Bridge demolition method near existing expressway and overpass navigable channel

Abstract

The application discloses a bridge demolishing method near existing expressway and overpassing navigable channel. The bridge demolishing method near existing expressway and overpassing navigable channel comprises a bridge demolishing method crossing expressway and a bridge demolishing method overpassing navigable channel. The bridge demolishing method overpassing navigable channel comprises construction preparation and bridge demolishing. The bridge demolishing comprises first bridge deck accessory structure demolishing, first T beam demolishing, first lower structure demolishing and first connecting beam and pile foundation demolishing. The first T beam demolishing adopts combined operation of floating crane and automobile crane, adopts reverse method to hoist and transport the cut T beam crossing navigable channel to the bridge deck which has not been demolished, and then transports the T beam to temporary crushing site for crushing in sections. The bridge demolishing method provided by the application adopts combined hoisting and transporting of T beam by floating crane and automobile crane, can select the specification of the floating crane according to the size of the water surface construction area beside the bridge crossing navigable channel, can satisfy bridge demolishing under different construction conditions, and has small limitation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of bridge demolition, and more particularly relates to a bridge demolition method near an existing expressway and overpassing a navigable channel. BACKGROUND

[0002] With the continuous development of road and bridge construction, some bridges need to be demolished or reconstructed due to design life, planning and design (the channel does not meet the requirements of net width and height), engineering conflicts, accidents and other reasons. At present, the floating crane ship is usually used for hoisting and demolishing the bridge over the channel. Different specifications of floating crane ships can be selected for hoisting and demolishing according to the weight and size of the bridge to be demolished. However, for large (80T or more) floating crane ships, the construction area on one side of the bridge needs to be relatively wide due to the size of the floating crane ship, and the hoisting cannot be completed in the narrow construction area, which has certain limitations. SUMMARY

[0003] In view of the defects of the prior art, the purpose of the present application is to provide a bridge demolition method near an existing expressway and overpassing a navigable channel, which aims to solve the problem that the traditional bridge demolition method over the channel uses a floating crane ship to hoist a T beam, which requires a high water surface construction area on one side of the bridge, is not suitable for bridge demolition in a narrow construction area, and has certain limitations.

[0004] To achieve the above-mentioned purpose, in a first aspect, the present application provides a bridge demolition method over a navigable channel, and the equipment used for bridge demolition includes a floating crane ship and a truck crane. The bridge demolition method comprises the following steps:

[0005] (1) Preparation before construction: the side channel area of the bridge to be demolished over the channel is dredged to meet the construction requirements of the floating crane ship;

[0006] (2) Bridge demolition: including first bridge deck accessory structure demolition, first T beam demolition, first lower structure demolition and first tie beam and pile foundation demolition, wherein,

[0007] The first bridge deck accessory structure demolition: the bridge deck asphalt and the crash barrier of the bridge over the channel are demolished, and then the two ends of the T beam over the channel are cut;

[0008] The first T beam demolition: the floating crane ship and the truck crane are used in combination, the cut T beam over the channel is hoisted to the undemolished bridge deck by the reverse method, and then is transported to the temporary crushing site for crushing in sections;

[0009] The first lower structure demolition: the pier column in the bridge to be demolished over the channel is cut, and then the cap beam and the pier column are hoisted to the temporary crushing site for crushing by the floating crane ship;

[0010] The first connecting beam and pile foundation demolition: excavating the soil around the pile foundation in the bridge to be measured across the channel to the demolition depth, then cutting the pile foundation underwater, and then using the floating crane ship to hoist the cut pile foundation to the temporary crushing site for crushing.

[0011] In one of the embodiments, when the construction area width of the floating crane ship is 15-25 meters, the floating crane ship adopts 80T specification floating crane ship, and the automobile crane adopts 160T specification automobile crane.

[0012] In one of the embodiments, the grab bucket dredger is used for dredging the area of the side span channel.

[0013] In one of the embodiments, the two ends of the T beam across the channel are cut by using a rope saw.

[0014] In one of the embodiments, the pier column in the bridge across the channel is cut by using a diamond chain cutting machine; the soil around the pile foundation in the bridge across the channel is excavated to the demolition depth by using a water excavator; and the pile foundation in the bridge across the channel is cut underwater by using a diamond chain cutting machine.

