A method for installing a steel box girder in situ

Abstract

The application relates to a field construction installation method of a steel box girder, and belongs to the technical field of building construction, which comprises the following steps: S1, steel box girder factory internal blanking, manufacturing plate unit element, transportation to a site assembling field for matching assembly, and adopting a '3+1' matching assembling mode; S2, after beam blocks are assembled in an assembling area, the beam blocks are hoisted from an assembling field internal access road, a 110t self-walking flat car is adopted to transport the beam blocks to a pier hoisting area along a beam transportation access road, after the beam blocks are hoisted by a 120t bridge surface gantry crane, the flat car continues to straightly move forward, passes through the beam transportation access road between adjacent piers, returns to the internal access road along the beam transportation access road, and all the beam blocks are transported in this mode; S3, concrete bridge surface assembling is carried out; and S4, approach bridge composite beam assembling is carried out. The application has the effect of reducing construction difficulty.

Description

Technical Field

[0001] This application relates to the technical field of building construction, and in particular to a method for on-site construction and installation of steel box girders. Background Technology

[0002] As people's living standards improve, there is an increasing number of construction projects, including bridge construction.

[0003] Due to the unique geographical environment of the Jinsha River Bridge, the Jinsha River is not navigable, so the bridge beams cannot be transported by waterway and floating cranes cannot be used. Furthermore, the Jinsha River Bridge is a single-tower cable-stayed bridge, and using cable cranes would be difficult to implement and too costly.

[0004] Regarding the aforementioned technologies, the inventors believe that the construction process is complex and presents significant construction difficulties. Summary of the Invention

[0005] In order to reduce the difficulty of construction, this application provides a method for on-site construction and installation of steel box girders.

[0006] The on-site construction and installation method for steel box girders provided in this application adopts the following technical solution:

[0007] A method for on-site construction and installation of steel box girders includes the following steps:

[0008] S1. Steel box girders are cut and fabricated in the factory, and then transported to the construction site assembly yard for matching and assembly. The "3+1" matching and assembly method is adopted.

[0009] S2. After the beam blocks are assembled in the assembly area, they are lifted from the access road in the assembly yard and transported to the pier lifting area by a 110t self-propelled flatbed truck along the beam transport access road. After the 120-ton gantry crane on the bridge deck lifts the beam blocks, the flatbed truck continues to move forward straight, passes through the beam transport access road between adjacent piers, and returns to the access road in the yard along the beam transport access road. All beam blocks are transported in this way.

[0010] S3. Assemble the concrete bridge deck;

[0011] S4. Assemble the composite beams of the approach bridge.

[0012] By adopting the above technical solutions, the entire construction process is carried out through assembly, which reduces the difficulty of construction and achieves the effect of reducing construction difficulty.

[0013] Optionally, in step S1, the assembly jig in the assembly area uses concrete as a strip foundation, with H-shaped steel distribution beams and horizontal adjustment templates laid on top.

[0014] By adopting the above technical solutions, concrete strip foundations are more robust, resulting in higher construction safety and achieving the effect of improving construction safety.

[0015] Optionally, in step S1, the following components are installed: the left and right box bottom plates are fitted with jigs; the left and right box partition plates are fitted with jigs; the left and right box inner and outer web plates are fitted with jigs; the middle crossbeam partition plate is fitted with jigs; the bridge deck is fitted with jigs; the anchor box is fitted with jigs; and the vent is fitted with jigs.

[0016] By adopting the above technical solution, the assembly frame is gradually assembled, thus reducing the difficulty of construction and achieving the effect of reducing construction difficulty.

[0017] Optionally, in step S1, the segmental assembly jig uses H-beams, is laid on a concrete strip foundation, and the theoretical port line and positioning line sampling points are marked.

[0018] By adopting the above technical solutions, theoretical port lines and positioning line ground sample points are delineated, making construction more accurate and achieving the effect of improving construction accuracy.

