High-speed hub cross overpass construction method

Abstract

The invention discloses a high-speed hub cross overpass construction method, which is used for realizing erection construction of an overpass steel box girder bridge body above an existing high-speed, and comprises the following steps: S1, carrying out roadbed widening and left and right side bridge lower structure construction on a construction road section of the existing high-speed; s2, a pile foundation, located in the existing high-speed middle division zone, of the overpass steel box girder bridge body is constructed; s3, construction of a lower structure of the existing high-speed middle high-related bridge is conducted; s4, the existing high-speed left-right overpass steel box girders and precast beams are erected in sequence, and a bridge deck system is constructed; and S5, pavement construction of the overpass steel box girder bridge body is conducted. According to the construction method, roadbed widening is conducted on the existing highway, construction is conducted by closing a single width during overpass construction, bidirectional traffic is conducted through opposite lanes, it is guaranteed that overpass construction is completed under the traffic state of the existing highway, the construction efficiency is improved, the construction period is short, and the influence of overpass construction on traffic of the existing highway is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road and bridge construction, in particular to a construction method for an overpass of a high-speed hub intersection. BACKGROUND

[0002] In recent years, the mileage of highways in China has steadily increased. With the development of social economy, at some hubs where highways intersect, overpass structures often need to be constructed on the basis of existing highways. The ideal construction method for such projects is to complete the construction under the premise of ensuring the traffic capacity of the existing highway. However, the difficulty lies in the construction of projects at interchange, road and bridge intersections. Since these intersections often have many obstacles and limited construction space, how to safely, efficiently and quickly complete the construction of the overpass box girder on the basis of ensuring the basic traffic capacity of the existing highway is the key and difficult point of such road and bridge projects. In the prior art, a patent application with publication number CN119553597A discloses a construction method for a middle pier of an overpass bridge under the condition of highway widening and traffic preservation, which comprises the following steps: site division, traffic information release, traffic arrangement, line adjustment, protection installation, mechanical access, middle strip removal, pile foundation construction, pile cap construction, cover beam construction in the form of support erection process, support edge protection construction, and precast box girder erection. The method can orderly and effectively quickly construct the middle pier of the overpass bridge under the condition of highway widening and traffic preservation on both sides of the highway, meet the quality and safety acceptance standards of the highway, satisfy the phased traffic guide and change nodes, efficiently construct, reduce the pressure on the existing highway traffic, and ensure driving safety. However, the method is a full-lane closed operation method, which has complex traffic control conditions and poor vehicle traffic capacity, and is not suitable for the construction of a high-speed hub. Therefore, the method needs to be improved and optimized for construction units. SUMMARY

[0003] The present application provides a construction method for an overpass of a high-speed hub intersection, which is used to realize the erection of an overpass steel box girder bridge body above an existing highway and comprises the following steps:

[0004] S1. Roadbed widening and left and right side bridge understructure construction are performed on a construction section of the existing highway.

[0005] S2. Pile foundations of the overpass steel box girder bridge body located in the middle strip of the existing highway are constructed.

[0006] S3. Construction of the understructure of a high bridge in the middle of the existing highway is performed.

[0007] S4, sequentially carrying out the construction of the existing high-speed left and right upper cross steel box girder, the erection of the prefabricated beam and the deck system, when carrying out the construction of the existing high-speed current width, closing the traffic of the existing high-speed current width, and using the other width of the existing high-speed lane for bidirectional traffic;

[0008] S5, carrying out the road surface construction of the upper cross steel box girder bridge body.

[0009] As a further illustration of the present application, the step S1 comprises culvert splicing, before the lengthening construction, longitudinally and continuously setting the Larsen steel sheet pile support along the existing road slope at the lengthening position, protecting the existing high-speed roadbed, and setting temporary steel sheet piles at the culvert top to ensure the normal steel sheet pile occlusion quality at both sides of the culvert body.

