Construction method of half-through concrete-filled steel tube arch bridge lattice beam

Abstract

The invention provides a half-through concrete filled steel tube arch bridge lattice beam construction method, which optimizes the division of construction segments of a lattice beam, prevents the lattice beam from being installed in place by avoiding arch ribs and cross brace structures among the arch ribs, and enables each construction segment of the lattice beam, especially an arch rib intersection segment, to move to an installation position through horizontal and vertical displacement. Therefore, the arch rib intersection section does not need to be inclined at a large angle to penetrate through the arch rib, and the construction risk caused by unbalanced stress of a lifting point or no stress of the lifting point in the large-angle inclined lifting process of the arch rib intersection section is avoided. And meanwhile, the hoisting capacity is designed by combining with a cable crane, the total number of construction segments of the lattice beam is reduced by dividing the optimized lattice beam segments, the hoisting frequency is reduced, the weight of the construction segments of the lattice beam is close to that of the arch rib segments, and then the construction efficiency is improved, and the construction cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a construction method for a lattice beam of a half-through steel tube concrete arch bridge. Background Art

[0002] In bridge construction, mid-span steel tube concrete arch bridges are widely used due to their unique structure and strong bearing capacity. The cable hoisting construction technology without brackets is difficult to be applied in the hoisting of the bridge deck of mid-span arch bridges. The reason is that the arch rib intersection section of the bridge deck lattice beam between arch ribs must pass through the arch ribs to be hoisted to the installation position during hoisting. However, due to the influence of the arch ribs and the cross braces between the arch ribs, the arch rib intersection section is difficult to pass through the arch ribs. Since the width of the lattice beam is usually smaller than the width of the outer edge of the arch rib, it is also difficult to implement the lattice beam hoisting outside the arch rib. Summary of the invention

[0003] In view of the technical problems mentioned in the above background technology, a construction method for a lattice beam of a mid-span steel tube concrete arch bridge is provided, which can avoid the obstruction of the arch ribs and the cross bracing structure between the arch ribs to the installation of the lattice beam, while improving the construction efficiency and reducing the construction cost.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for constructing a lattice beam of a half-through steel tube concrete arch bridge. The lattice beam of the half-through steel tube concrete arch bridge in the prior art includes a plurality of construction segments, which are divided into two construction segment groups symmetrically arranged relative to the midline of the bridge span and a joint segment connecting the two construction segment groups. Each construction segment group includes an end segment, an arch rib intersection segment I, an arch rib intersection segment II, an arch rib intersection segment III and N standard segments connected in sequence along the longitudinal direction of the bridge. The end segment is located at the end of the lattice beam, the arch rib intersection segment I, the arch rib intersection segment II and the arch rib intersection segment III are connected in sequence along the longitudinal direction of the bridge. III are all arranged at the intersection of the lattice beam and the arch rib, and each includes an intersection section main beam and at least one intersection section secondary beam connected to the intersection section main beam, the length of the intersection section main beam of the arch rib intersection section III is greater than the arch rib spacing between the two arch ribs, and the intersection section main beam of the arch rib intersection section III is located below the arch rib, the intersection section secondary beam of the arch rib intersection section III is located between the arch ribs, the joint section connects the standard sections of the two groups of construction segment groups, and the construction method of the lattice beam of the half-through steel tube concrete arch bridge comprises the following steps:

[0006] S1, optimize the division of lattice beam construction sections: divide the intersection section secondary cross beams of the original arch rib intersection section II to the original arch rib intersection section I to form a new arch rib intersection section I; divide all the intersection section secondary cross beams of the original arch rib intersection section III to the intersection section main cross beams of the original arch rib intersection section II to form a new arch rib intersection section II, and divide the intersection section main cross beam of the original arch rib intersection section III to one of the standard sections to form a reference section, so that each construction section group includes an end section, a new arch rib intersection section I, a new arch rib intersection section II, a reference section and N-1 standard sections that are sequentially connected along the longitudinal bridge direction;

[0007] S2, after the lattice beam segment division is completed, a structural collision check is performed on the installation of the new arch rib intersection section I and the new arch rib intersection section II by drawing drawings or three-dimensional modeling, and after the check is passed, step S3 is entered;

[0008] S3, hoisting of lattice beam construction segments: according to the divided construction segments and in accordance with the preset hoisting sequence, the divided multiple construction segments are hoisted using a bracket-free cable hoisting system.

[0009] Furthermore, step S3 includes the following steps:

[0010] S31, using a bracket-free cable hoisting system to hoist the reference segment from below the arch rib to a predetermined installation position, and after being in place, connecting the reference segment to four hoisting rods at the installation position of the reference segment to form an installation fulcrum;

[0011] S32, hoisting the new arch rib intersection section II from above the arch rib to a predetermined installation position by using a bracket-free cable hoisting system, and after being in position, fixing one end of the new arch rib intersection section II to one end of the reference section, and supporting and fixing the other end of the new arch rib intersection section II on the lower support of the half-through steel tube concrete arch bridge;

[0012] S33, using a bracket-free cable hoisting system to hoist the new arch rib intersection section I from above the arch rib to a predetermined installation position, and after being in position, fixing one end of the new arch rib intersection section I to an end of the new arch rib intersection section II away from the reference section, and supporting and fixing the other end of the new arch rib intersection section I on an upper support of the half-through steel tube concrete arch bridge;

[0013] S33, using a bracketless cable hoisting system to hoist the end section from above the arch rib to a predetermined installation position, after being in position, one end of the end section is supported and fixed on the upper support and fixedly connected to an end of the new arch rib intersection section I away from the arch rib intersection section II, and the other end of the end section is supported and fixed on the arch seat of the half-through steel tube concrete arch bridge;

[0014] S33, hoisting one of the standard segments from below the arch rib to a predetermined installation position using a bracket-free cable hoisting system, connecting the standard segment to a hoisting rod after it is in place, and fixing one end of the standard segment to an end of the reference segment away from the arch rib intersection segment II;

[0015] S33, hoisting the remaining standard segments of the construction segment group from below the arch rib to a predetermined installation position using a bracket-free cable hoisting system, connecting them with the hoisting rods at corresponding positions after they are in place, and fixing the N-1 standard segments in sequence in a direction away from the corresponding reference segment;

[0016] S34, using a bracket-free cable lifting system to lift the joint section from below the arch rib to a predetermined installation position, connecting it to the lifting rod at the corresponding position after it is in place, and fixing the joint section to the standard sections of the two construction segment groups to complete the joint of the lattice beam.

