Method for rapid demolition of a bridge

Abstract

The application discloses a bridge rapid dismantling method, comprising the following steps: modeling the bridge structure by using finite element software, and outputting a collapse trajectory prediction graph; carrying out full-section clearing before construction, setting a temporary detour to divert vehicles, and arranging a movable sound barrier and a fog gun dust suppression system; during construction, multiple intelligent synchronous control diamond rope saws / chain saws are adopted to carry out underwater or water mist dust suppression synchronous cutting, and a hydraulic breaking hammer point type breaking is carried out on the bridge deck pavement layer; pre-cutting or prestress release is carried out at key connecting points; a jack fixing frame is installed at the abutment, a jack is placed, the beam body is longitudinally pushed, and the beam body and the pier column collapse along the specified direction; construction data are collected in real time by using a strain gauge and an inclinometer, and are compared with a digital model; if the measured displacement exceeds the predicted value, parameter iterative updating based on an extended Kalman filtering algorithm is automatically triggered, and the construction is continued. The application can rapidly dismantle the bridge structure in a short time, and reduces surrounding traffic disturbance.

Description

Technical Field

[0001] This invention belongs to the field of concrete bridge demolition construction technology, specifically a method for rapid bridge demolition. Background Technology

[0002] With the rapid development of transportation in my country, most bridges can no longer meet current traffic demands and need to be demolished and rebuilt. However, when demolishing large concrete bridges, the demolition machinery requires a certain amount of working space and may even need to temporarily close roads. If the demolition operation takes a long time, it will cause significant disruption to regional transportation.

[0003] Based on this, an integrated bridge demolition solution is provided that can minimize traffic disruption, shorten construction period, and improve safety and environmental friendliness. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a method for rapid bridge demolition, which can quickly dismantle the bridge structure in a short period of time and reduce traffic disturbance in the surrounding area.

[0005] The technical solution to achieve the above objectives is: A method for rapid bridge demolition includes: Step S1: Model the bridge structure using finite element software, simulate the structural state of the piers and beams after pre-cutting or prestress release, calculate the jacking force required when the bridge collapses, and output the collapse trajectory prediction diagram. Step S2: Before construction, the entire section of the site is cleared. Infrared monitoring is used to confirm that there are no vehicles left in the closed area. Temporary access roads are set up to divert vehicles. Mobile sound barriers and fog cannon dust suppression systems are deployed using quick-assembly temporary supports and protective sheds. Step S3: During construction, multiple intelligent synchronously controlled diamond wire saws / chain saws are used for underwater or water mist dust suppression synchronous cutting, and the bridge deck pavement layer is broken by hydraulic breakers in a point-type manner. Step S4: Pre-cut or release pre-stress at key connection points; Step S5: Install the jack fixing frame at the abutment, place the jacks, and push the beam longitudinally until the beam and pier collapse in the specified direction. Step S6: Real-time construction data is collected using strain gauges and inclinometers and compared with the digital model. If the measured displacement exceeds the predicted value, parameter iterative updates based on the extended Kalman filter algorithm are automatically triggered to obtain real-time jacking force data. Construction continues until completion. Step S7: After construction is completed, a mobile crushing station is set up to crush the concrete blocks on site and recover the reinforcing steel bars through electromagnetic sorting for green recycling.

[0006] Preferably, step S1 includes: Step S11: Use Midas Civil (a finite element analysis software for bridges and civil engineering) or ANSYS (a general-purpose multiphysics simulation platform) to build a three-dimensional model of the bridge, input material parameters, and consider the effects of bridge aging to correct the model's elastic modulus and bearing capacity. Step S12: Set the V-shaped cut at the bottom of the pier and the construction error, simulate the weakening effect of the cut on the structural stiffness, and analyze the prestress release sequence; Step S13: Apply axial load to the pier column, obtain the first buckling mode through eigenvalue buckling analysis, extract the critical load coefficient, calculate the critical force in combination with the self-weight load, and calculate the jacking force considering the safety factor. Step S14: Simulate the plastic development of the material during the jacking process, output the force-displacement curve, take the load corresponding to the inflection point as the critical value, and output the collapse trajectory prediction diagram through explicit dynamic analysis.

