Construction Method of Spatial Y-Shape Steel Box Arch Bridge

Abstract

The present invention discloses a construction method for a spatial Y-shaped steel box arch bridge, comprising: establishing a construction reference model; according to the construction reference model, symmetrically erecting a plurality of main arch rib segments to be assembled section by section, installing a plurality of the secondary arch rib segments to be assembled on the main arch rib segments to form a zone to be lapped, erecting a temporary support in the zone to be lapped to form a support area on one side of the zone to be lapped, hoisting a plurality of the connecting rib segments to be assembled in the support area to form a hoisting opening area, and continuously hoisting the main arch rib main beam segments to be assembled in the hoisting opening area to assemble and form the spatial Y-shaped steel box arch bridge. By adopting the construction method of cable hoisting and combining it with the construction reference model, the present invention reduces the project cost, reduces the construction difficulty, is more applicable to the construction process of the spatial Y-shaped steel box arch bridge, ensures the safety during the construction process of the spatial Y-shaped steel box arch bridge, and provides a reference for similar projects of the same kind.

Description

Technical Field

[0001] The present invention relates to the technical field of the construction of spatial Y-shaped steel box arch bridges, and particularly relates to a construction method for spatial Y-shaped steel box arch bridges. Background Art

[0002] In the related art, the spatial Y-shape is a new type of arch bridge shape. Different from ordinary arch bridges, the arch ring and arch seat of the spatial Y-shaped arch bridge are divided into single-arch segments and double-arch segments, and the arch ring is in a Y shape in space. The spatial Y-shaped arch bridge has a novel structure. The design scheme abandons the traditional two-dimensional arch rib structure form, adopts a new mode of combined single and double arches with the main and auxiliary arches jointly bearing force, and is a spatial three-dimensional curve arch. Such a special-shaped arch is the first case in China. At present, steel box arch bridges are recognized by more and more people. Different from ordinary steel truss arch bridges and concrete-filled steel tube arch bridges, there are very few construction cases for this new type of structure, and there is little relevant research, lacking relevant reference experience.

[0003] Therefore, when constructing a long-span Y-shaped steel box rib arch bridge, its stress condition during the construction process is very different from that of other types of bridges, and the existing construction methods are difficult to ensure the safety during the bridge construction process. Summary of the Invention

[0004] The main purpose of the present invention is to provide a construction method for a spatial Y-shaped steel box arch bridge, aiming to solve the technical problem that when constructing a long-span Y-shaped steel box rib arch bridge in the prior art, its stress condition during the construction process is very different from that of other types of bridges, and the existing construction methods are difficult to ensure the safety during the bridge construction process.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The present invention provides a construction method for a spatial Y-shaped steel box arch bridge. The spatial Y-shaped steel box arch bridge includes a main arch rib main beam, auxiliary arch ribs, and connecting ribs. The method includes:

[0007] Precast and assemble the main arch rib main beam, the auxiliary arch ribs, and the connecting ribs to obtain a plurality of main arch rib main beam segments to be assembled, a plurality of auxiliary arch rib segments to be assembled, and a plurality of connecting rib segments to be assembled;

[0008] Establish a construction reference model;

[0009] According to the construction reference model, symmetrically erect a plurality of the main arch rib segments to be assembled section by section to form main arch rib sections;

[0010] According to the construction reference model, install a plurality of the auxiliary arch rib segments to be assembled on the main arch rib sections to form a zone to be lapped;

[0011] According to the construction reference model, a temporary support is erected in the overlapping area to form a support area on one side of the overlapping area;

[0012] According to the construction reference model, a plurality of the connecting rib segments to be assembled are hoisted in the support area to form a hoisting opening area;

[0013] According to the construction reference model, the main arch rib main beam segments to be assembled are continuously hoisted in the hoisting opening area, and the space Y-shaped steel box arch bridge is assembled.

[0014] Optionally, in the above-mentioned construction method of the space Y-shaped steel box arch bridge, the steps of establishing the construction reference model include:

[0015] Image acquisition with an attached coordinate system is performed on the construction site to obtain a site model;

[0016] Site measurement, earthwork calculation, and simulated construction are carried out in the site model to obtain construction reference data;

[0017] According to the construction reference data, the construction reference model is established.

[0018] Optionally, in the above-mentioned construction method of the space Y-shaped steel box arch bridge, the step of symmetrically erecting a plurality of the main arch rib segments to be assembled section by section according to the construction reference model to form main arch rib segments includes:

[0019] According to the construction reference model, the process of the main arch rib segments to be assembled is simulated to obtain a hoisting construction simulation result;

[0020] According to the hoisting construction simulation result, a plurality of the main arch rib segments to be assembled are symmetrically erected section by section to form main arch rib segments.

