Gallery structure system conversion construction method

Abstract

The invention provides a gallery structure system conversion construction method, which belongs to the technical field of conversion construction, and comprises the following steps: step 1, executing a construction cantilever beam of gallery structure system conversion construction; 2, after the cantilever cross beam is constructed, the original gallery lower bent frame structure cross beam of the gallery system conversion project is suspended and dismantled; 3, after a beam of the bent frame structure on the lower portion of the original gallery is dismantled, a jacking system is installed; fourthly, after the jacking system is installed, bent frame structure stand columns on the lower portion of an original gallery of the gallery system conversion project are dismantled; and 5, after columns of the bent frame structure on the lower portion of the original gallery are dismantled, the beams are dropped, and system conversion is completed. The core problems that in existing system conversion construction, the work amount is large, cost is high, and efficiency is low are solved, and low-cost, high-efficiency and rapid conversion of a beam column system is achieved.

Description

Technical Field

[0001] This invention belongs to the field of conversion construction technology and also relates to the field of engineering construction. Specifically, it relates to a method for converting corridor structure systems, which is particularly applicable to the construction method for converting beam structure systems in supporting projects such as roads, docks, and storage yards. It is especially suitable for scenarios where existing obstructive structures need to be demolished and the existing frame is used to complete the system conversion, which can achieve efficient transformation of beam-column systems. Background Technology

[0002] In road and yard infrastructure projects, wharf approach bridges, and other similar projects, it is common for subsequent renovations and expansions to necessitate adjustments to the original structure. Taking a wharf approach bridge project as an example, this bridge is 498.278m long and 30m wide, consisting of two conveyor belt corridors above and a 7m wide driveway below. The corridor foundation uses a double-column frame structure and intersects the transfer station at a large angle. Due to renovation and expansion requirements, the original design placed the foundation of one corridor column at the corner in the middle of the approach bridge, severely obstructing the passage of engineering equipment. It was necessary to demolish this row of columns and the upper crossbeam, and then construct a new crossbeam using the transfer station's frame structure to form a transfer beam, thus completing the demolition of the old structure and the system conversion.

[0003] The existing system conversion construction method has obvious defects: traditional pier-beam system conversion requires the construction of foundations, abutments, piers, and beams sequentially from bottom to top. After the new structure is formed, the conversion device is installed to complete the system conversion. Finally, a special demolition platform needs to be built to dismantle the old structure. This process has three major problems: First, the workload is huge, requiring multiple construction processes, making the construction steps cumbersome; second, the process is complex, with construction and demolition processes being independent, requiring multiple adjustments to the construction flow, high precision requirements, and significant coordination difficulties; third, there are cost and schedule issues. The large amount of new structural construction and platform construction leads to a significant increase in material and labor costs, while the lengthy procedures greatly extend the total construction period, failing to meet the needs of rapid project progress. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a construction method for converting corridor structural systems. It aims to solve the core problems of large workload, high cost, and low efficiency in existing system conversion construction. Specifically, it addresses the following scenarios: when the original beam-column system needs repair or modification due to structural deficiencies (e.g., the original structure obstructing passage) or changes in the external environment (e.g., engineering renovation and expansion), how to avoid the cumbersome process of building multiple new structures and erecting demolition platforms in traditional construction, and achieve a low-cost, high-efficiency, and rapid conversion of the beam-column system.

[0005] The present invention employs the following technical solution.

[0006] A method for constructing a corridor structural system conversion includes:

[0007] Step 1: Construct the cantilever beams for the corridor structural system conversion construction;

[0008] Step 2: After constructing the cantilever beams, the original lower frame structure beams of the corridor system conversion project are suspended and dismantled.

[0009] Step 3: After removing the original lower frame structure beams of the corridor, install the jacking system;

[0010] Step 4: After installing the jacking system, remove the original lower frame structure columns of the corridor system conversion project;

[0011] Step 5: After removing the original lower frame structure columns of the corridor, lower the beams and complete the system conversion.

[0012] Preferably, step 1 specifically includes:

[0013] Reinforcing bars were implanted into the outer side of the frame beam of the transfer station using chemical anchoring; then, a cantilever construction platform was erected with the anchored bars as support; the beam reinforcement was tied and the formwork was erected on the cantilever construction platform, and finally concrete was poured to form the cantilever beam.

[0014] Preferably, in step 1, the method of implanting steel bars using chemical anchoring includes:

[0015] Scope of rebar installation: Rebar installation is required at the bottom, top, and sides of the newly added QZ-1 wall segment;

[0016] Preliminary treatment: First, roughen the concrete around the proposed QZ-1 wall segment so that the surface unevenness is not less than 4mm. After rinsing it clean with water, apply a layer of concrete interface binder before pouring the concrete.

