Construction method of dismantling old bridge and rebuilding suspension arch bridge to ensure traffic in water source protection area

Abstract

The invention relates to the technical field of bridges, and discloses a construction method for dismantling an old bridge in a water source protection zone and rebuilding a suspended arch bridge to ensure traffic, comprising pile foundation construction, trestle construction, dismantling of the old bridge, steel structure construction and beam lowering construction using a jack device; the construction method for dismantling an old bridge in a water source protection zone and rebuilding a suspended arch bridge to ensure traffic ensures normal traffic during the bridge construction process by erecting a first-layer steel trestle and assembling a second layer, and at the same time, a protective shed is erected on the steel trestle to ensure the safety of pedestrians and vehicles; and the safety of the water source protection zone is ensured by arranging a sewage net within a construction red line.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, in particular to a construction method for dismantling an old bridge in a water source protection area and rebuilding a suspender arch bridge to ensure traffic. Background Art

[0002] Bridges generally refer to structures erected over rivers, lakes, and seas to allow vehicles and pedestrians to pass smoothly. In order to adapt to the modern high-speed development of the transportation industry, bridges are also extended to buildings that are erected to cross mountain streams, poor geology, or meet other transportation needs to make travel more convenient. Bridges are generally composed of superstructures, substructures, supports, and ancillary structures. The superstructure, also known as the span structure, is the main structure for crossing obstacles; the substructure includes abutments, piers, and foundations; the supports are force transmission devices installed at the supporting locations of the span structure and piers or abutments; and the ancillary structures refer to the bridgehead slabs, conical slope protection, revetments, diversion projects, etc.

[0003] When building bridges, there are often various restrictions on the construction site, and some processes take too long, which has a great impact on traffic. Especially for the reconstruction of some old bridges with heavy traffic, it is even more necessary to ensure that the impact on traffic is minimized while not hindering the bridge construction. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a construction method for dismantling an old bridge in a water source protection area and rebuilding a suspended arch bridge to ensure traffic. The method has the advantages of continuous traffic during the dismantling and reconstruction of the bridge in a narrow site and no pollution to the water source protection area during the construction process, and solves the problem that when the geographical restrictions are too large, the impact of bridge construction on traffic is also large.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solution: A construction method for dismantling an old bridge in a water source protection area and rebuilding a suspender arch bridge to ensure traffic, comprising the following steps:

[0008] 1) Measure the location and use rotary drilling rigs to carry out pile foundation construction on both sides of the old bridge;

[0009] 2) During the foundation pit excavation process, drainage and water retaining works shall be set up.

[0010] Preferably, after excavating the foundation pit, the steel trestle construction is carried out, which specifically includes the following steps:

[0011] 1) First, two pollution screens were installed on the north and south sides of the old bridge;

[0012] 2) Construct steel trestle bridges on the north and south sides of Wangtong Road using the “fishing method” to drive steel pipe piles for one span and lay a span of bridge deck;

[0013] 3) Simultaneously install steel sheet piles for roadbed protection and steel pipe piles for supporting the demolition of old bridges nearby along the route;

[0014] 4) After the construction of the trestle is completed, the traffic will be diverted to the trestles on both sides, and the old bridge and old roadbed will be demolished.

[0015] Preferably, after the construction of the steel trestle is completed, the old bridge is dismantled, which specifically includes the following steps:

[0016] 1) Construction of load-bearing steel pipe piles on the north and south sides of the old bridge (completed in the previous step);

[0017] 2) Remove the load-bearing supports when erecting the old bridge under the bridge;

[0018] 3) Use two excavators with breakers to dismantle the bridge deck system symmetrically from the middle of the span to both sides;

[0019] 4) Cut and remove the web arch ring and main arch ring in blocks from the middle of the span to both sides. Remove the web arch first, then the main arch, and load and transport them while cutting (the size of the blocks is determined by the crane's rotation radius and lifting weight);

[0020] 5) Cut the hollow abutments on the east and west sides in layers and blocks from top to bottom, and transport them away with dump trucks while cutting.