[0021] Optionally, in the above-mentioned construction method of the space Y-shaped steel box arch bridge, the numbers of a plurality of the main arch rib segments to be assembled are L1 to L27, and the step of symmetrically erecting a plurality of the main arch rib segments to be assembled section by section according to the hoisting construction simulation result to form main arch rib segments includes:

[0022] The segments L1 to L5 are erected sequentially by a cable crane system and placed on a temporary support platform;

[0023] The remaining segments are hoisted to the left bank above the arch back in sequence according to the specific hoisting order by a cable system, and the segments L29 - L27 are directly in place on the temporary support platform;

[0024] The segments L25 - L21 are directly hoisted to the installation position by a hoisting spreader beam and fixed by a suspender;

[0025] After the sling conversion of other segments is completed on the hoisting platform, erection starts from L20 and L6 in reverse order from both sides to the middle, and the main span L13 segment is closed.

[0026] Optionally, in the above construction method of the spatial Y-shaped steel box arch bridge, the spatial Y-shaped steel box arch bridge further includes a closure member, and the area between the side spans L26 and L27 is the hoisting opening area. According to the construction reference model, the steps of continuing to hoist the segments to be assembled of the main arch rib main beam in the hoisting opening area and assembling to form the spatial Y-shaped steel box arch bridge include:

[0027] Hoist the segments to be assembled of the main arch rib main beam in the hoisting opening area to form a segment to be closed;

[0028] Hoist the closure member in the segment to be closed to form the spatial Y-shaped steel box arch bridge.

[0029] Optionally, in the above construction method of the spatial Y-shaped steel box arch bridge, multiple auxiliary arch ribs are symmetrically arranged, and each auxiliary arch rib is inclined outward compared with the spatial Y-shaped steel box arch bridge in the longitudinal direction of the bridge.

[0030] Optionally, in the above construction method of the spatial Y-shaped steel box arch bridge, the included angle between the auxiliary arch rib and the spatial Y-shaped steel box arch bridge in the longitudinal direction of the bridge is 5°.

[0031] Optionally, in the above construction method of the spatial Y-shaped steel box arch bridge, one side of the auxiliary arch rib is divided into 19 blocks, with a total of 38 segments.

[0032] Optionally, in the above construction method of the spatial Y-shaped steel box arch bridge, the axis between the main arch rib main beam and the connecting rib is a circular curve.

[0033] Optionally, in the above construction method of the spatial Y-shaped steel box arch bridge, the axis between the main arch rib main beam and the connecting rib changes gradually in a circular curve.

[0034] One or more of the above technical solutions provided by the present invention may have the following advantages or at least achieve the following technical effects:

[0035] A construction method of a spatial Y-shaped steel box arch bridge proposed by the present invention installs the main arch rib main beam, auxiliary arch ribs and connecting ribs by adopting a cable hoisting construction method in combination with a construction reference model, solves the problems of site layout such as narrow site and complex elevation, reduces the project cost, reduces the construction difficulty, is more suitable for the construction process of the spatial Y-shaped steel box arch bridge, ensures the safety during the construction process of the spatial Y-shaped steel box arch bridge, and provides a reference for similar projects similar to the spatial Y-shaped steel box arch bridge. Description of the Drawings

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these provided drawings.

[0037] Figure 1 It is a schematic flow chart of the construction method of the space Y-shaped steel box arch bridge of the present invention;

[0038] Figure 2 Schematic structural diagram of the mid-support type space special-shaped steel box arch bridge of the example of the present invention;

[0039] Figure 3 For Figure 2 Schematic structural diagram of one side view of the example structure;

[0040] Figure 4 For Figure 2 Schematic structural diagram of another side view of the example structure.

[0041] Explanation of the reference numerals:

[0042] Label Name Label Name 100 Girder body 420 Special-shaped secondary arch rib 200 First pier 430 Wind bracing 300 Second pier 440 Connecting rib 400 Special-shaped arch rib 510 First suspender 500 Suspender 520 Second suspender 410 Special-shaped main arch rib 600 Connecting beam

[0043] The realization of the object of the present invention, functional features and advantages will be further described in conjunction with the embodiments with reference to the drawings. Specific embodiments

[0044] To make the object, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0045] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back...) are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the drawings). If this specific posture changes, the directional indications will also change accordingly.

[0046] In the present invention, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or system comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or system. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or system comprising such element. Additionally, the meaning of "and / or" appearing throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where both A and B are satisfied simultaneously.

[0047] In the present invention, unless otherwise clearly specified and defined, terms such as "connect" and "fix" shall be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the communication inside two elements or the interaction relationship between two elements.

[0048] In the present invention, if there are descriptions involving "first", "second", etc., such descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature.

[0049] In the present invention, suffixes such as "module", "component", "part", "member" or "unit" used to represent elements are only for the convenience of explaining the present invention and have no specific meaning in themselves. Therefore, "module", "member" or "unit" can be used interchangeably.

[0050] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Additionally, the technical solutions of each embodiment can be combined with each other, provided that it is based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0051] The inventive concept of the present invention will be further elaborated below in conjunction with some specific embodiments.

[0052] The present invention provides a construction method for a spatial Y-shaped steel box arch bridge.

