Construction method of inverse construction of tower area truss girder of mountainous large-span cable-stayed bridge

Abstract

The present application relates to a kind of mountainous area long-span cable-stayed bridge tower area truss beam reverse construction method, first bracket is installed in cable tower lower crossbeam, then the crossbeam of lighter weight is hoisted to bracket using tower crane, and is installed in place by sliding, using crossbeam as bridge deck crane assembly platform, the installation of bridge deck crane is completed in advance, then the longitudinal beam of heavier weight is hoisted using bridge deck crane, and the installation of tower area truss beam is completed.The present application can effectively solve the problem that longitudinal beam of tower area truss beam cannot be hoisted when there is no large hoisting equipment in mountainous area.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction and relates to the construction of a long-span cable-stayed bridge in mountainous areas, specifically to a reverse construction method for the truss beams of the tower area of ​​a long-span cable-stayed bridge in mountainous areas. Background Technology

[0002] The steel beams of a steel-concrete composite long-span cable-stayed bridge are typically truss beams, consisting of two longitudinal beams running along the bridge direction, with a crossbeam connecting the two longitudinal beams at regular intervals. A concrete bridge deck is then laid on top of the truss beams. Truss beams are usually installed in segments. The truss beam segments in the tower area are supported by crossbeams under the towers. Generally, the tower area beam segments are installed first, followed by subsequent segments installed sequentially towards the side spans and the middle span. Due to the large weight of each segment, conventional hoisting equipment is insufficient for lifting them into position. Typically, after the tower area beam segments are constructed, a bridge deck crane is assembled on top of them to lift subsequent beam segments. Therefore, the installation of the tower area truss beams is a crucial step in the overall truss beam installation of the bridge.

[0003] The conventional method for installing truss beams in the tower area involves first hoisting two longitudinal beams, installing and securing them to the crossbeams below the tower, and then sequentially hoisting the crossbeams between the two longitudinal beams. After the crossbeams are installed, the bridge deck crane is assembled on the crossbeams. However, due to the heavy weight of the longitudinal beams in the tower area, they cannot be directly lifted using the tower crane or other conventional lifting equipment at the tower. Large lifting equipment such as truck cranes are usually required. But in mountainous areas, due to complex terrain and rugged roads, large lifting equipment often cannot reach the construction site. Without large cranes, how to install the truss beam segments in the tower area becomes a major challenge during construction. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a reverse construction method for the truss beam segment of the cable-stayed bridge tower area, which enables the successful installation of the beam segment in the tower area when large hoisting equipment cannot reach the site.

[0005] The technical solution of the present invention is as follows:

[0006] A method for constructing a truss beam in the tower area of ​​a long-span cable-stayed bridge in mountainous areas using a reverse construction method, characterized by the following steps:

[0007] Step 1: Use a tower crane to install a bracket on the lower crossbeam of the cable tower, and install the truss beam crossbeam sliding system and longitudinal beam sliding system on the bracket;

[0008] Step 2: Using a tower crane, the truss beams designed to be installed on the top of the lower crossbeam of the cable tower are lifted sequentially to the top of the side span of the bracket. Then, they are slid to the top of the lower crossbeam of the cable tower through the crossbeam sliding system on the bracket. Temporary small longitudinal beams are installed between adjacent crossbeams to connect the beams into a whole.

[0009] Step 3: Using a tower crane, lift the crossbeams located on the side span and mid-span of the lower crossbeam of the tower area onto the bracket in sequence, and adjust them into position through the crossbeam sliding system. Then, connect them to the crossbeam at the top of the lower crossbeam of the tower to form a whole through temporary small longitudinal beams.

[0010] Step 4: Anchor the truss beam at the top of the lower beam of the pylon to the lower beam of the pylon using fine-rolled threaded steel bars; anchor the beams on the side span and mid-span sides of the lower beam of the pylon to the bracket using fine-rolled threaded steel bars;

[0011] Step 5: Assemble the bridge deck crane on the top surface of the truss beam using a tower crane; after the bridge deck crane is assembled, conduct a trial lift, and it can be put into use only after the trial lift is passed.

