A method for vertically assembling, lifting, and rotating steel beams in the air for the erection of a suspension bridge.

Abstract

This invention relates to a method for vertically assembling, lifting, and rotating steel beams in the air for suspension bridges. The method includes the following steps: a temporary cable clamp suspends a lifting platform on the two main cables of the side span of the tower, and four lifting cranes are installed on the lifting platform; the first steel beam segment is transported to the base of the tower and placed vertically, then lifted by two cranes; the second beam segment is transported below the first beam segment and welded to it, and multiple segments are welded into a larger segment using the same method; the larger steel beam segment is vertically lifted, and the four cranes work together to rotate the steel beam in the air to a horizontal position, then the larger steel beam segment is installed; the temporary cable clamp suspends the lifting platform to the next position, and subsequent steel beams are installed sequentially using the same method. This invention eliminates the need for scaffolding, resulting in low construction costs, high speed, and high safety.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology, and relates to the construction of a long-span steel structure suspension bridge, specifically to a method for installing steel beams of a suspension bridge. Background Technology

[0002] Steel beams for long-span suspension bridges are typically installed using cable cranes. The steel beams are fabricated in sections, transported to the lifting points of the cable crane, which then lifts the beam sections, moves them to the installation position, installs the slings, and welds them to the already installed beam sections.

[0003] Cable-stayed installation is widely used and technically mature, but it is limited to the installation of main span steel beams in suspension bridges and cannot be applied to the installation of cable-free sections and side span beams.

[0004] The cable-free zone of a suspension bridge refers to the section of beams below the main tower where, due to the tower's influence, suspenders cannot be installed. These sections need to be supported on the lower crossbeams of the main tower, or have piers on one side, with the side span beams supported on those piers, without suspenders. Therefore, it is called the cable-free zone. Because of the tower's obstruction, cable cranes cannot directly lift beams to the installation position above the cable-free zone. For side span beams, the significant sag of the cable crane's cables in this area also prevents direct lifting of the side span steel beams.

[0005] Currently, the commonly used methods for installing cable-free sections and side span beams of suspension bridges include cable-mounted cranes, scaffolding, jacking, sliding, or a combination of the above methods.

[0006] Because cable-mounted cranes travel directly on the main cables of suspension bridges, when installing beam segments in cable-free zones, it's impossible to directly lift the beam segments to the installation position. After the cable-mounted crane lifts the beam segment and moves it close to the cable-free zone, a swinging method is used to move the beam segment onto the lower crossbeam and support. When installing side span beam segments using cable-mounted cranes, due to the lower height of the main cables in the side spans, it's generally impossible to move the beam along with the cable; it needs to be used in conjunction with the support method. Chinese patent CN2793147Y discloses a method for hoisting steel beams in cable-free zones of multi-span suspension bridges, which uses a combination of cable-mounted cranes and supports. This method includes a movable support and a fixed support. First, the cable-mounted crane lifts the steel beam onto the movable support, and then the movable support moves the steel beam to the installation position for installation, or the cable-mounted crane moves to the installation position unloaded to hoist the steel beam.

[0007] Other installation methods, including the bracket method, the jacking method, and the sliding method, also require the erection of a bracket.

[0008] Long-span suspension bridges often have high navigation clearance and a large height difference between the steel beams and the ground. Due to the terrain conditions, the height of the steel beams at the base of the side span towers is often also large. Therefore, the erection of scaffolding involves large material investment, high operational safety risks, and long construction periods. Especially for the cable-mounted crane method, there are also costs for equipment rental, steel beam transport slides and access roads in the yard, foundation treatment, installation, dismantling, and evacuation procedures, making the costs even higher. Summary of the Invention

[0009] The purpose of this invention is to provide a method for vertically assembling, lifting, and rotating suspension bridge steel beams in mid-air, which solves the problems of high cost, high risk, and low efficiency that are common in existing installation and construction methods for suspension bridges in cable-free areas and side spans.

[0010] The technical solution of the present invention is as follows:

[0011] A method for vertically assembling, lifting, and rotating steel beams for a suspension bridge in mid-air, characterized by the following steps:

[0012] (1) Install a suspended lifting platform: Install two temporary cable clamps on the two main cables on the side span of the suspension bridge tower, close to the tower. The two temporary cable clamps on each main cable are spaced apart. The four temporary cable clamps are suspended together by steel wire ropes to form a lifting platform. Four lifting cranes are installed on the lifting platform, with two cranes facing the tower and the other two facing the shore. Each crane is connected to a lifting rope.

