Pushing support structure spanning high-speed large-span steel box girder and construction method

Abstract

The invention discloses a pushing support structure spanning a high-speed large-span steel box girder and a construction method, and relates to the technical field of steel box girder construction. Comprising an assembling support and a pushing support, and the assembling support and the pushing support are arranged at the bottom of a steel box girder; the assembling support comprises a concrete independent foundation, a temporary support is installed on the concrete independent foundation, and a profile steel distribution beam is installed on the top of the temporary support. The pushing support comprises a concrete enlarged foundation, multiple sets of stand columns are installed on the concrete enlarged foundation, and transverse distribution beams are installed at the tops of the stand columns. A longitudinal pushing platform is mounted at the top of the transverse distribution beam, and a walking type pushing piece is fixedly mounted on the longitudinal pushing platform; a plurality of groups of steel box girders are arranged, and at least six steel box girders are spliced in each group; the steel box girders are distributed in an arc shape; a guide beam is installed in the advancing direction of the steel box beam. According to the steel box girder pushing support structure system, highway passing is not affected, and the steel box girder pushing support structure system is economical, firm and stable.

Description

Technical Field

[0001] The invention relates to the technical field of steel box girder construction, and in particular to a jacking support structure and a construction method for a high-speed large-span steel box girder. Background Art

[0002] Before the jacking construction of large-span steel box girders across highways, assembly supports and jacking supports need to be erected. The erection of the supports must not cause traffic interruption on the highway. The steel box girders are heavy, and during construction, the supports must be stable, meet safety requirements, and save support materials. Therefore, the construction site needs to adopt a steel box girder jacking support structure system that does not affect highway traffic and is economical, reliable, and stable.

[0003] To this end, we provide a jacking support structure and construction method for high-speed large-span steel box girders to solve the above problems. Summary of the invention

[0004] In view of the problems existing in the jacking construction of a large-span steel box girder across a highway, the present invention provides a jacking support structure and a construction method for a large-span steel box girder across a highway.

[0005] The steel box girder jacking support system installs assembly supports and jacking supports on the starting side of the steel box girder, installs jacking supports at the terminal section, installs support supports at the green belt location of the highway, and installs jacking machines on the jacking supports. The steel box girder segment is jacked from one side of the highway to the other side across the highway to the designed position using "walking jacking and sliding", ensuring safe passage of the highway during the construction of the steel box girder.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A jacking support structure for a high-speed large-span steel box girder, comprising an assembled support and a jacking support, wherein the assembled support and the jacking support are arranged at the bottom of the steel box girder, the assembled support is used to support the steel box girder, and the jacking support is used to push the steel box girder;

[0008] The assembled bracket includes a concrete independent foundation, a temporary support is installed on the concrete independent foundation, and a steel distribution beam is installed on the top of the temporary support;

[0009] The jacking support comprises a concrete enlarged foundation, on which columns are installed, and the columns are provided in multiple groups, and a transverse distribution beam is installed on the top of the columns; a longitudinal jacking platform is installed on the top of the transverse distribution beam, and a walking jacking member is fixedly installed on the longitudinal jacking platform, and the walking jacking member is suitable for pushing the steel box beam;

[0010] The steel box girders are arranged in multiple groups, and each group consists of at least 6 connected ones; the steel box girders are distributed in an arc shape; and guide beams are installed in the forward direction of the steel box girders.

[0011] A construction method for a jacking support structure of a high-speed large-span steel box girder, the construction process is as follows:

[0012] Step S1, stent design;

[0013] Step S2, support foundation construction;

[0014] Step S3, bracket installation;

[0015] Step S4, assembling the steel box girder in sections;

[0016] Step S5, guide beam installation;

[0017] Step S6, installing the pushing device;

[0018] Step S7, pushing the steel box girder;

[0019] Step S8, pushing the beam into place;

[0020] Step S9: remove the bracket.

[0021] In a further technical solution, in step S1, the support design includes overall support design, assembly support structure design, assembly support foundation preparation process, push support structure design and push support foundation preparation process;

[0022] The bracket includes a push bracket and a splicing bracket;

[0023] Step S11: Overall design of the bracket

[0024] At the starting position of the steel box girder push-up, assembly brackets and push-up brackets are set up in sections. The length of the steel box girder at the starting end meets the counterweight requirements for the steel box girder over the highway.