[0010] Further, in the step S4, when carrying out the steel box girder hoisting, a temporary support is set up to assist the support of the steel box girder of the upper cross steel box girder bridge body.

[0011] Further, the temporary support adopts a steel support combined with steel pipes and sectional steels, comprising an adjusting short column, an I-steel, a channel steel, a steel pipe stand and a foundation, the steel pipe stand is installed on the foundation, connected through the channel steel, the I-steel is arranged on the top of the steel pipe stand, and the adjusting short column is arranged on the I-steel.

[0012] Further, the temporary supports are arranged along the existing high-speed transversely to form steel pipe lattice columns, the steel pipe stands are connected by channel steel cross bracing and channel steel diagonal bracing, and after the temporary support is placed, a concrete guardrail is used for hard isolation protection.

[0013] Further, the foundation is a prefabricated expanded foundation, provided with a pre-embedded steel plate and a pre-embedded bolt, and the bottom of the temporary support is connected and fixed with the prefabricated expanded foundation through the pre-embedded bolt.

[0014] Further, the removal process of the temporary support comprises:

[0015] (1) first, the steel box girder is tightly pressed by a jack near the adjusting short column of the temporary support in the middle of the existing high-speed, the adjusting short column of the temporary support is flame cut, and then the jack is loosened;

[0016] (2) the steel box girder is tightly pressed by a jack at the position of the adjusting short column of the temporary support on both sides of the existing high-speed, the adjusting short column of the temporary support is flame cut, and then the jack is loosened;

[0017] (3) the disengagement of the adjusting short column from the steel box girder is observed, if not, the above steps are continuously carried out, until the steel box girder is disengaged from the adjusting short column, unloaded, and the bridge linearity is re-measured and qualified, and then the temporary support is removed.

[0018] The present application has the following beneficial effects:

[0019] The application carries out roadbed splicing and widening on the existing high-speed, carries out construction in the closed single span during overpass construction, utilizes the opposite lane for bidirectional traffic, ensures the overpass construction to be completed under the existing high-speed traffic state, improves the construction efficiency, shortens the construction period, and reduces the influence of overpass construction on the existing high-speed traffic. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The flow chart of the high-speed hub intersection overpass construction method of the application;

[0021] Figure 2 The roadbed splicing section view of the embodiment of the application;

[0022] Figure 3 The concrete guardrail structure view of the embodiment of the application;

[0023] Figure 4 The roadbed splicing process flow of the embodiment of the application;

[0024] Figure 5 The culvert lengthening view of the embodiment of the application;

[0025] Figure 6 The temporary support structure view of the embodiment of the application;

[0026] Figure 7 The temporary support arrangement view of the embodiment of the application;

[0027] Figure 8 The steel box girder hoisting step view of the embodiment of the application Figure 1 ;

[0028] Figure 9 The steel box girder hoisting step view of the embodiment of the application Figure 2 ;

[0029] Figure 10 The steel box girder hoisting step view of the embodiment of the application Figure 3 .

[0030] The drawings show: the existing high-speed 1, the widened roadbed 2, the concrete guardrail 3, the M24 bolt 4, the Larsen steel sheet pile 5, the adjusting short column 6, the I-steel 7, the channel steel 8, the steel pipe stand 9, the foundation 10. DETAILED DESCRIPTION

[0031] Embodiment:

[0032] The embodiments of the application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the application, but not all the embodiments.

[0033] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0034] like Figure 1 The method for constructing an overpass at a highway interchange, wherein the highway interchange includes an overpass steel box girder bridge and an existing highway, is used to erect the overpass steel box girder bridge above the existing highway, and includes the following steps:

[0035] S1, to widen the roadbed and construct the substructure of the bridges on the left and right sides of the existing highway construction section;

[0036] S2, Construction is carried out on the pile foundations of the overpass steel box girder bridge located in the median strip of the existing expressway;

[0037] S3, carry out the construction of the substructure of the existing highway intermediate bridge;

[0038] S4 will proceed with the construction of the steel box girder, precast beam erection, and bridge deck system on the left and right sides of the existing expressway in sequence. When the construction of the current lane of the existing expressway is carried out, the traffic on the current lane of the existing expressway will be closed, and the other lane of the existing expressway will be used for two-way traffic.

