Reverse building method of hyperbolic steel box girder

Abstract

The invention discloses a reverse building method for a hyperbolic steel box girder, which comprises the following steps of: S1, optimizing a model, and reducing the linear height difference of the steel box girder; s2, arranging a plurality of monitoring and measuring points at each stage when the steel box girder is assembled; and S3, the steel box girders are assembled according to the reverse construction sequence. The operation intensity of constructors is reduced, the full penetration welding quality is guaranteed, the production efficiency is improved, and therefore the safe and efficient production requirements are met.

Description

Technical Field

[0001] The invention relates to a bridge construction technology, and more particularly to a reverse construction method of a hyperbolic steel box girder. Background Art

[0002] In the existing road construction of the river crossing project, the steel box beam generally weighs about 2100 tons and has a span of 165m. The horizontal curve of the road design line is a circular curve with R = 600m, and the vertical curve is a circular arc section with a longitudinal slope of 2.7% and a transition from a circular curve of R = 6000m to a longitudinal slope of -2.71%. The beam section adopts a single box four-chamber section, with a 2% one-way transverse slope on the bottom plate and a 2% one-way transverse slope on the top plate. Figure 1 shown.

[0003] The entire bridge of this type of steel box girder is divided into 9 large sections longitudinally, such as Figure 2 As shown; it is divided into 7 small segments horizontally, such as Figure 3 As shown, there are 63 small segments in total, which are shipped in small segments.

[0004] At present, the manufacturing of traditional steel box girders mainly adopts the forward manufacturing scheme, that is, assembling and welding section by section in the order of "bottom plate → middle web plate → middle partition plate → side web plate → side partition plate → side web plate → top plate → cantilever structure". However, due to the serious fatigue problem in the later operation stage of the bridge, a full penetration weld is usually required between the web and the top plate. In the traditional forward manufacturing mode, this weld needs to be completed by overhead welding. Affected by the limited space between the U-ribs of the top plate, it is difficult to ensure the quality of full penetration welding with overhead welding, the weld qualification rate is low, and the workload of rework is large, which has a great impact on the manufacturing progress and cost control of the steel box girder. Therefore, it is very important to choose a reasonable welding posture. Summary of the invention

[0005] In view of the defects existing in the prior art, the purpose of the present invention is to provide a reverse construction method of a hyperbolic steel box girder, which can reduce the working intensity of construction personnel, ensure the quality of full penetration welding, and improve production efficiency, thereby achieving safe and efficient production requirements.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A reverse construction method for a hyperbolic steel box girder comprises the following steps:

[0008] S1, optimize the model to reduce the linear height difference of the steel box girder;

[0009] S2, arrange multiple monitoring and measuring points at each stage of the steel box girder assembly;

[0010] S3, assemble the steel box girder in reverse order.

[0011] Preferably, the step S1 specifically includes:

[0012] The steel box girder is divided into two large sections longitudinally, and then the transverse slope of the top plate of the steel box girder is leveled, and the construction drawing and linear frame model drawing are generated through the model software.

[0013] Preferably, the step S3 specifically includes the following steps:

[0014] S31, arranging the linear tire frame;

[0015] S32, upper tire top plate unit;

[0016] S33, install the diaphragm and web;

[0017] S34, welding base plate;

[0018] S35, install the ring cut and temporary matching parts;

[0019] S36, turning subsegment.

[0020] Preferably, the step S31 specifically includes:

[0021] The linear tire frame is arranged according to the ground sample line and the linear tire frame diagram. The line type is adjusted by the tooth plate elevation. After the linear tire frame is arranged, the linear tooth plate data is measured as a whole.

[0022] Preferably, the step S32 specifically includes:

[0023] Find the four endpoints of the segment according to the reference line, and start from the reference end and locate the top plate units in sequence from near to far;

[0024] After checking that the groove direction, gap and misalignment between the plate units meet the requirements, use card codes to fix the plate units.

[0025] Preferably, the step S33 specifically includes:

[0026] According to the engineering blueprint, the diaphragm and web are positioned, the fillet welds between the diaphragm and the top plate are welded first, then the fillet welds between the web and the diaphragm, and finally the full penetration welds between the web and the top plate.

[0027] Preferably, the step S34 specifically includes:

[0028] Before welding the base plate, check the size of the beam section, the base plate unit size, groove, and components. After confirming that everything is correct, install the base plate.

[0029] Preferably, the step S35 specifically includes:

[0030] After the segment is manufactured, temporary matching parts are installed at the transverse and longitudinal ring openings of the segment. When the steel box girder is assembled at the bridge site, the matching parts are used as a reference.