[0015] In the second aspect, the application provides a bridge demolition method near an existing highway and an overpass navigable channel, which comprises the bridge demolition method across the highway and the bridge demolition method across the navigable channel as described above, wherein the bridge demolition method across the highway comprises the following steps:

[0016] The second bridge deck auxiliary structure demolition: the bridge deck asphalt and the crash barrier of the bridge across the highway are demolished;

[0017] The second T beam demolition: the T beam across the highway is demolished by using the whole falling demolition construction method, wherein the T beam across the channel is demolished before the T beam across the highway is demolished;

[0018] The second substructure demolition: the pier column in the bridge across the highway is excavated, and then the excavated pier column is crushed;

[0019] The second connecting beam and pile foundation demolition: the connecting beam and the pile foundation in the bridge across the highway are demolished; the pile foundation is excavated, and then the excavated pile foundation is crushed.

[0020] In one of the embodiments, the T beam across the highway is demolished by using the staggered peak closed demolition construction.

[0021] In one of the embodiments, before the T beam across the highway is demolished, a ground protection layer is laid on the ground under the T beam across the highway.

[0022] In one of the embodiments, the T beam across the highway is divided into multiple construction sections along the bridge width direction, after the road is closed, the T beam across the highway is demolished from the outermost construction section, and the multiple construction sections are sequentially broken and demolished from outside to inside.

[0023] In one of the embodiments, when each construction section is demolished, the T beam concrete is chipped layer by layer from top to bottom and falls on the ground protection layer; after the concrete is chipped, the T beam steel framework and steel strand are dropped to the ground and are bent and packed; then the exposed steel is cut along the wet joint, and the T beam steel is dragged to the temporary stacking site.

[0024] The bridge demolition method across the navigable channel and the bridge demolition method near the existing highway and across the navigable channel provided by the application adopt floating crane ships and automobile cranes to jointly hoist the T beam, the specifications of the floating crane ships can be selected according to the size of the water surface construction area beside the bridge across the channel, the bridge demolition can meet different construction conditions, and the limitation is small. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a flow chart of the bridge demolition method across the navigable channel provided by the application;

[0026] Figure 2 is a schematic diagram of the bridge demolition principle provided by the application;

[0027] Figure 3 is a schematic diagram of the bridge demolition principle near the existing highway and across the navigable channel provided by the application;

[0028] Figure 4 is a schematic diagram of the T beam sectional demolition construction principle of the bridge across the highway in one embodiment of the application;

[0029] Figure 5 is a schematic diagram of the bridge demolition structure near the existing highway and across the navigable channel in one embodiment of the application;

[0030] Figure 6 is a flow chart of the bridge demolition method near the existing highway and across the navigable channel in one embodiment of the application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the application clearer, the application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0032] The application provides a bridge removal method crossing a navigable channel, to solve the problem that the traditional bridge removal method crossing a channel has strict requirements on the water surface construction area, and cannot be used for hoisting and removal in a narrow construction area.

[0033] Figure 1 The application provides a bridge removal method crossing a navigable channel, and refers to Figure 1 The bridge removal method includes two steps of preparation before construction and bridge removal, wherein the bridge removal includes first bridge deck accessory structure removal, first T beam removal, first lower structure removal, and first tie beam and pile foundation removal, and details are as follows:

[0034] S10, preparation before construction: the side channel area of the bridge to be removed crossing the channel is dredged to meet the construction requirements of the floating crane ship. Specifically, the side channel area can be dredged by a grab dredger.

[0035] S20, first bridge deck accessory structure removal: the bridge deck asphalt and the crash barrier of the bridge crossing the channel are removed, and then the two ends of the T beam crossing the channel are cut. Specifically, the bridge deck asphalt can be milled by a milling machine; the two ends of the T beam crossing the channel can be cut by a rope saw.

[0036] S30, first T beam removal: the floating crane ship and the automobile crane are combined to operate, the cut T beam crossing the channel is hoisted to the undemolished bridge deck by the reverse method, and then is transported to the temporary crushing site for crushing in sections.