[0025] Install jacking brackets at the terminal section and support brackets at the green belts on both sides of the expressway to temporarily support the guide beam; install a jacking machine on the jacking brackets to push the steel box beam segment from one side of the expressway to the other side across the expressway to the designed position;

[0026] Step S12: Assembling bracket structure design

[0027] When assembling the steel box girder on site, install temporary supports and arrange them on both sides of the butt joint of the steel box girder;

[0028] Temporary supports include circular tube lattice columns, steel distribution beams and concrete independent foundations; multiple groups of circular tube lattice columns are arranged and connected by welding;

[0029] Circular tube lattice columns are set at the interface of the steel box girder segments, and the steel box girder segments include interval K-interval R, with multiple groups of butt joints; 6 groups of circular tube lattice columns are set at the interface, and the distance between the circular tube lattice columns is 5m;

[0030] Step S13, assembly support foundation preparation process: temporary supports are all located on the existing ground. According to the temporary support foundation calculation book, the foundation bearing capacity of the pre-designed temporary support should not be less than 210Kpa;

[0031] After the foundation treatment is completed, cast the concrete independent foundation; the concrete strength grade is C30, the concrete independent foundation is 3000mm×3000mm, and the height is 500mm; a double-layer bidirectional steel mesh with a diameter of 10mm and a spacing of 150mm is set inside the concrete foundation; embedded parts are set on the top of the concrete foundation, and the circular tube lattice column is welded and fixed to the embedded parts, and the welding angle K is ≥12mm;

[0032] Step S14: Design of the push support structure

[0033] According to the requirements of the overall installation and construction plan, the main axis of the bridge is laid out using a total station on the leveled construction and assembly site; then, the control lines of each independent pier foundation and the bridge are laid out;

[0034] According to the pre-camber provided in the drawings and the installation pre-camber set to meet the alignment of the completed bridge, the two pre-cambers are superimposed to measure and control the temporary pier elevation;

[0035] Combined with the construction conditions of this project, the plane curve of the steel box girder is a circular curve and a transition curve. It is planned to push in the direction of the bridge plane curve. The ratio of the inner and outer arc push lengths is 100:112. Push in the tangent direction of the arc, and make a lateral correction every three steps. When assembling the steel box girder, it is carried out in the direction of the extension line of the line connecting the starting points of the outer web at the designed position, and the push direction is also in the direction of the extension line of the line connecting the starting points of the outer web.

[0036] Each set of jacking supports uses at least 4 Ф610*10mm steel pipes as columns, and is arranged in a longitudinal direction of 3m and a transverse direction of 2.5m;

[0037] The size of the concrete expanded foundation is 4m×6m×1m. A transverse distribution beam is installed on the top of the column. The transverse distribution beam is composed of four groups of 40a I-beams and is 4m long. The longitudinal jacking platform is located above the transverse distribution beam. The longitudinal jacking platform is composed of four groups of 588*300mm I-beams. The platform is 4m long. The walking jacking parts are installed on the longitudinal jacking platform.

[0038] Along the bridge, handover conversion columns and beams are arranged before and after the jacking equipment. The conversion columns are made of Ф273*7mm, and the beams are made of double-jointed 40a I-beams with a length of 4m.

[0039] Step S15, the preparation process of the jacking support foundation: the concrete enlarged foundation adopts C30 concrete, the foundation plane size is 4.5×4m, and the thickness is 1m; a double-layer steel mesh is arranged in the concrete enlarged foundation, the layout standard is D18@160, and 4 embedded plates are arranged thereon, the embedded plates correspond to the positions of the steel pipes, and the embedded plates have a size of 830×830×20mm;

[0040] After the original foundation of the soft pavement is leveled and rolled, a light dynamic probe is used for testing. When the foundation bearing capacity is greater than 200KPa, concrete hardening is directly used;

[0041] When the foundation bearing capacity is less than 200KPa, crushed stone replacement and compaction are used with a replacement size of 5×5.5m until the foundation bearing capacity is greater than 200KPa. After meeting the bearing capacity requirements, concrete hardening is carried out.

[0042] In a further technical solution, in step S2, the construction steps are:

[0043] a) Dig out the soft ground at the bottom of the foundation and backfill it with gravel;

[0044] b) A foundation bearing capacity test must be conducted before foundation construction, and the foundation bearing capacity must meet the calculation requirements;

[0045] c) The foundation measurement and layout position must be accurate, and the position of the foundation embedded parts must be accurate;

[0046] d) Strengthen the vibration of foundation concrete, and subsequently cover and water the concrete for maintenance to ensure the strength of the foundation concrete.

[0047] In a further technical solution, in step S3, the support component is hoisted by a car crane. During hoisting, the columns are installed first, and then the inter-column supports are installed between multiple groups of columns. The inter-column supports and the columns are fixed by welding. After the installation is completed, the support component needs to be reviewed. After it is accurate, the column base and the foundation embedded parts are fixed by high-strength bolts.

