A construction method for integral jacking and launching of a steel structure bridge in a narrow space

Abstract

The present invention provides a method for integral jacking and pushing construction of a steel structure bridge in a narrow space, comprising the following steps: strengthening the webs inside the box girder, symmetrically removing the stay cables on the box girder from both ends of the box girder towards the center of the box girder; gradually cutting the box girder cantilevers where the stay cables are connected to the box girder from both ends towards the center, and recording the cutting positions; jacking up the box girder to a first preset height through a jacking device and a jacking distribution beam; installing jacking brackets and jacking devices on both the existing piers and abutments and the temporary piers at the bottom of the box girder, and gradually pushing the box girder from the existing piers to the temporary piers in sections through the jacking devices; constructing the bottom of the original box girder, and after the construction is completed, performing a reset jacking and pushing operation on the box girder to push the box girder from the temporary piers to the existing piers; welding the box girder cantilevers again at the cutting positions, and simultaneously inspecting and constructing the reset box girder to restore it to the initial state.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and particularly relates to a method for integral jacking construction of a steel structure bridge in a narrow space. Background Art

[0002] In recent years, with the continuous development of urban roads, there are a large number of construction sites in full swing in various cities. During the construction of subway tunnels, the underground traffic roads are becoming increasingly developed, and it is more and more difficult for the new subway line to avoid existing bridges.

[0003] When the subway tunnel passes through adjacent structures, it will inevitably disturb existing structures such as bridges. Therefore, in order to reduce the impact on existing bridges under the condition of ensuring the normal construction of the new line, it is necessary to transfer the existing bridges before construction. The integral jacking construction of steel structure bridges has the characteristics of simple construction equipment, less impact on the surrounding environment, and high construction safety. These characteristics make the integral jacking construction of steel structure bridges more and more popular.

[0004] There are often a large number of buildings around the existing bridges in the urban area. Therefore, during the jacking process of the existing bridges, the construction space is narrow, resulting in the impact of the existing jacking construction method on the existing box girder itself and the surrounding buildings, ultimately affecting the safety and progress of the construction. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a method for integral jacking construction of a steel structure bridge in a narrow space to solve the problems existing in the prior art.

[0006] The present invention provides a method for integral jacking construction of a steel structure bridge in a narrow space, including the following steps:

[0007] Reinforce the webs in the box girder, symmetrically remove the stay cables on the box girder from both ends of the box girder towards the center of the box girder, and wind up and transport out the removed stay cables.

[0008] Gradually cut the box girder cantilever where the stay cable is connected to the box girder from both ends to the center, and record the cutting positions of the box girder cantilever.

[0009] Install a jacking support and a jacking device on the pier at the bottom of the box girder jacking line, arrange a jacking distribution beam at the bottom of the box girder, and jack up the box girder to a first preset height through the jacking device and the jacking distribution beam.

[0010] Install a jacking support and a jacking device on both the existing pier and the temporary pier at the bottom of the box girder, and gradually jack the box girder from the existing pier to the temporary pier in sections through the jacking device.

[0011] Construct the bottom of the original box girder. After the construction is completed, perform the reset and jacking operation on the box girder to jack the box girder from the temporary pier to the existing pier.

[0012] Re-weld the cantilever of the box girder at the cutting position, and at the same time, conduct inspection construction on the reset box girder to restore it to the initial state.

[0013] Preferably, the reinforcement of the web in the box girder includes: arranging stiffeners on the side of the web.

[0014] Preferably, the bottom of the stiffener is connected to the box body by full-penetration butt welding, and the stiffener is longitudinally connected to the web by double-sided fillet welding.

[0015] Preferably, the specific steps of symmetrically removing the stay cables on the box girder from both ends of the box girder to the center of the box girder are as follows:

[0016] Process the locking clip according to the size of the anchorage end of the box girder, arrange the locking clip at the anchorage ends of both ends of the box girder, and arrange tension rods at both ends of the locking clip. Anchorage devices are provided on the tension rods.

[0017] Connect the anchorage device supporting the tension rod to the end of the unloading device, and start the unloading device to conduct the force transmission of the connection between the stay cable and the box girder to the unloading device.