[0007] Preferably, in step S11, the input material parameters include, but are not limited to, material degradation parameters, effective prestress value of prestressed tendons, cross-sectional dimensions of pier columns and reinforcement ratio, and the effects of bridge aging include, but are not limited to, concrete carbonation depth and steel corrosion rate.

[0008] Preferably, in step S2, the closed area adopts a dual isolation of "traffic police guidance + water-filled barriers", wherein the water-filled barriers have built-in pressure sensors that automatically trigger an audible and visual alarm upon collision.

[0009] Preferably, in step S2, the mobile sound barrier is arranged along the construction boundary to reduce noise generated during construction, and the fog cannon dust suppression system is used to reduce dust generated during construction.

[0010] Preferably, in step S4, the key connection points include, but are not limited to, the bottom of the pier and the mid-span of the beam; Pre-cutting or prestress release involves: pre-cutting a V-shaped incision at the bottom of the pier and loosening the prestressing tendons in the mid-span area of ​​the continuous beam; Among them, an intelligent cutting robot is used to cut V-shaped slits.

[0011] Preferably, in step S6, fiber optic strain gauges are attached to the key sections of the pier column, wireless strain nodes are arranged in the mid-span of the beam, and inclinometers are installed at the top of the pier and the end of the beam.

[0012] Preferably, in step S7, the obtained final collapse data is imported into the crushing station path planning algorithm to perform optimal path planning.

[0013] Compared with the prior art, the beneficial effects of the present invention are: by temporarily closing traffic, modularly pre-dismantling the bridge deck system and ancillary structures, partially shearing the pier structure, and using a high-precision hydraulic device to push the main beam, the bridge collapses as a whole when it reaches the critical point of the bridge's bearing capacity. The demolition time of a single span can be effectively improved, and the time occupied by the traffic section can be shortened, thus realizing the rapid and green demolition of old concrete bridges with high traffic protection requirements. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of a method for rapid bridge demolition according to the present invention; Figure 2 This is a flowchart illustrating the process of using finite element software to model a bridge structure and output a predicted collapse trajectory in this invention. Figure 3 This is a schematic diagram of removing the longitudinal restraint with oxygen in an embodiment of the present invention; Figure 4 This is a schematic diagram of the cutting at bridge abutment #6 in an embodiment of the present invention; Figure 5 This is a schematic diagram of the jack slot at bridge abutment #6 in an embodiment of the present invention; Figure 6 This is a schematic diagram of the pre-cutting of the bottom of piers 2#-4# in an embodiment of the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] like Figure 1 As shown, a method for rapid bridge demolition includes: Step S1: Model the bridge structure using finite element software, simulate the structural state of the piers and beams after pre-cutting or prestress release, calculate the jacking force required when the beam collapses, and output the collapse trajectory prediction diagram.

[0017] like Figure 2 As shown, step S1 includes: Step S11: Use Midas Civil or ANSYS to build a three-dimensional model of the bridge, input material parameters, and consider the effects of bridge aging to correct the model's elastic modulus and bearing capacity. The input material parameters include, but are not limited to, material degradation parameters, effective prestress values ​​of prestressed tendons, pier column cross-sectional dimensions and reinforcement ratios. The effects of bridge aging include, but are not limited to, concrete carbonation depth and steel corrosion rate. Step S12: Set the V-shaped cut at the bottom of the pier and the construction error, simulate the weakening effect of the cut on the structural stiffness, and analyze the prestress release sequence; Step S13: Apply axial load to the pier column, obtain the first buckling mode through eigenvalue buckling analysis, extract the critical load coefficient, calculate the critical force in combination with the self-weight load, and calculate the jacking force considering the safety factor. Step S14: Simulate the plastic development of the material during the jacking process, output the force-displacement curve, take the load corresponding to the inflection point as the critical value, and output the collapse trajectory prediction diagram through explicit dynamic analysis.

[0018] Step S2: Before construction, the entire section of the site is cleared. Infrared monitoring is used to confirm that there are no vehicles left in the closed area. Temporary access roads are set up to divert vehicles (to guide vehicles away from the construction area). Mobile sound barriers and fog cannon dust suppression systems are deployed using quick-assembly temporary supports and protective sheds (to reduce road occupation time and space).