[0021] Preferably, after the demolition of the old bridge is completed, the steel structure construction is carried out, which specifically includes the following steps:

[0022] 1) The factory processes and manufactures the required unit components in advance;

[0023] 2) A two-story assembly platform is built above the trestle, a full-length sliding track is installed on the assembly platform, and a beam transport trolley is installed above the east side abutment;

[0024] 3) Protective sheds are set up on the steel trestles on the north and south sides below the assembly platform for the slow lane and sidewalk; steel trestles are constructed on the old roadbed and old bridge, and protective sheds are set up for the driving lane;

[0025] 4) After the steel structure units are transported to the site, the main beam segments are assembled according to the design plan at the east side bridgehead construction site;

[0026] 5) After the main beam segment is assembled, it is hoisted to the second-floor assembly platform by a crawler crane;

[0027] 6) Move the main beam to the designated position through the beam transport trolley and sliding track, adjust the main beam, and measure the positioning;

[0028] 7) After each segment is in place, it is welded with the previous segment, and a mobile protective shed is set up under the welding point: it not only provides a construction platform for welding personnel, but also prevents welding slag from falling and affecting driving safety;

[0029] 8) After the main beam is spliced, the main arch support is set up, and the large segment arch rib is hoisted onto the main beam by a crawler crane. The arch is transported to the designated position on the beam and hoisted onto the main arch support by a truck crane for splicing. After the arch ribs are assembled, the wind bracing cross-connections between the arch ribs are installed;

[0030] 9) Remove the arch rib supports, tension the hangers for the first time, and prepare to drop the beams.

[0031] Preferably, after the steel structure construction is completed, the beam dropping construction is carried out, which specifically includes the following steps:

[0032] 1) Install jacks on the completed abutment and support the beams of the second-floor assembly platform on the jacks;

[0033] 2) Dismantle the second-floor assembly platform, steel trestle, cofferdam and trash screen, etc.; demolition order: retreat and demolition from west to east;

[0034] 3) Gradually lower the bridge superstructure to the designed elevation through the jack system;

[0035] 4) Install the main beam of the small side span on the west side and pour iron sand concrete as weight; construct the back walls and slabs on both sides.

[0036] 5) Construct the second-floor slow-moving system structure, bridge deck pavement, anti-collision guardrail and other auxiliary structures; final adjustment of the hanger cable tension; and dynamic and static load tests of the entire bridge.

[0037] (III) Beneficial effects

[0038] Compared with the prior art, the present invention provides a construction method for dismantling an old bridge in a water source protection area and rebuilding a suspender arch bridge to ensure traffic, which has the following beneficial effects:

[0039] The construction method of demolishing the old bridge and rebuilding a suspended arch bridge to ensure traffic in the water source protection area ensures normal traffic during the bridge construction by setting up a first-layer steel trestle and a second-layer assembly. At the same time, a protective shed is set up on the steel trestle to ensure the safety of pedestrians and vehicles. The safety of the water source protection area is guaranteed by setting up sewage nets within the construction red line. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of foundation pit construction in the present invention;

[0041] Figure 2 It is a schematic diagram of the construction of the trestle in the present invention;

[0042] Figure 3 It is a schematic diagram of the second-layer working platform in the present invention;

[0043] Figure 4 It is a schematic diagram of the main beam construction in the present invention;

[0044] Figure 5It is a schematic diagram of the construction of the arch rib in the present invention;

[0045] Figure 6 It is a schematic diagram of the construction of the suspension rod in the present invention;

[0046] Figure 7 It is a schematic diagram of dismantling the auxiliary engineering facilities in the present invention;

[0047] Figure 8 It is a schematic diagram of the jack beam dropping construction in the present invention;

[0048] Fig. 9 This is a schematic diagram of the completion of construction in the present invention; 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] Example

[0051] The construction method of dismantling the old bridge in the water source protection area and rebuilding the suspender arch bridge to ensure traffic includes the following steps:

[0052] 1) Measure the location and use rotary drilling rigs to carry out pile foundation construction on both sides of the old bridge;

[0053] 2) During the foundation pit excavation process, drainage and water retaining works shall be set up.

[0054] See also Figure 1-9 The bored piles of large bridges are made of rotary drilling and full casing. The specific steps are construction layout → drilling rig in place and leveling → drilling into holes → measuring the depth and diameter of the holes → first hole cleaning → measuring the thickness of the sediment at the bottom of the hole and the hole depth → installing the steel cage → placing the guide pipe → second hole cleaning → measuring the hole depth → pouring underwater concrete → measuring the elevation of the top of the concrete pile → pulling out the guide pipe → pile formation.

[0055] After excavating the foundation pit, the steel trestle construction is carried out, which specifically includes the following steps:

[0056] 1) First, two pollution screens were installed on the north and south sides of the old bridge;

[0057] 2) Construct steel trestle bridges on the north and south sides of Wangtong Road using the “fishing method” to drive steel pipe piles for one span and lay a span of bridge deck;

[0058] 3) Simultaneously install steel sheet piles for roadbed protection and steel pipe piles for supporting the demolition of old bridges nearby along the route;

[0059] 4) After the construction of the trestle is completed, the traffic will be diverted to the trestles on both sides, and the old bridge and old roadbed will be demolished.

