Large-span continuous beam overpass business line cantilever state folding and pushing simulation monitoring method
By using the cantilever state closed top push simulation monitoring method on large-span continuous beams, a steel beam structure calculation model is established for simulation analysis and on-site consistency judgment, the deflection and displacement problems during the construction and use of large-span continuous beams are solved, and construction safety and finished product quality are improved.
Patent Information
- Application Number
- CN202411676489.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-21
- Publication Date
- 2025-03-11
AI Technical Summary
During the cantilever construction and later use of large-span continuous beams, due to factors such as the weight of the beam section, concrete shrinkage, and creep, it will cause large deflection and displacement, which will affect the aesthetics of the bridge, driving comfort and the stress of the main pier. Especially in the overhead construction of steel box beams in the slope-changing section, there are problems of high accuracy and safety requirements.
The cantilever state closed top pushing simulation monitoring method is adopted for the large-span continuous beam business line. By establishing a steel beam structure calculation model, the entire top pushing process is simulated and analyzed to realize visual dynamic simulation, and the simulation analysis results are consistently judged with the actual on-site monitoring results to ensure that all bridge components meet the design requirements.
Through simulation monitoring methods, the construction process can be dynamically adjusted, the beam displacement and deflection can be reduced, the construction safety and finished product quality of the bridge can be improved, and the accuracy and safety requirements of steel box beams in the slope-changing section can be met.
Smart Images
Figure CN119598583A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of building construction, and in particular to a method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam across an operating line. Background Art
[0002] With the continuous advancement of national construction, the construction of large-span continuous beam bridges across lines and navigation bridges is increasing. At present, most of them can be solved by the scaffolding cast-in-place method, prefabricated hoisting method, and cantilever construction method, but they all require long-term scaffolding formwork, steel bars and concrete pouring construction operations above the upper span route, or require different degrees of traffic closure, which greatly increases the long-term safety hazards of road construction. With the development of intelligent hydraulic jacking equipment, the walking jacking construction technology of cross-line bridges has been widely promoted and used. However, it was found during construction that the walking jacking is not suitable for bridges with large vertical curvature, especially the jacking construction of steel box girders in variable slope sections across operating highways, which have particularly high requirements for the accuracy and safety of linear control.
[0003] However, due to the cantilever construction adopted for long-span bridges, large deflections will occur during construction and later use due to the influence of factors such as the weight of the beam section itself, concrete shrinkage, creep, etc. The later linear shape and internal force conditions of prestressed concrete continuous rigid frame bridges are greatly affected by shrinkage creep and the temperature during closing. During the closing construction process, the actual temperature during closing may deviate from the design temperature. This temperature difference will cause the beam body to shift, causing the main pier to deviate and generate secondary stress. Similarly, the later shrinkage creep will also cause the beam body to produce vertical deflection and horizontal displacement as well as additional internal force, causing the main pier to deviate, affecting the appearance of the bridge and the driving comfort, and at the same time having an adverse effect on the stress of the main pier.
[0004] Therefore, it is an urgent problem for technical personnel in this field to propose a simulation monitoring method for closing and pushing the cantilever state of a large-span continuous beam across an operating line to solve the difficulties existing in the prior art. Summary of the invention
[0005] In view of this, the present invention provides a simulation monitoring method for the closing and pushing of a large-span continuous beam in a cantilever state across an operating line, establishes a steel beam structure calculation model, and simulates and analyzes the entire steel beam pushing process to achieve visual dynamic simulation and provide feedback for dynamic adjustment of on-site construction.
[0006] In order to achieve the above object, the present invention adopts the following technical solution:
[0007] A method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam across an operating line, comprising the following steps:
[0008] Obtain basic engineering data;
[0009] Establish a steel beam structure calculation model to simulate and analyze the steel beam closing and pushing process;
[0010] The consistency between the simulation analysis results and the actual monitoring results of the construction site is judged;
[0011] Monitoring ensures that all bridge components meet the design requirements.
[0012] Optionally, basic engineering data include weather, wind, and temperature data during jacking construction, the location and size of construction loads on the bridge, and the stress state of the steel box girder.
[0013] Optionally, the finite element analysis software MIDAS / Civil is used to perform modeling and simulation analysis on the steel beam structure.
[0014] Optionally, the specific contents of the consistency judgment between the simulation analysis results and the actual monitoring results of the construction site are as follows:
[0015] Based on the results of construction simulation analysis, the coordinate positions of the bridge line control points at each construction stage are determined, and actual monitoring is carried out at the construction site to ensure consistent positions. If the deviation is large, feedback is immediately provided to the construction site operators for adjustment. During the construction process, the bridge line is also comprehensively controlled through the beam drop elevation and bridge deck paving elevation.