[0019] In this embodiment, the closed area adopts a dual isolation system of "traffic police guidance + water-filled barriers". The water-filled barriers have built-in pressure sensors that automatically trigger an audible and visual alarm upon collision.

[0020] In this embodiment, a mobile sound barrier is arranged along the construction boundary to reduce noise generated during construction, and a fog cannon dust suppression system is used to reduce dust generated during construction.

[0021] Step S3: During construction, multiple intelligent synchronously controlled diamond wire saws / chainsaws are used for underwater or water mist dust suppression synchronous cutting, and hydraulic breakers are used to break the bridge deck pavement layer in a point-by-point manner to prevent metal fragments from flying when the bridge collapses as a whole.

[0022] Step S4 involves pre-cutting or releasing prestress at key connection points to disrupt the original equilibrium conditions of the structure, making it easier for it to collapse in the specified direction.

[0023] In the embodiments, key connection points include, but are not limited to, the bottom of the bridge piers and the mid-span of the beam; Pre-cutting or prestress release involves: pre-cutting a V-shaped incision at the bottom of the pier and loosening the prestressing tendons in the mid-span area of ​​the continuous beam; Among them, an intelligent cutting robot is used to cut V-shaped slits.

[0024] Step S5: Install a jack fixing frame at the abutment, place the jacks, and push the beam longitudinally until the beam and pier collapse in the specified direction.

[0025] Step S6: Real-time construction data is collected using strain gauges and inclinometers and compared with the digital model. If the measured displacement exceeds the predicted value, parameter iterative updates based on the extended Kalman filter algorithm are automatically triggered to obtain real-time jacking force data. Construction then continues until completion.

[0026] In this embodiment, fiber optic strain gauges are attached to the key sections of the pier column, wireless strain nodes are arranged at the mid-span of the beam, and inclinometers are installed at the top of the pier and the end of the beam.

[0027] Step S7: After construction is completed, a mobile crushing station is set up to crush the concrete blocks on site and recover the reinforcing steel bars through electromagnetic sorting for green recycling. The waste residue is used to make recycled aggregates, realizing on-site resource utilization.

[0028] In this embodiment, the final collapse data is imported into the crushing station path planning algorithm to perform optimal path planning.

[0029] Taking the demolition project of a high-pier overpass as an example, the bridge has a total of 6 spans, with the middle piers and beams being fixedly connected, and the lower part of the bridge is a highway.

[0030] Step 1: Model the bridge structure using finite element software to simulate the structural state of the piers and beams after pre-cutting or prestress release, and calculate the jacking force required when the bridge collapses.

[0031] Step 2, Traffic Closure: The highway at the bottom of the bridge will be closed, and vehicles will be directed to detour. After the interchange is closed, traffic police will lead the construction unit to check the closed area with the last vehicle to ensure that all social vehicles leave the closed area. At the same time, water-filled barriers will be used to close the highway traffic at the work sites where no social vehicles have been confirmed. Mobile sound barriers and fog cannon dust suppression systems will be set up, and warning tapes and reflective signs will be set up on the outside. During the construction period, all unrelated vehicles and personnel will be prohibited from entering the construction site.

[0032] Step 3: Verify the support structure of piers #1 and #5. If the supports have longitudinal restraints, use an oxygen cutter to remove the longitudinal restraints and cut the first span. Figure 3 As shown.

[0033] Step 4: Cut and install jack slots at abutment No. 6, such as... Figure 4 , 5 As shown, a road surface cutter was used for cutting, along with a jacking machine. The dimensions needed to accommodate a 500t jack were sufficient. Pre-cutting was performed on the bottom of piers #2-#4. Figure 6 As shown, the specific cutting depth is subject to calculation to ensure the structural safety before jacking.

[0034] Step 5: Install two 500t jacks at abutment #6 to push the entire bridge, causing it to tilt along the perpendicular direction of the cutting line. Real-time construction data is collected using strain gauges and inclinometers and compared with the digital model. If the measured displacement exceeds the predicted value, the parameters are automatically updated based on the extended Kalman filter algorithm to obtain real-time jacking force data. Construction continues until the bridge collapses.

