From the perspective of all the physical buildings of the bridge, the approach abutments at both ends are the dividing points between the route and the abutment.The part where the bridge opening crosses major obstacles (such as river channel) is called the main bridge.It is also called main bridge.The longitudinal top and bottom plate steel tendons of the main bridge are arranged in a spatial curve combining horizontal and vertical bending, so that the top plate steel tendons are centrally anchored in the support at the top of the web, while the bottom plate steel tendons are anchored in the tooth block close to the web, which has the following advantages: ① make the top plate pre-stressed with the strongest arm to maximize the mechanical performance; ②The tendon is arranged close to the web, so that the prestress is transmitted to the full section in a short way; ③The roof bundle is anchored in the support, which can not only avoid complex tooth block structure, facilitate construction, but also reduce the dead weight of box girder and save materials; ④The longitudinal steel tendons of the top and bottom plates are symmetrically anchored at the design position in S-shape on the plane, which can eliminate the transverse component force generated by the concentrated anchor point and improve the stress condition;
Due to the advantages of fully and reasonably utilizing land, rivers and space, sharing foundation and saving investment, the highway railway dual-use bridge has been successfully applied on large rivers in recent years.The existing bridge structures are divided into the following types:
(1) Steel truss cable-stayed bridge, such as Wuhan Tianxingzhou Yangtze River Bridge for both highway and railway, with a main span of 504 m, six lane highway in the upper layer and four line railway in the lower layer, the width of the upper and lower bridge decks is basically the same;
(2) Rigid suspension cable adopts three trusses to stiffen continuous steel truss girder bridge, such as Jinan Yellow River Highway Railway Dual purpose Bridge on Shijiazhuang Jinan Passenger Dedicated Line, with a main span of 180 m, six lane highway in the upper layer and four line railway in the lower layer;
(3) The width of partially cable-stayed lower bridge deck is basically the same, and three truss continuous steel truss composite beams are used, such as Zhengzhou Yellow River Road Railway Dual purpose Bridge, with a main span of 168 m, the width of the upper highway bridge of 32.5 m, the lower double track railway, three truss structure, and inclined side truss. The upper layer is a steel beam upper chord and concrete bridge.
The combined deck dual-use bridge formed by the combination of the Songhua River highway and railway panels on the Binbei Line adopts the stiffened continuous steel truss beam structure with a main span of 144 m, two straight trusses for the main truss, and the orthogonal special-shaped plate structure is adopted for the highway and railway bridge decks in consideration of the use function, terrain, geology, hydrology, navigation, cold weather and other factors.At that time, the bridge will become the longest highway railway bridge across the river in Heilongjiang Province, which will not only greatly improve the railway transportation capacity of Binbei Line, but also become an important transportation corridor connecting the new urban area of Jiangbei and the old urban area of Jiangnan, with extremely important social and economic significance.Combined with relevant research, this paper elaborates the overall idea of the structural design of the main bridge, and introduces the main design elements such as truss height, truss width, bridge deck system, materials, etc.
Project overview
Binbei Line Songhuajiang Road Railway Dual purpose Bridge Reconstruction Project is located in the urban area of Harbin.The existing Binbei Bridge, located at K2+620 of Binbei Line, is the earliest highway railway bridge across the river in China. It was completed and opened to traffic in December 1933, and has been in operation for 81 years.According to the appraisal, the remaining life of the main members of the steel beam of Binbei Bridge is seriously insufficient, and the disease is obvious. Under normal conditions, the service life of Binbei Bridge will expire in 2016.Therefore, it is decided to reconstruct the bridge and remove the existing bridge after reconstruction.The reconstructed bridge site is 50 m downstream of the existing Binbei Bridge, parallel to the existing Binbei Bridge, and 2.2 km away from the dikes on both banks of the Songhua River.The main line of Binbei Line of the reconstructed railway is 7.0 km long, and the bridge length is 4.171 km.According to the route planning trend of railway and highway, the upper and lower layers of highway and railway are arranged in the main bridge section across the river and the approach bridge section of Jiangbei beach.The approach bridge of Jiangbei Highway is bent out of the plane after it is close to the Beida Embankment (at the location of railway pier 53), and is located at the upstream side of the railway;The south bank highway approach bridge bends out on the plane after passing the south embankment (at the location of railway pier 17) and is located at the downstream side of the railway.