[0039] S5, proceed with road surface construction for the overpass steel box girder bridge.

[0040] This invention widens the roadbed of an existing expressway and closes one lane during overpass construction, allowing two-way traffic using the opposite lane. This ensures the existing expressway remains open to traffic while the overpass construction is completed, improving construction efficiency, shortening the construction period, and reducing the impact of the overpass construction on the existing expressway's traffic flow. Specifically, in this embodiment, the expressway hub intersection overpass construction method aims to ensure vehicle traffic during the half-lane road diversion period by temporarily widening the lanes within a certain length (e.g., 1.58km) of the existing expressway's left and right lanes. The average width of the widened roadbed is set according to the actual situation (5m), and its standard cross-section diagram is attached. Figure 2 As shown. To ensure the stability of the widened roadbed, the widened roadbed 2 consists of a rockfill subgrade + 16cm graded crushed stone + 22cm 4% water-stabilized base course + 36cm 5% thick water-stabilized crushed stone base course + 8cm AC25C coarse-grained asphalt concrete + 6cm medium-grained asphalt concrete + 4cm fine-grained modified asphalt concrete. See appendix. Figure 3As shown, the outer side guardrails of the 1.5m wide fiberglass cloth laid between the road surfaces of the widened sections in the embodiment are surrounded by concrete guardrails 3, and the longitudinal connection between the concrete guardrails is achieved by using angle steel, and the back steel supports with a longitudinal distance of 2m are closely arranged on the back, the back steel supports are anchored on the road surface on the side of the construction area by M24 bolts 4, and the anchoring depth is 19cm. The roadbed widening process of step S1 in the embodiment is shown in the attached Figure 4 As shown.

[0041] Referring to the attached Figure 5 As shown, the culvert splicing in step S1 of the embodiment also includes that the existing road slope is continuously and longitudinally supported by the Larsen steel sheet piles 5 before the extension construction, and the existing highway roadbed is protected, and the culvert top is provided with temporary steel sheet piles to ensure the normal steel sheet pile occlusion quality on both sides of the culvert body. When the cantilever height is less than 6m, the Larsen steel sheet pile SP-I is used, and when the cantilever height is less than 8m, the Larsen steel sheet pile SP-V is used, and the length of the Larsen steel sheet pile needs to ensure that the anchoring depth in the soil is not less than 0.8 times the pit depth, and is appropriately adjusted according to the geological conditions and the filling height, so as to meet the requirements of the culvert extension construction at different pit depths. The roadbed slope behind the culvert platform is excavated by grading, and does not need to be supported by steel sheet piles. After the construction is completed, all the steel sheets are pulled out.

[0042] Before the existing culvert cone protection slope, wing wall and other affiliated structures are removed, the Larsen steel sheet piles are supported along the existing road slope at the extension position, and the supporting range is accurate to the range of the backfilling of the culvert platform. The length of the steel sheet pile needs to be determined according to the height of the proposed culvert passage and the site conditions, and the anchoring depth in the soil is not less than 0.8 times the pit depth, so as to prevent the soil from being unstable and collapsed due to vehicle vibration, affecting the safety of driving, and safety warning signs are set on the roadside to remind passing vehicles.

[0043] According to the site construction conditions, the single insertion method is used. From one corner, each block is inserted and inserted without stopping in the middle. Therefore, the pile machine has a short walking route, the construction is simple, and the setting speed is fast. However, due to single insertion, it is easy to tilt to one side, the cumulative error is not easy to correct, and the flatness of the wall surface is difficult to control.

[0044] ①First, the axis of the steel sheet pile is determined by the survey personnel, and guide piles can be set at certain intervals, and then the guide wire is hung as a guide line, and the axis of the steel sheet pile is controlled by the guide line during piling. In the case of high axial normal requirement, a guide frame is used.