[0017] Furthermore, two adjacent construction sections are fixedly connected by a combination of high-strength bolt connection and welding.

[0018] Furthermore, during lifting, lifting equipment is connected on opposite sides of the reference section, the standard section and the joint section, and an adapter is provided on the lifting equipment. The adapter is located outside the vertical projection of the arch rib, and the adapter is connected to the lifting rope of the bracket-free cable lifting system.

[0019] Furthermore, the lifting device includes a main beam and two lifting ears, one end of the main beam is rotatably connected to the adapter; the two lifting ears are fixed to the bottom surface of the main beam, the two lifting ears and the adapter are spaced apart along the length direction of the main beam, and the lifting ears are detachably connected to the lifting ring of the construction section to be lifted.

[0020] Furthermore, the main beam includes two transverse plates, two vertical plates and two groups of stiffening plates, the transverse plates are parallel to the horizontal plane, and the two transverse plates are arranged in parallel and spaced apart in the vertical direction; the two vertical plates are arranged in spaced apart along the width of the transverse plates, and the vertical plates are vertically fixedly connected to the two transverse plates to enclose and form a cavity; the two groups of stiffening plates are respectively arranged on opposite sides of the cavity, and the multiple stiffening plates in each group are arranged in spaced apart along the length of the transverse plates, and each stiffening plate is fixedly connected to the two transverse plates and the vertical plates; the adapter is arranged outside one end of the cavity and rotatably connects one end of the two transverse plates; the lifting ear is fixed on the bottom surface of one of the transverse plates.

[0021] Furthermore, the lifting ear includes two ear plates and a latch, and the two ear plates are relatively spaced apart along the length direction of the transverse plate to form a plug-in space for inserting a lifting ring on the construction section; the latch is detachably inserted through the two ear plates and the lifting ring.

[0022] Furthermore, the standard section includes a standard section main beam and a standard section secondary beam fixedly connected to the standard section main beam, and the lifting ring on the standard section is arranged on the top surface of the standard section secondary beam to be staggered with the position of the lifting rod embedded pipe on the standard section main beam.

[0023] Furthermore, before using the sling for lifting, the reaction forces at each lifting point under the most unfavorable eccentric lifting condition are calculated by modeling to verify the structural stability of the sling and the strength of the sling itself, so as to ensure construction safety.

[0024] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0025] 1. The above-mentioned method for constructing lattice beams of mid-span steel tube concrete arch bridges optimizes the construction segment division of lattice beams, avoids the obstruction of lattice beam installation by arch ribs and cross bracing structures between arch ribs, so that each construction segment of the lattice beam, especially the arch rib intersection segment, can be moved to the installation position through horizontal + vertical displacement, thereby eliminating the need to tilt the arch rib intersection segment at a large angle to allow it to pass through the arch rib, and avoiding the construction risk caused by unbalanced force on the lifting point or lack of force on the lifting point during the large-angle tilt of the arch rib intersection segment. At the same time, combined with the lifting capacity of the cable crane design, the optimized lattice beam segment division reduces the total number of lattice beam construction segments, reduces the number of hoisting times, and makes the weight of the lattice beam construction segment close to the weight of the arch rib segment, which is conducive to improving construction efficiency and reducing construction costs.

[0026] 2. In the above-mentioned method for constructing lattice beams of mid-span steel tube concrete arch bridges, during the hoisting process of the construction segments of the lattice beams, the reference segment is first installed, and the reference segment is connected to four hangers at the installation position of the reference segment to form an installation fulcrum, and then the arch rib intersection segment II, arch rib intersection segment I and the end segment are installed in sequence from the installation fulcrum as the starting point toward the arch foot, and then combined with the optimization of the construction segment division of the lattice beam, each construction segment, especially the arch rib intersection segment II, arch rib intersection segment I and the end segment where no hangers are provided, has a fulcrum for installation, so that there is no need to install a bracket for supporting the construction segment during the hoisting process, thereby truly realizing the bracket-free cable hoisting construction and further improving the construction efficiency.

[0027] 3. In the above-mentioned lattice girder construction method of the mid-span steel tube concrete arch bridge, two adjacent construction sections are fixedly connected by a combination of high-strength bolt connection and welding, which reduces the influence of welding deformation on the overall stability of the bridge and ensures the strength and stability of the joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of construction segment division of a lattice girder of a mid-through steel tube concrete arch bridge in the prior art;

[0029] Figure 2for Figure 1 An enlarged structural view of a construction segment group and a closing segment of a lattice beam shown;

[0030] Figure 3 It is a structural schematic diagram of a part of the lattice beams of a mid-through concrete-filled steel tube arch bridge in the prior art after installation;

[0031] Figure 4 It is a schematic diagram of the construction segment division of a lattice beam of a half-through steel tube concrete arch bridge according to a preferred embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of a portion of lattice beams after installation in a preferred embodiment of the present invention;

[0033] Figures 6 to 9 A schematic diagram of a construction method of a lattice beam of a mid-through steel tube concrete arch bridge according to a preferred embodiment of the present invention;

[0034] Fig.10 It is a schematic diagram of the connection between the hanger and the construction segment according to a preferred embodiment of the present invention;

[0035] Fig.11 This is a schematic diagram of the structure of the sling used in the preferred embodiment of the present invention;

[0036] Fig.12 for Fig.11 Bottom view of

[0037] Fig.13 The horizontal hanging model of the reference section;

[0038] Fig.14 is the finite element model of the spreader;

[0039] Fig.15 It is the internal force diagram of the lifting point during the lifting process of the reference section translation;

[0040] Fig.16 The internal force diagram of the lifting point during the lifting process of the reference section rotating 10° around the main beam of the reference section;

[0041] Fig.17 It is a schematic diagram of the local loading position and the magnitude of the force;

[0042] Fig.18 It is the stress diagram of Midas / Fea model (I);

[0043] Fig.19 It is the stress diagram of Midas / Fea model (II);

[0044] Fig. 20 It is the displacement map of Midas / Fea model;

[0045] Fig.21is the torsional buckling diagram of the overall sling;

[0046] Fig. 22 The horizontal plate at the bottom of the sling drives the whole sling to be subjected to torsional buckling.

