Method for installing steel arch rib of triple-span wide-beam narrow-arch through arch bridge

Abstract

The invention provides a three-span wide-beam narrow-arch through type arch bridge steel arch rib installation method which comprises the steps that when a steel box beam is assembled, cantilever arm units are temporarily not installed in the range of arch feet of steel arch ribs at the two ends, and then the steel arch ribs are installed through a cable crane. The width of the steel box girder in the arch springing range in the arch rib construction stage is reduced through rear installation of the steel box girder on the outer side of the arch springing position arch rib, and therefore the possibility of using a cable crane is achieved. The cable crane is adopted for hoisting to replace a beam surface support method for construction, so that beam surface support investment is reduced, and meanwhile the problem that large hoisting equipment cannot be arranged on the beam surface of the open-web steel box beam is solved. The invention provides two steel arch rib mounting schemes of beam-arch synchronous pushing and beam-arch separated construction, and a set of cable crane system is arranged for turnover use, or a plurality of sets of towers are put in at one time, and a plurality of cable cranes are adopted for hoisting construction. The method is low in material investment and simple in construction process, and meanwhile the problems that the open-web steel box girder surface operation space is limited, and the local stress performance of the steel box girder is poor are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of the construction of triple-span arch bridges, and particularly relates to a method for installing steel arch ribs of a triple-span wide-beam and narrow-arch through-arch bridge. Background Art

[0002] The main bridge of a certain bridge is designed as a triple-span basket-type through-arch bridge with a reticulated tied-arch system. Among them, the main span crosses a river, the width of the steel beam is 60.7m, the maximum width of the steel arch rib is 18.2m, the maximum rise of the side-span arch rib is 46.2m, the maximum rise of the main arch is 69.5m, and the height of the steel beam from the ground is 25m.

[0003] Based on the structural design characteristics of the project, the construction method of the upper structure is generally "synchronous jacking of beam and arch" or "beam first and then arch, arch erection on the beam". No matter which scheme is adopted for construction, for the erection construction of the steel arch rib on the ultra-wide steel box girder, generally, a hoisting device is arranged on the beam surface to erect the arch rib support and hoist the arch rib. The following disadvantages and limiting factors exist: 1. The load on the beam surface is large, and the force on the steel box girder may not meet the requirements. For the through-arch bridge system with a reticulated tied-arch structure, it is generally a "strong arch and weak beam" system. If a support is erected on the beam surface and a hoisting device is arranged on the beam surface, the force on the steel box girder structure does not meet the requirements in most cases, and the steel box girder needs to be strengthened, which will cause phenomena such as increased costs and delays in on-site construction.

[0004] 2. The working space on the beam surface of the open-web steel box girder is limited. The force of the open-web steel box girder is mainly transmitted through the vertical and horizontal diaphragms. When erecting a support on the beam surface, to ensure that the force on the steel beam meets the requirements, it is necessary to ensure that the support columns are located on the vertical and horizontal diaphragms or strengthen the steel box girder. At the same time, the hoisting setting and walking space are extremely limited, and the stacking on the beam surface is limited, making construction extremely inconvenient.

[0005] 3. The selection of hoisting equipment is limited, and the difficulty of equipment research and development is large. For the installation of the arch rib of the wide-beam and narrow-arch system, the hoisting equipment is generally arranged on the beam surface. For the hoisting of the 69.5m high-altitude steel arch rib segment, large truck cranes, gantry cranes and other equipment are required. Considering the force on the steel box girder structure, the optimal solution is to strengthen the position of the gantry crane track corresponding to the steel box girder when using a large gantry crane for hoisting. However, the installation of an ultra-high gantry crane on the beam surface and the operation risk and difficulty of the gantry crane are extremely high.

[0006] 4. Large investment in supports. If the "beam first and then arch, arch erected on the beam" plan is adopted, after the first continuous steel box girder is jacked into place, the arch rib support is erected on the beam surface, and the arch rib is erected before the support can be removed. The operation cycle from support erection to removal is relatively long. During this process, the second continuous steel box girder has been jacked into place, and an additional set of supports is required for the construction of the second continuous arch rib. If the beam-arch synchronous jacking construction is adopted, the overall jacking weight is large, and the investment in materials for temporary piers is extremely high. In addition, the arch rib support can only be removed after the first continuous integral jacking and beam dropping are completed. During this process, after the second continuous steel box girder is assembled, the arch rib support can be erected. At this time, the arch rib support cannot be recycled, and additional arch rib support materials need to be invested. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for installing steel arch ribs of a three-span wide-beam and narrow-arch through-arch bridge, so as to overcome the above technical problems existing in the prior art.