[0018] When the connection sleeve connecting the box girder and the stay cable is completely unloaded, remove the connection sleeve, lower the stay cable to make it sag naturally and approach the steel tower, and complete the unloading and relaxation of the stay cable.

[0019] Arrange a number of cable releasing trolleys along the length direction of the box girder on the bridge deck, and hoist the stay cable onto the cable releasing trolleys through slings.

[0020] Preferably, the specific steps of jacking the box girder to the first preset height through the jacking device and the jacking distribution beam are as follows:

[0021] Conduct a trial jacking on the box girder through the jacking device. During the trial jacking process, monitor the change in the flatness of the box girder and the pressure change of the jacking device in real time, and adjust the jacking device according to the changes.

[0022] After the jacking device is debugged, conduct the formal jacking. Jack the box girder to the first height through the jacking device, arrange cushion blocks at the bottom of the box girder, and let the jacking device return oil to make the box girder drop onto the cushion blocks.

[0023] Install cushion blocks at the bottom of the jacking device, repeat the above formal jacking operation several times. When the box girder reaches the second height, replace the cushion blocks with spacer blocks.

[0024] Continue the formal jacking operation on the spacer blocks until the box girder is jacked to the first preset height.

[0025] Preferably, the second height is 4 times the first height.

[0026] Preferably, the first preset height is 2.2 m.

[0027] Preferably, the process of gradually pushing the box girder from the existing pier to the temporary pier in sections by the pushing device specifically includes:

[0028] A leading girder and a trailing girder are respectively arranged at the front and rear ends of the box girder along the pushing direction of the box girder;

[0029] Connect the oil pipes and communication data of the pushing device, and conduct a trial push. During the trial push, the state of the pushing system under the load condition is detected in real time;

[0030] After the trial push is qualified, a formal push is carried out. The front end of the box girder is successively pushed to several temporary piers on the pushing route by the pushing device. After the box girder is pushed in place, the leading girder is removed;

[0031] The flatness of the box girder is detected in real time when the front end of the box girder reaches the temporary pier. The rotation angle of the box girder is adjusted according to the detection result of the flatness. After the box girder is pushed to the preset position, the box girder is lifted to the second preset height.

[0032] Preferably, the specific arrangement of the trailing girder at the rear end of the box girder includes:

[0033] A first sub-trailing girder is arranged at the rear end of the box girder along the pushing direction of the box girder;

[0034] The box girder is pushed a first distance along the pushing direction by the pushing device, and a second sub-trailing girder is arranged at the end of the first sub-trailing girder;

[0035] Then the box girder is pushed a second distance along the pushing direction by the pushing device, and a third sub-trailing girder is arranged at the end of the second sub-trailing girder to complete the installation of the trailing girder.

[0036] Preferably, both the first distance and the second distance are 10 m.

[0037] The beneficial effects of the present invention are as follows: For the integral jacking construction method of a steel structure bridge in a narrow space provided by the present invention, before construction, the webs of the bridge are first reinforced to prevent damage to the box girder caused by uneven stress during the jacking process. Then, the stay cables of the bridge are coiled, and at the same time, the cantilever of the box girder connected to the stay cables is cut. Then, the jacking device gradually jacks the box girder to a preset height, and a front guide beam and a rear guide beam are arranged at the front and rear ends of the box girder. In order to adapt to the narrow construction space on site, the rear guide beam is installed in sections, and a jacking device is used to jack the existing bridge onto the temporary pier. After the box girder is jacked in place, the front guide beam is removed in time to reduce the occupation of space. The integral jacking construction method of a steel structure bridge in a narrow space provided by the present invention reduces the damage to the bridge deck during construction and at the same time reduces the impact on the surrounding environment. After the construction is completed under the existing bridge, the original bridge deck is reset, reducing the construction cost and improving the construction efficiency. It reduces the impact on the structure of the existing bridge when the new tunnel is bored, improves the construction efficiency and progress, facilitates tunnel construction, and ensures the construction safety during the tunnel crossing of this area and the safety during operation.