[0016] Optionally, the actual monitoring content at the construction site is to perform stress monitoring on the most unfavorable points of each working condition on the guide beam, steel box beam and jacking support.
[0017] Optionally, a vibrating wire concrete strain gauge and a vibrating wire readout are used as stress monitoring instruments.
[0018] Optionally, the specific contents of monitoring to ensure that each bridge component meets the design requirements are:
[0019] During the jacking process, the vertical displacement and jacking force of the central controller of the jack are monitored to synchronously control the jacks working at the same time. The vertical displacement is used as the main indicator and the pressure value of each jack is used as a reference. The deviation of the actual linear shape is adjusted by adjusting the height of the temporary support pad.
[0020] Each time a stroke is pushed forward, the elevation data of the monitoring control point on the steel beam is measured and compared with the target line shape to reduce the internal stress in the process, so that the pushing process is safe and the line shape is consistent with the fitting.
[0021] It can be seen from the above technical solution that, compared with the prior art, the present invention provides a simulation monitoring method for the closing and pushing of a large-span continuous beam in a cantilever state across an operating line, which has the following beneficial effects: establishing a steel beam structure calculation model, and simulating and analyzing the entire steel beam pushing process, realizing visual dynamic simulation, and providing feedback for dynamic adjustment of on-site construction. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.
[0023] Figure 1 A flow chart of a method for simulating monitoring of closing and pushing of a cantilevered large-span continuous beam across an operating line provided by the present invention. DETAILED DESCRIPTION
[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0025] Reference Figure 1 As shown, the present invention discloses a method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam across an operating line, comprising the following steps:
[0026] Obtain basic engineering data;
[0027] Establish a steel beam structure calculation model to simulate and analyze the steel beam closing and pushing process;
[0028] The consistency between the simulation analysis results and the actual monitoring results of the construction site is judged;
[0029] Monitoring ensures that all bridge components meet the design requirements.
[0030] Furthermore, the basic engineering data include weather, wind, and temperature information during jacking construction, the location and size of the construction load on the bridge, and the stress state of the steel box girder.
[0031] Furthermore, the finite element analysis software MIDAS / Civil was used to carry out modeling and simulation analysis on the steel beam structure.
[0032] Furthermore, the specific contents of the consistency judgment between the simulation analysis results and the actual monitoring results of the construction site are as follows:
[0033] Based on the results of construction simulation analysis, the coordinate positions of the bridge line control points at each construction stage are determined, and actual monitoring is carried out at the construction site to ensure consistent positions. If the deviation is large, feedback is immediately provided to the construction site operators for adjustment. During the construction process, the bridge line is also comprehensively controlled through the beam drop elevation and bridge deck paving elevation.
[0034] Furthermore, the actual monitoring content at the construction site is to conduct stress monitoring on the most unfavorable points of each working condition on the guide beam, steel box beam and jacking support.
[0035] Furthermore, a vibrating wire concrete strain gauge and a vibrating wire reader are used as stress monitoring instruments.
[0036] Furthermore, the specific contents of monitoring to ensure that each bridge component meets the design requirements are as follows:
[0037] During the jacking process, the vertical displacement and jacking force of the central controller of the jack are monitored to synchronously control the jacks working at the same time. The vertical displacement is used as the main indicator and the pressure value of each jack is used as a reference. The deviation of the actual linear shape is adjusted by adjusting the height of the temporary support pad.
[0038] Each time a stroke is pushed forward, the elevation data of the monitoring control point on the steel beam is measured and compared with the target line shape to reduce the internal stress in the process, so that the pushing process is safe and the line shape is consistent with the fitting.
[0039] Specifically, the sliding multi-point continuous jacking method is adopted for construction, and a hydraulic crawler is used as the sliding drive equipment. A 50t hydraulic crawling jack is set on each side.
[0040] The jacking platform is set on the concrete beam and steel-concrete combination section on the small pile number side. The jacking part only includes the middle span GL steel box beam, not the steel-concrete combination section. The jacking direction is from the small pile number to the large pile number. The maximum total jacking weight is about 418t (the total weight of the steel beam is 358 tons, and the front and rear guide beams are about 60t). After the overall assembly of the steel beam on the on-site assembly platform is completed, the sliding jacking method is used to pull the fine-rolled threaded steel by the tensioning jack, drag the beam section to slide on the slideway set on the concrete beam, and pull the beam body into place. The span of the construction hole is 50m. In order to ensure construction safety, meet the anti-overturning requirements of the steel box beam, facilitate the jacking operation of the starting segment steel beam, and reduce the cantilever length of the steel beam itself and the stress during construction, according to the requirements of the design drawings, a 36m long steel guide beam is set at the front end of the steel box beam. When passing the hole, the maximum cantilever of the steel box beam is 14m.
