Construction method of vertical rotation step type half-through tied arch bridge main arch

Abstract

The present application relates to a kind of vertical rotation step-by-step half-through tied arch bridge main arch ring construction method, and arch ring is divided into two half spans and is laid on two shore approach on the bed, adopts vertical rotation buckle and hangs system and pulls arch ring vertical rotation, while using jacking system and jacks arch ring to move to midspan, repeatedly jacks, vertical rotation, gradually moves two half span arch ring to midspan closure.The present application combines jacking method and vertical rotation method organically, on the one hand, solves the problem that existing jacking method can only jacking whole span and is limited by span, on the other hand, solves the problem that existing vertical rotation method cannot be applied when there are obstacles in arch seat position, successfully realizes large-span main arch ring jacking installation.Whether it is bridge across navigable river or bridge across deep valley, whether river bank is gentle terrain or steep mountain, the present application can be applied, and large equipment is less, and construction risk and cost are low.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology and relates to the installation and construction of the main arch ring of a mid-span tied arch bridge, specifically to a method for constructing the main arch ring of a vertically rotating, step-by-step mid-span tied arch bridge. Background Technology

[0002] The main arch ring installation methods for mid-span tied arch bridges include the bracket method, the inclined tie-hanging method, the rotation method, and the jacking method. Each method has its own advantages, disadvantages, and applicable conditions. During bridge construction, the appropriate method can be selected according to the actual construction environment on site.

[0003] The scaffolding method involves erecting scaffolding under the arch ring for arch ring assembly. This method is simple to operate and has good safety, but it requires a large amount of scaffolding materials, has a long construction period, and is not suitable for cross-river bridges with navigation requirements or bridges spanning deep canyons.

[0004] The cable-stayed method involves using cable slings to suspend and assemble the arch ribs. During the assembly process, cable towers and cables are used on both banks to suspend the cantilevered arch ribs. This method has a wide range of applications, but the cable tension needs to be readjusted after each segment is assembled, making the operation cumbersome.

[0005] The rotation method involves dividing the arch into two half-spans, assembling them separately on both banks, and then rotating them to close the gap. This includes horizontal and vertical rotation. Horizontal rotation involves erecting supports on the bank to assemble the arch, then rotating it horizontally by 90° or 180° to close the gap. This method requires a large turntable and is relatively expensive. Vertical rotation involves erecting low supports at the bridge site to assemble the arch, with a hinge between the rear end of the arch and the arch seat. After assembly, a hook-and-loop system is used to vertically rotate the arch to close it. This method allows for low-level assembly of the arch ribs and has lower construction risks and costs. However, regardless of whether it is horizontal or vertical rotation, the rotation will be restricted when there are obstacles near the arch seat.

[0006] The jacking method involves assembling the entire main arch ring on the shore and then jacking it into place as a whole. This method can achieve off-site assembly of the arch ring and is not limited by the terrain of the bridge site area. However, it can usually only be jacked in whole spans and is limited by the span and height of the arch ring. It is only suitable for arch bridges with smaller spans. The construction difficulty and risk are greater when the span exceeds 70m.

[0007] like Figure 1As shown, a certain cross-river bridge is designed as a mid-span tied arch bridge. Navigation under the bridge needs to be maintained during construction, therefore the scaffolding method cannot be used. Approach bridges (100m) are located on both banks, with piers (300m) at the arch abutments (200m). Using the rotation method, whether horizontal or vertical, would be hindered by the piers, preventing proper rotation. The main arch (400m) has a large span, making the incremental launching method unsuitable. One bank of the bridge is relatively flat, while the other is a steep mountain (500m), making it difficult to erect cable-stayed pylons; therefore, the inclined-stayed method is also unsuitable. In summary, existing arch installation methods are all limited in their application to this bridge construction. Summary of the Invention

[0008] The purpose of this invention is to address the difficulties encountered in the construction of bridges mentioned above by providing a method for constructing the main arch ring of a vertically rotating, step-type, mid-span tied arch bridge, which enables the installation and construction of the main arch ring of a large-span river-crossing bridge without affecting river navigation.

[0009] The technical solution of the present invention is as follows:

[0010] A construction method for the main arch ring of a vertically rotating, step-type, mid-span tied arch bridge, characterized by the following steps:

[0011] (1) Complete the erection of the approach bridges on both sides of the arch bridge, and at the same time, use the bracket method to complete the assembly of the starting sections at both ends of the arch ring;

[0012] (2) Divide the main arch into two half-spans, erect low supports on the approach bridges on both sides, and then lay the two half-span arches together on the low supports.