[0047] Main component symbols

[0048] 100, lattice beam; 10, construction segment group; 11, reference segment; 12, end segment; 13, arch rib intersection segment I; 14, arch rib intersection segment II; 15, arch rib intersection segment III; 16, standard segment; 161, standard segment main beam; 162, standard segment secondary beam; 17, joint segment; 171, joint segment main beam; 172, joint segment secondary beam; 18, intersection segment main beam; 19, intersection segment secondary beam; 200, arch rib ; 210, cross brace; 21, upper chord tube; 23, lower chord tube; 25, web member; 30, upper support; 40, lower support; 50, sling; 51, adapter; 511, connecting hole; 52, main beam; 521, cross plate; 522, vertical plate; 523, stiffening plate; 524, cavity; 53, lifting ear; 531, ear plate; 533, latch; 54, pin shaft; 60, arch seat; 70, suspension rod; 80, lifting ring; 90, lifting rope. DETAILED DESCRIPTION

[0049] 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.

[0050] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0052] A preferred embodiment of the present invention provides a method for constructing a lattice beam of a mid-through steel tube concrete arch bridge. Figure 1 , Figure 2 and Fig.10 The prior art mid-through concrete-filled steel tube arch bridge generally includes a lattice beam 100 and two arch ribs 200 erected on the lattice beam 100 on opposite sides along the transverse direction of the bridge. Each arch rib 200 includes an upper chord tube 21, a lower chord tube 23, and a web member 25 connecting the upper chord tube 21 and the lower chord tube 23. The two arch ribs 200 are fixedly connected by a cross brace 210. The lower chord tube 23 of the arch rib 200 is connected to the lattice beam 100 by a hanger 70.

[0053] The lattice beam 100 of the mid-through steel tube concrete arch bridge of the prior art includes a plurality of construction segments (not shown), which are divided into two construction segment groups 10 symmetrically arranged relative to the center line of the bridge span and a joint section 17 connecting the two construction segment groups 10. Each construction segment group 10 includes an end segment 12, an arch rib intersection segment I13, an arch rib intersection segment II14, an arch rib intersection segment III15 and N standard segments 16 connected in sequence along the longitudinal bridge direction, where N is an integer greater than 1. Among them, the end segment 12 is located at the end of the lattice beam 100, and the arch rib intersection segment I13, the arch rib intersection segment II14 and the arch rib intersection segment III15 are arranged at the intersection of the lattice beam 100 and the arch rib 200. The arch rib intersection section I13, the arch rib intersection section II14, and the arch rib intersection section III15 each include an intersection section main cross beam 18 and at least one intersection section secondary cross beam 19 fixedly connected to the intersection section main cross beam 18. Figure 3 The length of the main cross beam 18 of the intersecting section of the arch rib intersection section III15 is greater than the distance between the two arch ribs 200, and the main cross beam 18 of the intersecting section of the arch rib intersection section III15 is located below the arch rib 200, and the secondary cross beam 19 of the intersecting section of the arch rib intersection section III15 is located between the arch ribs 200, that is, between the two arch ribs 200. The joint section 17 connects the standard sections 16 of the two construction segment groups 10. The construction method of the lattice beam of the mid-through steel tube concrete arch bridge in the prior art includes the following steps:

[0054] S100, hoisting of the end section 12: Since the end section 12 is located above the arch rib 200 as a whole, the end section 12 can be hoisted directly from above the arch rib 200 to the predetermined installation position by using a bracket-free cable hoisting system. After being in position, one end of the end section 12 is fixed to the arch seat 60 of the arch rib 200, and the other end is supported and fixed to the upper support 30 of the upper chord tube 21 of the arch rib 200. Since there is no suspension rod 70 at the installation position of the end section 12 to connect with the arch rib 200, the end section 12 is supported by the upper support 30 of the arch rib 200 and the arch seat 60 of the arch rib 200, so as to provide an installation fulcrum for the connection of subsequent construction sections.

[0055] S200, hoisting of the arch rib intersection section I13: the length of the main cross beam 18 of the arch rib intersection section I13 is greater than the distance between the two arch ribs 200, and the length of the secondary cross beam 19 of the arch rib intersection section I13 is less than the distance between the two arch ribs 200. Figure 3 It can be seen that since the main cross beam 18 of the intersection section of the arch rib intersection section I13 is arranged close to the end section 12, and the main cross beam 18 of the intersection section of the arch rib intersection section I13 is located above the arch rib 200, the arch rib intersection section I13 can be directly hoisted from above the arch rib 200 to the predetermined installation position by using a bracket-free cable hoisting system. After being in place, one end of the arch rib intersection section I13 is supported and fixed on the upper support 30 and fixedly connected to the end section 12. Since there is no suspension rod 70 for connection at the position where the arch rib intersection section I13 is located, the end of the arch rib intersection section I13 in the prior art that is away from the end section 12 is a cantilever end and cannot support the installation of the arch rib intersection section II14. It is necessary to set up a bracket below the end of the arch rib intersection section I13 that is away from the end section 12 to support the end of the arch rib intersection section I13 that is away from the end section 12 to prevent it from being suspended in the air.