[0060] After the steel trestle is constructed, the old bridge is dismantled, which specifically includes the following steps:

[0061] 1) Construction of load-bearing steel pipe piles on the north and south sides of the old bridge (completed in the previous step);

[0062] 2) Remove the load-bearing supports when erecting the old bridge under the bridge;

[0063] 3) Use two excavators with breakers to dismantle the bridge deck system symmetrically from the middle of the span to both sides;

[0064] 4) Cut and remove the web arch ring and main arch ring in blocks from the middle of the span to both sides. Remove the web arch first, then the main arch, and load and transport them while cutting (the size of the blocks is determined by the crane's rotation radius and lifting weight);

[0065] 5) Cut the hollow abutments on the east and west sides in layers and blocks from top to bottom, and transport them away with dump trucks while cutting.

[0066] See also Figure 1-9 After the construction of the bridge foundation piles is completed, the steel trestle is constructed on the foundation piles and the old bridge so that the traffic can continue to flow during the construction; the concrete structure of the old bridge is divided into blocks by static cutting, and then hoisted to the transport vehicle with a crane that meets the requirements and transported to the receiving site. The entire demolition process is based on the premise of ensuring the water quality safety of the Shenzhen Reservoir and the driving safety of Shawan Road. The traditional demolition process will pollute the water quality, so this plan adopts static cutting construction and demolition to ensure that the demolition construction will not affect the water quality safety of the Shenzhen Reservoir. Selection of cutting machinery: The main arch ring along the bridge top plate, bottom plate and ribs between the box chambers are cut by diamond circular saws, and the main arch ring cross bridge overall segmentation and belly arch and cross wall are cut by diamond wire saws. This demolition mainly uses diamond hydraulic blade saws and wire saw systems for static cutting construction, which has the characteristics of no vibration, high safety, fast construction speed, and no dust.

[0067] After the demolition of the old bridge is completed, the steel structure construction is carried out, which specifically includes the following steps:

[0068] 1) The factory processes and manufactures the required unit components in advance;

[0069] 2) A two-story assembly platform is built above the trestle, a full-length sliding track is installed on the assembly platform, and a beam transport trolley is installed above the east side abutment;

[0070] 3) Protective sheds are set up on the steel trestles on the north and south sides below the assembly platform for the slow lane and sidewalk; steel trestles are constructed on the old roadbed and old bridge, and protective sheds are set up for the driving lane;

[0071] 4) After the steel structure units are transported to the site, the main beam segments are assembled according to the design plan at the east side bridgehead construction site;

[0072] 5) After the main beam segment is assembled, it is hoisted to the second-floor assembly platform by a crawler crane;

[0073] 6) Move the main beam to the designated position through the beam transport trolley and sliding track, adjust the main beam, and measure the positioning;

[0074] 7) After each segment is in place, it is welded with the previous segment, and a mobile protective shed is set up under the welding point: it not only provides a construction platform for welding personnel, but also prevents welding slag from falling and affecting driving safety;

[0075] 8) After the main beam is spliced, the main arch support is set up, and the large segment arch rib is hoisted onto the main beam by a crawler crane. The arch is transported to the designated position on the beam and hoisted onto the main arch support by a truck crane for splicing. After the arch ribs are assembled, the wind bracing cross-connections between the arch ribs are installed;

[0076] 9) Remove the arch rib supports, tension the hangers for the first time, and prepare to drop the beams.

[0077] See also Figure 1-9 When constructing the overall steel structure of the bridge, a two-story construction platform is set up on the top of the steel trestle for passing vehicles. By assembling and constructing the main body and steel structure of the bridge on the two-story construction platform, it can reduce the impact on traffic and reduce the occupation of the construction site.

[0078] After the steel structure is constructed, the beam drop construction is carried out, which specifically includes the following steps:

[0079] 1) Install jacks on the completed abutment and support the beams of the second-floor assembly platform on the jacks;

[0080] 2) Dismantle the second-floor assembly platform, steel trestle, cofferdam and trash screen, etc.; demolition order: retreat and demolition from west to east;

[0081] 3) Gradually lower the bridge superstructure to the designed elevation through the jack system;

[0082] 4) Install the main beam of the small side span on the west side and pour iron sand concrete as weight; construct the back walls and slabs on both sides.

[0083] 5) Construct the second-floor slow-moving system structure, bridge deck pavement, anti-collision guardrail and other auxiliary structures; final adjustment of the hanger cable tension; and dynamic and static load tests of the entire bridge.