[0012] Step 6: Use the bridge deck crane to lift the truss beam longitudinal beam designed to be installed on the top of the lower crossbeam of the pylon to the top of the side span of the bracket, and then use the longitudinal beam sliding system on the bracket to slide it to the top of the lower crossbeam of the pylon and connect it with the truss beam crossbeam already installed on the top of the lower crossbeam of the pylon.

[0013] Step 7: Use the bridge deck crane to sequentially lift the longitudinal beams of the tower area truss beams located on the side span and mid-span sides, and connect them to the corresponding transverse beams respectively;

[0014] Step 8: Anchor the longitudinal beams of the truss beams at the top of the lower crossbeam of the tower to the lower crossbeam of the tower using precision-rolled threaded bars to complete the connection between the truss beams in the tower area and the lower crossbeam of the tower; then remove the temporary small longitudinal beams and brackets between the crossbeams in sequence to complete the construction of the beam segments in the tower area.

[0015] The installation sequence of the longitudinal and transverse beams of the tower truss in this invention is the reverse of the traditional construction sequence, hence it is called the reverse construction method. This invention utilizes a bracket installed on the transverse beam under the tower. First, a tower crane is used to hoist the lighter transverse beams onto the bracket. The transverse beams serve as an assembly platform for the bridge deck crane, allowing for the early installation of the bridge deck crane. Then, the bridge deck crane is used to hoist the heavier longitudinal beams, completing the installation of the tower truss beams. This effectively solves the problem of difficult installation of the longitudinal beams of the steel truss in tower areas when large lifting equipment is unavailable in mountainous regions. Attached Figure Description

[0016] Figure 1 This is a construction flowchart of the present invention;

[0017] Figure 2 This is a schematic diagram of the bracket's longitudinal structure;

[0018] Figure 3 This is a schematic diagram of the transverse bridge structure of the bracket;

[0019] Figure 4 This is a schematic diagram of the bracket's planar structure;

[0020] Figure 5 This is a cross-sectional view of the beam sliding system;

[0021] Figure 6 This is a cross-sectional view of the longitudinal beam sliding system;

[0022] Figure 7 This is a side view structural diagram of a crossbeam sliding system or a longitudinal beam sliding system;

[0023] Figure 8 This is a schematic diagram of the longitudinal state of a truss beam being hoisted onto a bracket beam sliding system;

[0024] Figure 9 This is a schematic diagram of the transverse state of a truss beam being hoisted onto a bracket beam sliding system.

[0025] Figure 10 This is a schematic diagram of the longitudinal state of the truss beam at the top of the lower beam of the cable tower when it is installed in place.

[0026] Figure 11 This is a schematic diagram of the longitudinal state of the truss beam when all the crossbeams are installed in place.

[0027] Figure 12 This is a schematic diagram of the anchorage status of the crossbeams of the truss beams along the bridge direction;

[0028] Figure 13 This is a schematic diagram of the transverse direction of the truss beam's anchorage state;

[0029] Figure 14 This is a schematic diagram showing the bridge deck crane assembled on the crossbeam of the truss beam.

[0030] Figure 15 A schematic diagram showing the lifting of an intermediate longitudinal beam onto the side span of the bracket using a bridge deck crane;

[0031] Figure 16 This is a schematic diagram showing the state when the middle longitudinal beam is slid to a certain position using the longitudinal beam sliding system;

[0032] Figure 17 This is a schematic diagram showing the state when the other intermediate longitudinal beam is installed in place;

[0033] Figure 18 This is a schematic diagram showing the state of the entire longitudinal beam when it has been hoisted into place.

[0034] Figure 19 This is a schematic diagram showing the state after the truss beams in the tower area have been installed and anchored. Detailed Implementation

[0035] The construction process diagram of this invention is as follows: Figure 1 As shown, the specific implementation method is as follows:

[0036] Step 1: As Figure 2 , Figure 3 , Figure 4 As shown, firstly, a bracket is installed on the lower crossbeam of the cable tower using a tower crane, and then the truss beam sliding system and the longitudinal beam sliding system are installed on the bracket.

