Construction method for dismantling superstructure of overline single-box multi-chamber cast-in-place reinforced concrete bridge
Technical Field
The invention belongs to the technical field of bridge construction, and particularly relates to a construction method for dismantling an upper structure of a cross-line single-box multi-chamber cast-in-place reinforced concrete bridge.
Background
With the rapid development of national traffic infrastructure, part of highway bridges built in early stage cannot completely meet the current traffic demand, and the existing highway bridge reconstruction projects are increased day by day. Especially, in recent years, the rapid development of cities makes the demolition and reconstruction of viaducts which cannot meet the traffic demand urgent. The method has the advantages that the scientific construction scheme is selected to demolish the urban overpass highway bridge and update, install and construct, and the method has very important significance for ensuring the safe operation of the busy road trunk and the smooth construction of reconstruction and expansion of the highway bridge.
Disclosure of Invention
The invention aims to provide a construction method for removing an upper structure of a cross-line single-box multi-chamber cast-in-place reinforced concrete bridge, aiming at the defects in the prior art of bridge removal.
The invention is realized by the following technical scheme.
The invention relates to a construction method for dismantling an upper structure of a cross-line single-box multi-chamber cast-in-place reinforced concrete bridge, which is characterized by comprising the following steps of: the construction method specifically comprises the following steps.
A. And the periphery of the bridge is enclosed to protect underground pipelines.
B. And crushing and dismantling the bridge deck pavement layer and the concrete anti-collision pier.
C. And synchronously chiseling the flange plates of the cross box girders.
D. Dismantling the remaining cantilever-free box body: firstly, dismantling the non-cantilever box body of the over-line bridge span, and then dismantling other non-cantilever box bodies of the bridge span in sequence.
E. And (4) synchronously chiseling off pier top cross beams on two sides of each bridge span.
The construction method for dismantling the superstructure of the overline single-box multi-chamber cast-in-place reinforced concrete bridge is characterized by comprising the following steps of: the concrete method of the step A is that the surrounding influence range of the bridge is enclosed and sealed before the bridge is dismantled, sand bags are paved at the positions where main pipelines exist under bridge spans, and backing plate steel plates are paved at the positions of important pipelines.
The construction method for dismantling the superstructure of the overline single-box multi-chamber cast-in-place reinforced concrete bridge is characterized by comprising the following steps of: b, firstly, symmetrically removing the bridge deck pavement layer on two sides; and then cutting off the connecting reinforcing steel bars of the anti-collision pier and the bridge deck pavement layer, and crushing and dismantling the anti-collision pier after pushing the anti-collision pier towards the inner side of the bridge deck.
The construction method for dismantling the superstructure of the overline single-box multi-chamber cast-in-place reinforced concrete bridge is characterized by comprising the following steps of: and C, temporarily closing the traffic, organizing a large number of dismantling machines to longitudinally, synchronously and transversely symmetrically remove all the cross box girder flange plates of the full bridge from outside to inside.
The construction method for dismantling the superstructure of the overline single-box multi-chamber cast-in-place reinforced concrete bridge is characterized by comprising the following steps of: the concrete method of the step D is that the area where each bridge span cantilever-free box body is located is divided into three construction areas. The construction first area is a plane area where the overpass bridge spans, and the construction second area and the construction third area are respectively arranged on the left side and the right side of the overpass bridge span. The construction is that firstly, the dismantling construction is started in the area, and then the dismantling construction of the area II and the area III is carried out after the construction is finished.
The construction method for dismantling the superstructure of the overline single-box multi-chamber cast-in-place reinforced concrete bridge is characterized by comprising the following steps of: the concrete method of the step E is that each bridge span synchronously chisels off pier top cross beams on two sides in sequence to break the middle part of the cross beam; the rest beam bodies slowly fall onto the dumbbell-shaped sand bags on the pier sides along with the cross beams, and the longitudinal main ribs in the middle of the box body are cut off to enable the beam bodies to fall to the ground.
The construction method for dismantling the superstructure of the overline single-box multi-chamber cast-in-place reinforced concrete bridge is characterized by comprising the following steps of: and calculating and analyzing the actual structure stress state of each stage of the dismantling construction, and ensuring that the structure stress of each stage of the dismantling construction is in a safe range under the action of self weight.