[0037] In step S30, referring to Figure 2 , the step of hoisting the cut T beam crossing the channel to the undemolished bridge deck by the reverse method by combining the floating crane ship and the automobile crane, specifically: the automobile crane is parked on the bridge deck near one end of the bridge to be removed crossing the channel, and hoists one end of the T beam crossing the channel; the floating crane ship is parked on the water surface where the bridge crossing the channel can be constructed, and hoists the other end of the T beam crossing the channel; then the lifting arms of the floating crane ship and the automobile crane are controlled to lift the whole T beam crossing the channel, and then the floating crane ship and the automobile crane are controlled to move towards the undemolished bridge (such as the direction indicated by the arrow in Figure 2 ), until the whole lifted T beam crossing the channel is completely above the bridge deck of the undemolished bridge; then the floating crane ship and the automobile crane are controlled to land, and the removed T beam crossing the channel is placed on the bridge deck of the undemolished bridge; then the removed T beam crossing the channel is transported to the temporary crushing site in sections for crushing.

[0038] It can be understood that the specifications of the floating crane ship and the automobile crane can be selected according to the area of the workable water surface and the weight of the T beam to be hoisted. It should be understood that when the water surface construction area is limited due to conflicting projects or obstacles that are not easy to remove on one side of the cross-river bridge, a small floating crane ship and an automobile crane can be used for combined hoisting, and the cut cross-river T beam is hoisted to the undemolished bridge deck by the reverse method for segmented transportation. Specifically, when the cross-river bridge has only one side of the water surface available for construction, and the construction water surface width is 15-25 meters, a 80T specification floating crane ship and a 160T specification automobile crane can be preferably used for combined hoisting.

[0039] S40, first lower structure demolition: the pier column in the cross-river bridge to be tested is cut, and then the floating crane ship is used to hoist the bent cap and the pier column to the temporary crushing site for crushing. Specifically, the pier column in the cross-river bridge to be tested can be cut by a diamond chain cutting machine.

[0040] S50, first tie beam and pile foundation demolition: excavate the soil around the pile foundation in the cross-river bridge to be tested to the demolition depth, then underwater cut the pile foundation, and then use the floating crane ship to hoist the cut pile foundation to the temporary crushing site for crushing. Specifically, the soil around the pile foundation in the cross-river bridge can be excavated to the demolition depth by using an overwater excavator, and then the pile foundation in the cross-river bridge is underwater cut by using a diamond chain cutting machine.

[0041] The bridge demolition method provided by the present application uses a floating crane ship and an automobile crane to jointly hoist the T beam, and the specifications of the floating crane ship can be selected according to the size of the water surface construction area beside the cross-river bridge, which can meet the bridge demolition under different construction conditions and has small limitations.

[0042] Figure 3 is a schematic diagram of the bridge demolition principle near the existing expressway and the bridge across the navigable channel provided by the present application, as shown in Figure 3 The bridge equipment near the existing expressway and the bridge across the navigable channel provided by the present application includes a floating crane ship and an automobile crane, and the demolition method includes the cross-river bridge demolition method and the above-mentioned bridge across the navigable channel demolition method, wherein the cross-river bridge demolition method includes steps S100, S200, S300 and S400, which are described in detail as follows:

[0043] S100, second bridge deck auxiliary structure demolition: the bridge deck asphalt and the crash barrier of the cross-river bridge are demolished. Specifically, the bridge deck asphalt can be milled by using a milling machine.

[0044] In step S100, when the cross-river bridge is demolished, staggered peak closed demolition construction can be used. Specifically, the scheme of night construction can be adopted, which has less impact on the highway traffic compared with daytime construction.

[0045] S200, the second T beam is removed: the construction mode of the whole falling removal is used to remove the T beam crossing the highway, wherein the T beam crossing the waterway is removed before the T beam crossing the highway.

[0046] In step S200, before the T beam crossing the highway is removed, a ground protection layer can be laid at the ground below the T beam crossing the highway to prevent the impact of the whole beam falling during the removal process on the ground and damage the ground.

[0047] Further, when there is a conflict project on one side of the bridge crossing the highway, in order to avoid the removal of the bridge crossing the highway from affecting the conflict project, the T beam crossing the highway can be divided into multiple construction sections along the bridge width direction, such as Figure 4 As shown, Figure 4 The T beam of the bridge crossing the highway provided by the present application is shown in the schematic diagram of the T beam segmented removal construction principle of the bridge crossing the highway. After the road is closed, the T beam crossing the highway is removed from the construction section farthest from the conflict project, and multiple construction sections are sequentially removed from the outside to the inside. Specifically, after one construction section is completed, the removal work of another construction section is performed, and each construction section removes the T beam layer by layer from top to bottom when removing the T beam, and the T beam is chipped and falls on the ground protection layer; after the T beam is chipped, the steel reinforcement framework and steel strand of the T beam are dropped to the ground and are bent and packed; then the exposed steel is cut along the wet joint, and the T beam steel is dragged to the temporary storage site; until all construction sections are completed.