[0037] The bracket includes multiple longitudinal load-bearing beams 2 arranged along the bridge direction at the top of the lower crossbeam 1 of the pylon. The multiple longitudinal load-bearing beams are symmetrically distributed on both sides of the center line of the lower crossbeam along the bridge direction. Each longitudinal load-bearing beam extends to the side span side and the middle span side of the lower crossbeam at both ends, and the length of each longitudinal load-bearing beam is greater than the length of the truss beam in the tower area. Each longitudinal load-bearing beam 2 is connected to a diagonal brace 3 at both ends between the side span side and the middle span side of the lower crossbeam. The upper end of the diagonal brace is welded to the longitudinal load-bearing beam, and the lower end is anchored to the pre-embedded steel plate 4 embedded in the lower crossbeam of the pylon. Multiple web members 5 are welded between the longitudinal load-bearing beams 2 and the diagonal brace 3. Multiple transverse load-bearing beams 6 are welded to the top of the multiple longitudinal load-bearing beams 2 in the transverse direction on both sides of the lower crossbeam of the pylon.

[0038] The truss beam crossbeam sliding system includes two crossbeam slide rails 7 erected along the bridge direction on the transverse load-bearing beam of the bracket. The two crossbeam slide rails are symmetrically arranged on both sides of the center line of the crossbeam along the bridge direction under the cable tower. Each crossbeam slide rail 7 is equipped with multiple crossbeam trolleys 8.

[0039] The truss beam longitudinal beam sliding system includes four longitudinal beam slide rails 9 erected along the bridge direction on the transverse load-bearing beam of the bracket. The four longitudinal beam slide rails 9 are respectively set on both sides of the bridge support 11 at both ends of the lower crossbeam of the cable tower. Each longitudinal beam slide rail 9 is equipped with multiple longitudinal beam trolleys 10.

[0040] like Figure 5 , Figure 6 , Figure 7 As shown, each crossbeam slide rail 7 includes a track beam 71, on which a U-shaped sliding track 72 is welded; each crossbeam trolley 8 includes a support plate 81, with two sets of pulleys 82 at the bottom of the support plate, the pulleys 82 being supported in the U-shaped sliding track 72; the structures of the longitudinal beam slide rail 9 and the longitudinal beam trolley 10 are the same as those of the crossbeam slide rail and the crossbeam trolley.

[0041] Step Two: As Figure 8 , Figure 9 , Figure 10 As shown, the truss beam 12 located at the top of the lower crossbeam of the tower is being hoisted. Due to the obstruction of the tower, this part of the beam cannot be directly hoisted into place. First, the truss beam 12, which is designed to be installed at the top of the lower crossbeam 1 of the tower, is lifted sequentially to the top of the side span of the bracket using a tower crane. Then, it is slid to the top of the lower crossbeam of the tower through the beam sliding system on the bracket. Temporary small longitudinal beams are installed between adjacent crossbeams to connect the beams into a whole.

[0042] After each crossbeam 12 is lifted onto the bracket, its two ends are supported on the two crossbeam trolleys 8 of the crossbeam sliding system, and then the crossbeam trolleys are pulled or pushed to slide along the crossbeam slide rail to move the crossbeam 12 into position longitudinally.

[0043] like Figure 3 , Figure 9 As shown, in a specific implementation of the present invention, due to the large distance between the two crossbeam slide rails, to prevent the crossbeam from deflecting downwards in the middle, two sets of pad beams 13 can be set between the two crossbeam slide rails. Each set of pad beams includes two lower pad beams 131 arranged in the direction of the bridge, and multiple spreader beams 132 are erected in the direction of the bridge between the two lower pad beams. Two upper pad beams 133 are erected in the direction of the bridge on the spreader beams. The two sets of pad beams are symmetrically arranged on both sides of the center line of the lower crossbeam of the cable tower. Each crossbeam 12 is supported at both ends on the two crossbeam trolleys 8, and the middle part is supported on the two sets of pad beams 13.

[0044] Furthermore, when the overall weight of a crossbeam is large, to reduce the lifting weight, the crossbeam 12 can be divided into 3 segments for hoisting. The spacing between the two sets of support beams is appropriately set. The two ends of the middle segment are supported on the upper support beams of the two sets of support beams facing inwards from the bridge, respectively. The two ends of the other two segments are supported on a crossbeam pulley and an upper support beam of the same set of support beams facing outwards from the bridge, respectively. After the 3 segments are hoisted into place, the ends of two adjacent crossbeam segments located on the same set of support beams are connected by a connecting plate 121. A certain gap exists between the two upper support beams, facilitating the installation of the connecting plate.