[0038] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic flow chart of the integral jacking construction method of a steel structure bridge in a narrow space provided by an embodiment of the present invention;

[0040] Figure 2 It is a schematic connection diagram of the stay cable and the box girder in this embodiment;

[0041] Figure 3 It is a schematic diagram of the cross-section position of the box girder in this embodiment

[0042] Figure 4 is Figure 3 a schematic diagram of the web reinforcement structure of the first cross-section of the box girder in

[0043] Figure 5 is Figure 3 a schematic diagram of the web reinforcement structure of the second cross-section of the box girder in

[0044] Figure 6 It is a schematic diagram of the stiffener structure in this embodiment;

[0045] Figure 7 is Figure 3 a schematic diagram of the cross-section structure of the bridge head and the bridge tail in

[0046] Figure 8 It is a schematic diagram before the box girder is jacked;

[0047] Figure 9Schematic diagram of the front guiding beam and the rear guiding beam before the installation of the box girder;

[0048] Figure 10 Schematic diagram after the box girder is jacked;

[0049] Figure 11 Schematic diagram after the box girder is jacked back for reset;

[0050] Figure 12 Schematic diagram of the box girder reset to the existing pier;

[0051] Main reference numerals

[0052] 10. Stay cable; 11. Box girder cantilever; 12. Reinforcing rib; 13. Manhole; 14. Box girder; 15. Existing pier; 16. Front guiding beam; 17. Rear guiding beam; 18. Temporary pier.

[0053] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific embodiments

[0054] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0055] The present invention provides a method for integral jacking construction of a steel structure bridge in a narrow space, including the following steps: strengthening the web in the box girder, symmetrically removing the stay cables on the box girder from both ends of the box girder to the center of the box girder, and coiling and transporting the removed stay cables out; gradually cutting the box girder cantilever where the stay cable is connected to the box girder from both ends to the center, and recording the cutting position of the box girder cantilever; installing a jacking support and a jacking device on the pier at the bottom of the box girder jacking line, arranging a jacking distribution beam at the bottom of the box girder, and jacking the box girder to a first preset height through the jacking device and the jacking distribution beam; installing a jacking support and a jacking device on both the existing pier and the temporary pier at the bottom of the box girder, and gradually jacking the box girder from the existing pier to the temporary pier in sections through the jacking device; constructing the bottom of the original box girder, and after the construction is completed, performing a reset jacking operation on the box girder to jack the box girder from the temporary pier to the existing pier; welding the box girder cantilever again at the cutting position of the box girder cantilever, and at the same time, inspecting and constructing the reset box girder to restore it to the initial state. The method for integral jacking construction of a steel structure bridge in a narrow space provided by the present invention reduces the influence on the existing bridge structure when a new tunnel passes through the existing bridge structure, improves the construction efficiency and progress, facilitates tunnel construction, and ensures the construction safety during the tunnel passing through this area and the safety during operation.

[0056] Please refer to Figure 1, shown is the integral jacking construction method for a steel structure bridge in a narrow space provided by an embodiment of the present invention. The integral jacking construction method for a steel structure bridge in a narrow space provided by this embodiment can effectively reduce the impact on the existing box girder itself and surrounding buildings in the narrow space, improve the construction efficiency and progress, facilitate tunnel construction, and ensure the construction safety during the tunnel passing through this area and the safety during operation.

[0057] Specifically, the integral jacking construction method for a steel structure bridge in a narrow space provided by this embodiment specifically includes the following steps:

[0058] Step S10, reinforce the webs inside the box girder, symmetrically remove the stay cables on the box girder from both ends of the box girder towards the center of the box girder, and wind up and transport out the removed stay cables.

[0059] In this embodiment, symmetrically removing the stay cables on the box girder from both ends of the box girder towards the center of the box girder specifically includes the following steps:

[0060] Step S101, process the locking clamps according to the dimensions of the anchorage ends of the box girder, arrange the locking clamps at the anchorage ends at both ends of the box girder, and arrange tension rods at both ends of the locking clamps. Anchors are provided on the tension rods.