[0045] ②Prepare the pile cap and send the pile: the piling machine lifts the steel sheet pile, and the workers manually right the position.

[0046] ③Single pile continuous, pay attention to the top elevation of the pile.

[0047] ④ During the driving process, the inclination of each pile should be measured and monitored at any time to ensure that it does not exceed 2%. If the inclination is too large and cannot be corrected by pulling it together, it should be pulled out and driven again.

[0048] Specifically, in step S4, during the hoisting of the steel box girder, temporary supports are erected to assist in supporting the upper span of the steel box girder. See Appendix. Figures 6-7 As shown, the temporary support described in this embodiment is a steel support system composed of steel pipes and structural steel sections: including adjusting short columns 6, I-beams 7, channel steel 8, steel pipe columns 9, and foundations 10. The adjusting short columns are used to adjust the flatness and control the elevation of the steel box girder; after the steel box girder is in place, the adjusting short columns are used to control the flatness and elevation of the assembled steel box girder. The I-beams mainly serve to distribute forces and provide jacking and sliding support. The temporary support and foundation mainly serve to provide temporary support and bear the weight of the steel box girder, and are dismantled after the steel box girder is installed. The temporary support uses φ273×8 steel pipe columns, with 10# channel steel used for transverse connections between columns, 10# channel steel for diagonal bracing, and double-splitting 2×I40a I-beams for distribution beams. Pads and leveling steel pipes are installed at the top of the columns to adjust the flatness of the assembled steel box girder, with a height of 300mm. All components of the temporary support are made of Q235 steel.

[0049] To avoid affecting lane traffic, the temporary support structure is 1.5m wide and has three steel pipe lattice columns arranged laterally. The steel pipe columns are connected by channel steel horizontal bracing and channel steel diagonal bracing. The spacing between the steel pipe columns in the transverse direction is 3 meters. After the temporary support structure is placed, it is protected by concrete guardrails to prevent impact.

[0050] During the installation of steel box girders, the erection of temporary supports is a crucial step. A comprehensive inspection must be conducted before hoisting the steel box girders. Key checks include the verticality of the supports and the overall stability of the support system. The top elevation of all temporary supports must be re-measured. Installation edges and centerlines must be measured and marked on the piers and all temporary supports. Positioning blocks must be welded, and settlement observation points must be set up.

[0051] The temporary support system utilizes steel pipe lattice columns and reinforced concrete spread foundations. The columns are Φ273*8mm steel pipe columns, fixed at the column bases with pre-embedded steel plates. The distribution beams at the column tops are made of 2*I40a steel sections, and the adjusting short columns at the top of the distribution beams are made of φ200 round pipes. The top surface is cut at different angles according to the cross slope of the box girder to ensure dense and stable support. Other diagonal braces use 10# channel steel components. Diagonal braces are added in the plane using a triangular structure to ensure support stability. Each set of supports has a vertical up-and-down channel supported by φ14 threaded steel bars, with protective cages and fall arrestors. Temporary supports are set according to the location characteristics of the steel box girder and the segmented locations of the beam processing. During the overspan construction, temporary supports are erected for temporary support. The temporary support structure controls the elevation and alignment of the steel box girder, ensuring that the girder's alignment meets design requirements.

[0052] Referring to the drawings Figures 8-10 As shown in the figure, in the step S4, the traffic of the existing highway is closed, and the other existing highway is used for bidirectional traffic. Specifically, the steel box girder overpass hoisting of the embodiment is carried out according to the following steps:

[0053] Step one:

[0054] 1. According to the traffic organization scheme, the right lane of the existing highway is closed, and the left lane is used for single-lane bidirectional traffic.

[0055] 2. The A / D ramp is erected across the right lane and the outer support of the highway.