[0045] Step 3: As Figure 11 As shown, after the top crossbeam of the lower crossbeam of the tower is installed in place, the tower crane is used to lift the crossbeams 12 located on the side span and middle span of the lower crossbeam of the tower area onto the bracket in sequence, and adjust them into place through the crossbeam sliding system. Then, they are connected to the top crossbeam of the lower crossbeam of the tower through temporary small longitudinal beams 14 to form a whole.

[0046] Step Four: As Figure 12 , Figure 13 As shown, during the construction of the lower crossbeam of the pylon, finely threaded reinforcing bars are pre-embedded at the top of the pylon. After all the crossbeams are installed in place, the truss beam 12 located at the top of the lower crossbeam of the pylon is anchored to the lower crossbeam 1 of the pylon using finely threaded reinforcing bars 15. The crossbeams 12 on the side span and the middle span of the lower crossbeam of the pylon are anchored to the longitudinal load-bearing beam 2 of the bracket using finely threaded reinforcing bars 15.

[0047] Step 5: As Figure 14 As shown, after the truss beam crossbeam is anchored, the bridge deck crane 16 is assembled on the top surface of the truss beam crossbeam 12 using a tower crane; after the bridge deck crane is assembled, a trial lift is carried out, and it can be put into use only after the trial lift is qualified.

[0048] Step Six: As Figure 15 , 16As shown in Figure 17, the truss beam longitudinal beam 17 located at the top of the lower crossbeam of the pylon is installed using a bridge deck crane. Due to the obstruction of the pylon, this part of the longitudinal beam cannot be directly hoisted into place. First, the truss beam longitudinal beam 17, which is designed to be installed at the top of the lower crossbeam of the pylon, is lifted by the bridge deck crane onto the longitudinal beam trolley on the longitudinal beam sliding system at the top of the side span of the bracket. Then, the longitudinal beam sliding system is used to slide it to the top of the lower crossbeam of the pylon and connect it with the truss beam crossbeam 12 already installed at the top of the lower crossbeam of the pylon.

[0049] Step Seven: As Figure 18 As shown, the longitudinal beams 17 of the tower area truss beam located on the side span and the middle span are hoisted sequentially by the bridge deck crane 16 and connected to the corresponding transverse beams 12 respectively.

[0050] Step 8: As Figure 19 As shown, during the construction of the lower crossbeam of the tower, a finely threaded bar 15 is pre-embedded at the position of the longitudinal beam of the truss beam at the top of the lower crossbeam; the longitudinal beam 17 of the truss beam at the top of the lower crossbeam of the tower is anchored to the lower crossbeam of the tower through the finely threaded bar 15, thus completing the connection between the truss beam of the tower area and the lower crossbeam of the tower; then, the temporary small longitudinal beams connecting each crossbeam, the anchor bars between the crossbeam and the bracket, and the bracket are removed in sequence to complete the construction of the beam segment of the tower area.