[0013] (2) Lifting the first beam segment: Transport the first steel beam segment to one side of the tower root span and place it vertically. Weld two lifting lugs on the top of the first beam segment. Lower the lifting ropes of the two cranes near the tower and connect them to the lifting lugs of the first beam segment to lift the first beam segment to a height greater than that of one beam segment.

[0014] (3) Vertical splicing of beam segments: The second beam segment is transported to the bottom of the first beam segment and placed vertically. The bottom of the first beam segment is placed on the second beam segment, and the two beam segments are welded together. Two cranes lift the welded beam segment to a height greater than that of a beam segment. The subsequent beam segments are welded using the same method. Two or more segments are welded into a large segment steel beam. Two lifting lugs are welded on the bottom beam segment facing the shore.

[0015] (4) Steel beam lifting: Two cranes lift the welded large-section steel beams as a whole to a height exceeding that of the crossbeams under the suspension bridge;

[0016] (5) Steel beam rotation in the air: The two cranes on the lifting platform facing the shore are connected to the lifting lugs on the lowest section of the steel beam by the lifting rope and tighten the lifting rope to lift it upward. At the same time, the two cranes facing the main tower slowly loosen the lifting rope to rotate the steel beam in the air to a horizontal state.

[0017] (6) Install steel beams: Four cranes simultaneously lower the steel beams to the installation height. If there are piers in the side span, support the steel beams on the piers. If there are slings in the side span, connect the steel beams to the slings. Then the cranes slowly loosen the slings until the load is zero, and the installation of a span or a large section of steel beams is completed.

[0018] (7) Move the temporary cable clamps and suspended lifting platform to the next steel beam installation position, and install the subsequent steel beams in accordance with the above method.

[0019] This invention provides a novel method for installing steel beams in suspension bridges, enabling safe and rapid installation of steel beams in cable-free zones and side spans. Compared with existing technologies, it offers at least the following advantages:

[0020] Compared with traditional scaffolding, jacking, and sliding methods, this invention saves on the hardened area of ​​the site, the investment in scaffolding materials, and the labor and machinery costs for scaffolding erection and dismantling, while also reducing safety risks.

[0021] Compared with the cable-mounted crane method, the rental, processing and modification costs, and slide and foundation treatment costs required for cable-mounted cranes are relatively high due to the small number of cable-free areas and side span steel beams. The cost of using the present invention is much lower than that of the cable-mounted crane method. Moreover, the present invention can also reduce the high-altitude operation risks of assembling and dismantling cable-mounted cranes and save construction time.

[0022] Since this invention does not require the erection of a support frame, the higher the clearance of the steel beam, the more prominent the installation cost advantage of this invention becomes. Attached Figure Description

[0023] Figure 1 This is a construction flowchart of the present invention;

[0024] Figure 2 This is a schematic diagram of the installation status of the lifting system;

[0025] Figure 3 This is a schematic diagram showing the state when the lifting system vertically lifts the first steel beam segment to a certain height;

[0026] Figure 4 This is a schematic diagram of the vertical splicing status between beam segments;

[0027] Figure 5 This is a schematic diagram showing the vertical lifting of the assembled large steel beam segments;

[0028] Figure 6 This is a schematic diagram of the steel beam rotating in the air;

[0029] Figure 7 This is a schematic diagram showing the state of a large steel beam after installation. Detailed Implementation

[0030] The construction process of this invention is as follows: Figure 1 As shown, the specific construction method is as follows:

[0031] (1) Install a suspended lifting platform: such as Figure 2 As shown, two temporary cable clamps 3 are installed on the two main cables 2 on the side span of the suspension bridge tower 1, near the tower. The two temporary cable clamps 3 on each main cable 2 are spaced apart. The four temporary cable clamps 3 are suspended by steel wire ropes 4 and a lifting platform 5 is suspended. Four lifting cranes 6 are installed on the lifting platform 5, two of which face the tower and the other two face the shore. Each crane 6 is connected to a lifting rope 7.

[0032] In practice, to reduce the weight of the suspended lifting platform, the suspended lifting platform 5 can be assembled from multiple steel trusses, with platform panels laid on the steel trusses.

