CN116043713A - A Method for Erection of Steel Girders of Suspension Bridge by Vertical Assembly and Lifting in Air - Google Patents

Abstract

The invention relates to a method for erecting steel girders of a suspension bridge by vertical assembly and vertical lifting in the air, comprising the following steps: using temporary cable clips to suspend a lifting platform on two main cables at the side spans of the cable tower, and installing four lifting cranes on the lifting platform machine; transport the first steel beam section under the tower and place it vertically, use two cranes to lift the first beam section; transport the second beam section below the first beam section and weld it with the first beam section, And use the same method to weld multiple sections into a large section; vertically lift the large section steel beam, and cooperate with 4 cranes to rotate the steel beam to a horizontal state in the air, and then install the large section steel beam; move the temporary cable clamp Lift the platform in the air to the next position, and use the same method to install the subsequent steel beams in sequence. The invention does not need to set up supports, and has low construction cost, high speed and high safety.

Description

A Method for Erection of Steel Girders of Suspension Bridge by Vertical Assembly and Lifting in Air

technical field

The invention belongs to the technical field of bridge construction, and relates to the construction of a long-span steel structure suspension bridge, in particular to a method for installing and constructing a suspension bridge steel girder.

Background technique

Steel girders of long-span suspension bridges are usually hoisted by cable cranes. Steel girders are processed in sections, transported to the bottom of the lifting point of the cable crane, the cable lifts the lifting beam section, carries the beam to the installation position, installs the sling, and welds with the installed beam section.

The cable crane installation method is widely used and the technology is mature, but it is only limited to the installation of steel girders in the main span of suspension bridges, and cannot be applied to the hoisting of cable-free areas and side span girder sections.

The cable-free area of the suspension bridge refers to the part of the beam section under the main tower of the suspension bridge. Due to the influence of the tower body, the sling cannot be installed. It is supported on the pier without slings, so it is called the no-cable area. Due to the blockage of the tower, the cable crane cannot directly lift the beam section above the installation position of the cable-free area; for the side-span beam section, the cable crane cannot directly lift the side-span steel beam because the cable of the cable crane has a large sag in this area Beam section.

At present, for the installation of the cable-free area and the side-span beam section of the suspension bridge, the commonly used methods include the cable-mounted crane method, the bracket method, the jacking method, the sliding method, or a combination of the above methods.

Since the cable-loaded crane directly walks on the main cables of the suspension bridge, when the cable-loaded crane is used to install the beam section in the cable-free area, it cannot directly lift the beam section to the installation position. After the area, use the swing method to move the beam section to the lower beam and the support; when using the cable-loaded crane to install the side span beam section, due to the low height of the main cable of the side span, it is generally impossible to walk with the beam, so it needs to be used in combination with the support method . Chinese patent CN2793147Y discloses a method for hoisting steel girders in the cable-free area of a multi-span suspension bridge, which uses a method of combining a cable-loaded crane with a bracket, which includes a movable bracket and a fixed bracket, and the steel beam is first lifted by the cable-loaded crane Lift it to the movable support, and then move the steel beam to the installation position for installation by the movable support, or move the cable-loaded crane to the installation position without load to hoist the steel beam.

The rest of the installation methods, including bracket method, jacking method, sliding method, etc., also need to set up brackets.

Long-span suspension bridges often have relatively high navigation clearance, and the height difference between the steel girder and the ground is relatively large. Due to the topographical conditions of the suspension bridge in mountainous areas, the height of the steel girder at the root of the side-span tower from the ground is often relatively large, so there is a large investment in materials and labor in erecting the bracket. The problems of high safety risks and long construction period; especially for the cable-loaded crane method, there are still equipment rental, transportation slides and sidewalks in the steel beam field, foundation treatment and other costs, installation, dismantling, entry and exit and other procedures, the cost is higher .

Contents of the invention

The purpose of the present invention is to provide a method for erecting steel girders of suspension bridges with vertical splicing and lifting in the air, so as to solve the problems of high cost, high risk, and low efficiency generally existing in the installation and construction methods of cable-free areas and side-span girder sections of suspension bridges.

