Dismounting method for foundation pit steel trestle slope surface

Abstract

The invention discloses a method for disassembling a foundation pit steel trestle slope, which comprises steel upright posts, spandrel girders, bailey trusses, distributive girders and a bridge deck steel plate and comprises the following steps of: firstly, disassembling trestle handrails on a trestle panel, then disassembling the trestle panel, then disassembling bailey, sequentially disassembling cross beams, diagonal bracings and the steel upright posts, and finally disassembling the trestle panel, the distributive girders and the bridge deck steel plate. The materials are transferred once after one working procedure is completed or are transferred in a unified manner finally; the trestle is dismantled from the high position to the low position, the steel trestle is dismantled, the trestle and the temporary steel pipe columns of the trestle are dismantled in a hole span-by-hole mode, and safe and efficient dismantling is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, in particular to a method for disassembling a slope surface of a foundation pit steel trestle. Background Art

[0002] In the prior art, mechanized demolition equipment, such as hydraulic shears, pneumatic hammers or demolition robots, are generally used to dismantle bridge steel trestles. In order to improve efficiency and safety, segmented demolition is generally adopted: the steel trestles are divided into multiple sections that are easy to manage and dismantle. Through pre-set demolition points, each section is gradually dismantled to reduce the impact on the undemolished parts. Some construction methods implement real-time monitoring during the demolition process to monitor the demolition progress and the stability of the structure. However, its demolition method cannot fully adapt to the demolition method of the inclined steel trestles in the foundation pit. Due to the internal force in the foundation pit caused by the long-term rolling of vehicles, there will be interference from related uncertain dynamic loads during demolition, which can easily cause sudden stress on the structure, and related problems need to be classified and handled.

[0003] Therefore, it is necessary to provide a method for disassembling the slope of a foundation pit steel trestle to solve the above technical problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for dismantling the slope of a foundation pit steel trestle to solve the problem in the above background technology of how to safely and efficiently dismantle and transport the entire Bailey beam after the construction is completed.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for disassembling the slope of a steel trestle bridge in a foundation pit, wherein the steel trestle bridge comprises steel columns, load-bearing beams, Bailey frames, distribution beams and trestle bridge panels, wherein the trestle bridge panels are installed on the steel columns according to the designed slope, wherein the bridge deck steel plate transfers the load to the steel columns evenly through the load-bearing beams, Bailey frames and distribution beams, Bailey frames are arranged on the steel pipe columns, cross beams are arranged on the Bailey frames, and inclined trestle bridge panels are arranged on the cross beams, and scissor braces are arranged between the steel pipe columns to ensure the connection between the columns;

[0006] The overall dismantling construction process of the steel trestle is to first remove the trestle railings on the trestle deck, then remove the trestle deck, then remove the Bailey, then remove the beams, scissor braces and steel pipe columns in turn, and finally transfer the materials. The specific process includes:

[0007] Step (1): dismantling the trestle railings and trestle panels. Since the trestle panels are welded to the distribution beams, the railings on the trestle panels are first dismantled, and then the trestle panels and the distribution beams are separated by cutting and welding, and then hoisted and packaged in categories;

[0008] Step (2): Remove the Bailey frame and Bailey truss beams of the trestle bridge. Use a truck crane to operate at the edge of the foundation pit to remove the steel trestle bridge, so that the Bailey beams form a group of two connected ones; manually remove the Bailey pins, and finally lift them onto a flatbed transport vehicle, which is then transported to a designated location on the shore and manually remove the Bailey truss beams; repeat the above work until the Bailey truss beams are completely removed; the Bailey beams are removed as a whole span, and can only be removed when there is no impact on the whole after the Bailey beams are removed; before removing the Bailey beams, use a cutting knife to "ride the card" at the Bailey and the load-bearing beam. The dismantled "riding cards" are placed in woven bags for centralized treatment; workers must wear safety helmets, life jackets and safety ropes before cutting the "riding cards"; when cutting the "riding cards", workers stand on the top of the load-bearing beams, and the safety ropes are hooked on the Bailey beams that have not been dismantled; the diagonal bracing connecting bolts between the Bailey frames are removed and recycled in woven bags; the dismantled channel steel supports are manually handed over to the workers on the trestle for centralized stacking; the lower Bailey pins are removed first, and the upper Bailey pins are removed after the crane lifts the Bailey beam to be dismantled slightly upwards;