[0061] Specifically, as Figure 2 shown, the stay cables 10 are symmetrically arranged from the steel tower towards both ends. Therefore, when removing the stay cables, they are gradually and symmetrically removed from both ends of the box girder towards the steel tower direction. The anchorage end of the box girder is the force-releasing end. Therefore, when removing the stay cables, 2 sets of locking clamps are required, which are respectively arranged at the anchorage ends on both sides of the box girder. One end of the locking clamp clamps the ear of the adjusting end opposite to the anchorage end of the box girder, and the other end of the locking clamp clamps the top of the anchor of the anchorage end of the box girder; tension rods are arranged at both ends of the locking clamp. The connecting rod uses two φ16 fine-rolled threaded steel tension rods to form a reaction frame as a whole.

[0062] Step S102, connect the anchor matching the tension rod to the end of the force-releasing device, and start the force-releasing device so that the force transmitted from the connection between the stay cable and the box girder is conducted to the force-releasing device;

[0063] Specifically, in this embodiment, two 10t jacks are installed simultaneously as the force-releasing device. The ends of the jacks are tightened with the anchors matching the tension rods. After installation, start the device to make the jacks hold the force and transfer the force to the jacks.

[0064] Step S103, when the connection sleeve connecting the box girder and the stay cable is completely free of force, remove the connection sleeve, let the stay cable droop naturally and move closer to the steel tower to complete the force-releasing and relaxation of the stay cable;

[0065] Specifically, after the original box girder connection sleeve is no longer stressed, loosen the connection sleeve, and the jack returns oil to relieve the force. After the jack has completed one stroke of returning oil, tighten and fix the connection sleeve again. Repeat this cycle until the cable force is completely released. After the cable is released, use a chain block to reverse-traction the cable anchor head to remove the release device, and slowly loosen the chain block to make the cable slowly sag and move closer to the steel tower position, so that the stay cable is completely in a natural sag state.

[0066] Step S104: Arrange a number of cable releasing trolleys along the length direction of the box girder on the bridge deck at a preset distance, and hoist the stay cable onto the cable releasing trolleys through slings.

[0067] Specifically, in this embodiment, to avoid friction between the stay cable and the bridge deck, the cable releasing trolleys are installed before the stay cable contacts the bridge deck. After the cable force of the stay cable is completely released, a truck crane is arranged on the bridge deck to lift the tower-end stay cable by using slings to loosen the tower-end stay cable. After the worker removes the fixed pin, the truck crane slowly lowers, and hoists and places the stay cable on the bridge deck. During the process of laying the stay cable on the bridge deck and unfolding it, a cable spreading trolley is installed under the cable at a certain distance to prevent the stay cable from rubbing against the bridge deck and damaging the PE protective layer, protecting the original bridge deck from being damaged.

[0068] Before constructing the box girder, it is first necessary to reinforce the webs inside the box girder to prevent uneven stress during the jacking process from damaging the box girder, so as to ensure the strength of the jacking web construction support points during the jacking process. Specifically, as Figure 3 and Figure 4 shown, stiffeners 12 are respectively arranged on the webs at the left and right ends of the box girder; the web stiffeners at the left end are arranged on the left side of the web, and the web stiffeners at the right end are arranged on the right side of the web. The web and the stiffeners can be fixed by welding. In addition, in this embodiment, since the structures of the webs at different cross-sections of the bridge are different, as Figure 3 and Figure 5 shown, stiffeners 12 can also be arranged on both sides of the webs at the left and right ends of the box girder. The specific structure of the stiffeners can be selected according to needs. As Figure 6 shown, several schematic diagrams of the stiffener structures of the present invention are shown. Further, the dimensions of the stiffeners can respectively adopt one or more of 1752×18×150, 488×18×150, 361×18×150, 379×18×150. The bottom of the stiffener is connected to the box body by full penetration butt welding, and the quality grade of the butt weld is grade I; the stiffener and the web are longitudinally connected by double-sided fillet welding, and the quality grade of the double-sided fillet weld is grade II. During the jacking process, it should be ensured that the longitudinal temporary support length is not less than (8d + 150), where d is the longitudinal spacing of adjacent jacking stiffeners. As Figure 3 and Figure 7As shown in the figure, manholes 13 need to be built at the bridgeheads and the bridge tails of the box girder. The manholes at the bridgeheads and the bridge tails are distributed on the bottom slab and the end cross diaphragms. There are 8 at one end of the bottom slab and 8 at one end of the end cross diaphragm, and they are distributed on both sides of the web of the jacking line in the transverse direction of the bridge. A total of 32 manholes are newly added to the whole bridge.