[0048] S300, the second lower structure is removed: the pier column in the measured bridge crossing the highway is excavated, and then the excavated pier column is broken. Specifically, the excavated pier column can be broken by a breaker after the excavated pier column in the measured bridge crossing the highway is excavated by an excavator.

[0049] S400, the second tie beam and pile foundation are removed: the pile foundation in the measured bridge crossing the highway is excavated, and then the excavated pile foundation is broken. Specifically, the excavated pile foundation can be broken by a breaker after the excavated pile foundation in the measured bridge crossing the highway is excavated by an excavator.

[0050] It should be noted that for the bridge removal method provided by the present application adjacent to the existing highway and crossing the navigable waterway, when the bridge T beam is removed, only the removal of the T beam crossing the waterway is completed before the removal of the T beam crossing the highway. For this purpose, the bridge removal method provided by the present application adjacent to the existing highway and crossing the navigable waterway can be used to remove the bridge crossing the waterway first and then remove the bridge crossing the highway; of course, the bridge deck accessory structures in the bridge crossing the waterway and the bridge crossing the highway can be removed simultaneously, and the remaining structures can be removed at different times. Specifically, the specific removal method can be selected according to the actual engineering requirements of the completion period and the environmental factors of the construction, and the present embodiment is not limited.

[0051] In one specific embodiment, the method for removing a bridge adjacent to an existing highway and above a navigable channel provided by the present application can be applied to the removal of a bridge above the Gucheng Port (a navigable channel) and the Nanke Road (a highway) of the Shanghai-Nanjing Expressway.

[0052] It should be noted that the Shanghai-Nanjing Expressway was completed and opened to traffic in 1996, and the widening reconstruction of the eight-lane expressway was completed in 2006. The existing bridge of the Shanghai-Nanjing Expressway above the Gucheng Port is a 9*30m T-beam, with a full bridge width of 42.5m, a clear width of the navigable hole of 28m, and a side height of 4.5m. Since the clear width and height of the navigable hole do not meet the navigation requirements of the III-class channel, the old bridge needs to be removed and rebuilt in situ.

[0053] However, a new Baotong Bridge is newly built on one side of the Shanghai-Nanjing Expressway, and the width between the new Baotong Bridge and the north line of the Shanghai-Nanjing Expressway is only 19m. During the construction process, the T-beam in the water cannot be hoisted by only relying on a small floating crane due to the narrow construction area, and a large floating crane cannot work due to its own size.

[0054] As shown in Figure 5 To achieve the removal of the bridge above the Gucheng Port (a navigable channel) and the Nanke Road (a highway) of the Shanghai-Nanjing Expressway, the present embodiment will adopt a construction method of using a 160T truck crane and an 80T floating crane to work together and using a reverse method. During the construction process, neither the driving vehicles of the Baotong Bridge nor the right lane of the Shanghai-Nanjing Expressway will be threatened, and the collision with the Baotong Bridge and the right lane of the Shanghai-Nanjing Expressway can be avoided.

[0055] As shown in Figure 6The specific demolition method used to realize the demolition of the bridge overpass of the Shanghai-Nanjing Expressway across Qingyang Port (navigable channel) and Nankel Road (expressway) mainly includes three steps of preliminary preparation, bridge demolition and site cleaning and channel acceptance. The preliminary preparation mainly refers to the entry of technology, personnel, materials and equipment into the construction area. The grab dredger is used to dredge the areas in the side span channel that do not meet the construction conditions of the floating crane ship. The bridge demolition mainly includes the demolition of the bridge deck auxiliary structure, the demolition of the T-beam, the demolition of the lower structure, and the demolition of the tie beam and pile foundation. In the process of demolishing the bridge deck auxiliary structure, the milling machine is first used to mill the whole bridge deck asphalt, and then the crusher, pick and other equipment are used to demolish the whole bridge deck crash barrier. The main channel navigation hole position is cut by a rope saw. In the process of demolishing the T-beam, the 80T floating crane ship and the 160T automobile crane are used to jointly lift and transport the T-beam to the undemolished bridge deck, and then the T-beam is transported to the temporary crushing site for crushing in sections. The T-beam across Nankel Road is demolished by the whole falling construction method. In the process of demolishing the lower structure, the diamond chain cutting machine is used to cut the pier column, and the 80T floating crane ship is used to lift and transport the cap beam and the pier column to the temporary crushing site. In the process of demolishing the tie beam and pile foundation, the water excavator is used to excavate the earth around the pile foundation to the demolition depth, and the diamond chain cutting machine is used to cut the pile foundation underwater. After the above work is completed, the site cleaning and channel acceptance work is carried out. The above-mentioned parts are demolished on the shore by the crusher, transported by the loader and truck, and finally the channel acceptance is carried out.