The construction method for dismantling the superstructure of the overline single-box multi-chamber cast-in-place reinforced concrete bridge is characterized by comprising the following steps of: and the bridge spans in each construction area are removed in a symmetrical mode of transversely extending from outside to inside and longitudinally extending from the middle to two ends, and the top plate, the web plate and the bottom plate are sequentially removed. And reserving a pier top beam of each bridge span, keeping each bridge span in a flat and stable state temporarily, and keeping the longitudinal main rib of the middle part of the box body not disconnected temporarily.
The present invention has the following advantages.
(1) The construction method has the advantages of simple steps, reasonable design, simple and convenient construction and lower input construction cost.
(2) The use effect is good, the influence on the existing line is small, the safety risk is minimum, the quality is guaranteed, the resource waste can be avoided to the maximum extent, the construction cost is reduced, the construction progress is fast, and the construction period is short.
(3) The adopted pipeline protection device is scientific in design, high in practical value and low in investment cost.
(4) The construction scheme is reasonable in design, and the two sides of the whole bridge are synchronously and symmetrically dismantled, so that the whole hole box girder is temporarily in a smooth and stable state.
(5) The demolished concrete waste residues are shipped along with demolition, so that the construction benefit can be effectively improved, the construction period is shortened, the construction cost is reduced, the construction process is safe and reliable, the construction risk is very small, and the economic benefit and the social benefit are remarkable.
In conclusion, the method has the advantages of simple steps, reasonable design, simple and convenient construction, good use effect, safety and reliability in the construction process, short construction period, economy and practicability, and can simply, conveniently and quickly finish the construction process for dismantling the superstructure of the overline single-box multi-chamber cast-in-place reinforced concrete bridge.
Drawings
FIG. 1 is a longitudinal cross-sectional view of a bridge to be dismantled according to the present invention.
Fig. 2 is a cross-sectional view of a box girder to be removed according to the present invention.
FIG. 3 is a top plan view of a bridge to be demolished in accordance with the present invention.
FIG. 4 is a diagram of the pipeline protection of the present invention.
Wherein, 1 is the anticollision mound, 2 is the bridge deck pavement layer, 3 is the flange board, 4 is the roof, 5 is the web, 6 is the bottom plate, 7 is the sand bag, 8 is the pier, 9 is the crossbeam, 10 is the overline, 11 is the pipeline, 12 is the steel sheet, 13 is the box of no cantilever.
Detailed Description
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Before the overpass bridge is dismantled, the influence range around the bridge construction is enclosed, and a sand bag 7 is fully paved under the bridge for loading protection. When dismantling the bridge body, at first carry out the breakage with bridge floor annex, bridge deck pavement layer 2 and concrete anticollision mound 1 and demolish, then chisel out case roof beam flange board 3, carry out the breakage respectively to roof 4, web 5 and the bottom plate 6 of no cantilever box in proper order again and demolish, in time clear away concrete waste residue and the reinforcing bar that breaks away.
Before dismantling, a sand bag 7 is paved at the position with a main pipeline below each bridge span, the width of the sand bag exceeds the safe width of the pipeline by at least 0.5 m, the thickness of the sand bag is 0.5 m above the road surface, and a steel plate 12 is paved at the lower part of the sand bag at the important pipeline position.
When the bridge is dismantled, bridge deck auxiliary facilities, street lamps, steel guardrails and the like are dismantled firstly, and traffic facilities, indication boards, pipelines, color lamp tube belts and the like on the bridge are dismantled by municipal related property units.
Removing the bridge deck pavement layer, wherein the length of one-time removal is controlled at 1/3 of a single bridge span, and the two sides of the bridge deck pavement layer are symmetrically removed; and then cutting off the steel bars connected with the anti-collision pier 1 and the bridge deck pavement layer 2 by using gas cutting, pushing down the anti-collision pier by using an excavator to incline towards the inner side of the bridge, crushing and decomposing the anti-collision pier into small concrete fragments by using a hydraulic impact hammer, and then disassembling and transporting the concrete fragments.