[0069] Step S20: Gradually cut the cantilever of the box girder where the stay cable is connected to the box girder from both ends to the center, and record the cutting positions of the cantilever of the box girder.

[0070] Specifically, in this embodiment, in order to bear the weight of passing vehicles and the box girder, several box girder cantilevers 11 perpendicular to the axial direction of the box girder are provided on the existing box girder. The stay cables are connected to the box girder through the box girder cantilevers to bear part of the gravity of the box girder and the vehicle. During the specific implementation, during the jacking process of the box girder, there are existing buildings blocking between the box girder cantilevers on the jacking advance route, and the operation space is narrow during the jacking process. Therefore, it is necessary to cut the box girder cantilever to reduce the impact on the surrounding environment on the jacking route. Specifically, the box girder cantilever can be removed by gas cutting. During the cutting process, use the pulling force of the towing rope to slowly lower the box girder cantilever. During the lowering period, a special person is arranged on site to command. The landing position needs to be fully covered with flexible facilities such as tires and rubber sheets to prevent the impact force of the box girder cantilever landing from damaging the bridge and the box girder cantilever itself. A 5 cm protection plate is reserved at the connection between the box girder cantilever and the main girder, and after completion, it is polished and painted with rust inhibitor; when manually removing, a hanging basket is used to provide an operation platform.

[0071] Step S30: Install a jacking support and a jacking device on the pier at the bottom of the box girder jacking line, arrange a jacking distribution beam at the bottom of the box girder, and jack the box girder to the first preset height through the jacking device and the jacking distribution beam.

[0072] Specifically, in this embodiment, the jacking support is installed on both sides of the pier under the existing box girder. 4 steel supports are arranged for each pier column, and the adjacent supports are connected by steel sections to form a lattice form and hold the pier column; for the jacking support of the abutment jacking, it is installed inside the original abutment. 2 steel supports are arranged for each jacking point, and the adjacent supports are connected by steel sections to form a lattice form and are fixedly connected to the abutment body through steel sections. Specifically, the first pre-reviewed height is 2.2 m.

[0073] In this embodiment, jacking the box girder to the first preset height through the jacking device and the jacking distribution beam specifically includes the following steps:

[0074] Step S301: Conduct a trial jacking of the box girder through the jacking device. During the trial jacking process, monitor the change of the flatness of the box girder and the pressure change of the jacking device in real time, and debug the jacking device according to the change.

[0075] Step S302, after the jacking device is debugged, perform the formal jacking. Use the jacking device to jack up the box girder to the first height, arrange the backing plates at the bottom of the box girder, and let the oil return in the jacking device so that the box girder drops onto the backing plates.

[0076] Specifically, in this embodiment, when using the jacking device to jack up the box girder to the first height of 5 cm, arrange 5-cm backing plates at the bottom of the box girder, and then let the oil return in the jacks in the jacking device, so that the box girder slowly drops until it is stressed by the backing plates.

[0077] Step S303, install backing plates at the bottom of the jacking device, repeat the above formal jacking operation several times. When the box girder reaches the second height, replace the backing plates with spacer blocks.

[0078] Specifically, in this embodiment, after the box girder slowly drops onto the backing plates, install 5-cm backing plates at the bottom of the jacking device, repeat Step S302. When the box girder reaches the second height of 20 cm, replace the backing plates with spacer blocks.

[0079] Step S304, continue the formal jacking operation on the spacer blocks until the box girder is jacked up to the first preset height.