[0009] Step (3): After removing the cross beam and Bailey beam, remove the steel load-bearing beam. Before removing the load-bearing beam, cut off the limiting steel plate. To cut off the corbel, first cut off the weld between the top surface of the corbel and the load-bearing beam, then make a hole in the steel plate on the side of the corbel, pass the lifting buckle through the hole, and then cut off the weld between the corbel and the steel pipe column. The removal of the load-bearing beam depends on the on-site conditions. Cut along the joints during assembly as much as possible, and then hoist the whole beam. Before lifting the load-bearing beam, weld lifting ears or cut holes on the load-bearing beam, and then hoist it with wire rope. During the hoisting process, prevent the load-bearing beam from swinging left and right due to inertia, which may cause risks. Use a wind rope to pull it until it is hoisted to a flatbed truck. After the load-bearing beam is removed, use a truck crane or truck crane to lift it onto a flatbed truck, and pull it to the backyard for orderly storage.

[0010] Step (4): Remove the scissors brace. First remove the flat joint and the scissors brace. Before removing the steel pipe column, the flat joints and scissors brace between adjacent steel pipe columns must be cut off. The cutting order is to cut the lower flat joint first, then cut the scissors brace, and finally cut the upper flat joint. Cut the lower flat joint first. During the flat joint cutting process, the operator always ties the safety rope to the load-bearing beam, first cut a hole in the flat joint, then cut one end of the flat joint, and finally cut the other end of the flat joint, and use a car crane for lifting; then cut the scissors brace, first Use one end of the wire rope to tie the cross of the scissors brace, hang the other end on the hook, install the safety bolt, cut off the four corners of the scissors brace, and then hoist it as a whole; during the dismantling process, in order to prevent the object from swinging, ropes are used on site for traction to prevent safety accidents; then, cut off the upper flat joint in the same order as the lower flat joint, first cut off one end, and then cut off the other end; after all the upper and lower flat joints and scissors braces are dismantled, use a car crane to lift them onto a flatbed truck and pull them to the backyard for orderly storage;

[0011] Step (5): After the steel pipe column is removed, the steel pipe column can be removed. A hole is cut at the top of the steel pipe, and the hole at the top of the steel pipe column is suspended with a steel wire rope. Then, the welding part between the bottom of the steel pipe column and the embedded steel plate of the basement floor is cut off; the cut part is hoisted to the rear site for orderly stacking, and then the next section of the steel pipe column is removed;

[0012] Step (6): Material transfer: according to the order of material stacking, the materials are transferred to a safe location by crane and transported to the next construction pit by vehicle.

[0013] When the Bailey frame is removed in step (3), a pre-lifting test is performed before lifting. The pre-lifting test is performed by fixing the crane wire rope in the middle of the Bailey frame of the upper and lower Bailey pins that have been removed. The lifting risk factor is calculated during lifting. When the risk factor is greater than 2, the lifting is performed normally. However, when the risk factor is less than 2, the lifting is suspended and the lifting equipment is checked, as well as the relevant load conditions.

[0014] The formula for the risk factor is: Among them, f is the risk factor, F 极限荷载 is the ultimate load of the crane wire rope, F 自重 is the deadweight of the steel truss, G 工人 For the self-respect of the construction workers, F 风 is the wind load; F 动 is the dynamic load; α is the wind load coefficient, which takes a value of 1.2 to 1.7; β is the dynamic load coefficient, which takes a value of 1.15 to 1.45.

[0015] When removing the steel pipe column in step (6), a plasma cutter is used. The cutting edge should be smooth and burr-free. The edge of the steel plate after cutting needs to be polished to remove any burrs or uneven parts.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0017] 1. The demolition of the trestle bridge in this application is from high to low, the steel trestle bridge is dismantled, and the trestle bridge and its temporary steel pipe columns are dismantled span by span to achieve safe and efficient demolition;

[0018] 2. This application further ensures the safety requirements of construction through pre-hoisting and risk factor assessment;

[0019] 3. The steel trestle disassembly method of the present application realizes the reuse of disassembled materials, which greatly ensures cost reduction and efficiency improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 It is the step flow of the demolition method of the present invention;