Claims

1. A method for constructing a truss beam in the tower area of ​​a long-span cable-stayed bridge in mountainous areas using a reverse construction method, characterized in that... Includes the following steps: Step 1: Use a tower crane to install a bracket on the lower crossbeam of the cable tower, and install the truss beam crossbeam sliding system and longitudinal beam sliding system on the bracket; The bracket includes multiple longitudinal load-bearing beams arranged along the bridge direction on the top of the lower crossbeam of the pylon. The multiple longitudinal load-bearing beams are symmetrically distributed on both sides of the center line of the lower crossbeam along the bridge direction. Each longitudinal load-bearing beam extends to the side span side and the middle span side of the lower crossbeam of the pylon at both ends, and the length of each longitudinal load-bearing beam is greater than the length of the truss beam in the tower area. Each longitudinal load-bearing beam is connected to a diagonal brace at both ends between the side span side and the middle span side of the lower crossbeam of the pylon. The upper end of the diagonal brace is welded to the longitudinal load-bearing beam, and the lower end is anchored to a pre-embedded steel plate embedded in the lower crossbeam of the pylon. Multiple web members are welded between the longitudinal load-bearing beams and the diagonal brace. Multiple transverse load-bearing beams are welded to the top of the multiple longitudinal load-bearing beams on both sides of the lower crossbeam of the pylon in the transverse direction. The truss beam crossbeam sliding system includes two crossbeam slide rails erected along the bridge direction on the transverse load-bearing beam of the bracket. The two crossbeam slide rails are symmetrically arranged on both sides of the center line of the crossbeam along the bridge direction under the cable tower. Each crossbeam slide rail is equipped with multiple crossbeam trolleys. The truss beam longitudinal beam sliding system includes four longitudinal beam slide rails erected along the bridge direction on the transverse load-bearing beam of the bracket. The four longitudinal beam slide rails are respectively set on both sides of the bridge support at both ends of the lower crossbeam of the cable tower, and each longitudinal beam slide rail is equipped with multiple longitudinal beam trolleys. Each crossbeam slide rail includes a track beam with a U-shaped sliding track welded on it; each crossbeam trolley includes a support plate with two sets of pulleys at the bottom, the pulleys being supported in the U-shaped sliding track; the structure of the longitudinal beam slide rail and the longitudinal beam trolley is the same as that of the crossbeam slide rail and the crossbeam trolley. Step 2: Using a tower crane, the truss beams designed to be installed on the top of the lower crossbeam of the cable tower are lifted sequentially to the top of the side span of the bracket. Then, they are slid to the top of the lower crossbeam of the cable tower through the crossbeam sliding system on the bracket. Temporary small longitudinal beams are installed between adjacent crossbeams to connect the beams into a whole. Step 3: Using a tower crane, lift the crossbeams located on the side span and mid-span of the lower crossbeam of the tower area onto the bracket in sequence, and adjust them into position through the crossbeam sliding system. Then, connect them to the crossbeam at the top of the lower crossbeam of the tower to form a whole through temporary small longitudinal beams. Step 4: Anchor the truss beam at the top of the lower beam of the pylon to the lower beam of the pylon using fine-rolled threaded steel bars; anchor the beams on the side span and mid-span sides of the lower beam of the pylon to the bracket using fine-rolled threaded steel bars; Step 5: Assemble the bridge deck crane on the top surface of the truss beam using a tower crane; after the bridge deck crane is assembled, conduct a trial lift, and it can be put into use only after the trial lift is passed. Step 6: Use the bridge deck crane to lift the truss beam longitudinal beam designed to be installed on the top of the lower crossbeam of the pylon to the top of the side span of the bracket, and then use the longitudinal beam sliding system on the bracket to slide it to the top of the lower crossbeam of the pylon and connect it with the truss beam crossbeam already installed on the top of the lower crossbeam of the pylon. Step 7: Use the bridge deck crane to sequentially lift the longitudinal beams of the tower area truss beams located on the side span and mid-span sides, and connect them to the corresponding transverse beams respectively; Step 8: Anchor the longitudinal beams of the truss beams at the top of the lower crossbeam of the tower to the lower crossbeam of the tower using precision-rolled threaded bars to complete the connection between the truss beams in the tower area and the lower crossbeam of the tower; then remove the temporary small longitudinal beams and brackets between the crossbeams in sequence to complete the construction of the beam segments in the tower area.

2. The construction method of the truss beam in the tower area of ​​a long-span cable-stayed bridge in mountainous areas according to claim 1, characterized in that: Two sets of pad beams are installed between the two crossbeam slide rails. Each set of pad beams includes two lower pad beams installed in the direction of the bridge. Multiple spreader beams are erected in the direction of the bridge between the two lower pad beams. Two upper pad beams are erected in the direction of the bridge on the spreader beams. The two sets of pad beams are symmetrically installed on both sides of the center line of the lower crossbeam of the tower.

3. The construction method of the truss beam in the tower area of ​​a long-span cable-stayed bridge in mountainous areas according to claim 2, characterized in that: Each crossbeam is hoisted in three segments. The two ends of the middle segment are supported on the upper pad beams of two sets of pad beams facing the inside of the bridge, while the two ends of the other two segments are supported on a crossbeam trolley and an upper pad beam of a set of pad beams facing the outside of the bridge, respectively. The ends of two adjacent crossbeam segments on the same set of pad beams are connected by connecting plates.

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