Bridge construction conditions
The bridge site is located in the urban area of Harbin. The large geomorphic units along the line are mainly the Songhua River alluvial plain and the Songhua River floodplain. The terrain is flat and the ground elevation is generally 98~124 m.The traffic conditions along the line are convenient, and there are many buildings in Jiangnan area.The surface layer is composed of miscellaneous fill, alluvial fill and silty clay. The upper foundation soil is mainly composed of sandy soil. The middle layer is uneven with clay interlayer of varying thickness, and the lower part is Cretaceous silty mudstone.The climate in this region is in the northern cold zone, with annual temperature of 36.4 and minimum temperature of - 38.1;The maximum freezing depth is 2.05m, and the annual average relative humidity is 66%.Songhua River is a seasonal frozen river. It is generally frozen in the middle of November and thawed in the first and middle of April of the next year. The frozen days are about 150 days. The ice thickness is generally 1.1 m, and the maximum is 1.6 m.The peak horizontal acceleration of bedrock ground motion at the level of 10% of the site's 50 year exceedance probability is 0.088 g.
Main technical standards
4.1 Main technical standards of railway
Railway grade: Grade;Design speed: 120 km/h;Number of main lines: double line;Design load: medium live load.
4.2 Main technical standards for urban roads
Road grade: urban expressway;Calculated running speed: 60 km/h;Design load: urban level A, crowd 3.5 kN/m;Deck layout: two-way six lane+2.0 m sidewalks on both sides, the full width of the deck is 30 m.4.3 Design flood frequency and bridge construction gauge design flood frequency: 1/100;Check flood frequency: 1/300;Bridge construction gauge: it shall be handled according to the construction gauge of mixed passenger and freight railway (V ≤ 160km/h) - bridge construction gauge (electric traction section);Channel level: the channel level of the river reach in the bridge area is national;Navigable clear width: meet the requirements of 115 m (95 m plus 20 m to be widened due to the angle greater than 5 °) for single hole and single line navigation of class channel;Navigable clear height: the south branch is the main channel, and the north branch is the auxiliary channel. When the main and auxiliary channels are designed with navigable water levels, the clear height of navigable holes is ≥ 13 m.
Main bridge design
5.1 Span layout
According to the construction conditions and engineering natural conditions of Songhua River Bridge, under the condition of making full use of the topography and landform of the bridge site and meeting the navigation requirements and hydrological conditions, the construction organization scheme shall be comprehensively considered.The navigable spans of the main bridge of this bridge are arranged as follows: 2-96 m+(96+2 × 144+96) m+6-96 m;The 1-96m simply supported tied arch is used for the part of the railway approach bridge crossing the north bank embankment, and the rest of the railway approach bridges are in the form of 24m and 32m standard T-beams.
5.2 Division of Joint Chiefs
Rail expansion adjusterIt is the weak link of the track. Considering the safety, comfort and less maintenance of the line, it should be avoided to set or set less rail expansion regulators.As the line is subject to the requirements of the track connection of Hadong Station and the navigation clearance of the main hole, 19 # and 20 # piers are located on the longitudinal slope and vertical curve respectively, and 21~32 # piers are located on the flat slope section.According to the specification, the rail expansion adjuster should not be set on the longitudinal slope and vertical curve, so the 19 # and 20 # piers should not be set with the rail expansion adjuster.According to the specification, for steel beams with a temperature span greater than 100 m, each temperature span shall be equipped with a rail expansion adjuster.Based on the above considerations, the span arrangement is determined as 2-96 m simply supported steel truss+(96+2 × 144+96) m continuous steel truss+6-96 m simply supported steel truss, and the fixed support of the continuous beam is set at 24 # pier.Except that the rail temperature span between No. 20 and No. 24 piers of the main bridge is more than 100 m, the rail temperature span on other spans is less than 100 m. The main bridge only needs to set one rail expansion adjuster at No. 21 pier.
5.5 Selection of railway bridge deck system
The deck system of railway steel truss girder mainly includes steel-concrete composite deck systemOrthotropic plateThere are two types of steel bridge deck.As this bridge is a continuous beam structure, the maximum length of the main bridge is 480 m, the lower layer is a double track railway, with large live load, the beam out of plane bending and the concrete slab being seriously tensioned, and the bridge site is located in a severe cold area, with great impact of freeze-thaw damage, and the concrete crack resistance cannot be guaranteed, therefore, the railway deck of this bridge is characterized by light deadweight, strong bearing capacity, good integrityThe orthogonal special-shaped plate structure that can participate in the overall stress of the structure is paved with waterproof layer+6 cm thick wear-resistant layer.