When the bridge body is removed, the hydraulic impact hammer is adopted transversely along the bridge to symmetrically chisel the bridge body simultaneously, the full bridge is firstly removed, each span box girder flange plate 3 is arranged, then the span line bridge span cantilever-free box body 13 is removed, then other bridge span cantilever-free box bodies are sequentially removed, finally the middle cross beams 9 of the pier tops on two sides are chiseled synchronously, the principle that the middle cross beams extend to two ends from the middle of each span is adopted along the longitudinal span of the bridge, and the bridge body is broken and removed. Chiseling is strictly according to the principle of symmetry, and the stability of the beam body in the chiseling process of the hydraulic impact hammer is ensured.
Temporarily closing traffic, organizing a large number of dismantling machines to carry out longitudinal synchronous and transverse symmetrical chiseling on the full-bridge box girder flange plates.
And calculating and analyzing the actual structure stress state of each stage of dismantling construction, and ensuring that the structure stress of each stage of dismantling construction is in a safe range under the action of self weight.
The area of each bridge span cantilever-free box body 13 is divided into three construction areas. The construction first area is a plane area where the overpass bridge spans, and the construction second area and the construction third area are respectively arranged on the left side and the right side of the overpass bridge span. The construction is that firstly, the dismantling construction is started in the area, and then the dismantling construction of the area II and the area III is carried out after the construction is finished.
Take a five-span bridge as an example but not limited to a five-span bridge. The overall bridge dismantling concept is to dismantle the flange plates of the full-span beam body, then dismantle the 3 rd span box girder of the span line, and finally dismantle the 1-3 span and 3-5 span residual box girders.
And 3, dismantling the spanning box girder: after dismantling, timely transporting out the steel bars and the concrete slag;
1 st to 3 rd span box girder dismantling: span 3 → span 2 → span 1;
3, detaching the 3 rd to 5 th span box girder: 3 rd span → 4 th span → 5 th span;
the 3 rd span in the full-bridge range is greatly influenced by height and traffic factors due to the span line, the long-arm head picking machines and the long-arm scissor machines are arranged on two sides of the bridge collapse to cooperatively operate, the head picking machines are arranged on two sides of the remaining bridge collapse, and after the traffic conditions are met, the structural objects are integrally chiseled from the flange plate 3 in the axial direction at one time on site after a dismantling command is given.
And the bridge spans in each construction area are removed in a symmetrical mode of transversely extending from outside to inside and longitudinally extending from the middle to two ends, and the top plate, the web plate and the bottom plate are sequentially removed. The pier top beam 9 of each bridge span is reserved to keep each span to be temporarily in a smooth and stable state, and the longitudinal main rib of the middle part of the box body is not disconnected temporarily.
The exposed reinforcing steel bars after the concrete is chiseled off are cut off in time by gas cutting, the concrete waste residues and the cut reinforcing steel bars fall freely, and the weight of the beam body at the upper part of the bridge is reduced gradually. By manual cooperation, adopt the machine of digging in time loading with reinforcing bar and concrete sediment and clear the fortune, need ensure during the clear fortune that top no concrete sediment drops to plan safety.
When the bridge breaks, the beam body above the common single column is easy to topple over, and the danger is large. For preventing the roof beam body from toppling, guarantee construction safety, at every group pier stud below along the horizontal pile sand bag 7 of bridge, sand bag 7 is the dumbbell shape, plays interim supporting role to the roof beam body.
Each bridge span sequentially and synchronously chisels off pier top cross beams 9 on two sides, so that the middle parts of the cross beams 9 are broken; the rest beam bodies slowly fall onto the dumbbell-shaped sand bags on the pier sides along with the cross beams, the longitudinal main reinforcements in the middle of the box body are cut off manually by using gas cutting or a handheld hydraulic type reinforcement shear to enable the beam bodies to fall to the ground, and the waste slag is timely cleaned after the beam bodies are broken.
The method is characterized in that damage to the existing road cannot be avoided after the viaduct is dismantled, the damaged road needs to be repaired, and cold-mixed asphalt is paved on the damaged road at night subsequently.