[0053] Refer to Figures 1 to 4 , Figure 1It is a schematic flow chart of the construction method of the space Y-shaped steel box arch bridge of the present invention; Figure 2 Schematic structural diagram of the half-through space special-shaped steel box arch bridge of the example of the present invention; Figure 3 For Figure 2 Schematic structural diagram of one side view of the example structure; Figure 4 For Figure 2 Schematic structural diagram of another side view of the example structure.

[0054] In an embodiment of the present invention, as Figures 1 to 4 shown, a construction method of a space Y-shaped steel box arch bridge, the space Y-shaped steel box arch bridge includes a main arch rib main beam (beam body 100), a secondary arch rib (special-shaped secondary arch rib 420) and a connecting rib, and the method includes:

[0055] Step S100: Prefabricate and assemble the main arch rib main beam, the secondary arch rib and the connecting rib to obtain a plurality of main arch rib main beam segments to be assembled, a plurality of secondary arch rib segments to be assembled and a plurality of connecting rib segments to be assembled;

[0056] Step S200: Establish a construction reference model;

[0057] Step S300: According to the construction reference model, symmetrically erect a plurality of main arch rib segments to be assembled section by section to form main arch rib sections;

[0058] Step S400: According to the construction reference model, install a plurality of secondary arch rib segments to be assembled on the main arch rib sections to form a to-be-lapped area;

[0059] Step S500: According to the construction reference model, erect a temporary support in the to-be-lapped area to form a support area on one side of the to-be-lapped area;

[0060] Step S600: According to the construction reference model, hoist a plurality of connecting rib segments to be assembled in the support area to form a hoisting opening area;

[0061] Step S700: According to the construction reference model, continue to hoist the main arch rib main beam segments to be assembled in the hoisting opening area and assemble them to form a space Y-shaped steel box arch bridge.

[0062] Specifically, as Figures 2 to 4 shown, an embodiment of the half-through space special-shaped steel box arch bridge of the present invention is proposed.

[0063] In this embodiment, please refer to Figure 2, This medium - supported spatial steel box arch bridge. The medium - supported spatial steel box arch bridge spans across a valley and includes: a beam body 100. A central axis extending along its length direction is formed on the beam body 100. A first pier 200 is arranged on the central axis. The first pier 200 is located below one end of the beam body 100 and is connected to the beam body 100. Two second piers 300 are respectively arranged on both sides of the central axis. And the two second piers 300 are located below the end of the beam body 100 far from the first pier 200 and are connected to the beam body 100. A special - shaped arch rib 400 is arranged along the central axis. One end of the special - shaped arch rib 400 is connected to the first pier 200, and the other end has two connecting parts, and each connecting part correspondingly connects to one second pier 300. And, a plurality of suspender bars 500 are arranged vertically and at intervals along the central axis on the beam body 100. The bottom ends of the suspender bars 500 are all connected to the beam body 100, and the top ends are all connected to the special - shaped arch rib 400.

[0064] The technical solution of the present invention is to set the beam body 100, form a central axis extending along its length direction on the beam body 100, then set the first pier 200 below the central axis at one end of the beam body 100 and connect the first pier 200 to the beam body 100. Then, set a second pier 300 on each side at the end of the beam body 100 far from the first pier 200, and at the same time connect both second piers 300 to the beam body 100. Then, arrange the special - shaped arch rib along the central axis, and connect one end of the special - shaped arch rib to the first pier 200, and set two connecting parts at the other end, and make each connecting part correspondingly connect to one second pier 300. At the same time, set a plurality of suspender bars 500, arrange the plurality of suspender bars 500 at intervals along the central axis and make the bottom ends of the suspender bars 500 all connected to the beam body 100, and the top ends are all connected to the special - shaped arch rib. Use the special - shaped arch rib to lift the beam body 100 through a plurality of suspender bars 500, and transfer the self - weight of the bridge and the load borne through the two ends of the special - shaped arch rib to the ground through the piers. Furthermore, it can ensure the stability of the special - shaped steel arch bridge during the implementation of the present invention, and solve the technical defect that it is impossible to ensure both the stability and aesthetics of the special - shaped steel arch bridge in the related technology.

[0065] In some embodiments, the special - shaped arch rib 400 includes a special - shaped main arch rib 410. The top ends of the suspender bars 500 are all connected to the special - shaped main arch rib 410. One end of the special - shaped main arch rib 410 is connected to the first pier 200, and the other end has two connecting parts. The special - shaped main arch rib 410 includes a single - arch rib segment and a double - arch rib segment connected to each other. The single - arch segment is arranged close to the first pier 200. One end of the double - arch rib segment is connected to the first pier 200, and the other end extends in the direction away from the first pier 200 and is divided to form two connecting parts.

[0066] In some embodiments, the connection between the single-arch rib segment and the double-arch rib segment is arc-shaped and smoothly transitions, and the arcs of the single-arch rib segment and the double-arch rib segment are the same.