[0056] S300, hoisting of the arch rib intersection section II14: the arch rib intersection section II14 is located between the two arch ribs 200, and since the overall width of the arch rib intersection section II14 is smaller than the distance between the two arch ribs 200, the arch rib intersection section II14 can be hoisted directly from above the arch rib 200 to the predetermined installation position by using a bracket-free cable hoisting system. After being in place, one end of the arch rib intersection section II14 is fixedly connected to the end of the arch rib intersection section I13 away from the end section 12, and the other end of the arch rib intersection section II14 is supported and fixed on the lower support 40 of the lower chord tube 23 of the arch rib 200.

[0057] S400, hoisting of arch rib intersection section III15: Since the length of the main cross beam 18 of the intersection section of the arch rib intersection section III15 is greater than the distance between the two arch ribs 200, and the main cross beam 18 of the intersection section of the arch rib intersection section III15 is arranged on the side of the arch rib intersection section III15 away from the arch rib intersection section II14 and below the arch rib 200, and the secondary cross beam 19 of the intersection section of the arch rib intersection section III15 is arranged on the side of the arch rib intersection section III15 close to the arch rib intersection section II14 and between the arch ribs 200, the arch rib intersection section III15 cannot be directly lifted from the arch rib intersection section III15. The arch rib 200 or the arch rib 200 is vertically lifted to the preset installation position. The arch rib intersection section III15 needs to be tilted at a large angle to continuously adjust the posture of the arch rib intersection section III15 until the arch rib intersection section III15 passes through the arch rib 200 and can be lifted to the installation position. However, due to the influence of the arch rib 200 and the cross brace 210 between the arch ribs 200, it is difficult for the arch rib intersection section III15 to pass through the arch rib 200, and the lifting difficulty is large, resulting in reduced construction efficiency; and the tilted lifting of the arch rib intersection section III15 causes uneven force at each lifting point, which can easily cause construction risks.

[0058] S500, using a bracket-free cable hoisting system to hoist one of the standard segments 16 from below the arch rib 200 to a predetermined installation position, and after being in position, the standard segment 16 is connected to the suspension rod 70, and one end of the standard segment 16 is fixedly connected to an end of the arch rib intersection segment III15 away from the arch rib intersection segment II14;

[0059] S600, hoist the remaining standard segments 16 of the construction segment group 10 from below the arch rib 200 to the predetermined installation position by using a bracket-free cable hoisting system, connect them with the hoisting rod 70 at the corresponding position after they are in place, and fix the N-1 standard segments 16 in sequence in a direction away from the corresponding end segment 12;

[0060] S700, use the bracket-free cable lifting system to lift the joint section 17 from under the arch rib 200 to the predetermined installation position, connect it with the suspension rod 70 at the corresponding position after it is in place, and fix the joint section 17 to the standard section 16 of the two construction segment groups 10, so as to complete the joint of the lattice beam 100.

[0061] From the above, it can be seen that when the lattice beam segment division method of the prior art is used in combination with the existing support-free cable hoisting construction process for the construction of the lattice beam of the mid-span steel tube concrete arch bridge, when the arch rib intersection section I13 without a hanger is hoisted, a support needs to be set up to support the cantilever end of the arch rib intersection section I13, and the arch rib intersection section III15 cannot be directly lifted vertically from below the arch rib 200 or above the arch rib 200 to the preset installation position, and needs to be lifted by a large angle tilting during the hoisting. The arch rib intersection section III15 needs to continuously adjust the posture of the arch rib intersection section III15 until it passes through the arch rib 200 before it can be hoisted to the installation position. However, due to the influence of the arch rib 200 and the cross brace 210 between the arch ribs 200, it is difficult for the arch rib intersection section III15 to pass through the arch rib 200, and the hoisting difficulty is large, resulting in reduced construction efficiency; and the inclined hoisting of the arch rib intersection section III15 causes uneven force at each hoisting point or no force at the hoisting point, which can easily cause construction risks.

[0062] Please also see Figure 4 and Figure 5 In order to solve the above problems, a preferred embodiment of the present invention provides a method for constructing a lattice beam of a half-through steel tube concrete arch bridge, comprising the following steps:

[0063] S1, optimize the division of the construction segments of the lattice beam 100: divide the intersection segment secondary cross beam 19 of the original arch rib intersection segment II14 to the original arch rib intersection segment I13 to form a new arch rib intersection segment I13; divide all the intersection segment secondary cross beams 19 of the original arch rib intersection segment III15 to the intersection segment main cross beam 18 of the original arch rib intersection segment II14 to form a new arch rib intersection segment II14, and divide the intersection segment main cross beam 18 of the original arch rib intersection segment III15 to one of the standard segments 16 to form a reference segment 11, so that each construction segment group 10 includes an end segment 12, a new arch rib intersection segment I13, a new arch rib intersection segment II14, a reference segment 11 and N-1 standard segments 16 connected in sequence along the longitudinal bridge direction. Compared with the prior art, this division method cancels the arch rib intersection segment III15, reduces the number of construction segments, and is beneficial to improving the efficiency of lifting.

[0064] S2, after the lattice beam 100 is segmented, a structural collision check is performed on the installation of the new arch rib intersection section I13 and the new arch rib intersection section II14 by drawing or three-dimensional modeling. If the check passes, that is, no collision occurs, the process proceeds to step S3.

[0065] S3, hoisting of lattice beam 100 construction segments: according to the divided construction segments and in accordance with the preset hoisting sequence, the divided multiple construction segments are hoisted using a bracket-free cable hoisting system.