[0022] Figure 2 It is a side view of the steel trestle foundation pit ramp structure of the present invention;

[0023] Figure 3 It is a schematic diagram of dismantling the Bailey frame of the present invention;

[0024] Figure 4 It is a schematic diagram of Bailey frame hoisting of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1

[0027] See also Figure 1-Figure 4 The present invention provides a technical solution: a method for disassembling the slope of a steel trestle bridge in a foundation pit, wherein the steel trestle bridge comprises steel columns, load-bearing beams, Bailey frames, distribution beams and trestle bridge panels, wherein the trestle bridge panels are installed on the steel columns according to the designed slope, wherein the bridge deck steel plate transfers the load to the steel columns evenly through the load-bearing beams, Bailey frames and distribution beams, Bailey frames are arranged on the steel pipe columns, cross beams are arranged on the Bailey frames, and inclined trestle bridge panels are arranged on the cross beams, and scissor braces are arranged between the steel pipe columns to ensure the connection between the columns;

[0028] The overall dismantling construction process of the steel trestle is to first remove the trestle railings on the trestle panel, then remove the trestle panel, then remove the Bailey, and then remove the beams, scissor braces and steel pipe columns in turn, and finally transfer the materials. The specific process includes:

[0029] Step (1): dismantling the trestle railings and trestle panels. Since the trestle panels are welded to the distribution beams, the railings on the trestle panels are first dismantled, and then the trestle panels and the distribution beams are separated by cutting and welding, and then hoisted and packaged in categories;

[0030] Step (2): Remove the Bailey frame and Bailey truss beams of the trestle bridge. Use a truck crane to operate at the edge of the foundation pit to remove the steel trestle bridge, so that the Bailey beams form a group of two connected ones; manually remove the Bailey pins, and finally lift them onto a flatbed transport vehicle, which is then transported to a designated location on the shore and manually remove the Bailey truss beams; repeat the above work until the Bailey truss beams are completely removed; the Bailey beams are removed as a whole span, and can only be removed when there is no impact on the whole after the Bailey beams are removed; before removing the Bailey beams, use a cutting knife to "ride the card" at the Bailey and the load-bearing beam. The dismantled "riding cards" are placed in woven bags for centralized treatment; workers must wear safety helmets, life jackets and safety ropes before cutting the "riding cards"; when cutting the "riding cards", workers stand on the top of the load-bearing beams, and the safety ropes are hooked on the Bailey beams that have not been dismantled; the diagonal bracing connecting bolts between the Bailey frames are removed and recycled in woven bags; the dismantled channel steel supports are manually handed over to the workers on the trestle for centralized stacking; the lower Bailey pins are removed first, and the upper Bailey pins are removed after the crane lifts the Bailey beam to be dismantled slightly upwards;

[0031] Step (3): After removing the cross beam and Bailey beam, remove the steel load-bearing beam. Before removing the load-bearing beam, cut off the limiting steel plate. To cut off the corbel, first cut off the weld between the top surface of the corbel and the load-bearing beam, then make a hole in the steel plate on the side of the corbel, pass the lifting buckle through the hole, and then cut off the weld between the corbel and the steel pipe column. The removal of the load-bearing beam depends on the on-site conditions. Cut along the joints during assembly as much as possible, and then hoist the whole beam. Before lifting the load-bearing beam, weld lifting ears or cut holes on the load-bearing beam, and then hoist it with wire rope. During the hoisting process, prevent the load-bearing beam from swinging left and right due to inertia, which may cause risks. Use a wind rope to pull it until it is hoisted to a flatbed truck. After the load-bearing beam is removed, use a truck crane or truck crane to lift it onto a flatbed truck, and pull it to the backyard for orderly storage.