[0008] To this end, the technical solution provided by the present invention is as follows: A method for installing steel arch ribs of a three-span wide-beam and narrow-arch through-arch bridge. When assembling the steel box girder, the cantilever units are not installed temporarily within the range of the arch feet of the two-end steel arch ribs, and then the steel arch ribs are installed by using a cable crane. After the same continuous steel box girder and steel arch ribs are installed in sequence, they are integrally jacked, and after synchronous jacking and beam dropping, the construction of the next continuous steel box girder and steel arch ribs is carried out.

[0009] For the installation construction of large-span and ultra-high arch ribs, first assemble and jack the steel box girder, and then use a cable crane to hoist the steel arch ribs.

[0010] The specific process includes the following steps: Step 1) Erect the steel box girder assembly platform and the cable crane gantry respectively. Assemble the first continuous steel box girder on the steel box girder assembly platform, and use the cable crane to hoist the first continuous steel arch ribs. Step 2) Dismantle the cable crane system to a height lower than the bottom elevation of the steel box girder, and jack the first continuous integral into place and drop the beam. Step 3) Assemble the second continuous steel box girder, restore the cable crane system, and hoist the second continuous steel arch ribs. Step 4) Dismantle the cable crane system to a height lower than the bottom elevation of the steel box girder, and jack the second continuous integral into place and drop the beam. Step 3) Assemble the third continuous steel box girder, restore the cable crane system, and hoist the third continuous steel arch ribs.

[0011] The specific process includes the following steps: Step 1) Erect the steel box girder assembly platform, and erect the cable crane gantry at each continuous end to the height of the bottom of the steel box girder. Step 2) Assemble and jack the first continuous steel box girder, and then install the first continuous cable crane on the first continuous cable crane gantry. Step 3) Lift and install the first set of steel arch ribs, and jack and position the second set of steel box girders for assembly. Step 4) Dismantle the first set of cable cranes, and then install and construct the second set of cable cranes. Step 5) Lift and install the second set of steel arch ribs, and jack and position the third set of steel box girders for assembly. Step 6) Dismantle the second set of cable cranes, and then install and construct the third set of cable cranes. Step 7) Lift and install the third set of steel arch ribs.

[0012] There is one set of cable cranes.

[0013] The cable crane is for one span and is erected by multiple sets of tower frames.

[0014] The long span is 300m - 500m, and the super high arch rib is an arch rib of 50m - 100m.

[0015] The cable crane gantry is erected at both ends of the steel box girder assembly platform along the longitudinal bridge direction.

[0016] Between Step 1) and Step 2), it also includes installing the support rods and cantilever units between the beam and the arch.

[0017] The beneficial effects of the present invention are: The method for installing steel arch ribs of a three-span wide-beam and narrow-arch through-arch bridge provided by the present invention, by installing the steel box girders outside the arch ribs at the arch foot position later, reduces the width of the steel box girders in the arch foot range during the construction stage of the arch ribs, thus making it possible to use cable cranes. By using cable cranes for lifting instead of the beam-supported scaffold method for construction, the investment in beam-supported scaffolds is reduced, and at the same time, the problem of the inability to arrange large lifting equipment on the beam surface of the open-web steel box girder is solved.

[0018] The present invention provides two steel arch rib installation schemes: synchronous jacking of the beam and the arch and separate construction of the beam and the arch. One set of cable crane systems is set up respectively for turnover use, or multiple sets of tower frames are invested at one time, and multiple-span cable cranes are used for lifting construction. The present invention has less material investment and simple construction technology, and at the same time solves the problems of limited working space on the beam surface of the open-web steel box girder and poor local mechanical properties of the steel box girder. Description of the Drawings

[0019] Figure 1 It is the elevation view of the three-span wide-beam and narrow-arch bridge type layout of the present invention; Figure 2 It is the top view of the three-span wide-beam and narrow-arch bridge type layout of the present invention; Figure 3 It is the elevation view of the construction of the first set of steel box girders and steel arch ribs in the embodiment of the present invention; Figure 4 It is the elevation view of the construction of the second set of steel box girders and steel arch ribs in the embodiment of the present invention; Figure 5It is the elevation view of the construction of the third continuous steel box girder and steel arch rib in the embodiment of the present invention; Figure 6 It is the top view of the construction of the third continuous steel box girder and steel arch rib in the embodiment of the present invention.