[0013] (3) A slide rail is laid on the top surface of the approach bridge along the longitudinal center line of the arch ring at the orthographic projection position. A jacking system is set on the slide rail. The jacking system includes a jacking cylinder. A rail clamp is set at the rear end of the jacking cylinder. A slider is connected to the front end of the cylinder. A jacking ear plate is welded on the slider. A cross brace is welded between the two arch ribs of each half-span arch ring. A hinged ear plate is welded on the cross brace at the rear end of the arch ring. The hinged ear plate on the cross brace at the rear end of the arch ring is hinged to the jacking ear plate on the slider through a rotating shaft.

[0014] (4) Set up a fastening system behind the approach bridges on both sides, and connect the fastening system and the front end of the arch on each side with a fastening cable;

[0015] (5) Tension the ties to make the arch rotate vertically upward and detach from the support; then remove the support.

[0016] (6) Start the jacking device to jack the arch ring towards the middle of the span, so that the arch ring moves forward and rotates vertically upward at a certain angle while the arch ring moves forward.

[0017] (7) Temporarily anchor the rail clamp of the jacking device to the guide rail, then reduce the tension of the cleaving cable to increase the length of the cleaving cable and rotate the main arch ring downwards at a certain angle.

[0018] (8) Release the anchoring of the jacking device and the guide rail, and push the arch forward again. Repeat steps (6) and (7) to move the arch forward gradually until the rear end of the arch moves above the starting section.

[0019] (9) Anchor the jacking device to the track; by adjusting the length of the sling, rotate the arch to the designed installation angle, then connect the two half-span arches to the two starting sections respectively, and then close the two half-span arches together.

[0020] (10) Remove the starting section support, jacking device and fastening system, and complete the installation of the main arch ring.

[0021] This invention organically combines the existing jacking and vertical rotation methods, integrating the advantages of both while overcoming their shortcomings. For the jacking method, this invention divides the arch ring into two half-spans for jacking, solving the problem that existing jacking methods can only jack the entire span and are therefore limited by span, thus enabling the jacking installation of large-span arch rings. For the vertical rotation method, this invention allows for the horizontal assembly of the arch ring in different positions, longitudinally moving it to the installation location for closure, solving the problem that existing vertical rotation methods cannot be applied when there are obstacles at the arch seat location, thus expanding the scope of application of the vertical rotation method.

[0022] This invention has a wide range of applications. It can be used for bridges that cross navigable waterways or deep valleys, and it can be used for bridges with gentle terrain or steep mountains. Moreover, it requires less investment in large equipment and has low construction risks and costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the design structure of a mid-span tied arch bridge.

[0024] Figure 2 This is a construction flowchart of the present invention;

[0025] Figure 3 This is a schematic diagram of the arched ring horizontal assembly.

[0026] Figure 4 This is a side view of the arch jacking system;

[0027] Figure 5 This is a schematic diagram of the planar structure of the arch jacking system;

[0028] Figure 6 This is a schematic diagram of one implementation method of the arch vertical rotation and fastening system;

[0029] Figure 7 This is a schematic diagram of another implementation of the arched vertical rotating hook system;

[0030] Figure 8 A schematic diagram showing the state of the arch assembly support after dismantling.

[0031] Figure 9 This is a schematic diagram showing the forward movement and upward vertical rotation of the jacking arch;

[0032] Figure 10 This is a schematic diagram showing the state of the arch ring pausing its upward thrust and rotating vertically downwards;

[0033] Figure 11 A schematic diagram showing the state of the arch ring being pushed forward and rotated upward again;

[0034] Figure 12 This is a schematic diagram showing the state of the arch after its rear end has moved above the starting section;

[0035] Figure 13 This is a schematic diagram showing the state of the main arch ring after its closure;

[0036] Figure 14 A schematic diagram of the planar structure connecting the arch and the starting section. Detailed Implementation

[0037] Figure 2 This is a flowchart of the construction method of the present invention. The following refers to... Figure 1 The specific implementation of the present invention will be described using the bridge shown as an example. In this embodiment, the bridge is designed as a mid-span tied arch bridge, with the main span crossing a navigable waterway. Approach bridges are set on both banks; one bank's approach bridge leads to gentle terrain, while the other bank's approach bridge leads to a steep mountain. The specific construction method is as follows:

[0038] (1) As Figure 3 As shown, the approach bridges on both sides of the arch bridge were erected first, and the starting section 1 at both ends of the arch ring was assembled using the bracket method.

[0039] (2) Divide the main arch into two half-span arches 2, erect low supports on the approach bridges 100 on both sides, and then lay the two half-span arches 2 on the low supports.