[0066] Please also see Figures 6 to 9In this embodiment, step S3 includes the following steps:

[0067] S31, using a bracketless cable hoisting system to hoist the reference section 11 from below the arch rib 200 to a predetermined installation position, and after being in place, connecting the reference section 11 to four hoisting rods 70 at the installation position of the reference section 11 to form an installation fulcrum;

[0068] S32, using a bracket-free cable hoisting system to hoist the new arch rib intersection section II14 from above the arch rib 200 to a predetermined installation position, and after being in position, one end of the new arch rib intersection section II14 is fixedly connected to one end of the reference section 11, and the other end of the new arch rib intersection section II14 is supported and fixed on the arch support 40 of the half-through steel tube concrete arch bridge;

[0069] S33, using a bracket-free cable hoisting system to hoist the new arch rib intersection section I13 from above the arch rib 200 to a predetermined installation position, and after being in position, one end of the new arch rib intersection section I13 is fixedly connected to an end of the new arch rib intersection section II14 away from the reference section 11, and the other end of the new arch rib intersection section I13 is supported and fixed on the upper support 30 of the half-through steel tube concrete arch bridge;

[0070] S33, using a bracketless cable hoisting system to hoist the end section 12 from above the arch rib 200 to a predetermined installation position, after being in position, one end of the end section 12 is supported and fixed on the upper support 30 and fixedly connected to an end of the new arch rib intersection section I13 away from the arch rib intersection section II14, and the other end of the end section 12 is supported and fixed on the arch seat 60 of the half-through steel tube concrete arch bridge;

[0071] S33, using a bracket-free cable hoisting system to hoist one of the standard segments 16 from below the arch rib 200 to a predetermined installation position, and after being in position, the standard segment 16 is connected to the suspension rod 70, and one end of the standard segment 16 is fixedly connected to an end of the reference segment 11 away from the arch rib intersection segment II14;

[0072] S33, using a bracket-free cable hoisting system to hoist the remaining standard segments 16 of the construction segment group 10 from below the arch rib 200 to a predetermined installation position, and after being in place, connect them to the hanger 70 at the corresponding position, and fix the N-1 standard segments 16 in sequence in a direction away from the corresponding reference segment 11;

[0073] S34, using a bracket-free cable lifting system to lift the joint section 17 from under the arch rib 200 to a predetermined installation position, after it is in place, it is connected to the suspension rod 70 at the corresponding position, and the joint section 17 is fixedly connected to the standard sections 16 of the two construction segment groups 10 to complete the jointing of the lattice beam 100.

[0074] The above-mentioned method for constructing the lattice beam of a mid-span steel tube concrete arch bridge optimizes the construction segment division of the lattice beam 100, that is, the main cross beam 18 of the intersection segment of the original arch rib intersection segment III15 is divided into one of the standard segments 16 to form a reference segment 11, and all the secondary cross beams 19 of the original arch rib intersection segment III15 are divided into the main cross beam 18 of the intersection segment of the original arch rib intersection segment II14 to form a new arch rib intersection segment II14, so that the arch rib intersection segment can avoid the arch ribs and the cross bracing structure between the arch ribs blocking the lattice beam from being installed in place, so that each construction segment of the lattice beam, especially the arch rib intersection segment, can also be moved to the installation position through horizontal + vertical displacement, so that there is no need to tilt the arch rib intersection segment at a large angle to make it pass through the arch rib, thereby avoiding the construction risk caused by unbalanced force on the lifting point or lack of force on the lifting point during the large-angle tilt of the arch rib intersection segment. At the same time, combined with the lifting capacity of the cable crane design, the optimized lattice beam segment division reduces the total number of lattice beam construction segments and reduces the number of lifting times, which is beneficial to improving construction efficiency and reducing construction costs.

[0075] In the above-mentioned method for constructing the lattice beam of a mid-span steel tube concrete arch bridge, during the hoisting process of the lattice beam construction segment, the reference segment 11 is first installed, and the reference segment 11 is connected to the four hangers 70 at the reference segment installation position to form an installation fulcrum, and then the arch rib intersection segment II14, the arch rib intersection segment I13 and the end segment 12 are installed in sequence in the direction of the arch foot with the installation fulcrum as the starting point, and then combined with the optimization of the construction segment division of the lattice beam 100, each construction segment, especially the arch rib intersection segment II14, the arch rib intersection segment I13 and the end segment 12 where no hangers are provided, has a fulcrum, so that there is no need to install a bracket for supporting the construction segment during the hoisting process, thereby truly realizing the bracket-free cable hoisting construction and further improving the construction efficiency.

[0076] In the prior art, two adjacent construction segments are fixedly connected by welding, which results in a large number of welding points. The construction segments are deformed due to welding, which reduces the overall stability of the bridge. In this embodiment, to solve this problem, two adjacent construction segments are fixedly connected by combining high-strength bolt connection and welding, that is, some connection points are connected by high-strength bolts to reduce the impact of welding deformation on the overall stability of the bridge and ensure the strength and stability of the joint.

[0077] Since the widths of the reference section 11, the standard section 16 and the joint section 17 are all smaller than the distance between the outer edges of the two arch ribs 200, during the hoisting process of the reference section 11, the standard section 16 and the joint section 17, it is necessary to connect the hoists 50 on both sides of the reference section 11, the standard section 16 and the joint section 17 along the transverse direction. Figures 10 to 12, the hoist 50 is provided with an adapter 51, and the adapter 51 is connected to the lifting rope 90 of the bracketless cable lifting system. In this embodiment, the standard section 16 also includes a standard section main beam 161 and a standard section secondary beam 162 fixedly connected to the standard section main beam 161. The joint section 17 also includes a joint section main beam 171 and a joint section secondary beam 172 fixedly connected to the joint section main beam 171. The lifting rings connecting the reference section 11 and the hoist 50, the lifting rings connecting the standard section 16 and the hoist 50, and the lifting rings connecting the joint section 17 and the hoist 50 are all set on the secondary beams of the corresponding construction sections to stagger the positions of the pre-buried pipes of the hangers (not shown) on the corresponding main beams.