[0019] Optionally, in step S1, after all plate units are assembled, temporary lifting lugs are welded, and the beam segment is removed from the mold after passing inspection, each segment is divided into three blocks: left and right side boxes and a middle box, and stored in the beam segment storage area, waiting for the beam transport vehicle to transport it to the pier lifting station.

[0020] Optionally, in step S2, the steel beam components must be stored according to type and assembly sequence, using sleepers as support for the components. Multiple layers of major components are strictly prohibited to avoid component twisting. Important and easily corroded components such as high-strength bolt connections must be stored in designated beam segment storage areas according to specifications. The steel beam storage area must be well-drained and free of standing water. The sleeper support layer must be flat and compacted.

[0021] By adopting the above technical solution, the steel beams are stored in a way that protects them, thus achieving the desired effect of protecting the steel beams.

[0022] Optionally, in step S3, the bridge deck assembly jig uses 28 φ500×16×600 straight seam steel pipes as the pier support jig. According to the ground line map, the left box girder is positioned by the plumb line. Before hoisting, pads are placed on the pier support jig. The middle crossbeam box girder is hoisted onto the pier support jig and stored. The left box girder is slowly inserted. The right box girder is hoisted onto the pier support jig and stored. It is slowly inserted close to the middle crossbeam box girder. The longitudinal butt welds of the left and right box girder and the middle box girder are connected. The temporary lifting lugs are removed and the hoisting lugs are welded.

[0023] Optionally, in step S3, a beam storage area is set on the concrete beam to facilitate beam storage after the beam is assembled.

[0024] By adopting the above technical solution, the setting of the beam storage area can store steel beams and achieve the effect of storing steel beams.

[0025] Optionally, in step S3, the beam is transported on the concrete bridge deck.

[0026] By adopting the above technical solutions, beams can be transported on the bridge deck in a convenient and efficient manner.

[0027] Optionally, in step S4, the following steps are performed: marking the ground line, making the formwork, positioning the formwork on the longitudinal beam, positioning the cross bracing components, positioning the horizontal connecting rods and node plates, welding the node plates to the longitudinal beams, installing the steel formwork segment components, welding the formwork to the longitudinal beams, welding the formwork butt welds, installing and welding temporary hoisting lugs, and welding temporary connectors for the installation interfaces.

[0028] By adopting the above technical solution and following the above steps, the composite beams of the approach bridge are assembled, thus achieving the effect of installing the composite beams of the approach bridge. Attached Figure Description

[0029] Figure 1 This is a construction flowchart of an embodiment of this application. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0031] This application discloses a method for on-site construction and installation of steel box girders.

[0032] A method for on-site construction and installation of steel box girders includes the following steps:

[0033] S1. Reference Figure 1 Steel box girder components are cut and fabricated in the factory, then transported to the assembly yard on site for matching and assembly. The total area of ​​the assembly yard under the bridge is 38 meters × 200 meters, with a storage area for plate units, a matching jig area, and a beam block painting (storage area). It is equipped with two 20-ton gantry cranes and one 120-ton gantry crane. The on-site assembly area is 34 meters × 66 meters, using a "3+1" matching assembly method. The assembly jig in the assembly area uses concrete strip foundations, with H-shaped steel distribution beams and horizontal adjustment templates laid on top. After the steel box girder is fully assembled, the beam segments are transported from the assembly yard to the No. 6 pier lifting station by a beam transport flatbed truck via a beam transport access road, waiting for the gantry crane at the lifting station to lift them.

[0034] The segmental assembly jig uses H-beams, laid on a concrete strip foundation, and is designed to mark the theoretical ports.