[0084] See also Figure 1-9After the main body and steel structure of the bridge are completed, multiple sets of jack installation systems are used, and the cap is used as the jack reaction force foundation. Steel supports are installed on the cap. Traffic is closed, the limit device is installed, and the PLC synchronous control system is used to drop to the designed height step by step. Two HW300*300H steel welded limit outer steel frames are welded on the cap; two HW300*300H steel welded limit inner steel frames are welded at the bottom of the main beam. The limit inner steel frame maintains a 2cm gap with the limit outer steel frame to form a pull-out type, and extends into the limit outer steel frame 500mm. Every 1m of the drop, the top 1m section of the limit outer steel frame is cut off by gas cutting, and then the next drop stroke is continued.

[0085] Step 1: Before falling, both jacks are removed from the cylinder. During a falling stroke, the hydraulic jack and the follower jack are retracted synchronously until a 20cm falling process is completed;

[0086] Step 2: With the follower jack mechanically locked, remove the support for the next stroke of the hydraulic jack;

[0087] Step 3: After the hydraulic jack is out of the cylinder, lock the pressure retaining ring and remove the support that follows the next stroke of the jack.

[0088] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Construction method of dismantling old bridges and rebuilding suspended arch bridges to ensure traffic in water source protection areas. Features: The steps include: 1) Measure the location and use rotary drilling rigs to carry out pile foundation construction on both sides of the old bridge; 2) During the excavation process of the foundation pit, drainage and water retaining works shall be set up; After excavating the foundation pit, the steel trestle construction is carried out, which specifically includes the following steps: 1) First, two pollution screens were installed on the north and south sides of the old bridge to protect the water source; 2) Construct steel trestle bridges on the north and south sides of Wangtong Road using the "fishing method" to drive steel pipe piles for one span and lay a span of bridge deck; 3) Simultaneously install steel sheet piles for roadbed protection and steel pipe piles for supporting the demolition of old bridges nearby along the route; 4) After the construction of the trestle is completed, the traffic will be diverted to the trestle on both sides, and the old bridge and old roadbed will be demolished; After the steel trestle is constructed, the old bridge is dismantled, which specifically includes the following steps: 1) Construction of load-bearing steel pipe piles on the north and south sides of the old bridge; 2) Remove the load-bearing supports of the old bridge under the bridge; 3) Use two excavators with breakers to dismantle the bridge deck system symmetrically from the middle of the span to both sides; 4) Cut and remove the ventral arch ring and the main arch ring in blocks from the middle of the span to both sides. Remove the ventral arch first, then the main arch, and load and transport them away while cutting; 5) Cut the hollow abutments on the east and west sides in layers and blocks from top to bottom, and transport them away with dump trucks while cutting; After the demolition of the old bridge is completed, the steel structure construction is carried out, which specifically includes the following steps: 1) The factory processes and manufactures the required unit components in advance; 2) A two-story assembly platform is built above the trestle, a full-length sliding track is installed on the assembly platform, and a beam transport trolley is installed above the east side abutment; 3) Protective sheds are set up on the steel trestles on the north and south sides below the assembly platform for the slow lane and sidewalk; steel trestles are constructed on the old roadbed and old bridge, and protective sheds are set up for the driving lane; 4) After the steel structure units are transported to the site, the main beam segments are assembled according to the design plan at the east side bridgehead construction site; 5) After the main beam segment is assembled, it is hoisted to the second-floor assembly platform by a crawler crane; 6) Move the main beam to the designated position through the beam transport trolley and sliding track, adjust the main beam, and measure the positioning; 7) After each segment is in place, it is welded with the previous segment, and a mobile protective shed is set up under the welding point: it not only provides a construction platform for welding personnel, but also prevents welding slag from falling and affecting driving safety; 8) After the main beam is spliced, the main arch support is set up, and the large segment arch rib is hoisted onto the main beam by a crawler crane. The arch is transported to the designated position on the beam and hoisted onto the main arch support by a truck crane for splicing. After the arch ribs are assembled, the wind bracing cross-connections between the arch ribs are installed; 9) Remove the arch rib supports, tension the hangers for the first time, and prepare to drop the beams.

2. The construction method for dismantling an old bridge and rebuilding a suspender arch bridge to ensure traffic in a water source protection area according to claim 1, It is characterized in that After the steel structure is constructed, the beam drop construction is carried out, which specifically includes the following steps: 1) Install jacks on the completed abutment and support the beams of the second-floor assembly platform on the jacks; 2) Dismantle the second-floor assembly platform, steel trestle, cofferdam and trash screen; demolition order: retreat and demolition from west to east; 3) Gradually lower the bridge superstructure to the designed elevation through the jack system; 4) Install the main beam of the small side span on the west side and pour iron sand concrete for weighting; construct the back walls and slabs on both sides; 5) Construction of the second-floor slow-moving system structure, bridge deck pavement and anti-collision guardrail auxiliary structure; final adjustment of the hanger cable tension; and dynamic and static load tests of the entire bridge.

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