5.6 Selection of highway bridge deck system
The structural forms of highway steel truss bridge deck systems that have been built or are under construction at home and abroad mainly include: overall steel deck+ordinary concrete (10 cm thick)+asphalt concrete (9 cm thick), overall steel deck+high-performance asphalt concrete (5-7 cm thick), and composite beam deck.Through comprehensive comparison, the project costs of the three schemes are not much different, but the bridge site area is in severe cold climate, and the mature application experience of bridge deck pavement in this area is particularly important. Therefore, the design adopts steel deck+10 cm concrete pavement+9 cm ordinary pavementasphalt concretePavement scheme.
5.7 Structural design of main bridge
5.7.1 Main truss design
Through comprehensive comparison, the triangular truss with vertical bars is adopted as the main truss. The transverse center distance between the two main trusses is 14 m, the truss height is 14 m, and the node spacing is 14 m.The stiffening chord is set at the middle pier of the main bridge (96+2 × 144+96) m span. The stiffening chord is 10 m high, and two inter section ranges are set on both sides;The main trusses of other spans are parallel chord trusses;The upper and lower chords and stiffening chords of the main truss adopt box sections. The bars with less stress on the web members of the main truss and the tension bars are I-shaped. The bars with greater stress and the compression bars are box shaped.The maximum lifting weight of the rod is about 45 t.The members at the stiffening chord are made of Q420qE steel with high strength, and the members of the main truss at the horizontal chord and the deck system are made of Q370qE steel.
5.7.2 Coupling system
In order to ensure the transverse stability of the main beam frame, a transverse connection system is set at each node. The connection system is a triangular truss structure with a truss height of 2500 mm. The connection tie bars are H-shaped sections.
5.7.3 Support
The main bridge is arranged as 2-96 m+(96+2 × 144+96) m+6-96 m, and the fixed bearings are respectively set at 19 # pier, 20 # pier and 24-30 # pier.The 144m span middle pier of the main bridge adopts 80 000 kN spherical steel bearings, and the side piers and secondary side piers adopt 20 000 kN and 70 000 kN spherical steel bearings.The 96 m simply supported steel truss beam adopts 20000 kN spherical steel bearing.
5.7.4 Expansion joint device
D720mm type is adopted at 21 # pier of expansion joint device of main bridge, D160mm type is adopted at 19 # pier, and D240mm type is adopted at 20 #, 25 #~31 # piers.
5.8 Construction scheme of main bridge
Piers 22~24 and 28~31 of the main bridge are underwater piers. The trestle and pier platform scheme is adopted for the construction of the foundation and pier abutment, and the cushion cap is adoptedDouble wall steel cofferdamConstruction.Other pier bored piles are constructed by island construction, and cushion caps are constructed bySteel sheet pile cofferdamConstruction.
The steel beam erection is based on the construction scheme of erecting temporary buttresses, erecting beams by crane and closing in the middle on the shore and in the water (without affecting the navigation position).First, the bridge is erected from 21 # and 25 # piers to 22 # and 23 # piers respectively to the closure opening;After closure, the girder erection crane of 22 # pier will turn around and erect simply supported steel beams towards 19 # pier;The crane for erecting beams at 23 # pier is turned back and simply supported steel beams are erected towards 31 # pier;The simply supported steel truss is temporarily connected with the continuous steel truss, and the simply supported steel truss cantilever part of the highway lags behind the erection and installation of one hole.After installation, the bridge deck accessories shall be constructed.