[0031] Preferably, the step S36 specifically includes:

[0032] After the segment group has passed the pre-assembly comprehensive inspection, the lifting lugs are installed, and the process support is installed according to the finite element analysis results. Then the tire is dismantled and the lifting lug installation and lifting slings must be inspected and qualified before turning over. The single small segment is turned over using the workshop crane.

[0033] The reverse construction method of a hyperbolic steel box girder provided by the present invention breaks the traditional thinking of steel box girder construction, solves the problem of low qualification rate of full penetration welds between the web and the top plate, improves production efficiency, enhances quality stability, and reduces manufacturing cycle. The reasonable design of the linear frame reduces the padding materials, reduces the construction height, ensures the safety of construction personnel, reduces the project safety risk to a relatively safe level, and reduces the cost of safety measures. Thousands of monitoring and measurement points are woven into a dense network to strictly monitor the manufacturing accuracy of each stage of the project and escort the smooth implementation of the project. It has achieved innovation in existing bridge manufacturing technology and provided a mature solution for subsequent projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the model of a hyperbolic steel box girder;

[0035] Figure 2 It is a longitudinal segmental schematic diagram of a hyperbolic steel box girder;

[0036] Figure 3 It is a transverse segmental schematic diagram of a hyperbolic steel box girder;

[0037] Figure 4 It is a schematic diagram of the optimization of the first section model on the steel box girder in the reverse construction method of the present invention;

[0038] Figure 5 It is a schematic diagram of the optimization of the second section model on the steel box girder in the reverse construction method of the present invention;

[0039] Figure 6 It is a cross-sectional schematic diagram of the arrangement of monitoring and measuring points on a steel box girder in the reverse construction method of the present invention;

[0040] Figure 7 It is a cross-sectional schematic diagram of the arrangement of the linear tire frame on the steel box beam in the reverse construction method of the present invention;

[0041] Figure 8 It is a schematic diagram of the top plate unit being placed on the tire in the reverse construction method of the present invention;

[0042] Fig. 9 It is a schematic diagram of the installation of the diaphragm and the web in the reverse construction method of the present invention;

[0043] Fig.10It is a schematic diagram of changing the welding of the web plate and the top plate in the reverse construction method of the present invention to flat welding;

[0044] Fig.11 It is a schematic diagram of bottom plate welding in the reverse construction method of the present invention;

[0045] Fig.12 It is a schematic diagram of the arrangement of temporary matching parts in the reverse construction method of the present invention;

[0046] Fig.13 It is a schematic diagram of turning over a small segment in the reverse construction method of the present invention. DETAILED DESCRIPTION

[0047] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0048] The invention provides a reverse construction method of a hyperbolic steel box girder, comprising the following steps:

[0049] S1, optimize the model to reduce the linear height difference of the steel box girder

[0050] The top plate of the steel box girder generally has a 2% transverse slope. After the model is inverted, the linear height difference of the top plate reaches 600mm, and the corresponding linear frame height will exceed 2 meters. In order to reduce the construction height and ensure the safety of construction workers, the entire bridge is divided into two large sections: GL1~GL5 and GL6~G9. At the same time, the 2% transverse slope on the top plate is flattened. The construction drawing and linear frame drawing are generated through the model software, such as Figure 4 and Figure 5 As shown in the figure, the linear height difference of the optimized steel box girder is only 167mm, which effectively improves the safety of project implementation. At the same time, it reduces the padding materials and reduces the project cost.

[0051] S2, arrange multiple monitoring measurement points at each stage of steel box girder assembly

[0052] In order to ensure the manufacturing accuracy of the project, thousands of monitoring and measuring points are arranged in all directions at multiple stages of the steel box girder assembly. Monitoring is carried out from the stages of linear frame layout, laying of tire bottom plate, and covering of top plate to ensure the smooth erection of the subsequent bridge. Each monitoring and measuring point can extract data from the model to quickly and easily understand the project manufacturing situation. Figure 6As shown, D1 / D7 is the measurement point of the contact position between the center of the linear tooth plate and the end of the top plate; D2 / D6 is the measurement point of the intersection position between the inner side of the outer web plates on both sides and the top plate; D3 / D5 is the measurement point of the intersection position between the center of the inner web plates on both sides and the top plate; D4 is the measurement point of the intersection position between the center of the middle web plate and the top plate. The above measurement points are used for measurement after the top plate unit is installed. D8 / D12 is the measurement point of the intersection position between the inner side of the outer web plates on both sides and the bottom plate; D9 / D11 is the measurement point of the intersection position between the center of the inner web plates on both sides and the bottom plate; D10 is the measurement point of the intersection position between the center of the middle web plate and the bottom plate. The above measurement points are used for measurement after the bottom plate is covered.