[0067] In some embodiments, the planar graph of the special-shaped main arch rib 410 projected orthogonally onto the beam body 100 is in a Y shape.

[0068] In some embodiments, the special-shaped arch rib 400 further includes two special-shaped secondary arch ribs 420, which are respectively arranged on both sides of the special-shaped main arch rib 410, and the heights of the two special-shaped secondary arch ribs 420 are both higher than that of the special-shaped main arch rib 410.

[0069] In some embodiments, in the width direction of the beam body 100, the two special-shaped secondary arch ribs 420 are both arranged at intervals with the special-shaped main arch rib 410.

[0070] In some embodiments, the special-shaped arch rib 400 further includes a plurality of wind braces 430, which are arranged at intervals along the central axis, and one end of each wind brace 430 is connected to the special-shaped secondary arch rib 420, and the other end is connected to the special-shaped main arch rib 410.

[0071] In some embodiments, the special-shaped arch rib 400 further includes at least two connecting ribs 440, which are arranged at intervals along the central axis, and each connecting rib 440 is arranged between the double-arch rib segments.

[0072] In some embodiments, the plurality of suspension rods 500 includes a plurality of first suspension rods 510 and a plurality of second suspension rods 520, each of the first suspension rods 510 is arranged at intervals along the central axis, and the bottom ends of the first suspension rods 510 are all connected to the beam body 100, and the top ends are connected to the single-arch rib segment. The plurality of second suspension rods 520 are symmetrically and arranged at intervals on both sides of the central axis, and the bottom ends of the second suspension rods 520 are all connected to the beam body 100, and the top ends are all connected to the double-arch rib segment.

[0073] In some embodiments, a connecting beam 600 is further connected between the two second bridge piers 300.

[0074] The technical solution of the present invention is to set a beam body 100, form a central axis extending along its length direction on the beam body 100, then set a first pier 200 below the central axis at one end of the beam body 100, and connect the first pier 200 to the beam body 100. Then, two second piers 300 are respectively set on both sides of the end of the beam body 100 far from the first pier 200, and at the same time, both second piers 300 are connected to the beam body 100. Then, the special-shaped arch ribs are arranged along the central axis, and one end of the special-shaped arch ribs is connected to the first pier 200, and two connecting parts are arranged at the other end, and each connecting part is correspondingly connected to a second pier 300. At the same time, multiple suspenders 500 are set, and the multiple suspenders 500 are arranged at intervals along the central axis and the bottom ends of the suspenders 500 are all connected to the beam body 100, and the top ends are all connected to the special-shaped arch ribs. The special-shaped arch ribs are used to lift the beam body 100 through multiple suspenders 500, and the self-weight and the load borne by the bridge are transmitted to the ground through the piers at both ends of the special-shaped arch ribs, so that the stability of the special-shaped steel arch bridge can be ensured during the implementation of the present invention, and the technical defect that the stability and aesthetics of the special-shaped steel arch bridge cannot be ensured at the same time in the related technology is solved.

[0075] In one embodiment, the steps of establishing a construction reference model include:

[0076] Step A100: Collect images of the construction site with an attached coordinate system to obtain a site model;

[0077] Step A200: Conduct site measurement, earthwork calculation, and simulated construction in the site model to obtain construction reference data;

[0078] Step A300: Establish a construction reference model according to the construction reference data.

[0079] In one embodiment, the steps of successively and symmetrically erecting multiple main arch rib segments to be assembled to form main arch rib segments according to the construction reference model include:

[0080] Step B100: Simulate the process of the main arch rib segments to be assembled according to the construction reference model to obtain the hoisting construction simulation results;

[0081] Step B200: Successively and symmetrically erect multiple main arch rib segments to be assembled according to the hoisting construction simulation results to form main arch rib segments.

[0082] In one embodiment, the numbers of multiple main arch rib segments to be assembled are L1 to L27. The steps of successively and symmetrically erecting multiple main arch rib segments to be assembled according to the hoisting construction simulation results to form main arch rib segments include:

[0083] Step C100: The segments L1 to L5 are successively erected by a cable crane system and placed on a temporary support platform;

[0084] Step C200: For the remaining segments, use the cable system to hoist the steel beam segments above the arch back to the left bank in the specific hoisting sequence. The L29 - L27 segments are directly positioned on the temporary support platform.

[0085] Step C300: Directly use the hoisting spreader beam to hoist the L25 - L21 segments to the installation position and fix them with the suspender bars.

[0086] Step C400: After the sling conversion is completed on the hoisting platform for the other segments, start erecting from L20 and L6 in a reverse order from both sides to the middle, and the L13 segment in the main span is closed.

[0087] In one embodiment, the spatial Y - shaped steel box arch bridge further includes a closure member. The area between the side - span L26 and L27 is the hoisting opening area. According to the construction reference model, continue to hoist the segments of the main arch rib main beam to be assembled within the hoisting opening area. The steps of assembling the spatial Y - shaped steel box arch bridge include:

[0088] Step D100: Hoist the segments of the main arch rib main beam to be assembled within the hoisting opening area to form a segment to be closed.