[0041] The jacking slope, the longitudinal section of the jacking steel box girder is located on a straight line of +2.3%, and the plane is located on a flat curve. In order to facilitate the jacking construction, the jacking end is set on the side of the small pile number. During jacking, the accuracy of the position of the beam in the transverse and longitudinal directions of the bridge should be ensured, and corrections should be made in time.
[0042] The jacking slideway uses two steel rails installed on the existing cast-in-place box girder as a jacking construction slideway. A hydraulic sliding system is installed on the two rails. One end of the hydraulic crawler is connected to the sliding track with a wedge-shaped clamp, and the other end is connected to the sliding tire frame or component in the form of a hinge point. A hydraulic cylinder is used in the middle to drive the crawling.
[0043] The jacking guide correction device is used to control the center line of the beam body to always be within the design range during the jacking process. Five jack devices are set on the left and right sides of the jacking sliding track respectively. They are composed of ordinary flat rollers and mechanical jacks. By adjusting the jacks, the flat rollers apply a lateral force to the box beam to achieve the correction effect. The guide device must have sufficient bearing capacity.
[0044] In a specific embodiment, the total length of this continuous beam is 298.0m, and the calculated span is (73.25+150+74.25)m, of which the middle span of 55m (including two 2.5m steel-concrete mixed sections) is a steel-concrete composite beam, the distance from the center line of the side support to the beam end is 0.75m, the center distance of the side support in the transverse direction of the bridge is 5.4m, and the center distance of the middle support in the transverse direction of the bridge is 5.7m. The cross-section beam height of the middle support is 9.8m, the cross-section beam height of the mid-span and side span straight section is 5.8m, and the lower edge of the beam bottom changes according to a 1.6-order parabola. The beam body is a single-box single-chamber, variable height, and variable cross-section box beam. The top plate thickness of the box beam is 47cm, and the local thickening near the support is 77cm; the web thickness is 50~70~90cm, and the bottom plate thickness is 45~121.5cm. The whole joint is equipped with transverse partitions at the end support and the middle support, and the transverse partitions are provided with holes for inspection personnel to pass through. Bridge deck width: Net width on the inner side of the protective wall is 4.4m, beam top width is 8.5m, bottom plate width is 6.6m, and the total width of the bridge building is 8.8m.
[0045] The steel beam jacking of the present invention adopts the sliding jacking method to pull the fine rolled threaded steel bar by the tensioning jack, drag the beam section to slide on the slideway set on the concrete beam, pull the beam body to install in place, and then use the crane installed on the top of the steel-concrete mixed section to drop the beam. The steel beam jacking, beam dropping and closing are all carried out directly above the operating line.
[0046] The finite element analysis software MIDAS / Civil is used to carry out modeling and simulation analysis of the steel beam structure.
[0047] Based on the results of construction simulation analysis, the coordinate positions of the bridge line control points at each construction stage are determined, and actual monitoring is carried out at the construction site to ensure consistent positions. If the deviation is large, feedback is immediately provided to the construction site operators for adjustment. During the construction process, the bridge line is also comprehensively controlled through the beam drop elevation and bridge deck paving elevation.
[0048] During the jacking process, the vertical displacement and jacking force of the central controller of the jack are monitored, and the jacks working simultaneously are controlled synchronously. The vertical displacement is taken as the main indicator and the pressure value of each jack is used as a reference. The deviation of the actual linear shape is adjusted by adjusting the height of the temporary support. The elevation data of the monitoring control point on the steel beam is measured for each advancement stroke, and compared with the target linear shape to reduce the internal stress in the process, so that the jacking safety and linear shape of the jacking process are consistent with the fitting.
[0049] The specific content of the jacking construction is that since the jacking construction time is long, it cannot be completed in one construction skylight, and it needs to be jacked up in stages. The jacking itinerary for each stage is as follows:
[0050] The first step: Use a 200t crawler crane to complete the lifting operation of the steel box girder segment, and promptly follow up to complete the linear adjustment, code welding, etc. After the non-destructive testing is qualified, complete the node repainting and complete the interface welding between the guide beam and the GL segment.
[0051] The second step: the first round of pushing, pushing forward 26m to ensure the safety and stability of the beam structure.