[0078] In this embodiment, the adapter 51 connected to the lifting rope 90 is located outside the vertical projection of the arch rib 200, so that the lifting rope 90 is located outside the arch rib 200, so as to prevent the horizontal brace 210 between the two arch ribs 200 from affecting the horizontal movement of the reference section 11, the standard section 16 and the joint section 17. There is no horizontal brace 210 between the arch ribs 200 at the installation position of the corresponding end section 12, the new arch rib intersection section I13 and the new arch rib intersection section II14, so the lifting rope 90 can be directly connected to the lifting rings on the end section 12, the new arch rib intersection section I13 and the new arch rib intersection section II14 for lifting.

[0079] In this embodiment, the lifting device 50 includes a main beam 52 and two lifting ears 53. One end of the main beam 52 is rotatably connected to the adapter 51. The two lifting ears 53 are fixed to the bottom surface of the main beam 52. The two lifting ears 53 and the adapter 51 are spaced apart along the length direction of the main beam 52. The lifting ears 53 are detachably connected to the construction section to be lifted.

[0080] Specifically, the main beam 52 includes two transverse plates 521, two vertical plates 522 and two groups of stiffening plates 523. The transverse plates 521 are parallel to the horizontal plane and are arranged in parallel and spaced apart in the vertical direction. The two vertical plates 522 are arranged in space along the width of the transverse plates 521. The vertical plates 522 are vertically fixedly connected to the two transverse plates 521 to enclose and form a cavity 524. The two groups of stiffening plates 523 are respectively arranged on opposite sides of the cavity 524. The multiple stiffening plates 523 in each group are arranged in space along the length of the transverse plates 521. Each stiffening plate 523 is fixedly connected to the two transverse plates 521 and the vertical plates 522. The double-web box-type sling composed of the two transverse plates 521, the two vertical plates 522 and the two groups of stiffening plates 523 can improve the torsional resistance of the sling 50 to meet the rigidity requirements of the construction.

[0081] The adapter 51 is arranged outside one end of the cavity 524 and is rotatably connected to one end of the two horizontal plates 521. In this embodiment, one end of the adapter 51 is rotatably connected to one end of the two horizontal plates 521 through a pin 54, and the other end of the adapter 51 is provided with a connection hole 511 for connecting with a lifting rope. Specifically, the lifting rope 90 can be connected to the connection hole 511 through a shackle (not shown). The lifting ear 53 is fixed on the bottom surface of one of the horizontal plates 521. In this embodiment, the lifting ear 53 includes two ear plates 531 and a latch 533. The two ear plates 531 are relatively spaced along the length direction of the horizontal plate 521 to form an insertion space (not shown) for inserting the lifting ring on the construction segment; the latch 533 can be detachably inserted through the two ear plates 531 and the lifting ring 80 between the two ear plates 531, so as to connect the construction segment to be hoisted with the sling 50.

[0082] The effect of the construction method of the lattice beam of a half-through steel tube concrete arch bridge of the present invention is described below with reference to a specific embodiment.

[0083] A super-large bridge is 514 meters long, and its main bridge is a single-span mid-through steel tube concrete arch bridge with a length of 356 meters (calculated span 340m, rise-span ratio 1:4.00, arch axis coefficient m=1.5), spanning the Hongshui River. According to the characteristics of the project, the upper steel structure of the main bridge adopts the cable hoisting construction technology without brackets. The design of the cable hoisting system without brackets is briefly described as follows:

[0084] The maximum allowable lifting weight of the designed hoisting system is 160t. The system is a single main span double cableway structure - 2*80t cableway. The maximum lifting weight of a single cableway is 80 tons, and both sets of cableways can work independently. The whole bridge is equipped with 4 sets of working cables, with a designed lifting weight of 5t. The main span of the cable system is 545.0m, the tail span of the small pile number is 229.5m, and the tail span of the large pile number is 234m.

[0085] The design parameters of the upper steel structure of a mid-through steel tube concrete arch bridge are summarized in Tables 1 and 2:

[0086] Table 1 Statistics of main arch rib segment weight

[0087]

[0088]

[0089] Table 2 Statistical table of weight of each construction section of lattice beam in the prior art

[0090]

[0091] According to the above parameter statistics, the maximum lifting weight of the arch rib segment is 145.6 tons, and the lifting weight of the largest construction segment of the lattice beam is 121.7 tons. The weight difference between the two is 23.9 tons, and the weight difference accounts for 16.41% and 19.64% of the weight of the largest arch rib and the largest lattice beam respectively. It can be concluded that there is still room for optimization in the theoretical weight of the original steel structure design.

[0092] In the construction method of the lattice beam of the mid-span steel tube concrete arch bridge of this embodiment, three key factors, namely, the columns on the arch, the positions of the lattice beam supports on the bridge, and the installation position of the lattice beam, as well as other factors, are comprehensively considered, and a new method for dividing the lattice beam construction segments is proposed. After optimizing the division of the lattice beam construction segments by using step S1, the weight statistics of the lattice beam hoisting segments after optimization are shown in Table 3.

[0093] Table 3 Statistical table of weight of lattice beam hoisting segments after optimization

[0094]

[0095]

[0096] After the lattice beam construction segment is optimized, the maximum lifting weight of the arch rib segment is 145.6 tons, and the maximum lifting weight of the lattice beam construction segment is 151.5 tons. The weight difference between the two is 5.9 tons, accounting for 4.05% and 3.89% respectively. It can be concluded that the theoretical weight of the optimized segment is more reasonable, which is conducive to reducing construction costs.