[0040] (3) Lay a slide rail 3 at the orthographic projection position along the longitudinal center line of the arch ring on the top surface of the approach bridge, and install a jacking system 4 on the slide rail; such as Figure 4 , Figure 5 As shown, the jacking system 4 includes a jacking cylinder 41, a rail clamp 42 is provided at the rear end of the jacking cylinder, a slider 43 is connected to the front end of the cylinder, and a jacking ear plate 44 is welded on the slider 43; a cross brace 21 is welded between the two arch ribs of each half-span arch ring 2, and a hinged ear plate 22 is welded on the cross brace at the rear end of the arch ring, and the hinged ear plate 22 on the cross brace at the rear end of the arch ring is hinged to the jacking ear plate 44 on the slider through a rotating shaft;

[0041] (4) An anchoring system is installed behind the approach bridges on both banks, and a cable 5 is connected between the anchoring system on each bank and the front end of the arch. During construction, the specific structure of the anchoring system can be set according to the terrain on both banks.

[0042] like Figure 3 , Figure 6 As shown, the terrain on one bank of this bridge is relatively flat. The arch rib fastening system can adopt a conventional fastening tower + anchor structure. A fastening tower 6 is set behind the approach bridge, and an anchor 7 is poured behind the fastening tower 6. An anchor beam 8 is set on the top of the fastening tower 6. The back cable 9 is connected between the rear end of the anchor beam 8 and the anchor 7. A continuous jack 10 is set at the front end of the anchor beam. The fastening cable 5 is connected between the continuous jack 10 and the front end of the arch ring 2.

[0043] like Figure 3 , Figure 7 As shown, the other side of the bridge is a steep mountain, making it impossible to install a buckle tower. Therefore, the arch rib buckle system adopts the form of rock anchor, making full use of the mountain terrain. Rock anchor 11 is poured at an appropriate height on the mountain 400. An anchor pull connector 12 is set at the front end of the rock anchor 11. The anchor pull connector 12 is connected to the continuous jack 10. The buckle cable 5 is connected between the continuous jack 10 and the front end of the arch ring 2.

[0044] (5) Figure 8 As shown, the continuous jacks of the fastening system are activated to tension the fastening cable 5, causing the arch ring 2 to rotate vertically upwards and detach from the arch ring assembly bracket, and then the bracket is removed.

[0045] (6) Figure 9 As shown, the jacking system 4 is activated by jacking cylinders to jack the arch ring towards the mid-span, causing the arch ring 2 to move forward. As the arch ring 2 moves forward, it is pulled by the tension of the ties and will rotate vertically upward at a certain angle.

[0046] During actual construction, if the arch ring cannot move forward during jacking, the tensioning cables can be stretched to make the arch ring rotate vertically upwards, appropriately increasing the angle between the arch ring and the horizontal plane, so that the arch ring can automatically rotate vertically upwards when subjected to forward jacking force. Jacking should be stopped when the arch ring 2 rotates vertically upwards to an angle with the horizontal plane of no more than 80°. This is to prevent the arch ring from rotating too much (more than 90°) and causing backward tilting, and also to allow the arch ring to naturally rotate vertically downwards by gravity when the tensioning cables 5 extend.

[0047] (7) Figure 10 As shown, the rail clamp of the jacking system 4 is temporarily anchored to the guide rail, and then the tension of the cleaving cable is reduced, so that the length of the cleaving cable 5 is increased, and the arch ring 2 rotates vertically downwards at a certain angle due to gravity.

[0048] When the arch ring rotates downwards and the angle between it and the horizontal plane is not less than 30°, stop loosening the ties so that the arch ring can smoothly rotate upwards when the jacking device pushes forward.

[0049] (8) Through the pushing and vertical rotation in steps (6) and (7) above, the arch 2 moves forward a certain distance. Figure 11 As shown, release the anchoring of the jacking device to the guide rail, and push the arch forward again. Repeat steps (6) and (7) to gradually move the arch forward until... Figure 12As shown, move the rear end of the arch 2 above the starting section 1;

[0050] (9) such as Figure 13 As shown, the jacking device is anchored to the track; by adjusting the length of the zipper 5, the two half-span arches are rotated vertically to the designed installation angle, and then the two half-span arches 2 are connected to the two starting sections 1 respectively, and then the two half-span arches are joined together to complete the installation of the main arch 400.

[0051] like Figure 14 As shown, after the arch ring moves above the starting section, there is a certain gap between the rear end of the arch ring 2 and the upper end of the starting section 1. In order to connect the arch ring with the starting section, after the arch ring is adjusted to the right angle, the closure section 13 is welded between the rear end of the two half-span arch rings 2 and the upper end of the two starting sections 1 respectively for connection. Then, the closure section is welded between the front end of the two half-span arch rings.

[0052] (10) After the main arch ring is closed at 400mm, the starting section support, jacking device and fastening system are removed to complete the installation of the main arch ring.