[0052] Step 3: The second jacking stroke is 30m to ensure that the front end of the structure is supported on the top surface of the reinforced concrete box girder.
[0053] Step 4: The third push stroke is 30m, and the push is completed. Remove the front guide beam and the rear guide beam, and install the beam drop bracket.
[0054] The fifth step: drop the beam as a whole, weld the closing section, remove the beam drop bracket, and complete the bridge deck paint spraying.
[0055] In order to ensure that the steel box girder meets the design linear requirements and stress state after the final bridge is completed, it is necessary to analyze the construction process under various working conditions in the dynamic and static state, and under the influence of wind, temperature, sunshine and other environmental factors during the assembly and pushing process, find out the unfavorable state and maximum deformation value, and conduct detailed observation and effective control, including the following contents:
[0056] (1) Observe the contact condition of the bottom plate of the steel box girder on the cushion beam, and detect and analyze the internal forces of the web and bottom plate of the steel box girder under the most unfavorable stress state.
[0057] (2) Deformation of steel box girder segments after transportation and lifting into place.
[0058] (3) The longitudinal length changes due to temperature, uneven sunlight, and cumulative welding errors; the wind force affects the top push, the elevation of the plane point of the main longitudinal beam, and the lateral position (coordinate) changes.
[0059] (4) Observation of steel box girder deflection, measurement of vertical angular deflection of the end joint of each span, stress testing of key sections; observation and stress testing of steel guide girder deflection and deformation.
[0060] Vibrating wire concrete strain gauge and vibrating wire readout instrument are used as stress monitoring instruments.
[0061] Before installing the closing section, use a total station to measure and lay out the axis and outer edge of the beam section on the temporary pier, and weld the limit and guide devices at the edge position to make the installation direction clear in advance.
[0062] When the closing section is installed, the total station tracks and measures the entire installation process. When it is close to the installation position, it is adjusted with a manual hand winch. When the beam axis meets the control requirements, the force is slowly unloaded. After unloading, the total station observes the control point again. At this time, the beam axis should meet the control requirements. The hand winch is used to fine-tune the beam axis until the beam line meets the requirements, and then the closing section and the adjacent edge segment are welded with the code plate.
[0063] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.
[0064] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam across an operating line, characterized in that: The following steps are involved: Obtain basic engineering data; Establish a steel beam structure calculation model to simulate and analyze the steel beam closing and pushing process; The consistency between the simulation analysis results and the actual monitoring results of the construction site is judged; Monitoring ensures that all bridge components meet the design requirements.
2. According to claim 1, a method for simulating monitoring of closing and pushing of a cantilever state of a large-span continuous beam over an operating line, characterized in that: Basic engineering data include weather, wind, and temperature information during jacking construction, the location and size of construction loads on the bridge, and the stress state of the steel box girder.
3. The method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam over an operating line according to claim 1 is characterized in that: The finite element analysis software MIDAS / Civil is used to carry out modeling and simulation analysis of the steel beam structure.
4. The method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam over an operating line according to claim 1 is characterized in that: The specific contents of the consistency judgment between the simulation analysis results and the actual monitoring results of the construction site are as follows: Based on the results of construction simulation analysis, the coordinate positions of the bridge line control points at each construction stage are determined, and actual monitoring is carried out at the construction site to ensure consistent positions. If the deviation is large, feedback is immediately provided to the construction site operators for adjustment. During the construction process, the bridge line is also comprehensively controlled through the beam drop elevation and bridge deck paving elevation.
5. The method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam over an operating line according to claim 4 is characterized in that: The actual monitoring content at the construction site is to conduct stress monitoring on the most unfavorable points of each working condition on the guide beam, steel box beam and jacking support.
6. The method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam over an operating line according to claim 5 is characterized in that: Vibrating wire concrete strain gauge and vibrating wire readout instrument are used as stress monitoring instruments.
7. The method for simulating and monitoring the closing and pushing of a cantilever state of a large-span continuous beam over an operating line according to claim 1 is characterized in that: The specific contents of monitoring to ensure that each bridge component meets the design requirements are as follows: During the jacking process, the vertical displacement and jacking force of the central controller of the jack are monitored to synchronously control the jacks working at the same time. The vertical displacement is used as the main indicator and the pressure value of each jack is used as a reference. The deviation of the actual linear shape is adjusted by adjusting the height of the temporary support pad. Each time a stroke is pushed forward, the elevation data of the monitoring control point on the steel beam is measured and compared with the target line shape to reduce the internal stress in the process, so that the pushing process is safe and the line shape is consistent with the fitting.