[0053] S3, assemble the steel box girder in reverse order

[0054] The overall assembly of the steel box girder adopts a scheme in which all the segments of GL1~GL5, GL6~GL9 are pre-assembled in a continuous matching manner and completed on the overall assembly frame at the same time. The top plate is used as the bottom plate, the ground sample line is drawn, and the linear frame is arranged. According to the reverse order of "top plate→middle web→middle partition→side web→side partition→side web→bottom plate", three-dimensional step-by-step advancement is achieved, and assembly and welding are carried out section by section. During assembly, the focus is on controlling the linear shape of the bridge, the geometric shape and dimensional accuracy of the steel box girder, and the precise matching of adjacent interfaces to ensure smooth matching of the overall linear shape and ports. Specifically, the following steps are included:

[0055] S31, layout of linear tire frame

[0056] The linear tire frame is arranged according to the ground sample line and the linear tire frame diagram. The linearity is adjusted by the tooth plate elevation. Each set of tire frames has a total of 23 tooth plates, of which 7 linear tooth plates are set, and the rest are auxiliary reinforcement tooth plates, such as Figure 7 After the linear tire frame is arranged, the linear tooth plate data is measured as a whole.

[0057] S32, upper tire plate unit

[0058] Find the four endpoints of the segment according to the reference line. Starting from the reference end, locate the top plate units in order from near to far. After checking that the groove direction, gap, and misalignment between the plate units meet the requirements, use the card code to fix the plate unit. The card code is required to be installed in 2000mm increments. Figure 8 To ensure that the diaphragm, web and top plate are in close contact, the linear elevation of the top plate at the web and diaphragm positions should be measured and adjusted.

[0059] S33, install the diaphragm and the web

[0060] Combined with the construction blueprint, and using the diaphragm on the top plate to locate the center line, position and weld the middle diaphragm in turn, strictly ensuring the verticality of the diaphragm and the top plate and the spacing between the diaphragms. The diaphragms in the segment are different and cannot be used interchangeably. Assemble the diaphragms to the corresponding positions according to the drawings. At the same time, check the direction of the diaphragm butt groove to ensure the same direction. Position and weld the middle web of the middle diaphragm of the beam section, and strictly ensure the angle between the middle web and the top plate is about 88.85°. The angle between the side web and the top plate is about 75.85°. Assemble and weld in the order of "middle diaphragm → middle web → side diaphragm → side web", such as Fig. 9 After the diaphragm and web are positioned according to the drawing, the fillet welds between the diaphragm and the top plate are welded first, then the fillet welds between the web and the diaphragm, and finally the full penetration welds between the web and the top plate. The welding between the web and the top plate is changed from overhead welding to flat welding, such as Fig.10 As shown. Choose the best welding posture to avoid the influence of narrow space on welding quality. The pass rate of full penetration welds is greatly improved, the weld repair work is reduced, the assembly production efficiency is effectively improved, and the quality stability is improved.

[0061] S34, welding base plate

[0062] Before welding the bottom plate, check the beam section size, bottom plate unit size, groove, and components. After confirming that everything is correct, install the bottom plate. Fig.11 As shown. Position the bottom plate unit according to the longitudinal and transverse reference lines, and pay attention to the overlap of the groove inspection line of the top plate reference end and the groove inspection line of the bottom plate reference end to ensure that the overall ring of the beam section is flush. After the bottom plate unit is installed, check the groove direction, gap, and misalignment between the plate units. If they meet the requirements, use the card code to fix the plate unit. The card code is required to be installed in 2000mm increments. First weld the weld between the bottom plate and the partition, and then weld the weld between the bottom plate and the web.

[0063] S35, installation of ring cuts and temporary matching parts

[0064] After the large segment is assembled and the linear data meets the requirements, trim the assembly margin. After trimming the margin, open the grooves of the ring openings (top plate, bottom plate, web plate) according to the drawings. After the segment is manufactured, the longitudinal base line sample of the top plate unit is punched and led to the back of the top plate (non-U rib side). After the segment is manufactured in the factory, temporary matching parts are installed at the transverse and longitudinal ring openings of the segment, such as Fig.12 When assembling the steel box girder at the bridge site, the matching parts are used as the reference to ensure the installation accuracy.