[0053] Finally, suspenders 600 were installed on the main arch ring 400, and the main beam segments were transported by ship to the bottom of the arch ring. The main beam segments 700 were then hoisted one by one and connected to the suspenders, completing the process. Figure 1 The bridge construction shown.

Claims

1. A construction method of a main arch ring of a vertical rotation step-type half-through tied-arch bridge, characterized in that, The method comprises the following steps: (1) erecting approach bridges on both sides of the arch bridge, and simultaneously erecting the starting section of the arch ring at both ends by using the support method; (2) dividing the main arch ring into two half spans, erecting low supports on the approach bridges on both sides, and laying the two half spans of the arch ring on the low supports; (3) laying slide rails on the top surface of the approach bridge along the longitudinal center line of the arch ring, arranging a jacking system on the slide rails, and arranging a jacking oil cylinder in the jacking system, arranging a rail clamping device at the rear end of the jacking oil cylinder, connecting a slide block to the front end of the jacking oil cylinder, welding a jacking lug plate to the slide block, welding a horizontal support between the arch ribs on each half span of the arch ring, welding a hinged lug plate to the horizontal support at the rear end of the arch ring, and hingedly connecting the hinged lug plate on the horizontal support at the rear end of the arch ring to the jacking lug plate on the slide block through a rotating shaft; (4) arranging a buckling system at the rear of the approach bridges on both sides, and connecting a buckling cable between the buckling system on each side and the front end of the arch ring; (5) tensioning the buckling cable to make the arch ring vertically rotate upwards and be separated from the supports, and removing the supports; (6) starting the jacking device to jacking the arch ring towards the center of the span, and making the arch ring move forward and vertically rotate upwards by a certain angle; (7) temporarily anchoring the rail clamping device of the jacking device to the guide rail, then reducing the tension of the buckling cable to increase the length of the buckling cable, and making the main arch ring vertically rotate downwards by a certain angle; (8) removing the anchoring of the jacking device to the guide rail, jacking the arch ring forward again, and repeatedly performing steps (6) and (7) to make the arch ring move forward gradually until the rear end of the arch ring is moved above the starting section; (9) anchoring the jacking device to the rail, adjusting the length of the buckling cable to make the arch ring vertically rotate to the designed installation angle, then connecting the two half spans of the arch ring to the two starting sections respectively, and splicing the two half spans of the arch ring; (10) removing the starting section supports, the jacking device and the buckling system, and completing the installation of the main arch ring.

2. The construction method of the main arch ring of the vertical rotation step-type half-through tied arch bridge according to claim 1, characterized in that: In the case that the bank is a flat terrain, the arch rib buckling system adopts a buckling tower and an anchor block poured at the rear of the buckling tower, an anchor beam is arranged at the top of the buckling tower, a back cable is connected between the rear end of the anchor beam and the anchor block, and a continuous jack is arranged at the front end of the anchor beam, and the buckling cable is connected between the continuous jack and the front end of the arch ring.

3. The construction method of the main arch of the vertical rotation step-typed half-through tied-arch bridge according to claim 1, characterized in that: In the case that the rear of the approach bridge is a steep mountain, the arch rib buckling system adopts a rock anchor, the rock anchor is poured on the mountain at the rear of the approach bridge, an anchor pulling connector is arranged at the front end of the rock anchor, the continuous jack is connected to the anchor pulling connector, and the buckling cable is connected between the continuous jack and the front end of the arch ring.

4. The construction method of the main arch of the vertical rotation step-typed half-through tied-arch bridge according to claim 1, characterized in that: In step (6), the jacking is stopped when the arch ring is vertically rotated upwards to an angle of not more than 80° with the horizontal plane, so that the arch ring can naturally vertically rotate downwards when the buckling cable is elongated; in step (7), the buckling cable is loosened when the arch ring is vertically rotated downwards to an angle of not less than 30° with the horizontal plane, so that the arch ring can smoothly vertically rotate upwards when the jacking device jacks forward.

5. The construction method of the main arch of the vertical rotation step-typed half-through tied-arch bridge according to claim 1, characterized in that: In step (9), the two half spans of the arch ring are connected to the two starting sections respectively by welding splicing sections between the rear end of the two half spans of the arch ring and the upper end of the two starting sections; the two half spans of the arch ring are spliced by welding splicing sections between the front end of the two half spans of the arch ring. In step (9), the two half spans of the arch ring are connected to the two starting sections respectively by welding splicing sections between the rear end of the two half spans of the arch ring and the upper end of the two starting sections; the two half spans of the arch ring are spliced by welding splicing sections between the front end of the two half spans of the arch ring.

Images