[0048] In a further technical solution, in step S4, the following construction steps are included:

[0049] 1) Hoisting method

[0050] After the steel box girders are transported to the bridge site, they are lifted by a 350-ton crawler crane and placed on the permanent piers and temporary piers. Before the lifting, the placement of the crane is fully considered. During the lifting process, it is directed by a dedicated person and checked simultaneously with measuring instruments.

[0051] 2) Linear control

[0052] The linear control of the steel box girder should first be carried out in the factory; before lifting, control points and lines are set on the permanent piers and temporary piers, and control points and lines are set accordingly on the steel box girder; when the steel box girder is installed, the center line and longitudinal distance are controlled by the control points and lines pre-set on the piers, corresponding to the points and lines set on the steel box girder; at the same time, the measuring instruments are used for synchronous monitoring, and the elevation of the steel box girder is adjusted and controlled by two jacks installed on the piers. After the center line, longitudinal distance and beam elevation are adjusted, welding is carried out at the joints of each box section to ensure the smooth linear shape of the steel box girder.

[0053] In a further technical solution, in step S5, the following construction steps are included:

[0054] The guide beam is divided into N sections and transported to the site in loose parts for splicing and hoisting; it is partially reinforced with the steel box beam and welded into a whole.

[0055] In a further technical solution, step S6, installation of the push device

[0056] When the steel box girder is pushed by walking method, a total of 8 sets of pushing brackets are required, and 1 set of walking jacks is set on each bracket, for a total of 28 sets;

[0057] The steel box girder jacking adopts a walking type continuous jacking method. The steel box girder walking type jacking device is installed on the jacking bracket distribution beam. A group of crossbeams are arranged above the two groups of walking jacks to support the steel beam, and the bottom of the crossbeam is fixed to the jack.

[0058] In a further technical solution, in step S7, the steel box girder is pushed forward:

[0059] 1) First stage of pushing: the guide beam is pushed to the central dividing strip, and the steel box beam does not cross the expressway;

[0060] 2) Second stage of jacking: the guide beam jacks up the opposite main pier;

[0061] 3) The third stage of jacking: the opposite main pier on the steel box girder;

[0062] 4) Fourth stage jacking: opposite rear pier on the guide beam;

[0063] 5) Fifth stage: Pushing the steel box girder into place;

[0064] 6) The whole bridge is completed by lowering the beams: after lowering the beams, the last remaining segments are hoisted.

[0065] In a further technical solution, in step S8, beam dropping: all steel box beam segments are pushed into place, the guide beam is removed, and the overall line shape of the box beam is adjusted to the target line shape by a three-dimensional jack before the beam dropping work can be carried out;

[0066] Use the lower support cylinder of the walking type jacking equipment to carry out the beam dropping construction;

[0067] In step S9, the bracket is removed:

[0068] a) First, dismantle the I-beam, break the weld between the I-beam and the steel column, and use a winch to lift the I-beam and then lower it;

[0069] b) Each row of temporary support steel columns is laid down three times. After removing the anchor bolts at the column base, one winch is used to lift it from a high place, and another winch is used to lift the column base, and the two winches are used to pull the support down in opposite directions;

[0070] c) The laid-down support is hoisted onto a transfer flatbed truck using a 25T crane and then transported to the stacking site.

[0071] Compared with the prior art, the jacking support structure and construction method for a high-speed large-span steel box girder have the following beneficial effects:

[0072] The jacking support structure and construction method for the large-span steel box girder across the highway of the present invention solve the problem of the impact of the closure of the highway and interruption of traffic when installing the steel box girder across the highway, as well as the problem of long suspension of the steel box girder and the steel guide beam to safe passage, effectively ensures the passage of the highway under the bridge, and can complete the installation of the large-span steel box girder across the highway in a economical, fast and efficient manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a construction process flow chart of the present invention;

[0074] Figure 2 is a plan view of the bracket layout of the present invention;

[0075] Figure 3 It is a bracket elevation layout diagram of the present invention;

[0076] Figure 4 is a schematic diagram of an assembled bracket of the present invention;

[0077] Figure 5 is a schematic diagram of the jacking support of the present invention;

[0078] Figure 6 is a side view of the jacking support of the present invention;

[0079] Figure 7 It is a schematic diagram of a concrete enlarged foundation of the present invention;

[0080] Figure 8 is a cross-sectional schematic diagram of a concrete enlarged foundation of the present invention;

[0081] Fig. 9 is a schematic diagram of the central dividing strip of the present invention;

[0082] In the figure: 1. Assembling bracket; 2. Pushing bracket; 4. Steel box girder; 5. Guide beam; 11. Concrete independent foundation; 12. Steel distribution beam; 13. Circular tube lattice column; 21. Concrete enlarged foundation; 22. Column; 23. Horizontal distribution beam; 24. Longitudinal pushing platform; 25. Concrete hardening; 26. Gravel replacement; 27. Inter-column support; 28. Double-layer steel mesh; 29. ​​Embedded plate. DETAILED DESCRIPTION

[0083] 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.