[0089] Step D200: Hoist the closure member within the segment to be closed to form the spatial Y - shaped steel box arch bridge.

[0090] In one embodiment, multiple secondary arch ribs are symmetrically arranged, and each secondary arch rib is inclined outward compared to the spatial Y - shaped steel box arch bridge in the longitudinal direction of the bridge.

[0091] In one embodiment, the included angle between the secondary arch rib and the spatial Y - shaped steel box arch bridge in the longitudinal direction of the bridge is 5°.

[0092] In one embodiment, one - side of the secondary arch rib is divided into 19 blocks, with a total of 38 segments.

[0093] In one embodiment, the axis between the main arch rib main beam and the connecting rib is a circular curve.

[0094] In one embodiment, the axis between the main arch rib main beam and the connecting rib changes gradually as a circular curve.

[0095] For easy understanding, a specific embodiment is shown below:

[0096] The main arch rib is a spatial Y - shaped variable - section box arch. The vertical projection of the arch axis adopts a catenary curve, and the equation is. Among them, the clear span is 220m (corresponding to the pile numbers K35 + 205.000 - K35 + 425.000), the clear rise is 62.5m, the arch axis coefficient m = 1.347, and the rise - span ratio is 1 / 3.52. The plane projection of the arch axis is Y - shaped, with a single arch arranged on the right bank side of the Jinghe River and double arches arranged on the left bank side of the Jinghe River. The axis bifurcates at K35 + 288.500, and the included angle is 12.42°.

[0097] The height of the cross-section from the crown to the springing of the arch box ranges from 3.0 m to 6.6 m, and the width ranges from 2.0 m to 3.5 m. The top and bottom plates and the web plates adopt a variable thickness design from the crown to the springing of the arch, with the plate thickness ranging from 16 mm to 30 mm; the stiffeners are plate ribs; the spacing of the diaphragms is about 1.5 m, and the plate thickness is 12 mm - 24 mm.

[0098] The secondary arch ribs are symmetrically arranged and inclined outward by 5° around the connection line of the starting and ending points of their axes, presenting a three-dimensional spatial structure. The arch axis adopts a catenary curve, and the equation is, where the inner clear span of the secondary arch in the plane is 184.5 m, the clear rise is 43 m, the rise-span ratio is 1 / 4.29, and the arch axis coefficient m = 1.756;

[0099] The secondary arch adopts a circular steel pipe section with a diameter of 1.4 m and a plate thickness of 24 mm; the stiffeners are plate ribs with a thickness of 12 mm; the diaphragms have a thickness of 12 mm and are arranged corresponding to the side web plates of the connecting ribs of the main and secondary arches.

[0100] The main beam adopts a double-box double-cell T-shaped steel box girder with a beam length of 274.7 m and a standard cross-section width of 18.0 m. A viewing platform is provided at the connection between the double arches and the main beam. The width of the main beam in the widened section is 36.0, and the beam height is 2.0 m. Hanger steel anchor boxes are arranged inside the main beam.

[0101] The main beam is divided into 36 segments in total, and the segment numbers are LSO to LS35. LSO, LS1, LS34, and LS35 are constructed by supports, with the maximum weight of a segment being 360 t; the segments LS2 to LS33 are constructed by hoisting, with the maximum hoisting size being 7 m × 19.8 m and the maximum hoisting weight being 116.8 t. The segments of the main beam are temporarily connected by positioning yokes and bolts. After the welding of the main structure is completed, the temporary connections are cut off, the temporary connection areas are repaired by welding, and the surfaces are polished.

[0102] A 10 cm camber is set for the main span of the main beam and is continuously and smoothly developed from the mid-span to both sides according to a parabola. The parabola equation is y = -0.0000103x 2 + 0.1.

[0103] (1) The construction deepening work of the special-shaped structure is complex and difficult.

[0104] The mid-support spatial Y-shaped steel box arch bridge presents a Y-shaped structure both in the plane and in the elevation. The bridge structure design is novel and is the first case in China.

[0105] The design scheme abandons the traditional two-dimensional arch rib structure form, adopts a new mode of combined single and double, and the combined stress of the main and secondary arches. Moreover, it is a three-dimensional spatial curve arch, and the construction deepening work is complex and difficult.

[0106] (2) The control of the installation and positioning of the overweight segments at high altitude is difficult.

[0107] This project uses a cable hoisting system to install the steel structure members of the Jinghe Bridge. The installation and positioning control of overweight segments at high altitude are difficult.

[0108] The bridge has a large span, complex structure, huge hoisting segments, difficult linear control, high requirements for aerial docking accuracy, and high safety risks, posing extremely high requirements for component positioning.

[0109] (3) The installation and positioning control of overweight segments at high altitude are difficult.

[0110] The bridge spans across both banks of the Jinghe River, and the river valley in the bridge site area is "V"-shaped.