[0020] In the figure: 1. The first continuous steel arch rib; 2. The second continuous steel arch rib; 3. The third continuous steel arch rib; 4. The first continuous steel box girder; 5. The second continuous steel box girder; 6. The third continuous steel box girder; 7. The cantilever unit; 8. The stay cable; 9. The steel wire rope; 10. The cable crane gantry; 11. The steel box girder assembly platform; 12. Pier 1; 13. Pier 2. Specific Embodiments

[0021] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0022] Now refer to the accompanying drawings to introduce the exemplary embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely, and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the accompanying drawings are not limitations on the present invention. In the drawings, the same unit / element uses the same reference numeral.

[0023] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. In addition, it can be understood that the terms defined in the commonly used dictionary should be understood as having a meaning consistent with the context of their related fields, and should not be understood as idealized or overly formal meanings.

[0024] Embodiment 1 The present invention provides a method for installing the steel arch rib of a three-span wide-beam and narrow-arch through-type arch bridge. When assembling the steel box girder, the cantilever unit 7 is not installed temporarily within the range of the arch feet of the two-end steel arch ribs, and then the steel arch rib is installed by using a cable crane. The three-span wide-beam and narrow-arch bridge type is as Figure 1 and Figure 2 shown.

[0025] By installing the steel box girder (the cantilever unit 7 of the steel box girder) outside the arch rib at the arch foot position later, the present invention reduces the width of the steel box girder within the range of the arch foot during the construction stage of the steel arch rib, making it possible to use a cable crane, and solving the problems of difficult hoisting, limited working space on the beam surface, and large material input.

[0026] Embodiment 2 Based on Embodiment 1, the present invention provides a method for installing steel arch ribs of a three-span wide-beam and narrow-arch through-arch bridge. After the same-span steel box girder and steel arch ribs are installed in sequence, they are integrally jacked, and after synchronous jacking and placing the beam in place, the construction of the next-span steel box girder and steel arch ribs is carried out.

[0027] In view of the design characteristics of the wide-beam and narrow-arch structure of the through-arch reticulated tied-arch bridge, this embodiment adopts a beam-arch synchronous jacking scheme: erect a steel box girder assembly platform 11, and at the same time erect a cable crane gantry 10 at both ends (longitudinal bridge direction) of the assembly platform, then carry out the splicing and elongation of the steel girder (the cantilever unit 7 of the steel box girder in the arch foot range at both ends is not installed during the assembly process), carry out the installation and commissioning of the cable crane, then use the cable crane to install the steel arch ribs, then install the support rods between the beam and the arch, install the cantilever unit 7, remove the cable crane system to a height lower than the bottom of the steel box girder, then integrally jack and place the beam in place, carry out the assembly of the next-span steel box girder, restore the cable crane system, then carry out the first-span system conversion (force system conversion: the steel box girder changes from self-rigidity force-bearing to steel arch rib weight-bearing force-bearing), complete the installation of the suspension cables, carry out the installation of the second-span steel arch ribs 2, and then cycle in sequence to carry out the construction of the next span.

[0028] Embodiment 3 Based on Embodiment 1, the present invention provides a method for installing steel arch ribs of a three-span wide-beam and narrow-arch through-arch bridge. For the installation construction of large-span and ultra-high arch ribs, first assemble and jack the steel box girder, and then use a cable crane to hoist the steel arch ribs.

[0029] By setting up a tower at the outside of the arch foot of each span and using a cable crane system for hoisting construction. This embodiment adopts a beam-arch separate construction scheme: erect a steel box girder assembly platform 11, erect a cable crane gantry 10 at both ends of each span to the height of the bottom of the steel box girder, then assemble and jack the first-span steel box girder 4 (the cantilever unit 7 of the steel box girder in the arch foot range at both ends is not installed during the assembly process), complete the installation of the first-span cable crane, then hoist and install the first-span arch ribs, assemble and jack the second-span steel box girder 5 in place, then remove the first-span cable crane and construct the second-span cable crane, and then cycle in sequence to complete.

[0030] Among them, the large span is 300m - 500m, and the ultra-high arch rib is an arch rib of 50m - 100m.