[0056] The Nankel Road is a traffic artery in the bonded zone, and the overpass T-beam demolition is difficult, so it needs to be demolished by staggered peak closure construction. The staggered peak time is selected at night from 11:00 to 5:00 the next morning, a total of 6 hours. From the comprehensive analysis of the use efficiency of the machinery, the work efficiency of the personnel and the traffic conditions on site, the T-beam is divided into multiple construction sections along the bridge width direction, and the T-beam demolition construction starts from the northernmost construction section and proceeds from the outside to the inside of the multiple construction sections. When one construction section is completed, the demolition work of another construction section is carried out, until all the construction sections on the T-beam are completed.

[0057] Since there are 11 T-beams across the Nanke Road, each construction section can be demolished in three times, i.e. the construction mode of 4+4+3. On the first day, 4 T-beams in the northernmost construction section are demolished. 4 breakers are located on the ground road and parked on the north side of the bridge. After the road is closed, 4 breakers simultaneously break and demolish from outside to inside. The T-beam concrete is chipped from top to bottom layer by layer and falls on the ground protection layer to avoid damage to the road surface caused by the whole beam falling. After the concrete is chipped, the T-beam steel framework and steel strand are dropped to the ground and bent and packed by the breaker. After the chipping of 4 beams is completed, the exposed steel is cut along the wet joint, and the T-beam steel is dragged to the newly built bridge below the temporary storage site for arrangement and storage. The loader loads the concrete blocks into the truck and transports them out. Similarly, the other 4 and 3 T-beams in the northernmost construction section are demolished. After the demolition of this construction section, the same demolition method of 4+4+3 construction mode is used for the demolition of other construction sections until the bridge across the Nanke Road is completely demolished.

[0058] In order to reduce the impact of T-beam concrete falling on the road, a layer of geotechnical protection layer is laid on the ground before construction as road protection. Time arrangement: road protection laying time 0.5 hours, 4 beam demolition construction 3.5 hours, site cleaning time 1 hour, machine time 1 hour. Traffic is closed at 11pm and opened at 5am the next morning. During the construction process, due to limited space, a large number of machinery cannot be used for construction, and the traffic volume of Nanke Road is particularly large as the traffic artery of Kunshan Comprehensive Bonded Area every day. Only the night construction scheme can be adopted, and the traffic must be smooth at 5am the next morning during construction. Therefore, during the bridge demolition process, the 4+4+3 demolition scheme will be strictly followed.

[0059] Water pile foundation demolition: After the water pile foundation is dredged, the positioning pile dredger excavates to a position about 2.5m below the planned channel riverbed bottom elevation, and the diver cooperates with the rope saw cutting machine to cut the pile foundation underwater. After the soil is excavated to the specified elevation, the diver measures the water depth underwater, and after meeting the requirements, the diamond wire rope saw of the rope saw cutting machine is lowered to the specified elevation, and after the rope saw is fixed, the diver gets on shore and starts the rope saw cutting, and after the pile foundation is cut off, it is lifted to the specified temporary crushing site by the floating crane ship. After passing the acceptance of the channel department, crushing is carried out. According to the calculation, the length of a single pile foundation is about 7m, the diameter is 1.5m, the total volume is 12.36m3, and the weight is 30.9t. The lifting steel wire rope is also selected in the same way as the bent cap lifting, and no additional equipment is needed. The pile foundation lifting adopts 80t floating crane ship and dredger combined with 19m grabber with an angle of 60°, and the maximum lifting tonnage is 80t. The lifting calculation is 80t / 30.9t=2.6>1.1, which meets the requirements.