Technical scheme of the present invention is as follows:

A method for erecting steel girders of a suspension bridge vertically assembled and vertically lifted in the air, characterized in that it comprises the following steps:

(1) Install the suspended lifting platform: Install two temporary cable clips on the two main cables on the side span of the suspension bridge cable tower near the cable tower. There is a certain distance between the two temporary cable clips on each main cable, and 4 temporary cable clips. A hoisting platform is suspended by wire ropes, and 4 hoisting cranes are installed on the hoisting platform, two of which are facing the cable tower, and the other two are facing the shore, and each crane is connected with a sling;

(2) Lifting the first beam section: transport the first steel beam section to the side span of the tower root and place it vertically, weld two lifting lugs on the top of the first beam section, and the two sets close to the cable tower The lifting rope of the crane is lowered to connect with the lug of the first beam section, and the first beam section is lifted higher than the height of one beam section;

(3) Vertically splicing beam sections: transport the second beam section below the first beam section and place it vertically, place the first beam section below the second beam section, and weld the two beam sections; The crane lifts the welded beam section higher than the height of one beam section, and uses the same method to weld subsequent beam sections to weld two or more sections into a large section steel beam; when the last beam section faces the shore Two lifting lugs are welded on the side;

(4) Steel girder lifting: Two cranes lift the welded large segment steel girder to the height of the lower beam of the suspension bridge;

(5) Steel girder swivel in the air: the two cranes facing the shore on the lifting platform connect the lifting lugs on the lowermost section of the steel beam through the lifting rope and tighten the lifting rope to lift upwards. At the same time, the two cranes facing the main tower The machine slowly loosens the sling, and rotates the steel beam in the air to a horizontal state;

(6) Installation of steel girders: four cranes lower the steel girders to the installation height synchronously. The beam is connected with the sling; then the crane slowly releases the sling until the load is zero, completing the installation of a span or a large section of steel girder;

(7) Move the temporary cable clamp and the suspended lifting platform to the installation position of the next steel beam, and install the subsequent steel beam according to the above method.

The present invention is a brand-new installation method of steel girders of suspension bridges, which can safely and quickly install cable-free areas and side-span steel girders. Compared with the prior art, it has at least the following advantages:

Compared with the traditional support method, push method, and sliding method, the present invention saves the hardening area of the site, the input of support materials, and the labor and mechanical costs of support erection and removal, and reduces the risk of safe operation;

Compared with the cable-loaded crane method, due to the small number of cable-free areas and side-span steel beams, the rent, processing and restructuring costs, slideways and foundation treatment fees required for the cable-loaded crane are relatively high. It is much lower than the cable-loaded crane method, and the present invention can also reduce the high-altitude operation risk of assembly and dismantling of the cable-loaded crane unit, and save the construction period.

Since the present invention does not need to set up supports, the higher the clearance of the steel beam, the more prominent the advantage of the present invention is the installation cost.

Description of drawings

Fig. 1 is a construction flowchart of the present invention;

Fig. 2 is a schematic diagram of the installation state of the lifting system;

Fig. 3 is a schematic diagram of the state when the hoisting system lifts the first steel beam section vertically to a certain height;

Fig. 4 is a schematic diagram of the vertical splicing state between beam sections;

Fig. 5 is a schematic diagram of the state of vertically hoisting the spliced large-segment steel beam;

Fig. 6 is a schematic diagram of the state of the steel beam rotating in the air;

Fig. 7 is a schematic diagram of the state after the installation of a large section steel beam is completed.

Detailed ways

Construction process of the present invention is as shown in Figure 1, and concrete construction method is as follows:

(1) Install the suspended lifting platform: As shown in Figure 2, two temporary cable clips 3 are respectively installed on the two main cables 2 on the side span side of the suspension bridge cable tower 1 near the cable tower, and the two temporary cable clips on each main cable 2 The clips 3 have a certain distance, and the four temporary cable clips 3 are suspended by the steel wire rope 4 together to lift the platform 5, and four hoisting cranes 6 are installed on the lifting platform 5, two of which are facing the cable tower, and the other two are facing the shore. side, each hoist 6 is connected with a suspension rope 7;

During specific implementation, in order to reduce the self-weight of the suspended hoisting platform, the suspended hoisting platform 5 can be assembled by a plurality of steel trusses, and platform panels are laid on the steel trusses.

(2) Lifting the first beam section: as shown in Figure 3, transport the first steel beam section 81 to the side of the side span of the tower root and place it vertically, and weld two lifting lugs on the top of the first beam section , two cranes near the cable tower lower the suspension rope 7 to connect with the lugs of the first beam section 81, and the first beam section 81 is promoted to be greater than the height of a beam section.