[0035] The following are examples of positioning points: The left and right side box bottom plates are fitted with jigs, and positioning is controlled by aligning the bottom plate unit end lines with the jig lines. The bottom plate butt joints are welded. The left and right side box partition plates are fitted with jigs, and positioning is controlled by aligning the partition unit lines with the jig lines. The partitions are arranged perpendicular to the bottom plate, and the flatness of the partitions is controlled. The fillet welds between the partitions and the bottom plate are welded. The left and right side box inner and outer web plates are fitted with jigs, and positioning is controlled by aligning the web unit lines with the jig lines. The penetration welds between the inner and outer web plates and the bottom plate and partitions are welded. The middle crossbeam partition plate is fitted with jigs, and positioning is controlled by the center line of the crossbeam joint. The crossbeam joint and crossbeam...

[0036] The diaphragm is only spot-welded to the web and bottom plate of the left and right side boxes; the bridge deck's upper frame uses the top plate port dimensions to control the positioning of the top plate, first positioning the top plate unit in the middle of the crossbeam, then positioning the other top plate units sequentially from the middle to both sides, welding the fillet welds between the top plate and the diaphragm and web plate, and only spot-welding to the joints between the left and right side boxes and the top plate of the middle crossbeam; the anchor box upper frame requires precise measurement of the anchor box position and angle when installing the anchor box on the outer side of the outer web plate, and welding the full penetration fillet weld between the anchor box and the outer web plate; the vent fixture upper frame positions the vents on both sides of the left and right side boxes, and anchor pipe holes are opened in the top plate of the vent. Installing the anchor pipe requires precise measurement of the anchor pipe angle, welding of fillet welds between the anchor pipe and the top plate of the vent, and between the vent and the outer web of the side box; after all plate units are assembled, temporary hoisting lugs are welded, and after passing inspection, the beam segment is removed from the mold, and each segment is divided into three blocks: the left and right side boxes and the middle box, which are stored in the beam segment storage area, waiting for the beam transport vehicle to transport it to the No. 6 pier lifting station.

[0037] S2, Reference Figure 1 All steel beam components must be stored according to type and assembly sequence, using sleepers as support. Multiple layers of major components are strictly prohibited to avoid twisting. Important and easily corroded components, such as high-strength bolt connections, must be stored in designated beam segment storage areas according to specifications. The steel beam storage area must be well-drained and free of standing water. Sleeper pads must be flat and compacted to ensure stability and prevent slippage or tilting. Friction surfaces must be protected during component storage; construction and non-construction personnel are strictly prohibited from stepping on components. Stacking must be stable and reliable. The under-bridge assembly segment storage area uses ф450mm×20mm×1000mm steel pipes as pier supports. The left and right side box girder and the central crossbeam box girder are stored separately on the pier supports for cleaning and polishing.

[0038] After a single steel box girder segment is assembled, it is divided into three segments: two main box girders and one crossbeam. The largest segment is 3.5m high, 12.5m wide, and 16m long, and the heaviest segment weighs 105 tons. After the segments are assembled in the assembly area, they are lifted from the assembly yard access road and transported to the lifting area of ​​pier #6 using a 110t self-propelled flatbed truck. After the 120-ton gantry crane on the bridge deck lifts the segment, the flatbed truck continues forward, passing through the access road between piers #4 and #5, and then returns to the access road within the yard. All segments are transported in this manner.

[0039] The access road design was determined based on the dimensions and climbing ability of the beam transport flatbed trucks. Due to site constraints, the access road is L-shaped, with a total length of 156m, and is constructed entirely of 20cm thick C30 concrete. The section from the start to the curve is 50.5m long and 21m wide, with a maximum longitudinal slope not exceeding 13% and a turning radius of 30m. The section from the curve to the lifting station is 105.5m long and 13m wide, with a maximum longitudinal slope not exceeding 8%. Before hardening, a soil bearing capacity test was conducted on the excavated and backfilled soil of the access road, requiring a bearing capacity of 230KPa. Drainage ditches are installed on both sides of the access road, with a bottom width and depth of no less than 30cm and a slope consistent with the access road. Warning signs are placed at significant changes in the route at the start, the lifting station, and the curve. Pedestrian walkways are provided along the edge of the access road to separate the beam transport route from the pedestrian walkway. During beam transport, dedicated personnel direct traffic on site.