[0084] Example 1

[0085] A jacking support structure for a high-speed large-span steel box girder, comprising an assembly support 1 and a jacking support 2, wherein the assembly support 1 and the jacking support 2 are arranged at the bottom of a steel box girder 4, the assembly support 1 is used to support the steel box girder 4, and the jacking support 2 is used to push the steel box girder 4;

[0086] The assembled bracket 1 comprises a concrete independent foundation 11, a temporary support is installed on the concrete independent foundation 11, and a steel distribution beam 12 is installed on the top of the temporary support;

[0087] The jacking support 2 includes a concrete enlarged foundation 21, on which columns 22 are installed, and the columns 22 are provided with multiple groups, and a transverse distribution beam 23 is installed on the top of the columns 22; a longitudinal jacking platform 24 is installed on the top of the transverse distribution beam 23, and a walking jacking member is fixedly installed on the longitudinal jacking platform 24, and the walking jacking member is suitable for pushing the steel box beam 4;

[0088] There are multiple groups of steel box girders 4, and each group consists of at least 6 connected ones; the steel box girders 4 are distributed in an arc shape; and guide beams 5 are installed in the forward direction of the steel box girders 4.

[0089] A construction method for a jacking support structure of a high-speed large-span steel box girder, the construction process is as follows:

[0090] Step S1, stent design;

[0091] Step S2, support foundation construction;

[0092] Step S3, bracket installation;

[0093] Step S4, assembling the steel box girder into 4 sections;

[0094] Step S5, guide beam 5 installation;

[0095] Step S6, installing the pushing device;

[0096] Step S7, pushing the steel box girder 4;

[0097] Step S8, pushing the beam into place;

[0098] Step S9: remove the bracket.

[0099] In a further technical solution, in step S1, the bracket design includes the overall bracket design, the structure design of the assembled bracket 1, the basic preparation process of the assembled bracket 1, the structure design of the jacking bracket 2 and the basic preparation process of the jacking bracket 2;

[0100] The support includes a push support 2 and a splicing support;

[0101] Step S11: Overall design of the bracket

[0102] At the starting position of the steel box girder 4, an assembly bracket 1 and a pushing bracket 2 are arranged in sections, and the length of the steel box girder 4 at the starting end meets the counterweight requirement of the steel box girder 4 over the highway;

[0103] A pushing bracket 2 is installed at the terminal section, and a supporting bracket is installed at the green belt position on both sides of the expressway for temporary support of the guide beam 5; a pushing machine is installed on the pushing bracket 2 to push the 4 sections of the steel box beam from one side of the expressway to the other side to cross the expressway to the designed position; the core design method is to use "walking jacking and sliding" to push the 4 sections of the steel box beam from one side of the expressway to the other side to cross the expressway to the designed position.

[0104] Step S12: Structural design of the assembled bracket 1

[0105] When the steel box girder 4 is assembled on site, temporary supports are installed and arranged on both sides of the butt joint of the steel box girder 4;

[0106] The temporary support includes a circular tube lattice column 13, a steel distribution beam 12 and a concrete independent foundation 11; the circular tube lattice column 13 is provided in multiple groups and is connected by welding;

[0107] The steel box girder 4 sections are provided with round tube lattice columns 13 at the butt joints, and the steel box girder 4 sections include interval K-interval R, with multiple groups of butt joints; 6 groups of round tube lattice columns 13 are provided at the butt joints, and the intervals between the round tube lattice columns 13 are all 5m;

[0108] Step S13, assembling support 1 foundation preparation process: temporary supports are all located on the existing ground. According to the temporary support foundation calculation book, the foundation bearing capacity of the temporary support is pre-designed to be no less than 210Kpa;

[0109] After the foundation treatment is completed, cast the concrete independent foundation 11; the concrete strength grade is C30, the concrete independent foundation 11 is 3000mm×3000mm, and the height is 500mm; a double-layer bidirectional steel mesh with a diameter of 10mm and a spacing of 150mm is set inside the concrete foundation; embedded parts are set on the top of the concrete foundation, and the circular tube lattice column 13 is welded and fixed to the embedded parts, and the welding angle K≥12mm; for the existing pavement area, the foundation can be prefabricated at other locations and then hoisted into place by machinery. To ensure the safety of the support, the thickness of the temporary support across the road section should not be less than 500mm.