(3) Vertical splicing of beam sections: as shown in Figure 4, the second beam section 82 is transported to the bottom of the first beam section 81 and placed vertically, and the bottom of the first beam section is placed on the second beam section , weld the two beam sections; two cranes lift the welded beam section to a height greater than one beam section, and use the same method to weld subsequent beam sections to weld two or more sections into a large steel section Beam 8; Weld two lifting lugs on the side of the bottom beam section facing the shore.

(4) Steel girder hoisting: as shown in Figure 5, two cranes lift the welded large section steel girder 8 as a whole to a height exceeding the lower beam of the suspension bridge.

(5) steel beam aerial rotation: as shown in Figure 6, the two cranes facing the shore on the lifting platform connect the lifting lugs on the lowermost section of the steel beam 8 through the lifting rope 7 and tighten the lifting rope to lift upwards. At the same time, the two cranes towards the main tower slowly loosen the suspension ropes, and the steel beam 8 is swiveled in the air to a horizontal state.

(6) Installation of steel beams: as shown in Figure 7, four cranes lowered the steel beams to the installation height synchronously; To span steel girders, when the side span is provided with pier 9, support the steel girder 8 on the pier 9; if there is a sling between the steel girder and the main cable, connect the steel girder to the sling; then hang The machine slowly loosens the suspension rope until the load of the suspension rope is zero, and completes the steel beam installation of a span or a large section.

(7) Move the temporary cable clamp and the suspended lifting platform to the installation position of the next steel beam, and install the subsequent steel beam according to the above method.

Claims (2)

1. The overhead swivel erection method for the vertical splicing and vertical lifting of the suspension bridge steel beam is characterized by comprising the following steps of:

(1) Installing a suspended hoisting platform: two temporary rope clamps are respectively arranged at positions, close to the rope towers, on two main ropes at the side of the side span of the rope towers of the suspension bridge, a certain distance is reserved between the two temporary rope clamps on each main rope, 4 temporary rope clamps suspend a lifting platform together through a steel wire rope, 4 lifting cranes are arranged on the lifting platform, two cranes face the rope towers, the other two cranes face the shore, and each crane is connected with a lifting rope;

(2) Lifting the first beam section: the first girder segment is transported to one side of the tower root side span and vertically placed, two lifting lugs are welded on the first girder Duan Dingbu, and two cranes close to the cable tower are connected with the lifting lugs of the first girder segment by lowering lifting ropes, so that the first girder segment is lifted to be greater than the height of one girder segment;

(3) Vertical spliced girder section: placing a second beam Duan Yun to a first beam Duan Xiafang vertically, placing a first beam section below to a second beam section, and welding the two beam sections; the two cranes lift the welded beam sections to a height greater than that of one beam section, and the subsequent beam sections are welded by adopting the same method, so that two or more sections are welded into a large-section steel beam; welding two lifting lugs on the lowest beam section towards the bank side;

(4) And (3) hoisting a steel beam: the two cranes integrally lift the welded large-section steel girder to a height exceeding the height of the lower cross beam of the suspension bridge;

(5) Overhead steel beam swivel: two cranes facing the shore on the hoisting platform are connected with lifting lugs on the lowest section of the steel beam through lifting ropes and tighten the lifting ropes to lift upwards, and meanwhile, the two cranes facing the main tower slowly loosen the lifting ropes to turn the steel beam into a horizontal state in the air;

(6) And (3) installing a steel beam: synchronously lowering the steel beams to the installation height by 4 cranes, and supporting the steel beams on the piers under the condition that the piers are arranged on the side spans; under the condition that a sling is designed on the side span, connecting the steel beam with the sling; then the crane slowly loosens the lifting rope until the load is zero, and the installation of one span or one large-section steel beam is completed;

(7) And moving the temporary cable clamp and the suspended hoisting platform to the next steel beam installation position, and installing the subsequent steel beams according to the method.

2. The method for erecting the suspension bridge steel girder vertical splicing vertical lifting overhead swivel according to claim 1, wherein the method comprises the following steps: the suspended lifting platform is formed by assembling a plurality of trusses, and platform panels are paved on the steel trusses.

Images