[0111] The bedrock is exposed on both banks, the mountain slopes are steep, the natural slope is 600 - 750, locally 750 - 850, the water surface elevation of the river during the normal water period is 590m, and the water surface width is 15 - 30m.

[0112] The natural terrain environment is relatively harsh, bringing great difficulties to the construction.

[0113] This plan mainly includes the installation work of steel arch ribs and steel girders.

[0114] According to the construction experience of previous similar steel structure bridges, the main construction methods are as follows:

[0115] (1) This project adopts the organization and production mode of transporting steel girder segments processed in the factory to the site by road transportation for installation;

[0116] (2) The factory first completes the production tasks of steel arch rib segments and steel girder segments;

[0117] (3) Set up a pre-assembly site and a beam storage site at the bridge site construction area to solve the on-site storage and assembly use of the segments manufactured in the factory;

[0118] (4) Transport the steel arch rib segments and steel girder segments to the bridge site beam storage site by road transportation for storage and assembly operations;

[0119] (5) The pre-assembly site first completes the two-joint widening operation of the arch rib segments; after the arch rib segments are assembled, the assembly operation of the main girder segments begins;

[0120] (6) Use the cable crane to symmetrically erect the main arch rib segments section by section;

[0121] (7) After the installation of the main arch rib segments is completed, install the secondary arch segments;

[0122] (8) Set up temporary supports in the L1 - L6 and L27 - L29 intervals, and use the cable crane to complete the installation operation of the steel girder segments within the support area;

[0123] (9) Use the cable crane to complete the hoisting operation of the LS23 - LS5 segments section by section;

[0124] (10) Finally, complete the lifting operation of the LS24-LS25 segment in the beam lifting port area.

[0125] The following aspects should be done before installation:

[0126] (1) Re-measure the span and arch elevation, lay out the arch foot position and draw the line.

[0127] (2) Check and correct the embedded parts of the arch foot.

[0128] (3) Check the geometric dimensions and prefabrication construction quality of the arch ribs in the hoisting section.

[0129] (4) Carry out a comprehensive inspection of the lifting system and conduct a trial lift to verify the lifting capacity and system working status. The trial lift of the cable system includes the determination of the lifting weight and the selection of the weight, system observation, and collection and collation of test data.

[0130] The main arch ribs of the entire bridge have a total of 26 hoisting segments. The secondary assembled main arch rib segments are moved vertically and horizontally to the vertical bottom of the main cables by rail-type beam transport vehicles. After the segment geometric parameters and quality are inspected to meet the design requirements, they are ready for hoisting.

[0131] The steel main beam segments are transported from the processing plant to the pre-assembly site on the right bank (0# pier side) to complete the assembly and welding of the hoisted segments. The L1-L5 segments are sequentially erected using the cable hoist system and placed on the temporary support platform; the remaining segments are sequentially hoisted from the top of the arch back to the left bank using the cable system in a specific hoisting order, and the L29-L27 segments are directly in place on the temporary support platform; L25-L21 are directly hoisted to the installation position using the hoisting pole beam and fixed using the suspender (to prevent the super-wide segment from being unable to feed the beam from the feeding port); after the hoisting equipment conversion is completed on the hoisting platform, the other segments are erected from L20 and L6 in reverse order from both sides to the middle, and the main span L13 segment is closed. The side spans L26 and L27 are the hoisting ports, and finally the entire bridge is hoisted and closed.

[0132] Installation process of secondary arch ribs and connecting ribs

[0133] The auxiliary arch ribs are arranged symmetrically, and the connecting line between the starting and ending points around their axis is inclined 5° outward, forming a three-dimensional spatial structure.

[0134] The clear span of the secondary arch is 184.5m, and the rise is 43m. The secondary arch adopts a circular steel tube section with a diameter of 1.4m and a plate thickness of 24mm. According to the prefabrication production and transportation requirements of the workshop, the longest segment length is 14.885mm, and the secondary arch rib is divided into 19 blocks on one side, totaling 38 segments from FS1Z(Y) to FS19Z(Y). The weight of a single steel tube arch is less than one ton per meter, which meets the requirements of hoisting.

[0135] The axes of the main and secondary connecting ribs are circular curves, changing gradually. The cross-sectional dimension is 0.7m×1.0m, and the plate thickness is 20mm.

[0136] According to the specific site conditions and combined with previous construction experience, the welded parts of the box-shaped connecting rods are installed individually. After completing the connecting ribs of a section of the secondary arch rib, a section of the secondary arch rib is installed immediately.

[0137] (1) Use a drone equipped with five high-precision cameras, in cooperation with RTK positioning instruments, to collect images of the site with an attached coordinate system. Rapidly generate a high-precision site model according to Contest Capture. Thus, convenient site measurement, earthwork calculation, simulation of construction plans, etc. can be carried out.