[0040] S3. Reference Figure 1 The bridge deck is equipped with one assembly area and one beam segment storage area. The assembly area has an area of ​​35 meters × 18 meters and is equipped with one 120-ton gantry crane with a track span of 22 meters and a lifting height of 32 meters, two beam transport trolleys, and four beam transport trolley tracks. The beam transport trolley tracks are arranged on both sides of the bridge centerline, with a span of 7.7 meters between the tracks on both sides and a spacing of 1.2 meters between the tracks on each side. There are also four 100-ton hydraulic jacks. The assembly jig uses 28 steel pipes with a specification of Ф350×30×700 as pier supports. The pier supports are evenly distributed near the transverse diaphragms of the beam segments according to the beam segment structure. Seven pier supports are arranged in a single row along the bridge direction with the assembly area centerline as the reference, and four pier supports are arranged in the transverse direction with the bridge centerline as the reference.

[0041] The bridge deck assembly frame uses 28 φ500×16×600 straight seam steel pipes as the pier support frame.

[0042] The beams are evenly distributed to the left and right sides along the centerline of the bridge road. Based on the site survey map, the left side box girder is positioned using a plumb line. Before hoisting, pads are placed on the pier support frame to ensure the frame is on the same horizontal plane. Temporary supports are placed on the outer web and vents of the box girder to prevent overturning. The middle crossbeam box girder is hoisted onto the pier support frame for storage. The gantry crane lifts the beam segment and slowly inserts it near the left side box girder. After positioning, pads are inserted on the pier supports to ensure the left and right side box girder and the middle box girder are on the same plane. The right side box girder is hoisted onto the pier support frame for storage. The gantry crane lifts the beam segment and slowly inserts it near the middle crossbeam box girder. After positioning, pads are inserted on the pier supports to ensure the left and right side box girder and the middle box girder are on the same plane. The longitudinal butt welds of the left and right side box girder and the middle box girder are connected. Temporary lifting lugs are removed, and new lifting lugs are welded. After inspection and approval, the beam segment is removed from the support frame and awaits transport by the beam transport vehicle to the bottom of the bridge erecting machine.

[0043] A beam storage area is set up on the concrete beam, supported by four φ32.5cm concrete column piers, which facilitates the storage of the beam after it has been assembled on the beam.

[0044] The bridge deck segments were sequentially lifted using the 120t gantry crane lifting station at the tail of pier #6, and hoisted into the bridge deck assembly pier support frame for assembly. The assembled segments were then stored in the temporary storage area for later transport, depending on the construction schedule. After assembly, four 100-ton hydraulic jacks simultaneously lifted the segments, awaiting the arrival of the electric beam transport trolley. The trolley then slowly descended beneath the segments, while the four 100-ton hydraulic jacks continued their descent until the segments were securely placed on the trolley. Once on the trolley, the segments were slowly pulled to the bottom of the bridge erecting machine by a 20-ton winch, ready for erection.

[0045] Bridge crane hoisting.

[0046] S4, Reference Figure 1 Mark the ground layout, fabricate the formwork, position the formwork on the longitudinal beams, and pay attention to controlling the transverse spacing, transverse slope, and verticality of the web of the longitudinal beams; position the cross bracing components, horizontal connecting rods, and node plates, and weld the node plates to the longitudinal beams; install the steel formwork sections, weld the formwork to the longitudinal beams, and weld the butt joints of the formwork; install and weld temporary hoisting lugs, and weld temporary connectors for the installation interfaces; remove the formwork from the formwork after all inspections are passed.