[0017] Material requirements: HRB400 hot-rolled ribbed steel bars shall be used for rebar installation; Grade A adhesive shall be used, and the minimum hole depth, hole diameter, spacing and edge distance shall be determined according to the specifications.

[0018] Concrete construction: C40 fine aggregate concrete is used for pouring. Vibration is strengthened during pouring to ensure compaction. The water-cement ratio and slump of the newly poured concrete need to be controlled. Water curing should begin within 12 hours after pouring and the curing period is 2 weeks. The concrete is cured by wrapping it with two layers of burlap sacks and watering it regularly.

[0019] Preferably, in step 1, the water-cement ratio and slump of the newly poured concrete need to be controlled as follows:

[0020] Strength requirements: The QZ-1 wall segment needs to bear the load transmitted by the cantilever beam. The concrete strength grade is C40. According to the "Specification for Mix Proportion Design of Ordinary Concrete" (JGJ55-2011), the standard value of the axial compressive strength of C40 concrete is 40MPa. The mix proportion design needs to meet the linear relationship between water-cement ratio and strength.

[0021] Construction scenario: The QZ-1 wall segment is a rebar-reinforced component with a narrow pouring space, and it needs to be tightly bonded to the original structure. Therefore, the slump must balance fluidity and cohesion.

[0022] The specifications require that the water-cement ratio of fine aggregate concrete should not exceed 0.55, and the slump should be controlled between 100 and 150 mm.

[0023] Construction inspection: Before reinforcement, the reinforced concrete components at the proposed rebar location must be inspected. If any damage is found, it must be repaired first. New rebars must be precisely positioned according to the design drawings. If the original rebars are damaged during construction, the designer must be notified immediately for alternative handling.

[0024] Preferably, step 2 specifically includes:

[0025] Using the original corridor's own bottom beam as a support system, the original frame beam was fixed in reverse by steel wire ropes; the beam was dismantled in sections using the line cutting method, with the dismantling sequence being the middle section first and then the two ends: the beam was first divided into three equal parts, the middle section was cut off, and after the middle section was safely lifted off, the two ends were cut off and lifted off in sequence.

[0026] Preferably, step 3 specifically includes:

[0027] After the original frame structure beams are completely removed, a jacking system will be installed above the newly built cantilever beams; the jacking target is to lift the upper structure of the corridor by 5cm simultaneously.

[0028] Preferably, in step 3, the lifting system is equipped with 4 jacks, which are arranged at the junction of the cantilever beam and the upper steel beam, with 2 jacks at each end.

[0029] Preferably, in step 3, the method of synchronously lifting the upper structure of the corridor by 5cm includes:

[0030] Step 3-1: Prepare for installation and control the positioning of the lifting system;

[0031] Step 3-2: Assemble and debug the lifting system;

[0032] Step 3-3: Implement the tiered jacking control tiered scheme;

[0033] Steps 3-4: Implement load and displacement monitoring and control;

[0034] Steps 3-5: Perform pressure stabilization control after the jacking is in place.

[0035] Preferably, step 3-1 specifically includes:

[0036] Step 3-1-1: Verify the load-bearing capacity of the newly constructed cantilever beam. The verification formula is as follows:

[0037] ;

[0038] in This represents the maximum stress on the cantilever beam; This represents the design value for the axial compressive strength of C40 concrete. This refers to the cross-sectional area of ​​the cantilever beam under compression. This refers to the design value of the tensile strength of HRB400 steel bars. Given the total area of ​​the reinforcement in the tension zone of the cantilever beam, if the calculation results satisfy... Only if this condition is met can subsequent installation proceed; otherwise, the cantilever beam must be reinforced.

[0039] Step 3-1-2: Position the jacks according to the principle of symmetrical force and uniform distribution. Mark the position at the junction of the cantilever beam and the upper steel beam. The positioning deviation should be ≤2mm. Ensure that the center line connecting the four jacks is parallel to the axis of the beam and that the center of each jack is ≥150mm from the edge of the beam. After positioning, lay a 10mm thick steel plate at the bottom of the jacks. The contact surface between the steel plate and the beam should be ground smooth and coated with a thin layer of grease.

[0040] Preferably, step 3-2 specifically includes:

[0041] First, the jacking system is assembled, which uses a synchronous control system with one main controller and four sub-controllers. The main controller and sub-controllers are connected via wired communication, and each sub-controller controls one jack. A 50mm thick rubber pad is installed between the top of the jack and the upper steel beam. The size of the rubber pad is the same as the top of the jack, and it is used to buffer the impact force during the jacking process and prevent scratches on the surface of the steel beam.