[0138] (2) Optimization of the abutment excavation plan based on the three-dimensional real-scene model. In the early stage of construction, an abutment excavation model is established based on the terrain model obtained from the oblique photography model, which truly reflects the construction site conditions and arranges equipment reasonably.

[0139] (3) Processing and manufacturing based on the three-dimensional model. Establish a steel structure model of the Jinghe Bridge, including the main arch rib, secondary arch rib, connecting rib, main beam, suspender, etc., which is convenient for factory processing and on-site construction.

[0140] (4) Review of construction drawings based on the three-dimensional model. Create a BIM model according to the 2D design drawings, conduct dynamic visual display of the design results, intuitively understand the design scheme, and check the constructability of the design; during the process of model construction, discover and summarize drawing problems, communicate with the design institute in the early stage of construction, effectively reduce the rework cost of the construction party, and avoid delaying the construction period [4].

[0141] (5) Verify the feasibility of the hoisting plan based on the three-dimensional model to avoid cable collisions.

[0142] (6) Extract the material lists of the steel components on both banks based on the tower BIM model of the tower frame steel component material list, accurately calculate the engineering quantity, assist in cost control, and avoid false reporting.

[0143] (7) Based on the created BIM information project model and oblique photography terrain, quickly extract the earthwork excavation engineering quantity, which is convenient for project planning.

[0144] (8) Route planning based on the three-dimensional real-scene model. The slopes on both banks are steep, and the existing construction roads are relatively narrow, while the hoisting sections of the arch rib and main beam are huge in volume and mass; combined with the three-dimensional real-scene model to measure and plan the material transportation path, verify the rationality of the plan, and effectively ensure the safety of personnel, vehicles, and materials

[0145] (9) The elevation difference between the original construction access road and the designed access road at the connection is about 12 m. The construction excavation volume is large, the road surface slope is steep, and the access and transportation of personnel, vehicles, equipment, and materials are inconvenient, posing safety hazards. Based on the BIM model and the three-dimensional real-scene model, the plane and vertical curve element values at this location were adjusted to smoothly connect the access road in the adjusted area with the original construction access road and the designed access road. A triangular buffer area was set at the connection to facilitate vehicle avoidance and reduce safety hazards.

[0146] (10) Simulation of the construction plan for key and complex nodes. Simulate the splicing process of the main arch segments during the cable-supported erection stage and demonstrate it in the form of a video for technical disclosure.

[0147] (11) Integrate the three-dimensional real-scene model, GIS digital map, and BIM model for all specialties in-depth. Use forms such as roaming videos for plan display and visualization technical disclosure; VR immersive construction experience to discuss engineering plans and guide equipment installation.

[0148] (12) Cable-supported erection detection. The lofting data in the BIM design model is converted into accurate points and reflected in the construction site; the lofting data is imported back into the BIM model again for comparison and analysis with the model; output a detailed report on on-site operations to further improve the erection accuracy.

[0149] (13) Digital three-dimensional detection of steel structures. Use total station and other surveying equipment and precision control software to conduct digital three-dimensional detection of steel structures; three-dimensional digital computer simulation pre-assembly, which does not occupy the site, saves labor costs, avoids hoisting deformation, improves accuracy, shortens the construction period, reduces costs and increases efficiency.

[0150] (14) Application of the enterprise-level BIM platform. The enterprise-level BIM information management platform of China Railway 20th Bureau has a three-level management structure. The platform is deployed as "three terminals and one cloud", and the data is uniformly stored in the private cloud platform to ensure data security. The platform is divided into nine modules: model management, technical management, progress management, safety management, quality management, cost management, document management, monitoring management, and system management.

[0151] (15) BIM + GIS model management. Integrate the BIM model, oblique photography model, and GIS terrain data; quickly and intuitively view the three-dimensional model on the web page and mobile phone, query component information, annotation, measurement, roaming, etc. based on the model.

[0152] (16) Lightweight viewing of the model. Through the enterprise-level BIM platform, lightweight viewing of the model is realized, and the model and component attributes can be easily viewed on both the web page and mobile phone of the platform.

[0153] Through the research on the BIM technology in the installation construction process of the steel arch rib and main girder of the spatial Y-shaped steel box arch bridge, the following conclusions are obtained:

[0154] (1) Conduct BIM site layout plan simulation in advance to solve site layout problems such as narrow site and complex elevation, optimize equipment for site emergency rescue and communication based on the actual traffic conditions, and improve construction safety;

[0155] (2) Use the BIM model to accurately and quickly extract the quantities of engineering works, reduce calculation errors, and strictly control the quantities of steel bars and concrete; Reasonably arrange the site, make full use of the surrounding conditions and resources, and improve economic benefits;

[0156] (3) Conduct technical disclosure based on the BIM visual three-dimensional model and simulation, so that workers can understand the key points and difficulties of construction in advance and improve construction efficiency;

[0157] (4) Continuously update the three-dimensional real-scene model, site layout model, main structure model, etc. at important nodes during the entire construction period to fully reflect the construction status.