[0097] In addition, in this example, the connection points between the reference section 11 and the sling 50 and the connection points between the standard section 16 and the sling 50 are both set on the secondary beams of the corresponding sections. At this time, it can be determined that a certain eccentric force will be generated during the lifting process. Therefore, before using the sling to lift the standard section, it is necessary to verify the reaction force at each lifting point under the most unfavorable lifting weight (i.e., maximum lifting weight) eccentric lifting condition through modeling to verify the structural stability of the sling and the strength of the sling itself to ensure construction safety. The verification method is:

[0098] The lifting device 50 of this embodiment is manufactured by Q355C. During the lifting process, the adapter 51 of the lifting device 50 is connected to the main beam 52 by a pin 54, and the lifting lug 53 is connected to the construction segment by a latch 533. The pin 54 and the latch 533 are rotatable. Therefore, the main beam 52 will reach a self-balancing state with the rotation of the pin 54 and the latch 533. The main beam 52 is basically in a translation lifting state. Therefore, only the following two working conditions in Table 4 are considered:

[0099] Table 4 Calculation conditions of each construction section

[0100]

[0101] The hoist 50 is used for the construction section of the lattice beam under the arch, that is, the hoisting of the reference section 11, the standard section 16 and the closure section 17. Therefore, only the working condition of the reference section 11 (the heaviest section) is verified. The modeling and analysis are carried out using the Midas / Civil software. The model is as follows: Fig.13 As shown, the internal forces of the reference section 11 under various working conditions are statistically shown in Table 5.

[0102] Table 5 Segment internal force statistics

[0103]

[0104] Midas / Fea was used for entity analysis in this verification. The mesh was divided into tetrahedrons with a minimum mesh size of 10 mm. The steel plate material was Q355C. The load simulation was applied to the lifting ring by extracting the internal force of the Midas / Civil lifting point in a node coupling manner. The number of structural division units was 1472192 and the number of nodes was 327517. The finite element model of the lifting fixture 50 was obtained as follows: Fig.14 shown.

[0105] (1) Local stress verification of the first hanging section of the lattice beam

[0106] Midas / Civil was used to establish a lattice reference section model, simulate the translation lifting process and the 10° rotation around the heavier main beam, and extract the maximum internal force at the lifting point, such as Fig.15 , Fig.16 shown.

[0107] Depend on Fig.15 , Fig.16 It can be obtained that during the translation and lifting process of the reference segment 11, the maximum reaction force at the lifting point is F Z =365.5kN, the reaction force includes the deadweight of a sling; when the reference section 11 is lifted by rotating 10° around the reference section main beam 18, the maximum reaction force at the lifting point is F Z =353.7kN. From the perspective of force, the internal forces of each lifting point are relatively even when the analysis condition is rotated 10° around the main cross beam 18 of the reference section. At the same time, the latch 533 and the pin 54 can rotate. Therefore, this analysis condition can be more consistent with the actual lifting situation on site. For safety reasons, the support reaction force is taken as 40t, and the support reaction force is applied to the Midas / Fea model through node coupling. The loading diagram is as follows Fig.17 The calculation results are shown as Figure 18-19 shown.

[0108] Depend on Fig.18 It can be seen that the lattice beam hoist simulates the lifting process of the lattice beam under the action of 40t tension, ignoring some stress concentration points, the maximum Van Mises stress of the lifting lug 53 is 284.2Mpa, and the maximum stress position is as follows Fig.19As shown, the maximum stress is located at the connection between the lifting ear 53 and the horizontal plate 521 of the hanger 50; from the legend, it can be seen that the area with stress exceeding 213.2 MPa is less than 0.5%, and the area with relatively large stress is concentrated in the bending area of ​​the two horizontal plates 521 of the hanger 50.

[0109] Depend on Fig. 20 It can be seen that under the action of 40t pulling force, the vertical displacement of the sling 50 is 10.7mm, the total length of the sling 50 is 4580mm, and the vertical displacement value is less than L / 400mm, which can meet the requirements.

[0110] In summary, by analyzing the working conditions of the two lifting processes of the reference section hoist, the maximum support reaction force of 40t was taken for safety verification. The finite element calculation results show that the maximum stress position appears in the local position, and the area accounts for a small proportion. The finite element numerical simulation error cannot be ruled out. The welding quality of this position is strengthened on site, and the overall stress and displacement conditions of the structure can meet the requirements. Therefore, the force of the 40t hoist meets the requirements of the specification.

[0111] (2) Buckling modal analysis of sling

[0112] Under the action of 60t vertical load, the buckling mode of the spreader 50 was analyzed and five analysis modes were formed. The overall analysis results are shown in Table 6.

[0113] Table 6 Buckling analysis table of sling

[0114]

[0115] Mode 1 and Mode 2 belong to the buckling analysis of beams. Figure 21-22 shown.

[0116] It can be seen from the figure that the spreader will buckle and become unstable only when the bending reaches more than 12 cm. The actual displacement of the spreader 50 is 1 cm, which is much smaller than the buckling limit of 12 cm. Therefore, the double-web box-type spreader has good torsional resistance and can meet the stiffness requirements of the construction.

[0117] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for constructing a lattice beam of a half-through steel tube concrete arch bridge. The lattice beam of the half-through steel tube concrete arch bridge in the prior art comprises a plurality of construction segments, wherein the plurality of construction segments are divided into two construction segment groups symmetrically arranged relative to the midline of the bridge span and a joint segment connecting the two construction segment groups. Each construction segment group comprises an end segment, an arch rib intersection segment I, an arch rib intersection segment II, an arch rib intersection segment III and N standard segments sequentially connected along the longitudinal direction of the bridge. The end segment is located at the end of the lattice beam. The arch rib intersection segment I, the arch rib intersection segment II, the arch rib intersection segment III and N standard segments are connected in sequence along the longitudinal direction of the bridge. Section II and the arch rib intersection section III are both arranged at the intersection of the lattice beam and the arch rib, and both include an intersection section main beam and at least one intersection section secondary beam connected to the intersection section main beam, the length of the intersection section main beam of the arch rib intersection section III is greater than the arch rib spacing between the two arch ribs, and the intersection section main beam of the arch rib intersection section III is located below the arch rib, and the intersection section secondary beam of the arch rib intersection section III is located between the arch ribs, and the joint section connects the standard sections of the two groups of construction segment groups, characterized in that, The construction method of the lattice beam of the half-through steel tube concrete arch bridge comprises the following steps: S1, optimize the division of lattice beam construction sections: divide the intersection section secondary cross beams of the original arch rib intersection section II to the original arch rib intersection section I to form a new arch rib intersection section I; divide all the intersection section secondary cross beams of the original arch rib intersection section III to the intersection section main cross beams of the original arch rib intersection section II to form a new arch rib intersection section II, and divide the intersection section main cross beam of the original arch rib intersection section III to one of the standard sections to form a reference section, so that each construction section group includes an end section, a new arch rib intersection section I, a new arch rib intersection section II, a reference section and N-1 standard sections that are sequentially connected along the longitudinal bridge direction; S2, after the lattice beam segment division is completed, a structural collision check is performed on the installation of the new arch rib intersection section I and the new arch rib intersection section II by drawing drawings or three-dimensional modeling, and after the check is passed, step S3 is entered; S3, hoisting of lattice beam construction segments: according to the divided construction segments and in accordance with the preset hoisting sequence, the divided multiple construction segments are hoisted using a bracket-free cable hoisting system.