[0031] Embodiment 4 Based on Embodiment 1, the present invention provides a method for installing steel arch ribs of a three-span wide-beam and narrow-arch through-arch bridge. The specific process includes the following steps: Step 1) Erect a steel box girder assembly platform 11 and a cable crane gantry 10 respectively. Complete the assembly of the first-span steel box girder 4 on the steel box girder assembly platform 11, and use the cable crane wire rope 9 to complete the hoisting of the first-span steel arch rib 1; among them, the cable crane gantry 10 is erected at both ends of the steel box girder assembly platform 11 along the longitudinal bridge direction; during the assembly of the first-span steel box girder 4, ifFigure 2 As shown, the cantilever unit 7 is not installed temporarily; Step 2) Demolish the cable crane system to a level lower than the bottom elevation of the steel box girder (the distance between the steel box girder and the ground), and push the first continuous section integrally to the designed position and lower the girder; Step 3) Assemble the steel box girder 5 of the second continuous section, restore the cable crane system, and hoist the second continuous section of the steel arch rib 2; Step 4) Demolish the cable crane system to a level lower than the bottom elevation of the steel box girder, and push the second continuous section integrally to the designed position and lower the girder; Step 5) Assemble the steel box girder 6 of the third continuous section, restore the cable crane system, and hoist the third continuous section of the steel arch rib 3.

[0032] In this embodiment, there is one set of cable crane system. The cable crane system includes a cable crane gantry 10 and cable crane steel wires 9. The cable crane steel wires 9 are installed on the cable crane gantry 10 to hoist the steel arch rib. After hoisting in place, the steel arch rib is adjusted and temporarily fixed through a cable crane stay cable mechanism (including stay cables 8, fixed lifting lugs connected to the steel arch rib, tensioning jacks and anchors). The process is as follows: One end of the stay cable 8 pulls the steel arch rib, and the other end is fixed on the cable crane gantry 10, and fastening adjustment is carried out through the tensioning jacks and anchors.

[0033] In this embodiment, a three-span wide-beam and narrow-arch through arch bridge with a span of 280m + 420m + 280m is taken as an example to further illustrate the method of the present invention.

[0034] The first stage: Build a steel box girder assembly platform 11 in the range of Pier 1# 12 to Pier 2# 13, complete the assembly of the first continuous section of the steel box girder 4 (i.e., the side span of 280m), then install the cable crane, and use the cable crane to complete the hoisting of the first continuous section of the steel arch rib 1, as Figure 3 shown; The second stage: Demolish the cable crane at the position of Pier 2# 13 to a level lower than the bottom elevation of the steel box girder, push the first continuous section integrally to the designed position, and transform the assembly platform to meet the assembly requirements of the second continuous section of the steel box girder 5 (i.e., the middle span of 420m), and complete the assembly of the second continuous section of the steel box girder 5; Transform the cable crane to meet the hoisting requirements of the second continuous section of the steel arch rib 2, and complete the hoisting of the second continuous section of the steel arch rib 2, as Figure 4 shown; The third stage: Demolish the cable crane at the position of Pier 2# 13 to a level lower than the bottom elevation of the steel box girder, push the second continuous section integrally to the designed position, and transform the assembly platform to meet the assembly requirements of the third continuous section of the steel box girder 6 (i.e., the side span of 280m), and complete the assembly of the third continuous section of the steel box girder 6; Transform the cable crane to meet the hoisting requirements of the third continuous section of the steel arch rib 3, and complete the hoisting of the third continuous section of the steel arch rib 3. As Figure 5 and Figure 6 shown.

[0035] Embodiment 5 Based on Embodiment 1, the present invention provides a method for installing steel arch ribs of a triple-span wide-beam narrow-arch through-arch bridge, and the specific process includes the following steps: Step 1) Erect a steel box girder assembly platform 11, and erect a cable crane gantry 10 at each joint end to the height of the bottom of the steel box girder; Step 2) Assemble and push the first-span steel box girder 4, and then install the first-span cable crane on the first-span cable crane gantry 10; Step 3) Hoist the first-span steel arch rib 1, and assemble and push the second-span steel box girder 5 into place; Step 4) Dismantle the first-span cable crane, and then install and construct the second-span cable crane; Step 5) Hoist the second-span steel arch rib 2, and assemble and push the third-span steel box girder 6 into place; Step 6) Dismantle the second-span cable crane, and then install and construct the third-span cable crane; Step 7) Hoist the third-span steel arch rib 3.

[0036] In this embodiment, the cable crane is one span and is erected by multiple sets of tower frames. The cable crane system is one set, and it is installed and dismantled according to different construction stages to meet the construction needs. During the installation process, according to the different spans of the steel arch ribs to be assembled, the layout positions of the cable crane tower frames are adjusted.