[0080] Specifically, continue the jacking operation on the spacer blocks. After the box girder is jacked up another 5 cm, arrange backing plates on the spacer blocks. When the box girder reaches 40 cm, replace the backing plates with spacer blocks, and fix the newly arranged spacer blocks to the original spacer blocks. The fixing method of the new spacer blocks and the original spacer blocks can be bolt fixing or welding fixing to prevent the spacer blocks from becoming unstable due to the increased height. When the box girder is jacked up to the first preset height of 2.2 m, the jacking of the box girder is completed.

[0081] Step S40, install the jacking brackets and jacking devices on both the existing piers and the temporary piers at the bottom of the box girder, and gradually jack the box girder from the existing piers to the temporary piers in sections through the jacking devices.

[0082] Specifically, in this embodiment, the jacking device adopts an electro-mechanical-hydraulic integrated design and consists of vertical jacking jacks, horizontal jacking jacks, lateral deviation correction jacks and sliding devices. In this embodiment, install the jacking brackets and jacking devices on both the existing piers and the temporary piers at the bottom of the box girder. The specific steps of gradually jacking the box girder from the existing piers to the temporary piers in sections through the jacking devices are as follows:

[0083] Step S401, arrange the front guide beam and the rear guide beam at the front and rear ends of the box girder respectively along the jacking direction of the box girder.

[0084] Before the jacking, it is also necessary to carry out the foundation construction of the temporary piers and abutments, mainly including excavating the road surface around the temporary piers and abutments to pour the enlarged foundation, and reserving embedded parts before pouring the enlarged foundation for installing the upper structure of the temporary piers; after the installation of the upper structure of the temporary piers is completed, install the jacking equipment and the supporting cushion piers, and install the transverse distribution beam on the jacking equipment; as Figure 8 shown, install the jacking brackets and jacking devices on the existing piers and abutments 15 at the bottom of the box girder 14, and remove the jacking distribution beam at the bottom of the box girder. In order to ensure the anti-overturning stability of the box girder during movement and reduce the overhanging length of the beam to reduce the installation stress, as Figure 9 shown, arrange the front guide beam 16 and the rear guide beam 17 at the front and rear ends of the box girder respectively along the jacking direction of the box girder. Specifically, both the front guide beam 16 and the rear guide beam 17 are 30 m, and the rear guide beam 17 is installed in sections.

[0085] Specifically, the steps for installing the rear guide beam in sections are as follows: first, arrange the first sub-rear guide beam of 10 m at the rear end of the box girder, then jack the box girder along the jacking direction by the first distance of 10 m through the jacking device, and arrange the second sub-rear guide beam of 10 m at the end of the first sub-rear guide beam; finally, jack the box girder along the jacking direction by the second distance of 10 m through the jacking device, and then arrange the third sub-rear guide beam of 10 m at the end of the second sub-rear guide beam to complete the installation of the 30 m rear guide beam.

[0086] Step S402: Connect the oil pipes and communication data of the jacking device, and conduct a trial jacking. During the trial jacking process, the state of the jacking system under the load condition is detected in real time.

[0087] Step S403: After the trial jacking is qualified, conduct the formal jacking. Push the front end of the box girder to several temporary piers on the jacking route in turn through the jacking device. After the box girder is jacked in place, remove the front guide beam.

[0088] Specifically, in this embodiment, as Figure 9 shown, there are 3 existing piers and abutments 15 at the bottom of the box girder, and 4 temporary piers 18 are arranged on the jacking route.

[0089] Step S404: Detect the flatness of the box girder in real time when the front end of the box girder reaches the temporary pier, adjust the rotation angle of the box girder according to the detection result of the flatness, and after the box girder is jacked to the preset position, jack the box girder to the second preset height.