[0110] Step S14: Structural design of the push support 2

[0111] According to the requirements of the overall installation and construction plan, the main axis of the bridge is laid out using a total station on the leveled construction and assembly site; then, the control lines of each independent pier foundation and the bridge are laid out;

[0112] According to the pre-camber provided in the drawings and the installation pre-camber set to meet the alignment of the completed bridge, the two pre-cambers are superimposed to measure and control the temporary pier elevation;

[0113] Combined with the construction conditions of this project, the plane curve of steel box girder 4 is a circular curve and a transition curve. It is planned to be pushed in the direction of the bridge plane curve. The ratio of the inner and outer arc push lengths is 100:112. Push along the tangent direction of the arc, and make a lateral correction every three steps. When assembling steel box girder 4, it is carried out in the direction of the extension line of the line connecting the starting points of the outer web at the designed position, and the push direction is also in the direction of the extension line of the line connecting the starting points of the outer web.

[0114] Each group of jacking brackets 2 uses at least 4 Ø610*10mm steel pipes as columns 22, and is arranged in a longitudinal direction of 3m×lateral direction of 2.5m;

[0115] The size of the concrete enlarged foundation 21 is 4m×6m×1m. A transverse distribution beam 23 is installed on the top of the column 22. The transverse distribution beam 23 is composed of four groups of 40a I-beams and has a length of 4m. Above the transverse distribution beam 23 is a longitudinal jacking platform 24. The longitudinal jacking platform 24 is composed of four groups of 588*300mm I-beams. The platform is 4m long. The walking jacking member is installed on the longitudinal jacking platform 24.

[0116] Along the bridge, handover conversion columns and beams are arranged before and after the jacking equipment. The conversion columns are made of Ф273*7mm, and the beams are made of double-jointed 40a I-beams with a length of 4m.

[0117] Step S15, foundation preparation process of the jacking bracket 2: the concrete enlarged foundation 21 adopts C30 concrete, the foundation plane size is 4.5×4m, and the thickness is 1m; a double-layer steel mesh 28 is arranged in the concrete enlarged foundation 21, and the layout standard is D18@160, and 4 embedded plates 29 are arranged thereon, the embedded plates 29 correspond to the positions of the steel pipes, and the dimensions of the embedded plates 29 are 830×830×20mm;

[0118] After the original foundation of the soft pavement is leveled and rolled, a light dynamic probe is used for testing. When the foundation bearing capacity is greater than 200KPa, concrete hardening is directly used for 25;

[0119] When the foundation bearing capacity is less than 200 KPa, crushed stone replacement 26 is used for compaction, with a replacement size of 5×5.5 m, until the foundation bearing capacity is greater than 200 KPa. After meeting the bearing capacity requirements, concrete hardening 25 is carried out.

[0120] In a further technical solution, in step S2, the construction steps are:

[0121] a. Dig out the soft ground at the bottom of the foundation and backfill it with gravel;

[0122] b. A foundation bearing capacity test must be conducted before foundation construction, and the foundation bearing capacity must meet the calculation requirements;

[0123] c) The foundation measurement and layout position must be accurate, and the position of the foundation embedded parts must be accurate;

[0124] d) Strengthen the vibration of foundation concrete, and subsequently cover and water the concrete for maintenance to ensure the strength of the foundation concrete.

[0125] In a further technical solution, in step S3, the support component is hoisted by a car crane. During hoisting, the columns 22 are installed first, and then the inter-column supports 27 are installed between multiple groups of columns 22. The inter-column supports 27 and the columns 22 are fixed by welding. After the installation is completed, the support component needs to be reviewed. After it is accurate, the column base and the foundation embedded parts are fixed by high-strength bolts.

[0126] In a further technical solution, in step S4, the following construction steps are included:

[0127] 1. Hoisting method

[0128] After the segmented steel box girder 4 is transported to the bridge site, it is lifted by a 350-ton crawler crane and placed on the permanent support points and temporary piers of the bridge pier. Before lifting, the placement of the crane is fully considered. During the lifting process, it is directed by a dedicated person and checked simultaneously with measuring instruments.

[0129] 2-wire control

[0130] The linear control of the steel box girder 4 should first be carried out in the factory; before lifting, control points and lines are set on the permanent piers and temporary piers, and control points and lines are set accordingly on the steel box girder 4; when the steel box girder 4 is installed, the center line and longitudinal distance are controlled by the control points and lines pre-set on the piers, corresponding to the points and lines set on the steel box girder 4; at the same time, the measuring instruments are used for synchronous monitoring, and the elevation of the steel box girder 4 is adjusted and controlled by two jacks installed on the piers. After the center line, longitudinal distance and the elevation of the beam are adjusted, welding is carried out at the joints of each section of the box body to ensure the smoothness of the linear shape of the steel box girder 4.