[0060] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of removing a bridge over a navigable waterway, characterized by, The equipment used in the bridge dismantling includes a floating crane and a car crane, and the bridge dismantling method comprises the following steps: (1) Preparation before construction: the side span channel area of the bridge to be dismantled is dredged to meet the construction requirements of the floating crane; (2) Bridge dismantling: including first bridge deck auxiliary structure dismantling, first T beam dismantling, first lower structure dismantling and first tie beam and pile foundation dismantling, wherein, the first bridge deck auxiliary structure dismantling: the bridge deck asphalt and the crash barrier of the bridge across the channel are dismantled, and then the two ends of the T beam across the channel are cut; the first T beam dismantling: the floating crane and the car crane are used in combination, the cut T beam across the channel is hoisted to the undismantled bridge deck by using the backward method, and then is transported to the temporary crushing site for crushing; specifically, the car crane is parked on the bridge deck near one end of the bridge across the channel, hoists one end of the T beam across the channel, the floating crane is parked on the water surface where the bridge across the channel can be constructed, hoists the other end of the T beam across the channel, then controls the lifting of the lifting arms of the floating crane and the car crane, lifts the whole T beam across the channel, controls the floating crane and the car crane to move towards the undismantled bridge, until the whole lifted T beam across the channel is completely above the bridge deck of the undismantled bridge, controls the lowering of the floating crane and the car crane, and places the dismantled T beam across the channel on the bridge deck of the undismantled bridge, then transports the dismantled T beam across the channel to the temporary crushing site for crushing in sections; the first lower structure dismantling: the pier column in the bridge to be measured is cut, and then the bent cap and the pier column are hoisted to the temporary crushing site for crushing by using the floating crane; the first tie beam and pile foundation dismantling: the soil around the pile foundation in the bridge to be measured is excavated to the dismantling depth, the pile foundation is cut underwater, and then the cut pile foundation is hoisted to the temporary crushing site for crushing by using the floating crane.

2. The method of claim 1, wherein When the construction area width of the floating crane is 15-25 meters, the floating crane is of 80T specification, and the car crane is of 160T specification.

3. The method of claim 1, wherein The side span channel area is dredged by using a grab bucket dredger.

4. The method of claim 1, wherein The two ends of the T beam across the channel are cut by using a rope saw.

5. The method of claim 1, wherein The pier column in the bridge across the channel is cut by using a diamond chain cutting machine, the soil around the pile foundation in the bridge across the channel is excavated to the dismantling depth by using a water excavator, and the pile foundation in the bridge across the channel is cut underwater by using a diamond chain cutting machine.

6. A method of removing a bridge adjacent to an existing highway and overpassing a navigable waterway, characterized by, The bridge dismantling method across the highway and the bridge dismantling method across the navigable channel as claimed in any one of claims 1-5, wherein the bridge dismantling method across the highway comprises the following steps: second bridge deck auxiliary structure dismantling: the bridge deck asphalt and the crash barrier of the bridge across the highway are dismantled; second T beam dismantling: the T beam across the highway is dismantled by using the construction method of whole falling dismantling, wherein the bridge dismantling work across the channel is completed before the bridge dismantling work across the highway; second lower structure dismantling: the pier column in the bridge to be measured is excavated, and then the excavated pier column is crushed; Second connection beam and pile foundation demolition: the measured across the highway bridge in the pile foundation is excavated, and the excavated pile foundation is crushed.

7. The method of claim 6, wherein, The T beam across the highway is demolished by staggered peak closed demolition construction.

8. The method of claim 7, wherein, Before the T beam across the highway is demolished, a ground protection layer is laid at the ground below the T beam across the highway.

9. The method of claim 8, wherein, The T beam across the highway is divided into multiple construction sections along the bridge width direction, after the road is closed, the T beam across the highway is demolished from the outermost construction section, crushed and demolished in multiple construction sections from outside to inside in turn.

10. The method of claim 9, wherein, When each construction section is demolished, the T beam concrete is chipped from top to bottom layer by layer and falls on the ground protection layer; after the concrete is chipped, the T beam steel framework and steel strand are dropped to the ground and are bent and packed; then the exposed steel is cut along the wet joint, and the T beam steel is dragged to the temporary stacking site.

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