[0065] S36, turning over subsegment

[0066] After the segment group has passed the pre-assembly comprehensive inspection, the lifting lugs are installed, and the process support is installed according to the finite element analysis results, and then the tire is dismantled. Before turning over, the installation of the lifting lugs and the slings must be inspected and qualified to ensure that all components are welded and installed reliably. A single small segment is turned over using a workshop crane, such as Fig.13 As shown. The panel interferes with the wire rope, so the corner wrapping needs to be done in advance. To prevent the panel from deforming during the turning process, a turning reinforcement plate needs to be installed above the panel at the corresponding lifting lug position, and the reinforcement plate will be cut off after the turning operation is completed. After the turning of the small segment is completed, it will be transported to the sandblasting and painting workshop for painting and preparation for project shipment.

[0067] In summary, the reverse construction method of the present invention analyzes the feasibility of reverse construction of steel box girders by studying the characteristics and shipping forms of steel box girder projects. Considering that the weight of a single small segment is within 65 tons, the lifting capacity of the workshop crane meets the requirements for turning over the small segment. The small segments can be turned over one by one after pre-assembly in the workshop, which creates the necessary conditions for reverse construction of steel box girders. In addition, when the steel box girder is reversed, the top plate is used as the tire frame surface, and it is arranged according to the linear tire frame of the intelligent drawing, which can better control the linear shape of the bridge deck, thereby meeting the manufacturing accuracy of the hyperbolic bridge. With the goal of high quality, safety and high efficiency, a reasonable manufacturing plan is studied and formulated, and effective and effective construction measures are taken to promote the smooth progress of the steel box girder project. This construction technology has high overall efficiency, and the welding of the narrow space between the web and the top plate is changed from overhead welding to flat welding, which improves the welding posture, reduces the working intensity of the construction personnel, ensures the quality of full penetration welding, and improves production efficiency, thereby achieving safe and efficient production requirements.

[0068] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A reverse construction method for a hyperbolic steel box girder, characterized in that: The following steps are involved: S1, optimize the model to reduce the linear height difference of the steel box girder; S2, arrange multiple monitoring and measuring points at each stage of the steel box girder assembly; S3, assemble the steel box girder in reverse order.

2. The reverse construction method of a hyperbolic steel box girder according to claim 1, characterized in that: The step S1 specifically includes: The steel box girder is divided into two large sections longitudinally, and then the transverse slope of the top plate of the steel box girder is leveled, and the construction drawing and linear frame model drawing are generated through the model software.

3. The reverse construction method of a hyperbolic steel box girder according to claim 2, characterized in that: The step S3 specifically comprises the following steps: S31, arranging the linear tire frame; S32, upper tire top plate unit; S33, install the diaphragm and web; S34, welding base plate; S35, install the ring cut and temporary matching parts; S36, turning subsegment.

4. The reverse construction method of a hyperbolic steel box girder according to claim 3, characterized in that: The step S31 specifically includes: The linear tire frame is arranged according to the ground sample line and the linear tire frame diagram. The line type is adjusted by the tooth plate elevation. After the linear tire frame is arranged, the linear tooth plate data is measured as a whole.

5. The reverse construction method of a hyperbolic steel box girder according to claim 3, characterized in that: The step S32 specifically includes: Find the four endpoints of the segment according to the reference line, and start from the reference end and locate the top plate units in sequence from near to far; After checking that the groove direction, gap and misalignment between the plate units meet the requirements, use card codes to fix the plate units.

6. The reverse construction method of a hyperbolic steel box girder according to claim 3, characterized in that: The step S33 specifically includes: According to the engineering blueprint, the diaphragm and web are positioned, the fillet welds between the diaphragm and the top plate are welded first, then the fillet welds between the web and the diaphragm, and finally the full penetration welds between the web and the top plate.

7. The reverse construction method of a hyperbolic steel box girder according to claim 3, characterized in that: The step S34 specifically includes: Before welding the base plate, check the size of the beam section, the base plate unit size, groove, and components. After confirming that everything is correct, install the base plate.

8. The reverse construction method of a hyperbolic steel box girder according to claim 3, characterized in that: The step S35 specifically includes: After the segment is manufactured, temporary matching parts are installed at the transverse and longitudinal ring openings of the segment. When the steel box girder is assembled at the bridge site, the matching parts are used as a reference.

9. The reverse construction method of a hyperbolic steel box girder according to claim 3, characterized in that: The step S36 specifically includes: After the segment group has passed the pre-assembly comprehensive inspection, the lifting lugs are installed, and the process support is installed according to the finite element analysis results. Then the tire is dismantled and the lifting lug installation and lifting slings must be inspected and qualified before turning over. The single small segment is turned over using the workshop crane.

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