[0131] In a further technical solution, in step S5, the following construction steps are included:

[0132] The guide beam 5 is divided into N segments, which are transported to the site in loose parts for splicing and hoisting; and are partially reinforced with the steel box beam 4 and welded into a whole.

[0133] In a further technical solution, step S6, installation of the push device

[0134] When the steel box girder 4 is pushed by walking method, a total of 8 sets of pushing brackets 2 are required, and 1 set of walking jacks is set on each bracket, for a total of 28 sets;

[0135] The steel box girder 4 is pushed by a walking continuous pushing method. A walking pushing device for the steel box girder 4 is installed on the distribution beam of the pushing bracket 2. A group of crossbeams supporting the steel beam 28 is arranged above the two groups of walking pushes, and the bottom of the crossbeam is fixed with a jack.

[0136] In a further technical solution, in step S7, the steel box girder 4 is pushed forward:

[0137] 1 The first stage of pushing: the guide beam 5 is pushed to the position of the central dividing strip 6, and the steel box beam 4 does not cross the expressway;

[0138] 2 The second stage of pushing: the guide beam 5 pushes the opposite main pier;

[0139] 3 The third stage of jacking: steel box girder 4 on the opposite main pier;

[0140] 4 Fourth stage jacking: guide beam 5 goes up to the opposite rear pier;

[0141] 5 Fifth stage jacking: steel box girder 4 is jacked into place;

[0142] 6 The whole bridge is completed by lowering the beams: after lowering the beams, the last remaining segments are hoisted.

[0143] In a further technical solution, in step S8, the beam is dropped: the 4 segments of the steel box beam are all pushed into place, the guide beam 5 is removed, and the line shape of the box beam is adjusted to the target line shape as a whole by a three-dimensional jack before the beam drop work can be carried out;

[0144] Use the lower support cylinder of the walking type jacking equipment to carry out the beam dropping construction;

[0145] In step S9, the bracket is removed:

[0146] a First, dismantle the I-beam, break the weld between the I-beam and the steel column, and use a winch to lift the I-beam and then lower it;

[0147] b. Each row of temporary support steel columns is laid down three times. After removing the anchor bolts of the column feet, one winch is used to lift them from a high place, and another winch is used to lift the column feet, and the two winches are used to pull down the support in opposite directions;

[0148] c The laid-down bracket is hoisted onto the transfer flatbed truck using a 25T crane and then transported to the stacking site.

[0149] The jacking support structure and construction method for a large-span steel box girder across a highway solve the problem of the need to close the highway to interrupt traffic when installing the steel box girder across the highway, as well as the problem of long suspended steel box girders and steel guide beams affecting safe passage, effectively ensuring the passage of the highway under the bridge, and can complete the installation of the large-span steel box girder across the highway in an economical, fast and efficient manner.

[0150] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A jacking support structure for a high-speed large-span steel box girder, characterized in that: It comprises an assembling bracket (1) and a pushing bracket (2), wherein the assembling bracket (1) and the pushing bracket (2) are arranged at the bottom of a steel box girder (4), the assembling bracket (1) is used to support the steel box girder (4), and the pushing bracket (2) is used to push the steel box girder (4); The assembly support (1) comprises a concrete independent foundation (11), a temporary support is installed on the concrete independent foundation (11), and a steel distribution beam (12) is installed on the top of the temporary support; The jacking support (2) comprises a concrete enlarged foundation (21), on which columns (22) are installed, and the columns (22) are provided in multiple groups, and a transverse distribution beam (23) is installed on the top of the columns (22); a longitudinal jacking platform (24) is installed on the top of the transverse distribution beam (23), and a walking jacking member is fixedly installed on the longitudinal jacking platform (24), and the walking jacking member is suitable for pushing the steel box beam (4); The steel box girders (4) are provided in a plurality of groups, and each group is composed of at least 6 connected ones; the steel box girders (4) are distributed in an arc shape; and a guide beam (5) is installed in the forward direction of the steel box girders (4).

2. A construction method for a jacking support structure for a high-speed large-span steel box girder, characterized in that: The construction process is: Step S1, stent design; Step S2, support foundation construction; Step S3, bracket installation; Step S4, assembling the steel box girder (4) in sections; Step S5, installing the guide beam (5); Step S6, installing the pushing device; Step S7, pushing the steel box girder (4); Step S8, pushing the beam into place; Step S9: remove the bracket.