[0032] Step (4): Remove the scissors brace. First remove the flat joint and the scissors brace. Before removing the steel pipe column, the flat joints and scissors brace between adjacent steel pipe columns must be cut off. The cutting order is to cut the lower flat joint first, then cut the scissors brace, and finally cut the upper flat joint. Cut the lower flat joint first. During the flat joint cutting process, the operator always ties the safety rope to the load-bearing beam, first cut a hole in the flat joint, then cut one end of the flat joint, and finally cut the other end of the flat joint, and use a car crane for lifting; then cut the scissors brace, first Use one end of the wire rope to tie the cross of the scissors brace, hang the other end on the hook, install the safety bolt, cut off the four corners of the scissors brace, and then hoist it as a whole; during the dismantling process, in order to prevent the object from swinging, ropes are used on site for traction to prevent safety accidents; then, cut off the upper flat joint in the same order as the lower flat joint, first cut off one end, and then cut off the other end; after all the upper and lower flat joints and scissors braces are dismantled, use a car crane to lift them onto a flatbed truck and pull them to the backyard for orderly storage;

[0033] Step (6): After the steel pipe column is removed, the steel pipe column can be removed. A hole is cut at the top of the steel pipe, and the hole at the top of the steel pipe column is suspended with a steel wire rope. Then, the welding part between the bottom of the steel pipe column and the embedded steel plate of the basement floor is cut off; the cut part is hoisted to the rear site for orderly stacking, and then the next section of the steel pipe column is removed;

[0034] Step (5): Material transfer: according to the order of material stacking, the materials are transferred to a safe location by crane and transported to the next construction pit by vehicle.

[0035] When the Bailey frame is removed in step (3), a pre-lifting test is performed before lifting. The pre-lifting test is performed by fixing the crane wire rope in the middle of the Bailey frame of the upper and lower Bailey pins that have been removed. The lifting risk factor is calculated during lifting. When the risk factor is greater than 2, the lifting is performed normally. However, when the risk factor is less than 2, the lifting is suspended and the lifting equipment is checked, as well as the relevant load conditions.

[0036] The formula for the risk factor is: Among them, f is the risk factor, F 极限荷载 is the ultimate load of the crane wire rope, F 自重 is the deadweight of the steel truss, G 工人 For the self-respect of the construction workers, F 风 is the wind load; F 动 is the dynamic load; α is the wind load coefficient, which takes a value of 1.2 to 1.7; β is the dynamic load coefficient, which takes a value of 1.15 to 1.45.

[0037] When removing the steel pipe column in step (6), a plasma cutter is used. The cutting edge should be smooth and burr-free. The edge of the steel plate after cutting needs to be polished to remove any burrs or uneven parts.