[0090] Specifically, in this embodiment, for the convenience of description, the temporary piers are numbered 1-4 from left to right; when the front end of the 34.35m box girder is jacked to the No. 1 temporary pier, the alignment of the box girder is raised by 200mm, and it is vertically rotated -0.3° (clockwise rotation of 0.3°) with the bottom of the box girder at the front end as the center. Then it is jacked 25m, and it is vertically rotated -0.4° with the bottom of the box girder at the center line of the No. 1 temporary pier as the center, and the front end of the box girder reaches the No. 2 temporary pier. Then it is jacked 25m, and it is vertically rotated -0.4° with the bottom of the box girder at the center line of the No. 2 temporary pier as the center, the alignment of the box girder is lowered by 150mm, and the front end of the box girder reaches the No. 3 temporary pier. The box girder is jacked 25m and is vertically rotated -0.2° with the bottom of the box girder at the center line of L1 as the center; continue to jack 10m. As Figure 10 shown, after the box girder is jacked in place, the rear guide beam 17 is located on the No. 1 temporary pier. At this time, in order to reduce the occupation of space, the front guide beam can be removed in time, and part of the rear guide beam can also be removed according to needs. Then the box girder is lifted to the second preset height of 2m to meet the traffic demand under the bridge at the position of the temporary pier; for the convenience of subsequent construction, part of the guide beam can be removed to leave the road surface space as a construction passage.

[0091] Step S50, construct the bottom of the original box girder. After the construction is completed, perform a reset jacking operation on the box girder to jack the box girder from the temporary pier to the existing pier.

[0092] Specifically, construct the newly built project at the bottom of the original box girder. After the construction of the newly built part is completed, install a landing bracket on the temporary pier, and lower the box girder 2m through the landing bracket and place it on the temporary pier. As Figure 11 shown, then perform a reset jacking operation. The reset jacking operation is the reverse process of the jacking operation, so that the box girder 14 is jacked above the existing pier 15. The installation process is similar and will not be elaborated here. Remove the rear guide beam, rearrange the lifting distribution beam at the bottom of the box girder, and lower the box girder jacked to above the existing pier by 2.2m; as Figure 12 shown, so that the box girder 14 is reset to the existing pier.

[0093] Step S60, re-weld the box girder cantilever at the cutting position of the box girder cantilever, and at the same time inspect and construct the reset box girder to restore it to the initial state.

[0094] Re-weld at the cutting position of the original box girder cantilever, re-weld the box girder cantilever to the box girder, check and reinforce the box girder after resetting. If there are cracks in the original deck steel fiber concrete pavement, they should be treated (grouting for cracks with a width ≥ 0.15 mm, sealing for cracks with a width ≤ 0.15 mm). Re-pave the asphalt on the bridge deck system, construct a 10 cm thick carriageway pavement layer (7 cm UHPC concrete layer + 3 cm thick asphalt layer), install the stay cables, and finally apply anti-corrosion coating to the outer surface of the main girder, manhole and newly welded steel plate parts. By resetting the box girder to the existing piers, the construction cost is greatly reduced and the construction efficiency is also improved.

[0095] The integral jacking construction method for the steel structure bridge in a narrow space provided by the present invention, when the tunnel passes through the existing bridge piers, through equipment such as jacking and pushing devices and jacks, not only protects the original bridge deck from being damaged, but also can reduce the impact on the surrounding environment while the tunnel is completed; at the same time, after the new bridge is constructed, the original bridge deck is reset, greatly reducing the construction cost and improving the construction efficiency; reducing the impact on the existing bridge structure during the construction of the new tunnel, improving the construction efficiency and progress, facilitating the tunnel construction and ensuring the construction safety during the tunnel passing through this area and the operation safety.

[0096] It should be noted that the above implementation process is only to illustrate the feasibility of the present application, but this does not mean that the integral jacking construction method for the steel structure bridge in a narrow space of the present application only has the above implementation process. On the contrary, as long as the integral jacking construction method for the steel structure bridge in a narrow space of the present application can be implemented, it can be included in the feasible implementation solutions of the present application.