3. The construction method of a jacking support structure for a high-speed large-span steel box girder according to claim 2 is characterized in that: In step S1, the support design includes the overall support design, the structure design of the assembled support (1), the basic preparation process of the assembled support (1), the structure design of the jacking support (2), and the basic preparation process of the jacking support (2); The support comprises a push support (2) and a splicing support; Step S11: Overall design of the bracket At the starting position of the jacking of the steel box girder (4), an assembly bracket (1) and a jacking bracket (2) are arranged in sections, and the length of the steel box girder (4) at the starting end meets the counterweight requirement for the steel box girder (4) to cross the expressway; Install a jacking support (2) at the terminal section, and install a support support at the green belt position on both sides of the expressway to temporarily support the guide beam (5); install a jacking machine on the jacking support (2) to push the steel box beam (4) segment from one side of the expressway to the other side to cross the expressway to the designed position; Step S12: Assembling the bracket (1) Structural design When the steel box girder (4) is assembled on site, temporary supports are installed and arranged on both sides of the butt joint of the steel box girder (4); The temporary support comprises a circular tube lattice column (13), a steel distribution beam (12) and a concrete independent foundation (11); a plurality of groups of circular tube lattice columns (13) are arranged and are connected by welding; The steel box girder (4) is provided with a circular tube lattice column (13) at the segmented interface, and the steel box girder (4) segment includes a section K-section R, and multiple groups of butt joints; 6 groups of circular tube lattice columns (13) are provided at the interface, and the spacing between the circular tube lattice columns (13) is 5m; Step S13, assembling the support (1) Foundation preparation process: The temporary supports are all located on the existing ground. According to the temporary support foundation calculation book, the foundation bearing capacity of the temporary support is pre-designed to be no less than 210Kpa; After the foundation treatment is completed, a concrete independent foundation (11) is poured; the concrete strength grade is C30, the concrete independent foundation (11) is 3000mm×3000mm, and the height is 500mm; a double-layer bidirectional steel mesh with a diameter of 10mm and a spacing of 150mm is set inside the concrete foundation; embedded parts are set on the top of the concrete foundation, and the circular tube lattice column (13) is welded and fixed to the embedded parts, and the welding angle K is ≥12mm; Step S14: Structural design of the push support (2) According to the requirements of the overall installation and construction plan, the main axis of the bridge is laid out using a total station on the leveled construction and assembly site; then, the control lines of each independent pier foundation and the bridge are laid out; According to the pre-camber provided in the drawings and the installation pre-camber set to meet the alignment of the completed bridge, the two pre-cambers are superimposed to measure and control the temporary pier elevation; According to the construction conditions of this project, the plane curve of the steel box girder (4) is a circular curve and a transition curve. It is planned to push in the direction of the bridge plane curve. The ratio of the inner and outer arc push lengths is 100:

112. Push in the tangent direction of the circular arc, and make a lateral correction every three steps. When assembling the steel box girder (4), it is carried out in the direction of the extension line of the line connecting the starting points of the outer web at the designed position. The push direction is also in the direction of the extension line of the line connecting the starting points of the outer web. Each group of jacking brackets (2) uses at least four Ø610*10mm steel pipes as columns (22), and is arranged in a longitudinal direction of 3m and a transverse direction of 2.5m; The size of the concrete enlarged foundation (21) is 4m×6m×1m. A transverse distribution beam (23) is installed on the top of the column (22). The transverse distribution beam (23) is composed of four groups of 40a I-beams and has a length of 4m. Above the transverse distribution beam (23) is a longitudinal jacking platform (24). The longitudinal jacking platform (24) is composed of four groups of 588*300mm I-beams and has a platform length of 4m. A walking jacking member is installed on the longitudinal jacking platform (24). Along the bridge, handover conversion columns and beams are arranged before and after the jacking equipment. The conversion columns are made of Ф273*7mm, and the beams are made of double-jointed 40a I-beams with a length of 4m. Step S15, foundation preparation process of the jacking support (2): the concrete enlarged foundation (21) adopts C30 concrete, the foundation plane size is 4.5×4m, and the thickness is 1m; a double-layer steel mesh (28) is arranged in the concrete enlarged foundation (21), the layout standard is D18@160, and 4 embedded plates (29) are arranged thereon, the embedded plates (29) correspond to the positions of the steel pipes, and the dimensions of the embedded plates (29) are 830×830×20mm; After the original foundation of the soft pavement is leveled and rolled, a light dynamic probe is used for testing. When the foundation bearing capacity is greater than 200 KPa, concrete hardening is directly used (25); When the bearing capacity of the foundation is less than 200 KPa, crushed stone replacement (26) is used for compaction, with a replacement size of 5×5.5 m, until the bearing capacity of the foundation is greater than 200 KPa. After the bearing capacity requirement is met, concrete hardening (25) is performed.

