Incremental launching construction method for small-curve large-longitudinal-slope steel box girder

Abstract

The invention discloses a small-curve large-longitudinal-slope steel box girder incremental launching construction method which comprises the following steps that an incremental launching platform and temporary piers are erected and assembled, and incremental launching equipment is installed between the temporary piers; hoisting and lifting equipment of the steel box girder is installed, the pushing device and the hoisting and lifting equipment of the steel box girder are checked, and then the steel guide girder is installed; hoisting operation is conducted on the steel box girders, the steel box girders are adjusted according to sections in the hoisting process, and welding operation is conducted after the steel box girders are in butt joint; and the beam sections composed of the steel box beams are pushed through a walking machine, the pushed beam sections continue to be spliced, and construction is conducted circularly in this way till all the beam sections are pushed to the designated construction positions. By means of a series of optimization measures, upslope pushing is adjusted to be horizontal pushing, the measures of adding the bearing beam and the like, it is ensured that the beam body cannot be disengaged in the curve pushing process, the concrete anti-collision wall can be constructed firstly before pushing, follow-up expressway-crossing concrete construction is reduced, and the safety of steel box beam construction is improved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge deck construction, and in particular to a method for jacking construction of a steel box girder with a small curve and a large longitudinal slope. Background Art

[0002] Bridges are the basic spanning structures of highway projects. The design and construction of the superstructure are related to the safety progress of the entire bridge, as well as the safety and normal use of the spanning objects below.

[0003] With the development of infrastructure construction in my country, steel box girders are increasingly being used in bridges across highways due to their advantages such as light weight, large span, modular prefabrication, etc. Currently, there are mainly two construction techniques: pre-assembly in-situ erection and pre-assembly followed by jacking into place.

[0004] For the ramps across the highway in the hub interchange, they are mostly designed with a small turning radius and a large longitudinal slope. Compared with the jacking of a straight bridge span, the jacking of the steel box girder of this bridge span structure involves a series of technical and safety issues such as easy lateral air separation and easy longitudinal slippage. To this end, we propose a jacking construction method for a steel box girder with a small curve and a large longitudinal slope. Summary of the invention

[0005] The object of the present invention is to provide a method for jacking construction of a steel box girder with a small curve and a large longitudinal slope, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for top-pushing a steel box girder with a small curve and a large longitudinal slope, the steps of the construction method are as follows:

[0007] Step 1: Set up the assembling jacking platform and temporary piers, and install the jacking equipment between the temporary piers;

[0008] Step 2: Install the lifting equipment of the steel box beam, inspect the lifting equipment of the top push and steel box beam, and then install the steel guide beam;

[0009] Step 3: Lift the steel box girder, adjust the steel box girder by segment during the lifting process, and perform welding after the steel box girder is butt-jointed;

[0010] Step 4: Push the beam segments composed of steel box beams through the crawler machine, and continue to splice the beam segments after pushing, and repeat the construction cycle until each beam segment is pushed to the designated construction position;

[0011] Step 5: After the beam section is fully assembled, the jacking equipment is dismantled and moved away from the permanent support position. The beam is then dropped and the mounting support is installed in place.

[0012] Preferably, in the step 1, the temporary piers are arranged symmetrically, and the jacking equipment is installed between the symmetrically arranged temporary piers.

[0013] Preferably, in the step one, the jacking equipment is assembled in a group of two crawlers, and the two crawlers are driven by a pump station. The pump station has an external main control computer for centralized numerical control. The pump station can output the same oil pressure according to the pre-setting to make the two crawlers move synchronously, which is suitable for the jacking of straight bridges. It can also output different oil pressures to make the two crawlers move asynchronously, which is suitable for the jacking of curved bridges such as ramp bridges.

[0014] Preferably, in the step three, welding operation is performed after the steel box girders are butt-jointed, and flaw detection and testing are performed on the welds to ensure the stability of the welding and fixing of the steel box girders.