[0042] Next, start the main controller to control the four jacks to rise 10mm simultaneously and then fall 10mm simultaneously. Check whether the jacks extend and retract smoothly and whether the displacement data fed back by the sub-controller is consistent with the actual displacement. If there is any jamming or data deviation.

[0043] Then, preload is applied at 20% of the weight of the superstructure. The jacks are controlled to synchronously increase the pressure to the preload load and maintained for 30 minutes. Observe whether there are cracks in the cantilever beam and whether there is oil leakage from the jacks. Only after the preload is qualified can the formal jacking stage begin.

[0044] Preferably, step 3-3 specifically includes:

[0045] The 5cm lifting height is divided into 5 levels, each with a lifting height of 10mm. The lifting time for each level is controlled at 10-15 minutes, and synchronous control is implemented. A dual-parameter control strategy of displacement priority and pressure assistance is adopted. The main controller collects the displacement data of the four jacks in real time. When the deviation of a single jack from the average displacement is ≥0.5mm, the main controller automatically adjusts the output pressure of the corresponding sub-controller until the displacement deviation is ≤0.3mm. The synchronous control formula is as follows:

[0046] ;

[0047] in For the first The displacement deviation of the jack =1,2,3,4; For the first The actual displacement of the jack; This represents the average displacement of the four jacks.

[0048] Preferably, steps 3-4 specifically include:

[0049] Step 3-4-1, Perform load monitoring: The sub-controller of each jack collects pressure data in real time and calculates the actual load of each individual jack. ,in For the first The pressure value of a jack; This refers to the effective area of ​​the jack piston.

[0050] The load distribution deviation of the four jacks must be ≤5%, that is: ,in For the first The load distribution deviation of each jack; For the first The actual load of each jack; The average load of the four jacks is calculated. If the load distribution deviation exceeds 5%, the main controller will automatically reduce the pressure of the jack with the excessive load to prevent individual jacks from being overloaded.

[0051] Step 3-4-2, perform displacement monitoring: In addition to the displacement sensor built into the jack, laser displacement meters are installed at the four corner points of the upper steel beam in the corridor to monitor the overall displacement of the steel beam in real time and ensure that there is no horizontal deviation during the lifting process. That is, when the laser displacement meter detects a horizontal deviation of more than 1mm, the lifting is stopped immediately, the horizontal position of the jack is adjusted, and the lifting is continued only after the horizontal deviation is ≤0.5mm.

[0052] Preferably, steps 3-5 specifically include:

[0053] When the average displacement of the four jacks reaches 50mm, stop lifting and enter the pressure stabilization stage. During the pressure stabilization period, record the pressure and displacement values ​​of the jacks every 5 minutes. The pressure fluctuation must be ≤0.2MPa and the displacement change must be ≤0.1mm. If there is a sudden drop in pressure or a significant change in displacement, it is necessary to check whether there is a problem with the structural contact or jack leakage. After the problem is resolved, re-stabilize the pressure until the requirements are met.

[0054] Preferably, step 4 specifically includes:

[0055] After the upper structure of the corridor is stably raised to the designated height by the jacking system, the columns on both sides are erected and fixed by a truck crane; the columns are separated from the foundation by cutting, and after the cutting is completed, the columns are lifted away from the construction area by the truck crane.

[0056] Preferably, step 5 specifically includes:

[0057] After the columns are removed, permanent supports are installed at the designated locations on the cantilever beams. The lifting force of the jacks is released, causing the upper steel beams of the corridor to fall vertically until they are stably seated on the permanent supports. Once the steel beams are tightly fitted to the permanent supports and are under stable stress, the temporary lifting system is removed, completing the system conversion of the entire corridor structure.

[0058] The beneficial effects of the present invention are as follows, compared with the prior art:

[0059] 1. Significantly reduce project workload and construction costs

[0060] Without the need for traditional procedures such as building new foundations, pile caps, and piers, the cantilever beams are constructed by using the frame beams of the transfer station to install rebar, reducing the amount of new structural work by more than 70% and saving a lot of material costs such as concrete and steel bars.

[0061] When demolishing the old structure, there is no need to build a special demolition platform. The crossbeam at the bottom of the corridor is used as a reverse support, which saves the labor and equipment costs of platform construction and reduces the overall construction cost by 40%-50%.

[0062] 2. Simplify construction techniques and shorten the construction period.

[0063] The construction process is integrated into five core steps: building the transfer beam, dismantling the crossbeam, jacking up, dismantling the column, and lowering the beam. The process is closely linked, avoiding the redundancy of the process of separate construction and demolition in traditional construction.