[0097] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0098] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A construction method for integral jacking and pushing of a steel structure bridge in a narrow space, characterized in that, It includes the following steps: Reinforce the webs inside the box girder, symmetrically remove the stay cables on the box girder from both ends of the box girder towards the center of the box girder, and wind up and transport out the removed stay cables. Gradually cut the cantilevers of the box girder where the stay cables are connected to the box girder from both ends towards the center, and record the cutting positions of the box girder cantilevers. Install jacking brackets and jacking devices on the piers at the bottom of the box girder jacking line, arrange jacking distribution beams at the bottom of the box girder, and jack up the box girder to the first preset height through the jacking devices and jacking distribution beams. Install jacking brackets and jacking devices on both the existing piers and temporary piers at the bottom of the box girder, and gradually push the box girder from the existing piers to the temporary piers in sections through the jacking devices. Conduct construction on the bottom of the original box girder. After the construction is completed, perform a reset jacking operation on the box girder to push the box girder from the temporary piers to the existing piers. Weld the box girder cantilevers again at the cutting positions of the box girder cantilevers. At the same time, conduct inspection construction on the reset box girder and restore it to the initial state. The step of gradually pushing the box girder from the existing piers to the temporary piers in sections through the jacking devices specifically includes: Arrange a front guiding beam and a rear guiding beam at the front and rear ends of the box girder respectively along the jacking direction of the box girder. Connect the oil pipes and communication data of the jacking devices, and conduct a trial jacking. During the trial jacking process, detect the state of the jacking system under the load condition in real time. After the trial jacking is qualified, conduct a formal jacking. Push the front end of the box girder to several temporary piers on the jacking route in sequence through the jacking devices. After the box girder is jacked in place, remove the front guiding beam. Detect the flatness of the box girder in real time when the front end of the box girder reaches the temporary pier, adjust the rotation angle of the box girder according to the detection result of the flatness. After the box girder is jacked to the preset position, jack up the box girder to the second preset height. The step of arranging a rear guiding beam at the rear end of the box girder specifically includes: Arrange a first sub-rear guiding beam at the rear end of the box girder along the jacking direction of the box girder. Push the box girder along the jacking direction for a first distance through the jacking devices, and arrange a second sub-rear guiding beam at the end of the first sub-rear guiding beam. Then push the box girder along the jacking direction for a second distance through the jacking devices, and arrange a third sub-rear guiding beam at the end of the second sub-rear guiding beam to complete the installation of the rear guiding beam.

2. The construction method according to claim 1, characterized in that, The reinforcement of the webs inside the box girder includes: arranging stiffeners on the sides of the webs.

3. The construction method according to claim 2, characterized in that, The bottom of the stiffeners is connected to the box body by full penetration butt welding, and the stiffeners are longitudinally connected to the webs by double-sided fillet welding.

4. The construction method according to claim 1, characterized in that, The step of symmetrically removing the stay cables on the box girder from both ends of the box girder towards the center of the box girder specifically includes: Process clamping clips according to the sizes of the anchorage ends of the box girder, arrange the clamping clips at the anchorage ends at both ends of the box girder, and arrange tension rods at both ends of the clamping clips. Anchors are provided on the tension rods. Connect the anchors supporting the tension rods to the ends of the unloading devices, and start the unloading devices to conduct the force conduction of the connection between the stay cables and the box girder to the unloading devices. After the connection sleeves connecting the box girder and the stay cables are completely unloaded, remove the connection sleeves, let the stay cables droop naturally and move closer to the steel towers to complete the unloading and relaxation of the stay cables. Arrange several cable releasing trolleys on the bridge deck at preset distances along the length direction of the box girder, and hoist the stay cables onto the cable releasing trolleys through slings.

5. The construction method according to claim 1, wherein, The step of jacking up the box girder to the first preset height through the jacking devices and jacking distribution beams specifically includes: The box girder is tested by the jacking device. During the test jacking process, the flatness change of the box girder and the pressure change of the jacking device are monitored in real time, and the jacking device is debugged according to the changes; After the jacking device is debugged, formal jacking is carried out. The box beam is jacked to the first height by the jacking device, and a pad is arranged at the bottom of the box beam. The jacking device returns oil to make the box beam fall onto the pad; Install a pad at the bottom of the jacking device, repeat the above formal jacking operation several times, and when the box girder reaches the second height, replace the pad with a pad; Continue the formal jacking operation on the pad until the box girder is jacked to the first preset height.

6. The construction method according to claim 5, characterized in that, The second height is 4 times the first height.

7. The construction method according to claim 1, characterized in that The first preset height is 2.2 m.

8. The construction method according to claim 1, characterized in that, The first distance and the second distance are both 10 m.

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