2. The method for constructing a lattice beam of a half-through steel tube concrete arch bridge as claimed in claim 1, characterized in that: The step S3 comprises the following steps: S31, using a bracket-free cable hoisting system to hoist the reference segment from below the arch rib to a predetermined installation position, and after being in place, connecting the reference segment to four hoisting rods at the installation position of the reference segment to form an installation fulcrum; S32, hoisting the new arch rib intersection section II from above the arch rib to a predetermined installation position by using a bracket-free cable hoisting system, and after being in position, fixing one end of the new arch rib intersection section II to one end of the reference section, and supporting and fixing the other end of the new arch rib intersection section II on the lower support of the half-through steel tube concrete arch bridge; S33, using a bracket-free cable hoisting system to hoist the new arch rib intersection section I from above the arch rib to a predetermined installation position, and after being in position, fixing one end of the new arch rib intersection section I to an end of the new arch rib intersection section II away from the reference section, and supporting and fixing the other end of the new arch rib intersection section I on an upper support of the half-through steel tube concrete arch bridge; S33, using a bracketless cable hoisting system to hoist the end section from above the arch rib to a predetermined installation position, after being in position, one end of the end section is supported and fixed on the upper support and fixedly connected to an end of the new arch rib intersection section I away from the arch rib intersection section II, and the other end of the end section is supported and fixed on the arch seat of the half-through steel tube concrete arch bridge; S33, hoisting one of the standard segments from below the arch rib to a predetermined installation position using a bracket-free cable hoisting system, connecting the standard segment to a hoisting rod after it is in place, and fixing one end of the standard segment to an end of the reference segment away from the arch rib intersection segment II; S33, hoisting the remaining standard segments of the construction segment group from below the arch rib to a predetermined installation position using a bracket-free cable hoisting system, connecting them with the hoisting rods at corresponding positions after they are in place, and fixing the N-1 standard segments in sequence in a direction away from the corresponding reference segment; S34, using a bracket-free cable lifting system to lift the joint section from below the arch rib to a predetermined installation position, connecting it to the lifting rod at the corresponding position after it is in place, and fixing the joint section to the standard sections of the two construction segment groups to complete the joint of the lattice beam.

3. The method for constructing a lattice beam of a half-through steel tube concrete arch bridge as claimed in claim 1, characterized in that: The two adjacent construction sections are fixedly connected by a combination of high-strength bolts and welding.

4. The method for constructing a lattice beam of a half-through steel tube concrete arch bridge as claimed in claim 1, characterized in that: During hoisting, hoists are connected on opposite sides of the reference section, the standard section and the joint section. The hoists are provided with adapters, which are located outside the vertical projection of the arch rib and are connected to the lifting rope of the bracket-free cable hoisting system.

5. The method for constructing a lattice beam of a half-through steel tube concrete arch bridge as claimed in claim 4, characterized in that: The lifting device includes a main beam and two lifting ears, one end of the main beam is rotatably connected to the adapter; the two lifting ears are fixed to the bottom surface of the main beam, the two lifting ears and the adapter are spaced apart along the length direction of the main beam, and the lifting ears are detachably connected to the lifting ring of the construction section to be lifted.

6. The method for constructing a lattice beam of a half-through steel tube concrete arch bridge as claimed in claim 5, characterized in that: The main beam includes two transverse plates, two vertical plates and two groups of stiffening plates. The transverse plates are parallel to the horizontal plane, and the two transverse plates are arranged in parallel and spaced apart in the vertical direction; the two vertical plates are arranged in spaced apart along the width of the transverse plates, and the vertical plates are vertically fixedly connected to the two transverse plates to enclose and form a cavity; the two groups of stiffening plates are respectively arranged on opposite sides of the cavity, and the multiple stiffening plates in each group are arranged in spaced apart along the length of the transverse plates, and each stiffening plate is fixedly connected to the two transverse plates and the vertical plates; the adapter is arranged outside one end of the cavity and rotatably connects one end of the two transverse plates; the lifting ear is fixed on the bottom surface of one of the transverse plates.

7. The method for constructing a lattice beam of a half-through steel tube concrete arch bridge as claimed in claim 5, characterized in that: The lifting ear includes two ear plates and a latch, wherein the two ear plates are arranged relatively spaced apart along the length direction of the transverse plate to form a plug-in space for inserting a lifting ring on the construction section; the latch is detachably inserted through the two ear plates and the lifting ring.

8. The method for constructing a lattice beam of a half-through steel tube concrete arch bridge as claimed in claim 5, characterized in that: The standard section includes a standard section main beam and a standard section secondary beam fixedly connected to the standard section main beam. The lifting ring on the standard section is arranged on the top surface of the standard section secondary beam to be staggered with the position of the lifting rod embedded pipe on the standard section main beam.

9. The method for constructing a lattice beam of a half-through steel tube concrete arch bridge as claimed in claim 8, characterized in that: Before using the sling for lifting, the reaction forces at each lifting point under the most unfavorable eccentric lifting condition are calculated by modeling to verify the structural stability of the sling and the strength of the sling itself, so as to ensure construction safety.

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