[0035] Step 6: After the bridge collapses, the final collapse data is imported into the path planning algorithm of the crushing plant to plan the optimal path. The mobile crushing plant travels along the path, and the mobile blasting initially crushes the beams and piers. The fragments are then placed into the mobile crushing plant for on-site crushing of concrete blocks and magnetic separation and recycling of reinforcing steel. The waste residue is used to produce recycled aggregate, achieving on-site resource utilization.

[0036] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for rapid bridge demolition, characterized in that, include: Step S1: Model the bridge structure using finite element software, simulate the structural state of the piers and beams after pre-cutting or prestress release, calculate the jacking force required when the bridge collapses, and output the collapse trajectory prediction diagram. Step S2: Before construction, the entire section of the site is cleared. Infrared monitoring is used to confirm that there are no vehicles left in the closed area. Temporary access roads are set up to divert vehicles. Mobile sound barriers and fog cannon dust suppression systems are deployed using quick-assembly temporary supports and protective sheds. Step S3: During construction, multiple intelligent synchronously controlled diamond wire saws / chain saws are used for underwater or water mist dust suppression synchronous cutting, and the bridge deck pavement layer is broken by hydraulic breakers in a point-type manner. Step S4: Pre-cut or release pre-stress at key connection points; Step S5: Install the jack fixing frame at the abutment, place the jacks, and push the beam longitudinally until the beam and pier collapse in the specified direction. Step S6: Real-time construction data is collected using strain gauges and inclinometers and compared with the digital model. If the measured displacement exceeds the predicted value, parameter iterative updates based on the extended Kalman filter algorithm are automatically triggered to obtain real-time jacking force data. Construction continues until completion. Step S7: After construction is completed, a mobile crushing station is set up to crush the concrete blocks on site and recover the reinforcing steel bars through electromagnetic sorting for green recycling.

2. The method for rapid bridge demolition according to claim 1, characterized in that, Step S1 includes: Step S11: Use Midas Civil or ANSYS to build a three-dimensional model of the bridge, input material parameters, and consider the effects of bridge aging to correct the model's elastic modulus and bearing capacity. Step S12: Set the V-shaped cut at the bottom of the pier and the construction error, simulate the weakening effect of the cut on the structural stiffness, and analyze the prestress release sequence; Step S13: Apply axial load to the pier column, obtain the first buckling mode through eigenvalue buckling analysis, extract the critical load coefficient, calculate the critical force in combination with the self-weight load, and calculate the jacking force considering the safety factor. Step S14: Simulate the plastic development of the material during the jacking process, output the force-displacement curve, take the load corresponding to the inflection point as the critical value, and output the collapse trajectory prediction diagram through explicit dynamic analysis.

3. A method for rapid bridge demolition according to claim 2, characterized in that, In step S11, the input material parameters include, but are not limited to, material degradation parameters, effective prestress value of prestressed tendons, cross-sectional dimensions of pier columns and reinforcement ratio, and bridge aging effects include, but are not limited to, concrete carbonation depth and steel corrosion rate.

4. The method for rapid bridge demolition according to claim 1, characterized in that, In step S2, the closed area adopts a dual isolation of "traffic police guidance + water-filled barriers". The water-filled barriers have built-in pressure sensors that automatically trigger an audible and visual alarm when they collide.

5. A method for rapid bridge demolition according to claim 1, characterized in that, In step S2, the mobile sound barrier is arranged along the construction boundary to reduce the noise generated during construction, and the fog cannon dust suppression system is used to reduce the dust generated during construction.

6. A method for rapid bridge demolition according to claim 1, characterized in that, In step S4, key connection points include, but are not limited to, the bottom of the bridge pier and the mid-span of the beam. Pre-cutting or prestress release involves: pre-cutting a V-shaped incision at the bottom of the pier and loosening the prestressing tendons in the mid-span area of ​​the continuous beam; Among them, an intelligent cutting robot is used to cut V-shaped slits.

7. A method for rapid bridge demolition according to claim 1, characterized in that, In step S6, fiber optic strain gauges are attached to the key sections of the pier column, wireless strain nodes are arranged in the mid-span of the beam, and inclinometers are installed at the top of the pier and the end of the beam.

8. A method for rapid bridge demolition according to claim 1, characterized in that, In step S7, the obtained final collapse data is imported into the crushing station path planning algorithm to perform optimal path planning.

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