Durability study
Since the minimum design temperature of the bridge is - 43.1, the extreme minimum temperature minus 5, and the various mechanical performance indicators of structural steel for the bridge are not specified in the specification, the bridge simulated the ultra-low temperature environment of the bridge site to test the welding process of structural steel plates and various joint forms, and the test shows that the steel plates and welding quality technical standards under the ultra-low temperature environment meet:
(1) The yield strength (Rel) and tensile strength (Rm) of longitudinal and transverse butt weld metal shall not be lower than the standard value of base metal;
(2) The yield strength (Rel) of weld metal shall not be lower than the standard or actual value of base metal, and shall not exceed 100 MPa of the actual value of base metal;
(3) If the yield strength (Rel) of weld metal is too strong, the yield ratio shall be less than 0.85 (or the actual value of base material);
(4) Weld toughness: Charpy impact energy AkV of longitudinal and transverse butt joint zone III (weld, fusion line, heat affected zone) - 43: Q370qE is not less than 41 J, Q420qE is not less than 47 J.[1]
Demolition construction technology
Announce
edit
1 Project overview
Liuxihe Bridge is located at K7+426 of Cheitou Xinjie Section of Guanghua Highway, with a total length of about.The main bridge of Liuxihe Bridge is equipped with 336m hanging beamprestressed concreteT-shaped rigid frame bridge, with a span of 52.5m+, is arranged in left and right directions upstream and downstream.The 52.5m cantilever of T-frame of main bridge is used by prefabricated concealed pipe box girder sectionPrestressed steel strandCantilever assembled, and the beam segmentEpoxy resin adhesiveConnect.The cross section of the box girder is a single box with two chambers, and a partition wall is set at the root and end of the cantilever respectively.The width of the top and bottom plates of the left box girder is, respectively, and the width of the top and bottom plates of the right 11.5m9.36m box girder is, respectively;The center height of 13.45m11.16m in the box girder changes from 1.8m in block 11 to 4.8m in block 0 in a quadratic parabola.The hanging beam of the main bridge is 25m T beam, of which there are 6 T beams for each span on the left side and 7 T beams for each span on the right side.The width and height of the center beam of the hanging beam are all;The height of the side beam of the hanging beam is 1.78m 1.8m, and the width of the side beam of the left and right hanging beams is 1.8m 2.14m;The mid span web thickness of the hanging beam and the web thickness of the beam end are 2.21m and 0.14m respectively.The beam and T-beam are welded together through 0.36m T embedded steel plate at the side of diaphragm plate and top plate.Due to the sharp increase of traffic volume, the pile foundation of Liuxi River Bridge has subsided. Although the traffic department has formulated the traffic organization plan for the emergency rescue section of Liuxi River Bridge to carry out rescue and reinforcement, the inspection and identification results show that the original bridge is no longer suitable to continue to bear the traffic load, and new bridges need to be demolished and constructed to meet the increasing traffic demand and navigation grade requirements.As the blasting demolition scheme has such adverse factors as high construction risk, navigation closure, suspension of traffic, large warning range, etc., considering the navigation condition under the bridge, engineering economy and safety, according to relevant engineering experience and the proposal to use two 50m bridge erectors to connect the main bridge block 0 for temporary consolidation, the left 25mT beam andBlock 11 to 1 of the T-frame box girder, move the bridge erecting machine horizontally to the right bridge, and dismantle the right bridge according to the demolition method of the left bridge.
2. Demolition construction technology of main bridge
2.1 Demolition construction technology of suspended T-beam at both ends
Before removing the suspended T-beam, use the air cannon to chisel out the shockproof stops on both sides of the T-beam web on the bent cap or corbel;After installing the bridge erecting machine, first remove the connection between the two T beams directly below the bridge erecting machine, lift the two T beams away, take two T beams as a group, move the rest of the grouped T beams horizontally to the right below the bridge erecting machine, remove and lift the remaining beams piece by piece, and finally transfer the T beams to the chiseling area for chiseling.
2.1.1 Removal sequence
Follow the principle of "moving the beam without moving the machine" to remove the T-beam, that is, after the installation of the bridge erecting machine, keep the bridge erecting machine fixed, take two T-beams as a group, make them move horizontally under the bridge erecting machine, and remove them one by one.The removal sequence of the six T beams on the left side is as follows: remove T3 # beam → remove T4 # beam → horizontally move T5 # beam and # beam → remove T5 # beam → remove T6 # beam → horizontally move T6 # beam and # beam → remove # beam and # beam.T1 → T1 → T2T2
2.1.2 T-beam cutting
The connection between T-beams shall be cut by machinery and oxygen, the connection between concrete panels of T-beam roof shall be cut by disc cutter, the diaphragm plate body shall be cut by chain cutter, and the connecting steel plates between diaphragm plates shall be cut by oxygen.Before chain cutting, it is necessary to drill rope holes (hole diameter is 5cm, hole depth penetrates the wing plate) along the center line of the T-beam joint at 20cm on both sides of each diaphragm.Before the T-beam is moved horizontally in place, the two connected T-beam diaphragms, wet joints and panels cannot be cut. The T-beam can be cut after it is moved horizontally in place, and then removed piece by piece.Before cutting T-beams, use wooden wedges to fasten the bottom of diaphragms at both ends of each T-beam to the capping beam, so as to prevent adjacent T-beams from overturning during removal.