[0047] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for on-site construction and installation of steel box girders, characterized in that: Includes the following steps: S1. Steel box girder is cut and fabricated in the factory, and then transported to the construction site assembly yard for matching and assembly. The "3+1" matching and assembly method is adopted to assemble the plate unit into three independent beam blocks: two side boxes on the left and right sides and a middle box. S2. After the beam blocks are assembled in the assembly area, they are lifted from the access road in the assembly yard and transported to the pier lifting area by a 110t self-propelled flatbed truck along the beam transport access road. After the 120-ton gantry crane on the bridge deck lifts the beam blocks, the flatbed truck continues to move forward straight, passes through the beam transport access road between adjacent piers, and returns to the access road in the yard along the beam transport access road. All beam blocks are transported in this way. S3. On the concrete bridge deck, 28 φ500x16x600 straight seam steel pipes are used as pier support frames to assemble the left and right side boxes and the middle box of the three beam blocks to be transported onto the bridge, thus completing the bridge deck assembly of the steel box girder segment, and then transporting the subsequent beam blocks on the concrete bridge deck. S4. Assemble the composite beams of the approach bridge.

2. The on-site construction and installation method for a steel box girder according to claim 1, characterized in that: In step S1, the assembly jig in the assembly area uses concrete as a strip foundation, and H-shaped steel distribution beams and horizontal adjustment templates are arranged on top.

3. The on-site construction and installation method for a steel box girder according to claim 1, characterized in that: In step S1, the following are installed: the jigs on the bottom plates of the left and right boxes, the jigs on the partition plates of the left and right boxes, the jigs on the inner and outer web plates of the left and right boxes, the jigs on the partition plates of the middle crossbeam, the jigs on the bridge deck, the jigs on the anchor box, and the jigs on the vents.

4. The on-site construction and installation method for a steel box girder according to claim 3, characterized in that: In step S1, the segmental assembly jig uses H-beams and is laid on a concrete strip foundation, with theoretical port lines and positioning line sampling points marked out.

5. The on-site construction and installation method for a steel box girder according to claim 3, characterized in that: In step S1, after all plate units are assembled, temporary lifting lugs are welded, and after passing inspection, the beam segment is removed from the mold. Each segment is divided into three blocks: left and right side boxes and a middle box. These blocks are stored in the beam segment storage area, waiting for the beam transport vehicle to transport them to the pier lifting station.

6. The on-site construction and installation method for a steel box girder according to claim 1, characterized in that: In step S2, the steel beam components must be stored according to type and assembly order. Sleepers should be used as support for the components. It is strictly forbidden to stack the main components in multiple layers to avoid twisting of the components. Important and easily corroded components such as high-strength bolt connections should be stored in the designated beam segment storage area according to specifications. The steel beam storage site must be kept well-drained and free of standing water. The sleeper padding layer must be flat and compact.

7. A method for on-site construction and installation of a steel box girder according to claim 1, characterized in that: In step S3, the bridge deck assembly frame uses 28 φ500×16×600 straight seam steel pipes as the pier support frame. According to the ground line map, the left box girder is positioned by the plumb line. Before hoisting, pads are placed on the pier support frame. The middle crossbeam box girder is hoisted onto the pier support frame and stored. The left box girder is slowly inserted. The right box girder is hoisted onto the pier support frame and stored. It is slowly inserted close to the middle crossbeam box girder. The longitudinal butt welds of the left and right box girder and the middle box girder are connected. The temporary lifting lugs are removed and the hoisting lugs are welded.

8. A method for on-site construction and installation of a steel box girder according to claim 1, characterized in that: In step S3, a beam storage area is set up on the concrete beam to facilitate the storage of the beam after it has been assembled.

9. The on-site construction and installation method for a steel box girder according to claim 1, characterized in that: In step S4, the following steps are performed: marking the ground line, making the formwork, positioning the formwork on the longitudinal beam, positioning the cross bracing components, positioning the horizontal connecting rods and node plates, welding the node plates to the longitudinal beams, installing the steel formwork segment components, welding the formwork to the longitudinal beams, welding the formwork butt welds, installing and welding temporary hoisting lugs, and welding temporary connectors for the installation interfaces.

Images