[0015] Preferably, in the step 4, during the pushing process, the lifting jack in the crawler controls the oil cylinder to a set piston stroke through the control system, and the pushing device and the steel box beam are regularly separated from the cushion beam by a distance (controlled at 2 cm);

[0016] The control system synchronously controls the jacking jack cylinder to push the shifter to drive the steel box girder forward to the set piston stroke position. The steel box girder moves forward. When the steel box girder moves to the displacement set by the system, the jacking jack piston retracts and returns to make the steel box girder fall on the temporary support, and the force system is converted. The horizontal jack retracts and returns to its original state, completing a stroke jacking, and the construction is cyclic. The steel box girder is pushed. The above-mentioned action steps of the crawler machine are regarded as a cycle. By repeating this cycle, the steel box girder can be pushed and translated into place.

[0017] Preferably, in step 4, displacement observation is performed during horizontal jacking, mainly the centerline offset of the beam body and the horizontal and vertical displacement of the pier top, and the jacking equipment needs to be adjusted in time during the jacking process. The maximum offset value is taken as the allowable offset according to the design, and the coordinates are converted. Continuous observation is performed from the start of force application to the start of movement of the beam body. Once the displacement exceeds the maximum value, the force is immediately stopped and readjusted.

[0018] Preferably, in step 4, when the curved jacking is performed, it is achieved by adjusting the forward strokes of the two crawlers in the same pump station. During the actual on-site construction process, the forward stroke, deviation correction stroke, and jacking height of the crawler of the entire bridge need to be calculated for each stroke, and the deviation is corrected in real time according to the position of the web of the steel box girder.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: the construction method is used to push the steel box girder, and through a series of optimization measures, the uphill pushing is adjusted to horizontal pushing, and measures such as adding cushion beams ensure that the beam body cannot be empty during the curve pushing process, and a concrete anti-collision wall can be constructed before pushing, reducing subsequent concrete construction across the highway, thereby improving the safety of steel box girder construction, and at the same time, horizontal pushing can maximize the working performance of all crawlers, and the optimization measures for curve pushing greatly reduce the correction operation, greatly improving the construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a construction process diagram of the present invention.

[0021] Figure 2 It is a structural schematic diagram of the connection between the jacking device of the present invention and the bridge. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0023] Embodiment 1

[0024] like Figure 1 and Figure 2 As shown in , a method for pushing construction of a steel box girder with a small curve and a large longitudinal slope, the steps are as follows:

[0025] (1) Set up an assembly jacking platform and temporary piers (temporary cushion beams). The temporary piers are set between the steel box girder and the bridge piers. The temporary piers are set symmetrically to ensure stable load bearing on the steel box girder. The jacking equipment is installed between the temporary piers.

[0026] The jacking equipment is assembled in a group of two crawlers. The two crawlers are driven by a pump station. The pump station has an external main control computer for centralized numerical control. The pump station can output the same oil pressure according to pre-settings to make the two crawlers move synchronously, which is suitable for the jacking of straight bridges. It can also output different oil pressures to make the two crawlers move asynchronously, which is suitable for the jacking of curved bridges such as ramp bridges.

[0027] (2) Install the lifting and hoisting equipment of the steel box girder, inspect the jacking and lifting equipment of the steel box girder, and then install the steel guide beam.

[0028] (3) Lift the steel box girder and adjust it by segment during the lifting process. After the steel box girder is butt-jointed, weld it and perform flaw detection and inspection on the weld to ensure the stability of the welding fixation of the steel box girder. After completing the staged splicing of the steel box girder, connect the steel guide beam to the beam segment.

[0029] (4) The beam segments composed of the steel box beam are pushed by a crawler, and the pushed beam segments are further spliced, and the construction is repeated until each beam segment is pushed to the designated construction position;

[0030] During the pushing process, the lifting jack in the crawler controls the oil cylinder to the set piston stroke through the control system, and regularly moves the pushing device and the steel box beam away from the cushion beam by a certain distance (controlled at about 2 cm);

[0031] The control system synchronously controls the jacking jack cylinder to push the shifter to drive the steel box girder forward to the set piston stroke position. The steel box girder moves forward. When the steel box girder moves to the displacement set by the system, the jacking jack piston retracts and returns to make the steel box girder fall on the temporary support, and the force system is converted. The horizontal jack retracts and returns to its original state, completing a stroke jacking, and the construction is cyclic. The steel box girder is pushed. The above-mentioned action steps of the crawler machine are regarded as a cycle. By repeating this cycle, the steel box girder can be pushed and translated into place.

