
• a plurality of stabilizing lines 10 are attached in a fan-shaped pattern, but only to the first few, outer pontoons.
• the intermediate pontoons in this embodiment can drift with the currents or the wind.
• the pontoons must be allowed to rotate in order to compensate for the movement of the intermediate pontoons.
• Stabilizing lines 10 in this embodiment have a certain degree of slack, to pe ⁇ nit a certain amount of movement of the outer pontoons in order to prevent the angular deviation being ' concentrated at the shore.
• the pontoons are attached with the help of two perpendicular side anchor lines 11 that are attached to two curved stabilizing lines 12, that are arranged on each side of the bridge along the bridge's entire length and which are attached at each end to the shore. Both side lines 11 and stabilizing lines 12 are arranged at the same depth as the horizontal anchor lines 4.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Bridges Or Land Bridges (AREA)

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Publications (1)

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Cited By (4)

Families Citing this family (1)

Citations (8)

• 2003
  • 2003-12-19 NO NO20035693A patent/NO322193B1/no unknown
• 2004
  • 2004-12-16 WO PCT/NO2004/000391 patent/WO2005059255A1/en active Application Filing

Patent Citations (8)

Non-Patent Citations (1)

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