[0038] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for dismantling the slope of a steel trestle bridge in a foundation pit, wherein the steel trestle bridge comprises steel columns, load-bearing beams, Bailey frames, distribution beams and trestle panels, wherein the trestle panels are installed on the steel columns according to the designed slope, wherein the bridge deck steel plate transfers the load to the steel columns evenly through the load-bearing beams, Bailey frames and distribution beams, Bailey frames are arranged on the steel pipe columns, cross beams are arranged on the Bailey frames, and trestle panels arranged obliquely are arranged on the cross beams, and scissor braces are arranged between the steel pipe columns to ensure the connection between the columns; The overall dismantling construction process of the steel trestle is to first remove the trestle railings on the trestle panel, then remove the trestle panel, then remove the Bailey, and then remove the beams, scissor braces and steel pipe columns in turn. The material transfer is to complete a process, then transfer once or finally transfer uniformly. It is characterized by: The specific process includes: Step (1): dismantling the trestle railings and trestle panels. Since the trestle panels are welded to the distribution beams, the railings on the trestle panels are first dismantled, and then the trestle panels and the distribution beams are separated by cutting and welding, and then hoisted and packaged in categories; Step (2): Remove the Bailey frame and Bailey truss beams of the trestle bridge. Use a truck crane to remove the steel trestle bridge at the edge of the foundation pit, so that the Bailey beams form a group of two connected Bailey beams; manually remove the Bailey pins, and finally lift them onto a flatbed transport vehicle, which is then transported to a designated location on the shore and manually remove the Bailey truss beams; repeat the above work until the Bailey truss beams are completely removed; the Bailey beams are removed as a whole span, and can only be removed when there is no impact on the whole after the Bailey beams are removed; before removing the Bailey beams, use a cutting knife to "saddle the card" at the Bailey and the load-bearing beams. The dismantled "riding cards" are placed in woven bags for centralized treatment; workers must wear safety helmets, life jackets and safety ropes before cutting the "riding cards"; when cutting the "riding cards", workers stand on the top of the load-bearing beams, and the safety ropes are hooked on the Bailey beams that have not been dismantled; the diagonal bracing connecting bolts between the Bailey frames are removed and recycled in woven bags; the dismantled channel steel supports are manually handed over to the workers on the trestle for centralized stacking; the lower Bailey pins are removed first, and the upper Bailey pins are removed after the crane lifts the Bailey beam to be dismantled slightly upwards; Step (3): After removing the cross beam and Bailey beam, remove the steel load-bearing beam. Before removing the load-bearing beam, cut off the limiting steel plate. To cut off the corbel, first cut off the weld between the top surface of the corbel and the load-bearing beam, then make a hole in the steel plate on the side of the corbel, pass the lifting buckle through the hole, and then cut off the weld between the corbel and the steel pipe column. The removal of the load-bearing beam depends on the on-site conditions. Cut along the joints during assembly as much as possible, and then hoist the whole beam. Before lifting the load-bearing beam, weld lifting ears or cut holes on the load-bearing beam, and then hoist it with wire rope. During the hoisting process, prevent the load-bearing beam from swinging left and right due to inertia, which may cause risks. Use a wind rope to pull it until it is hoisted to a flatbed truck. After the load-bearing beam is removed, use a truck crane or truck crane to lift it onto a flatbed truck, and pull it to the backyard for orderly storage. Step (4): Remove the scissors brace. First remove the flat joint and the scissors brace. Before removing the steel pipe column, the flat joints and scissors brace between adjacent steel pipe columns must be cut off. The cutting order is to cut the lower flat joint first, then cut the scissors brace, and finally cut the upper flat joint. Cut the lower flat joint first. During the flat joint cutting process, the operator always ties the safety rope to the load-bearing beam, first cut a hole in the flat joint, then cut one end of the flat joint, and finally cut the other end of the flat joint, and use a car crane for lifting; then cut the scissors brace, first Use one end of the wire rope to tie the cross of the scissors brace, hang the other end on the hook, install the safety bolt, cut off the four corners of the scissors brace, and then hoist it as a whole; during the dismantling process, in order to prevent the object from swinging, ropes are used on site for traction to prevent safety accidents; then, cut off the upper flat joint in the same order as the lower flat joint, first cut off one end, and then cut off the other end; after all the upper and lower flat joints and scissors braces are dismantled, use a car crane to lift them onto a flatbed truck and pull them to the backyard for orderly storage; Step (5): After the steel pipe column is removed, the steel pipe column can be removed. A hole is cut at the top of the steel pipe, and the hole at the top of the steel pipe column is suspended with a steel wire rope. Then, the welding part between the bottom of the steel pipe column and the embedded steel plate of the basement floor is cut off; the cut part is hoisted to the rear site for orderly stacking, and then the next section of the steel pipe column is removed; Step (6): Material transfer: according to the order of material stacking, the materials are transferred to a safe location by crane and transported to the next construction pit by vehicle.

2. The method for dismantling the slope of a foundation pit steel trestle according to claim 1 is characterized in that: When the Bailey frame is removed in step (3), a pre-lifting test is performed before lifting. The pre-lifting test is performed by fixing the crane wire rope in the middle of the Bailey frame of the upper and lower Bailey pins that have been removed. The lifting risk factor is calculated during lifting. When the risk factor is greater than 2, the lifting is performed normally. However, when the risk factor is less than 2, the lifting is suspended and the lifting equipment is checked, as well as the relevant load conditions.

3. The method for dismantling the slope of a foundation pit steel trestle according to claim 2 is characterized in that: The formula for the risk factor is: Among them, f is the risk factor, F 极限荷载 is the ultimate load of the crane wire rope, F 自重 is the deadweight of the steel truss, G 工人 For the self-respect of the construction workers, F 风 is the wind load; F 动 is the dynamic load; α is the wind load coefficient, which takes a value of 1.2 to 1.7; β is the dynamic load coefficient, which takes a value of 1.15 to 1.

45.

4. The method for dismantling the slope of a foundation pit steel trestle according to claim 1 is characterized in that: When removing the steel pipe column in step (6), a plasma cutter is used. The cutting edge should be smooth and burr-free. The edge of the steel plate after cutting needs to be polished to remove any burrs or uneven parts.

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