[0032] (5) After the beam section is fully assembled, the jacking equipment is dismantled and moved away from the permanent support position. The beam is then dropped and the installation support is installed in place.

[0033] The specific operations that need to be paid attention to during horizontal pushing and curved pushing are as follows:

[0034] When pushing horizontally:

[0035] (1) Estimate the friction force based on the fulcrum reaction force of the working condition and verify it with the oil pressure gauge.

[0036] (2) If a sudden increase in the pushing force is found during the pushing process, the pushing should be stopped immediately and the cause should be checked, especially the support frame and sliding surface on the pushing equipment.

[0037] (3) Displacement observation: Displacement observation mainly refers to the centerline offset of the beam and the horizontal and vertical displacement of the pier top. During the jacking process, the jacking equipment needs to be used for timely adjustment. Pier top displacement observation is very important. The maximum displacement value is calculated based on the allowable displacement in the design. The coordinates are converted and continuously observed from the start of force application to the start of beam movement. Once the displacement exceeds the maximum value, the force is immediately stopped and readjusted.

[0038] (4) Applying jacking force: The magnitude of the jacking force is automatically adjusted by the main console according to the magnitude of the frictional resistance and is reflected by the oil gauge. The jack should be calibrated as required before use and the oil gauge should be calibrated.

[0039] (5) When pushing to the last beam section, special attention must be paid to whether the beam section has reached the designed position. It must be pushed to the final position at night when the temperature is stable according to the monitoring instructions, and the beam length must be carefully calculated and determined based on the temperature.

[0040] (6) When pushing the last section of the beam in each round and the last round, you should slow down the pushing speed to facilitate deviation correction and longitudinal movement into place.

[0041] When pushing the curve:

[0042] (1) The temporary supports and prefabrication and assembly of steel box girder segments of curved bridges are set according to the flat curve radius of the curved bridge. The weld width must be strictly controlled during on-site assembly of box girder segments to ensure that the overall line shape of the beam meets the design requirements.

[0043] (2) The guide beam and main beam of the curved bridge are installed at a 3° plane intersection angle to ensure that the guide beam can accurately reach the high-speed crawler on the opposite side during the jacking process.

[0044] (3) Curved jacking is theoretically achieved by adjusting the forward stroke of the two crawlers in the same pump station. During the actual on-site construction process, the forward stroke, correction stroke, and jacking height of the crawler of the entire bridge need to be calculated for each stroke, and the deviation must be corrected in real time according to the web position of the steel box girder. The correction action is too complicated and is not conducive to actual on-site construction.

[0045] The optimization solution actually adopted on site is to weld a set of pad beams on the crawler and place the elevation adjustment pads on the pad beams. In this way, the entire pushing process basically does not require complicated corrections. It is only necessary to adjust the crawler to gradually reach the temporary pier in front during the forward movement of the beam.

[0046] The quality of construction needs to be monitored during the construction process. The specific monitoring measures are as follows: Steel box girder axis monitoring: First, after the steel box girder is hoisted to the assembly platform, a mileage mark is made on the bottom surface of the steel box girder 1m (outside) away from the center line of the slideway with a red paint pen. The marking spacing is 1m. At the same time, a scale is drawn on the outside of the slideway with a paint pen, accurate to centimeters. In this way, the operators located next to each slideway during the jacking process can intuitively observe whether the advance on both sides is synchronized.

[0047] Secondly, when the relative mileage of the steel box girder is only fifteen meters away from the absolute mileage, the axis position of the measurement and control points at the inspection line of the top plate of the steel box girder is observed and compared with the design axis to determine the beam axis condition of the bridge.

[0048] Transverse deviation correction of steel box girder: During the process of pushing the steel box girder, the total station is used to monitor the transverse displacement of the bridge. When the transverse displacement deviation reaches 50mm, the deviation correction begins. The deviation correction process is completed by the transverse cylinder of the crawler. Each deviation correction is based on the actual offset and the maximum transverse deviation correction stroke of the crawler. The master control computer uniformly controls the deviation correction amount of each crawler.

[0049] Monitoring of temporary piers: Before pushing, measuring instruments (level and total station) should be set up on one side of the pushing. The pushing support and expanded foundation should be observed after the steel box girder is assembled and every 20 meters of pushing. The foundation settlement should be less than 2mm, the horizontal displacement of the support should be less than 5mm, and the synchronization accuracy of the pushing system should be no less than 5mm.