[0037] Embodiment 6 Based on Embodiment 4, the present invention provides a method for installing steel arch ribs of a triple-span wide-beam narrow-arch through-arch bridge. Between Step 1) and Step 2), it also includes installing beam-arch support rods and cantilever units 7.

[0038] The present invention installs the steel box girder outside the arch rib at the arch foot position, reducing the width of the steel box girder at the arch foot range during the construction stage of the arch rib, thereby making it possible to use a cable crane. By using a cable crane for hoisting instead of the beam-slab support method for construction, the investment in beam-slab supports is reduced, and at the same time, the problem of the inability to arrange large-scale hoisting equipment on the beam surface of the open-web steel box girder is solved.

[0039] The above examples are only illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. Any design identical or similar to the present invention falls within the protection scope of the present invention.

Claims

1. A method for installing a steel arch rib of a three - span wide - beam narrow - arch through - type arch bridge, characterized in that: When assembling the steel box girder, the cantilever units are not installed temporarily within the range of the arch feet of the steel arch ribs at both ends, and then the steel arch ribs are installed by a cable crane.

2. The installation method of the steel arch rib of a three-span wide-beam narrow-arch through arch bridge according to claim 1, characterized in that: After the steel box girders and steel arch ribs of the same continuous girder are installed in sequence, they are jacked as a whole. After synchronous jacking and placing the girders in position, the construction of the steel box girders and steel arch ribs of the next continuous girder is carried out.

3. A method for installing a steel arch rib of a three-span wide-beam narrow-arch through-arch bridge according to claim 1, characterized in that: For the installation construction of long-span and super-high arch ribs, first assemble and jack the steel box girder, and then use a cable crane to hoist the steel arch ribs.

4. A method for installing a steel arch rib of a three-span wide-beam narrow-arch through arch bridge according to claim 2, characterized in that: The specific process includes the following steps: Step 1) Set up the steel box girder assembly platform and the cable crane gantry respectively. Assemble the first continuous girder of the steel box girder on the steel box girder assembly platform, and hoist the first continuous girder of the steel arch ribs by the cable crane. Step 2) Demolish the cable crane system to a height lower than the bottom elevation of the steel box girder, and jack the first continuous girder as a whole and place the girder in position. Step 3) Assemble the second continuous girder of the steel box girder, restore the cable crane system, and hoist the second continuous girder of the steel arch ribs. Step 4) Demolish the cable crane system to a height lower than the bottom elevation of the steel box girder, and jack the second continuous girder as a whole and place the girder in position. Step 5) Assemble the third continuous girder of the steel box girder, restore the cable crane system, and hoist the third continuous girder of the steel arch ribs.

5. A method for installing a steel arch rib of a three-span wide-beam narrow-arch through-arch bridge according to claim 3, characterized in that: The specific process includes the following steps: Step 1) Set up the steel box girder assembly platform, and set up the cable crane gantry at each continuous girder end to the height of the bottom of the steel box girder. Step 2) Assemble and jack the first continuous girder of the steel box girder, and then install the first continuous cable crane on the cable crane gantry of the first continuous girder. Step 3) Hoist the first continuous girder of the steel arch ribs, and assemble and jack the second continuous girder of the steel box girder in place. Step 4) Demolish the first continuous cable crane, and then install and construct the second continuous cable crane. Step 5) Hoist the second continuous girder of the steel arch ribs, and assemble and jack the third continuous girder of the steel box girder in place. Step 6) Demolish the second continuous cable crane, and then install and construct the third continuous cable crane. Step 7) Hoist the third continuous girder of the steel arch ribs.

6. A method for installing a steel arch rib of a three-span wide-beam narrow-arch through arch bridge according to claim 2, characterized in that: The cable crane is a set.

7. A method for installing a steel arch rib of a three - span wide - beam narrow - arch through - type arch bridge according to claim 3, characterized in that: The cable crane is one continuous girder and is erected by multiple sets of tower frames.

8. A method for installing a steel arch rib of a three-span wide-beam narrow-arch through-arch bridge according to claim 3, characterized in that: The long span is 300m - 500m, and the super-high arch rib is an arch rib of 50m - 100m.

9. A method for installing a steel arch rib of a three-span wide-beam narrow-arch through-arch bridge according to claim 4, characterized in that: The cable crane gantry is set up at both ends of the steel box girder assembly platform along the longitudinal bridge direction.

10. A method for installing a steel arch rib of a triple-span wide-beam narrow-arch through-arch bridge according to claim 4, characterized in that: Between Step 1) and Step 2), it also includes installing the support rods between the beam and the arch and the cantilever units.

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