2.1.3 Hoisting of T-beam
Before lifting the T-beam, move the crown block directly above the T-beam, and ensure that the lifting point of the beam body is in the same line with the center of the beam.The upper steel wire rope of the hook is connected with the hook by iron wire to prevent the steel wire rope from shaking and unhooking;The arc steel plate shall be padded at the chamfer between the steel wire rope and the beam body to avoid serious bending damage of the steel wire rope at the chamfer.
Use the two overhead cranes of the bridge erecting machine to lift the T-beam. First, lift the T-beam at one end for about 5cm, and fasten the other end of the T-beam. After lifting the beam body, switch to the other end of the T-beam.Lift the T beam at both ends synchronously, and move the crown block longitudinally to the position of the beam transport flat car on the approach bridge deck when the bottom plate of the beam body is 1.2m higher than the bridge deck.
2.1.4 Transverse movement of T beam
The bridge erecting machine is fixed. After the T beam directly below it is hoisted, the T beams on both sides are horizontally moved to the space between the two main beams of the bridge erecting machine.Since the stability of single T-beam is poor, two T-beams are used to move horizontally together.If there is no transverse T-beam, first lift two (left) or one (right) T-beams in the middle of the main beam of the suspension bridge crane, and then group the rest of the beams and move them horizontally in two.Before the T-beam is moved horizontally, the jack, traction device, sliding device and other installation preparations shall be carried out. The T-beam shall be lifted by the jack. After the T-beam is lifted to meet the installation height of the slide, the support shall be removed, the slide shall be installed and leveled. At the same time, the slide shall be installed in the slide. The jack shall return oil to make the beam bottom fall to the top surface of the slide. Finally, the traction device shall be installed to complete the transverse movement of the beam.The key technology of T-beam transverse movement is as follows:
(1) T beam jacking.The jack is supported at the bottom of the web, near the outside of the bearing pad stone. Each T-beam is jacked by two jacks, one at each end.Jack lifting is controlled by the pump station located on the bridge deck. When the lifting height of T beam cannot meet the requirements of the installation height of the slide, it is necessary to temporarily support the T beam with a wooden wedge, place a small steel seat or steel plate under the jack, and lift the T beam again until the requirements are met.
(2) Slide fabrication and installation.The slideway adopts [28a channel steel and reversely buckles the [28a channel steel. A layer of 3mm thick stainless steel plate is laid at the bottom. The stainless steel plate and channel steel are fixed by electric welding. The upper part of the stainless steel plate is provided withteflonThe sliding block is made of [20a channel steel on the polytetrafluoroethylene sliding block. In the longitudinal direction, small reinforcing bars are set on both sides of the polytetrafluoroethylene sliding block to block the sliding block. After the T-beam is lifted to meet the installation height of the sliding block, the sliding block is installed on the bearing pad stone (the center line is aligned with the original bearing center line).Due to the limited construction spaceHand chain hoistThe slideway shall be installed in the way of mutual cooperation with the crown block.The installed slideway is placed on the transport ship and transported to the bottom of the removed T-beam. The crane is used to lift the slideway to the bottom of the T-beam. One end of the slideway is tied with a wire rope, and the slideway is sent to the installation position through a chain block.
(3) Transverse movement of beam body.Four T beams are bound with steel wire ropes (two are T beams that need to be moved horizontally, and two are T beams without slideways), and the beams on the slideways are slid by opposite pulling.In order to prevent the other two T beams without slideways from being pulled, use wooden wedges to fasten the bottom surface of the T beam diaphragm with the cap beam surface;At the same time, at the wing plate, use wooden wedges to fasten the wing plate with the back wall of the capping beam or the box girder diaphragm at the suspension.