[0050] Based on the analysis of various working conditions of the main beam according to the calculation, the working condition with the largest deflection of the main beam is selected as the most unfavorable working condition, and its deflection value is 61.9mm. This data is used as the allowable value for main beam monitoring and measurement during the jacking process. If it is found that the deformation of the steel box beam exceeds the allowable value, the construction will be stopped immediately, and the temporary support and steel box beam will be reinforced to ensure safety.

Claims

1. A method for pushing construction of a steel box girder with a small curve and a large longitudinal slope, characterized in that: The steps of this construction method are as follows: Step 1: Set up the assembling jacking platform and temporary piers, and install the jacking equipment between the temporary piers; Step 2: Install the lifting equipment of the steel box beam, inspect the lifting equipment of the top push and steel box beam, and then install the steel guide beam; Step 3: Lift the steel box girder, adjust the steel box girder by segment during the lifting process, and perform welding after the steel box girder is butt-jointed; Step 4: Push the beam segments composed of steel box beams through the crawler machine, and continue to splice the beam segments after pushing, and repeat the construction cycle until each beam segment is pushed to the designated construction position; Step 5: After the beam section is fully assembled, the jacking equipment is dismantled and moved away from the permanent support position. The beam is then dropped and the mounting support is installed in place.

2. The method for pushing construction of a steel box girder with a small curve and a large longitudinal slope according to claim 1 is characterized in that: In the step 1, the temporary piers are arranged symmetrically, and the jacking equipment is installed between the symmetrically arranged temporary piers.

3. The method for pushing construction of a steel box girder with a small curve and a large longitudinal slope according to claim 1 is characterized in that: In the step one, the jacking equipment is assembled in a group of two crawlers, which are driven by a pump station. The pump station has an external main control computer for centralized numerical control. The pump station can output the same oil pressure according to the pre-setting to make the two crawlers move synchronously, which is suitable for the jacking of straight bridges. It can also output different oil pressures to make the two crawlers move asynchronously, which is suitable for the jacking of curved bridges such as ramp bridges.

4. The method for pushing construction of a steel box girder with a small curve and a large longitudinal slope according to claim 1 is characterized in that: In the step three, welding operation is performed after the steel box girders are butt-jointed, and flaw detection and testing are performed on the welds to ensure the stability of the welding and fixing of the steel box girders.

5. The method for pushing construction of a steel box girder with a small curve and a large longitudinal slope according to claim 1 is characterized in that: In the step 4, during the pushing process, the lifting jack in the crawler controls the oil cylinder to set the piston stroke through the control system, and the pushing device and the steel box beam are regularly separated from the cushion beam by a distance (controlled at 2 cm); The control system synchronously controls the jacking jack cylinder to push the shifter to drive the steel box girder forward to the set piston stroke position. The steel box girder moves forward. When the steel box girder moves to the displacement set by the system, the jacking jack piston retracts and returns to make the steel box girder fall on the temporary support, and the force system is converted. The horizontal jack retracts and returns to its original state, completing a stroke jacking, and the construction is cyclic. The steel box girder is pushed. The above-mentioned action steps of the crawler machine are regarded as a cycle. By repeating this cycle, the steel box girder can be pushed and translated into place.

6. The method for pushing construction of a steel box girder with a small curve and a large longitudinal slope according to claim 1 is characterized in that: In step 4, displacement observation is performed during horizontal jacking, mainly the centerline offset of the beam body and the horizontal and vertical displacement of the pier top. The jacking equipment needs to be adjusted in time during the jacking process. The maximum offset value is calculated based on the allowable displacement in the design, and the coordinates are converted. Continuous observation is performed from the start of force application to the start of movement of the beam body. Once the displacement exceeds the maximum value, the force is immediately stopped and readjusted.

7. The method for pushing construction of a steel box girder with a small curve and a large longitudinal slope according to claim 1 is characterized in that: In step 4, when the curved jacking is performed, it is achieved by adjusting the forward stroke of the two crawlers in the same pump station. During the actual on-site construction process, the forward stroke, deviation correction stroke, and jacking height of the crawler of the entire bridge need to be calculated for each stroke, and the deviation is corrected in real time according to the position of the web of the steel box girder.

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