[0056] Step two: A ramp F section hoisting

[0057] 1. Construction content: A ramp section F; the right lane of the existing highway is closed; the hoisting machinery is stationed on the highway, and the transport vehicles are arranged in front of the hoisting machinery in turn.

[0058] 2. Construction sequence: F2→F1→FT1→FT2

[0059] 3. The main girder is hoisted by a 260t automobile crane, wherein the hoisting weight of F1 section is 36t, the automobile crane arm is 30.6m, the turning radius is 16m, the rated lifting weight is 47t, and the load rate is 77%, which meets the hoisting requirements.

[0060] Step three: A ramp section E-D hoisting

[0061] 1. Construction content: A ramp section E-D; the right lane of the existing highway is closed; the hoisting machinery is stationed on the highway, and the transport vehicles are arranged in front of the hoisting machinery in turn.

[0062] 2. Construction sequence: E2→E1→D2→D1→both sides of the arm;

[0063] 3. The main girder is hoisted by a 350t automobile crane, wherein the hoisting weight of D2 section is 50t, the automobile crane arm is 31m, the turning radius is 16m, the rated lifting weight is 78t, and the load rate is 64%; the operation radius of E2 section is maximum 18m, the section weight is 45t, the rated lifting weight is 58t, and the load rate is 78%, which meets the requirements.

[0064] Step four: D ramp section A / B hoisting

[0065] 1. Construction content: D ramp section A-B; the right lane of the existing highway is closed; the hoisting machinery is stationed on the highway, and the transport vehicles are arranged in front of the hoisting machinery in turn.

[0066] 2. Construction sequence: A2→A1→B2→B1→both sides of the arm;

[0067] 3. The main girder is hoisted by a 260t truck crane, wherein the hoisting weight of the A2 segment is 43t, the truck crane boom is 30.6m, the turning radius is 14m, the rated lifting capacity is 55t, and the load rate is 79%; the maximum operation radius of the A1 segment is 16m, the segmented weight is 38t, the rated lifting capacity is 47t, and the load rate is 81%, which meets the requirements.

[0068] Step five:

[0069] 1. According to the traffic organization scheme, the right lane of the existing highway is unblocked;

[0070] 2. According to the traffic organization scheme, the left lane of the existing highway is closed, and the right lane is changed to bidirectional traffic.

[0071] Step six: D ramp segment C / D hoisting

[0072] 1. Construction content: D ramp segment D-C; the left lane of the existing highway is closed; the hoisting machinery is positioned on the highway, and the transport vehicles are arranged in front of the hoisting machinery in turn;

[0073] 2. Construction sequence: D2-D1→C2-C1→both sides of the boom;

[0074] 3. The main girder is hoisted by a 260t truck crane, wherein the hoisting weight of the C2 segment is 36t, the truck crane boom is 30.6m, the rated lifting capacity is 47t, and the load rate is 77%, which meets the requirements.

[0075] Step seven: A ramp segment C-A hoisting

[0076] 1. Construction content: A ramp segment C-A; the left lane of the existing highway is closed; the hoisting machinery is positioned on the highway, and the transport vehicles are arranged in front of the hoisting machinery in turn;

[0077] 2. Construction sequence: C2-C1→A2-A1→B2-B1→both sides of the boom;

[0078] 3. The main girder is hoisted by a 260t truck crane, wherein the hoisting weight of the B2 segment is 45t, the truck crane boom is 30.6m, the turning radius is 14m, the rated lifting capacity is 55t, and the load rate is 82%; the maximum operation radius of the C2 segment is 18m, the segmented weight is 33t, the rated lifting capacity is 40t, and the load rate is 83%, which meets the requirements.

[0079] Step eight:

[0080] Steel box girder welding and painting.