2.2 Demolition construction technology of main bridge T-frame box girder
Divide the box girders on both sides of the T structure into 11 pieces, and use two 50m bridge erecting machines and lifting appliances to remove the box girders symmetrically on both sides.Mechanical cutting is mainly used to cut the connection between the box girder segments. First, the top and bottom plates of the box girder are cut by discs, and then the box girder webs are cut by rope saws.After the box girder segments are separated, use the traction device to rotate the box girder segments by 90 °, use the longitudinal traveling crane to place the girder segments on the pulley, and finally use the pulley to transport the girder segments to the subgrade of the approach bridge for crushing.See Figure 3 for the removal process of T-shaped box girder of main bridge.
2.2.1 Lifting appliance installation
After the removal of No. 11 block of box girder, the self-developed lifting appliance shall be installed.The spreader is made of double jointed 45 I-steel and double jointed 36 I-steel. The spreader is anchored to the beam body by means of suspenders (8 pieces of 40Cr steel with a diameter of 50mm).The lifting appliance is connected with the hook through the sling, which is made of 5cm thick manganese steel plate.When installing slings, first drill out the lifting holes and cutting holes, move the slings to the cutting block section, install the suspender (the suspender passes through the top plate chamfer and enters the box girder), install the triangle base plate and suspender double nuts in turn, and pre tighten the nuts;After the installation of the spreader, use a wrench to retighten the suspender bolt and pre lift it;Use 10tHand chain hoistConnect box girder wing plate and lifting hook with steel wire rope.
2.2.2 Installation of anti shake steel wire rope
When the lifting block is separated from the T-structure, a large impact force will be generated, which is not conducive to structural stability.In order to reduce the instant impact force when the beam body is separated, drill a hole with a diameter of 15cm on the top plate of the cutting beam block section, connect the fixed small shoulder pole steel wire (with a diameter of 28mm) at the front end of the beam body through a 10t chain block, and complete the temporary connection between the cutting beam block section and other blocks of the T-structure.
2.2.3 Beam cutting
The beam body shall be cut symmetrically on both sides in turn. When cutting, the maximum difference between the two ends of the main pier is allowedoneBlocks.In order to ensure the stability during the removal of box girder, only one beam section can be drilled with rope holes according to the design requirements.When cutting, the box girder shall cut the upper part of the top plate and web wedge along the cantilever joint, and the lower part of the bottom plate and web wedge shall not be cut.The top plate is cut by disc cutter, and the web plate is cut by rope cutter.In the cantilever section, the bridge is bonded with epoxy resin and cutPrestressed reinforcementAfter that, the box girder is separated from the connected blocks by its own weight.
2.2.4 Beam turning in the air
In order to ensure the smooth rotation of the beam body in the air, ensure that the beam body rotates around the center of the hook, and avoid the twisting of the sling during the rotation of the beam body, the beam body shall be rotated in the air according to the following steps: slowly loosen the wire rope of the reverse winch, loosen the length of about 15m, and at the same time loosen the reverse pull 10t hoist on both sides, so that the beam body is stable under the hook, and move the beam body down 1m through the hook;Move the beam forward to 15m from the rear outrigger;Start the two winches on the overhead crane, pull the hole in the middle of the box girder flange, synchronously operate the winch to rotate the beam 90 ° around the center of the hook, so that the traction wire ropes on both sides of the beam are on the same line, brake the traction winch, and reduce the rotational inertia of the box girder until the rotational inertia of the beam disappears.Finally, loosen the wire ropes of two hoists, lift the beam body to make its bottom 1.2m higher than the bridge deck, and move the beam body to the flat car longitudinally.See Figure 4 for the beam body turning in the air.
3 Conclusion
The main bridge of Liuxihe Bridge is with hanging beamprestressed concreteFor the demolition of T-shaped rigid frame bridge, a set of demolition construction technology for prestressed concrete T-shaped rigid frame bridge with hanging beams is proposed, which mainly includes: the removal technology of transverse movement of suspended T-beams at both ends, and the lifting and removal technology of T-shaped box girders.During the removal of the suspended T-beam at both ends, the principle of moving the beam without moving the machine is followed, and the T-beam is moved horizontally in two pieces to ensure the stability of the T-beam in the process of moving horizontally.In the demolition of T-frame box girder, in view of the construction difficulties of box girder hoisting, self-developed lifting tools were used, anti shaking devices were installed, and key technologies such as beam body turning in the air were used to ensure the safety of box girder demolition.The demolition of the bridge has been successfully completed. The entire construction process has not affected navigation, no use of water equipment, and little impact on the surrounding area. The bridge demolition construction technology can provide reference for other similar projects.[2]