4. The construction method of a jacking support structure for a high-speed large-span steel box girder according to claim 3 is characterized in that: In step S2, the construction steps are: a) Dig out the soft ground at the bottom of the foundation and backfill it with gravel; b) A foundation bearing capacity test must be conducted before foundation construction, and the foundation bearing capacity must meet the calculation requirements; c) The foundation measurement and layout position must be accurate, and the position of the foundation embedded parts must be accurate; d) Strengthen the vibration of foundation concrete, and subsequently cover and water the concrete for maintenance to ensure the strength of the foundation concrete.

5. The construction method of a jacking support structure for a high-speed large-span steel box girder according to claim 4 is characterized in that: In step S3, the support component is hoisted by a car crane. During the hoisting, the columns (22) are first installed, and then the inter-column supports (27) are installed between the multiple groups of columns (22). The inter-column supports (27) and the columns (22) are fixed by welding. After the installation is completed, the support component needs to be checked. After it is correct, the column base and the foundation embedded parts are fixed by high-strength bolts.

6. The construction method of a jacking support structure for a high-speed large-span steel box girder according to claim 4 is characterized in that: In step S4, the following construction steps are included: 1) Hoisting method After the segmented steel box beam (4) is transported to the bridge site, a 350-ton crawler crane is used to lift the steel box beam (4) and place it on the permanent support points and temporary support piers of the bridge. Before lifting, the placement of the crane is fully considered. During the lifting process, it is directed by a dedicated person and is checked synchronously with measuring instruments. 2) Linear control The linear control of the steel box girder (4) should first be carried out in the factory; before lifting, control points and lines are set on the permanent piers and temporary piers, and control points and lines are set on the steel box girder (4) accordingly; when the steel box girder (4) is installed, the center line and longitudinal distance are controlled by the control points and lines set in advance on the piers, corresponding to the points and lines set on the steel box girder (4); at the same time, the measurement instrument is used for synchronous monitoring, and the elevation of the steel box girder (4) is adjusted and controlled by two jacks installed on the piers. After the center line, longitudinal distance and beam elevation are adjusted, welding is performed at the joints of each section of the box body to ensure the smooth linear shape of the steel box girder (4).

7. The construction method of a jacking support structure for a high-speed large-span steel box girder according to claim 6 is characterized in that: In step S5, the following construction steps are included: The guide beam (5) is divided into N segments, which are transported to the site in bulk for splicing and hoisting; and are partially reinforced with the steel box beam (4) and welded into a whole.

8. The construction method of a jacking support structure for a high-speed large-span steel box girder according to claim 7 is characterized in that: Step S6: Installation of the push equipment When the steel box girder (4) is pushed by walking method, a total of 8 sets of pushing brackets (2) are required, and a set of walking jacks is set on each bracket, for a total of 28 sets; The steel box girder (4) is pushed by a walking continuous pushing method. A walking pushing device for the steel box girder (4) is installed on the distribution beam of the pushing bracket (2). A group of crossbeams supporting the steel beams (28) are arranged above the two groups of crossbeams, and the bottom of the crossbeam is fixed with a jack.

9. The construction method of a jacking support structure for a high-speed large-span steel box girder according to claim 8 is characterized in that: In step S7, the steel box girder (4) is pushed forward: 1) First stage jacking: the guide beam (5) is jacked to the position of the central dividing strip (6), and the steel box beam (4) does not cross the expressway; 2) Second stage of jacking: the guide beam (5) jacks up the opposite main pier; 3) The third stage of jacking: the steel box girder (4) is pushed onto the opposite main pier; 4) Fourth stage: the guide beam (5) is pushed onto the opposite rear pier; 5) Fifth stage: the steel box girder (4) is pushed into place; 6) The whole bridge is completed by lowering the beams: after lowering the beams, the last remaining segments are hoisted.

10. The construction method of a jacking support structure for a high-speed large-span steel box girder according to claim 9, characterized in that: In step S8, beam dropping: all the steel box beam (4) segments are pushed into place, the guide beam (5) is removed, and the overall line shape of the box beam is adjusted to the target line shape by a three-dimensional jack before the beam dropping work can be carried out; Use the lower support cylinder of the walking type jacking equipment to carry out the beam dropping construction; In step S9, the bracket is removed: a) First, dismantle the I-beam, break the weld between the I-beam and the steel column, and use a winch to lift the I-beam and then lower it; b) Each row of temporary support steel columns is laid down three times. After removing the anchor bolts at the column base, one winch is used to lift it from a high place, and another winch is used to lift the column base, and the two winches are used to pull the support down in opposite directions; c) The laid-down support is hoisted onto a transfer flatbed truck using a 25T crane and then transported to the stacking site.

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