[0158] The technical solution of the present invention combines the construction method of cable hoisting with the construction reference model to install the main arch rib main beam, secondary arch rib and connecting rib, solves the site layout problems such as narrow site and complex elevation, reduces the project cost, reduces the construction difficulty, is more suitable for the construction process of the spatial Y-shaped steel box arch bridge, ensures the safety during the construction process of the spatial Y-shaped steel box arch bridge, and provides a reference for similar projects similar to the spatial Y-shaped steel box arch bridge.

[0159] It should be noted that the above serial numbers of the embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments. The above embodiments are only optional embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the description and drawings of the present invention under the inventive concept of the present invention, or directly or indirectly applied to other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A construction method for a spatial Y-shaped steel box arch bridge, characterized in that, The space Y-shaped steel box arch bridge includes a main arch rib, a main beam, secondary arch ribs and connecting ribs, and the method includes: Precasting and assembling the main arch rib, the main beam, the secondary arch ribs and the connecting ribs to obtain a plurality of pre-assembled segments of the main arch rib, a plurality of pre-assembled segments of the secondary arch ribs and a plurality of pre-assembled segments of the connecting ribs; Establishing a construction reference model; According to the construction reference model, symmetrically erecting a plurality of the pre-assembled segments of the main arch rib section by section to form the main arch rib section; According to the construction reference model, installing a plurality of the pre-assembled segments of the secondary arch ribs on the main arch rib section to form a connection area; According to the construction reference model, erecting a temporary support in the connection area to form a support area on one side of the connection area; According to the construction reference model, hoisting a plurality of the pre-assembled segments of the connecting ribs in the support area to form a hoisting opening area; According to the construction reference model, continuously hoisting the pre-assembled segments of the main arch rib in the hoisting opening area to assemble and form the space Y-shaped steel box arch bridge; Among them, the step of establishing the construction reference model includes: Collecting images of the construction site with an attached coordinate system to obtain a site model; Performing site measurement, earthwork calculation and construction simulation in the site model to obtain construction reference data; According to the construction reference data, establishing the construction reference model.

2. The construction method of the spatial Y-shaped steel box arch bridge according to claim 1, characterized in that The step of symmetrically erecting a plurality of the pre-assembled segments of the main arch rib section by section according to the construction reference model to form the main arch rib section includes: According to the construction reference model, simulating the process of the pre-assembled segments of the main arch rib to obtain a hoisting construction simulation result; According to the hoisting construction simulation result, symmetrically erecting a plurality of the pre-assembled segments of the main arch rib section by section to form the main arch rib section.

3. The construction method of the space Y-shaped steel box arch bridge according to claim 2, characterized in that, The numbers of the plurality of pre-assembled segments of the main arch rib are L1 to L27, and the step of symmetrically erecting a plurality of the pre-assembled segments of the main arch rib section by section according to the hoisting construction simulation result to form the main arch rib section includes: The L1-L5 segments are erected in sequence by using a cable crane system and placed on a temporary support platform; The remaining segments are hoisted to the left bank from above the arch back in sequence by using a cable system according to the specific hoisting sequence, and the L29-L27 segments are directly in place on the temporary support platform; The L25-L21 segments are directly hoisted to the installation position by using a hoisting lifting beam and fixed by a suspender; After the hoisting tool is converted on the hoisting platform for other segments, starting from L20 and L6, they are erected in a reverse order from both sides to the middle, and the main span L13 segment is closed.

4. The construction method of the space Y-shaped steel box arch bridge according to claim 3, characterized in that, The space Y-shaped steel box arch bridge further includes a closure member, and the area between the side spans L26 and L27 is the hoisting opening area. The step of continuously hoisting the pre-assembled segments of the main arch rib in the hoisting opening area according to the construction reference model to assemble and form the space Y-shaped steel box arch bridge includes: Hoisting the pre-assembled segments of the main arch rib in the hoisting opening area to form a closure segment; Hoisting the closure member in the closure segment to form the space Y-shaped steel box arch bridge.

5. The construction method of the space Y-shaped steel box arch bridge according to any one of claims 1 to 4, characterized in that, The plurality of secondary arch ribs are symmetrically arranged, and each secondary arch rib is inclined outward compared with the space Y-shaped steel box arch bridge in the longitudinal direction of the bridge.

6. The construction method of the space Y-shaped steel box arch bridge according to claim 5, characterized in that, The included angle between the secondary arch rib and the spatial Y-shaped steel box arch bridge in the longitudinal direction of the bridge is 5°.

7. The construction method of the space Y-shaped steel box arch bridge according to claim 6, characterized in that, The secondary arch rib is divided into 19 blocks on one side, with a total of 38 segments.

8. The construction method of the spatial Y-shaped steel box arch bridge according to claim 7, characterized in that, The axis of the connecting rib between the main arch rib and the secondary arch rib is a circular curve.

9. The construction method of the spatial Y-shaped steel box arch bridge according to claim 8, characterized in that, The circular curve of the connecting rib changes gradually step by step.

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