[0033] (2) Lift the first beam segment: such as Figure 3 As shown, the first steel beam segment 81 is transported to one side of the tower root span and placed vertically. Two lifting lugs are welded to the top of the first beam segment. Two cranes close to the tower lower the lifting rope 7 to connect with the lifting lugs of the first beam segment 81, raising the first beam segment 81 to a height greater than that of a beam segment.

[0034] (3) Vertical splicing of beam segments: such as Figure 4 As shown, the second beam segment 82 is transported below the first beam segment 81 and placed vertically. The first beam segment is placed below the second beam segment, and the two beam segments are welded together. Two cranes lift the welded beam segment to a height greater than that of a single beam segment. The same method is used to weld subsequent beam segments, and two or more segments are welded into a large segment steel beam 8. Two lifting lugs are welded to the bottom beam segment facing the shore.

[0035] (4) Steel beam lifting: such as Figure 5 As shown, two cranes lifted the welded large steel beam segment 8 to a height exceeding that of the crossbeam under the suspension bridge.

[0036] (5) Steel beam aerial rotation: such as Figure 6 As shown, two cranes on the lifting platform facing the shore are connected to the lifting lugs on the lowest segment of the steel beam 8 via lifting ropes 7 and tighten the ropes to lift it upwards. At the same time, two cranes facing the main tower slowly loosen the lifting ropes, rotating the steel beam 8 in the air to a horizontal position.

[0037] (6) Install steel beams: such as Figure 7As shown, four cranes simultaneously lower the steel beam to the installation height. For steel beams in the cable-free area under the tower, the steel beam can be swung to the crossbeam under the tower and installed and fixed. For side span steel beams, if there is a pier 9 in the side span, the steel beam 8 is supported on the pier 9. If there is a sling between the steel beam and the main cable, the steel beam is connected to the sling. Then the crane slowly releases the sling until the sling load is zero, completing the installation of one span or one large segment of steel beam.

[0038] (7) Move the temporary cable clamps and suspended lifting platform to the next steel beam installation position, and install the subsequent steel beams in accordance with the above method.

Claims

1. A method for erecting a suspension bridge steel beam by vertical assembly and vertical lifting in the air using a rotating body, characterized in that, The method comprises the following steps: (1) installing a suspended lifting platform: two temporary cable clamps are installed on each of the two main cables on the side span of the cable-stayed bridge tower, with a certain distance between the two temporary cable clamps on each main cable, and the four temporary cable clamps suspend the lifting platform together through a steel wire rope, four lifting cranes are installed on the lifting platform, two of which are directed towards the tower and the other two are directed towards the shore, and each crane is connected to a lifting rope; (2) lifting the first beam segment: the first steel beam segment is transported to the tower root side span and placed vertically, two lifting lugs are welded on the top of the first beam segment, the lifting ropes of the two cranes directed towards the tower are connected to the lifting lugs of the first beam segment, and the first beam segment is lifted to a height greater than that of one beam segment; (3) vertically splicing the beam segments: the second beam segment is transported to below the first beam segment and placed vertically, the first beam segment is lowered onto the second beam segment, and the two beam segments are welded; the two cranes lift the welded beam segments to a height greater than that of one beam segment, and the subsequent beam segments are welded in the same way, two or more segments are welded into a large segment steel beam; two lifting lugs are welded on the lowermost beam segment towards the shore side; (4) lifting the steel beam: the two cranes lift the welded large segment steel beam to a height greater than the lower beam of the cable-stayed bridge; (5) in-air rotation of the steel beam: the two cranes directed towards the shore on the lifting platform connect the lifting lugs on the lowermost beam segment of the steel beam through the lifting ropes and tighten the lifting ropes to lift upwards, while the two cranes directed towards the tower slowly loosen the lifting ropes, and the steel beam is rotated in the air to a horizontal state; (6) installing the steel beam: the four cranes simultaneously lower the steel beam to the installation height, in the case of a bridge pier on the side span, the steel beam is supported on the bridge pier, and in the case of a suspension cable on the side span, the steel beam is connected to the suspension cable; then the cranes slowly loosen the lifting ropes until the load is zero, and the installation of one span or one large segment steel beam is completed; (7) moving the temporary cable clamps and the suspended lifting platform to the next steel beam installation position, and installing the subsequent steel beam according to the above method.

2. The method according to claim 1, wherein: The suspended lifting platform is composed of multiple steel trusses, and a platform panel is laid on the steel trusses.

Images