[0081] After the hoisting of the steel box girder is completed, the temporary support is removed, and during the removal of the temporary support:

[0082] (1) first adopt 20t jack to top the steel box girder near the adjusting short column of the existing high-speed intermediate temporary support, then flame cut the intermediate temporary support adjusting short column, the cutting amount is 10mm, then loosen the jack;

[0083] (2) adopt 20t jack to top the steel box girder at the adjusting short column position of the existing high-speed temporary support on both sides, then flame cut the adjusting short column of the temporary support on both sides, the cutting amount is 10mm, then loosen the jack;

[0084] (3) observe the disengagement of the adjusting short column and the steel box girder, if not disengaged, continue the above steps until the steel box girder is disengaged from the adjusting short column, unload is completed, after the bridge linear retest is qualified, remove the temporary support.

[0085] The above only describes the preferred embodiments of the present application, but cannot be understood as a limitation on the claims. The present application is not limited to the above embodiments, and the specific structure allows changes. In general, any changes made within the protection scope of the independent claims of the present application are within the protection scope of the present application.

Claims

1. A method for constructing an overpass at a highway interchange, the highway interchange comprising an overpass steel box girder bridge and an existing highway, the method being used to erect the overpass steel box girder bridge above the existing highway, characterized in that, Includes the following steps: S1, to widen the roadbed and construct the substructure of the bridges on the left and right sides of the existing highway construction section; S2, Construction is carried out on the pile foundations of the overpass steel box girder bridge located in the median strip of the existing expressway; S3, carry out the construction of the substructure of the existing highway intermediate bridge; S4 will proceed with the construction of the steel box girder, precast beam erection, and bridge deck system on the left and right sides of the existing expressway in sequence. When the construction of the current lane of the existing expressway is carried out, the traffic on the current lane of the existing expressway will be closed, and the other lane of the existing expressway will be used for two-way traffic. S5, proceed with road surface construction for the overpass steel box girder bridge.

2. The construction method for overpass crossings at highway hubs according to claim 1, characterized in that: Step S1 includes culvert splicing. Before the splicing construction, Larssen steel sheet piles are continuously driven longitudinally along the existing road slope at the splicing point to protect the existing highway subgrade. Temporary steel sheet piles are set at the top of the culvert to ensure the quality of the interlocking with the normal steel sheet piles on both sides of the culvert body.

3. The construction method for overpass crossings at highway hubs according to claim 1, characterized in that: In step S4, when hoisting the steel box girder, temporary supports are erected to assist in supporting the steel box girder spanning the bridge body.

4. The construction method for the overpass crossing of a high-speed hub according to claim 3, characterized in that: The temporary support is a steel support composed of steel pipes and structural steel, including adjusting short columns, I-beams, channel steel, steel pipe columns and foundation. The steel pipe columns are installed on the foundation and connected by the channel steel. The I-beams are set on the top of the steel pipe columns and the adjusting short columns are set on the I-beams.

5. The construction method for the overpass crossing of a high-speed hub according to claim 3, characterized in that: The temporary supports are arranged laterally along the existing highway to form steel pipe lattice columns. The steel pipe columns are connected by channel steel horizontal bracing and channel steel diagonal bracing. After the temporary supports are placed, they are protected by concrete guardrails.

6. The construction method for the overpass crossing of a highway hub according to claim 3, characterized in that: The foundation is a prefabricated enlarged foundation, which is equipped with embedded steel plates and embedded bolts. The bottom of the temporary support is connected and fixed to the prefabricated enlarged foundation by the embedded bolts.

7. The construction method for overpass crossings at highway hubs according to claim 4, characterized in that: The removal process of the temporary support includes: (1) First, use jacks to tighten the steel box girder near the adjusting short column of the existing highway intermediate temporary support, then use flame cutting to cut the adjusting short column of the intermediate temporary support, and then loosen the jacks. (2) Use jacks to tighten the steel box girder at the position of the adjusting short column of the temporary support on both sides of the existing highway, flame cut the adjusting short column of the temporary support on both sides, and then loosen the jacks. (3) Observe the separation of the adjusting short column from the steel box girder. If it has not separated, continue the above steps until the steel box girder and the adjusting short column are separated and unloaded. After the bridge linearity is retested and qualified, the temporary support is removed.

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