[0064] Taking a wharf approach bridge project as an example, traditional construction requires 60 days to complete the system conversion, while this invention only requires 25-30 days, shortening the construction period by more than 50% and meeting the needs of rapid project expansion and renovation.

[0065] 3. Improve construction safety and structural stability

[0066] The demolition of the old structure adopted a reverse hoisting + segmented cutting method to avoid the risk of beams and columns falling; the jacking system adopted four symmetrically arranged jacks to ensure that the upper structure was raised and lowered synchronously and to prevent the structure from deforming due to uneven stress.

[0067] The integration of rebar and freshly poured concrete strictly followed the specifications, and the installation of permanent supports ensured the long-term stability of the structure after the conversion. After testing, the settlement of the upper structure of the corridor after the conversion was less than 2mm, which met the design safety standards.

[0068] 4. Highly applicable and can be extended to various scenarios.

[0069] It is not only applicable to wharf approach bridge corridors, but can also be extended to road interchanges, yard transfer stations, industrial plants and other projects that require beam-column system conversion. It is especially suitable for scenarios that require the preservation of the superstructure and only the removal of the obstructing lower structure.

[0070] The construction process has minimal impact on the normal passage of surrounding engineering equipment (only temporarily occupying a local area when the columns are removed), solving the problem of traffic interruption caused by fully enclosed operations in traditional construction. Attached Figure Description

[0071] Figure 1 This is a flowchart of the corridor structure system conversion construction method in this invention. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0073] like Figure 1 As shown, a construction method for converting a corridor structure system includes:

[0074] This invention achieves system conversion through an integrated process of constructing transfer beams using existing structural reinforcement, dismantling the old structure with reverse-hanging supports, and jacking up and lowering the beams. The specific construction steps are as follows:

[0075] Step 1: Construct the cantilever beam (transfer beam) for the corridor structural system conversion construction.

[0076] In a preferred but non-limiting embodiment of the present invention, step 1 specifically includes:

[0077] Based on the existing frame beams of the transfer station, steel bars are implanted on the outside of the frame beams using chemical anchoring (the anchoring design must meet the QZ-1 anchoring requirements); then, a cantilever construction platform is erected with the anchored steel bars as support; the crossbeam steel bars are tied on the cantilever construction platform, the formwork is erected, and finally concrete is poured to form the cantilever crossbeam (i.e., the transfer beam).

[0078] In a preferred but non-limiting embodiment of the present invention, the method of implanting steel bars using chemical anchoring in step 1 includes:

[0079] The rebar installation design must meet the QZ-1 rebar installation requirements. The details of the QZ-1 rebar installation design are as follows:

[0080] Scope of rebar installation: Rebar installation is required at the bottom, top, and sides of the newly added QZ-1 wall segment;

[0081] QZ-1 wall segment is a numbered designation for specific shear wall components in engineering drawings. Each part has a clear meaning and must be interpreted in conjunction with industry-standard symbol rules.

[0082] QZ: According to the definition in the "Drawing Rules for Overall Plane Representation of Concrete Structure Construction Drawings" (11G101 series drawing set), QZ is the exclusive code for columns on shear walls. It refers to column members embedded in shear walls. It is usually used in scenarios where there are walls but no columns on the lower floor and columns are provided on the upper floor. It bears vertical loads and transmits horizontal forces.

[0083] “1”: This is the component number, representing the first specific instance of the column on this type of shear wall in the same project or the same area, used to distinguish it from other wall elements of the same type (such as QZ-2, QZ-3).

[0084] Wall segment: According to the definition in the Technical Specification for Concrete Structures of High-Rise Buildings (JGJ3-2002), a wall segment refers to an independent shear wall segment separated by a connecting beam, that is, the solid wall part at both ends of a connecting beam. Several wall segments are connected to form a wall segment. When the wall segment is combined with a column (such as QZ), it forms an integrated wall-column component, which has both the lateral stiffness of a shear wall and the vertical load-bearing capacity of a column.

[0085] Preliminary treatment: First, roughen the concrete around the proposed QZ-1 wall segment so that the surface unevenness is not less than 4mm. After washing it clean with water, apply a layer of concrete interface bonder before pouring concrete. When removing the protective layer of the original concrete beams and columns, the original steel bars in the beams / columns must be preserved, and it is strictly forbidden to damage the original steel bars.

[0086] Material requirements: The reinforcing steel used for rebar anchoring shall be HRB400 hot-rolled ribbed steel bars (fy=360N / mm²), which shall comply with the provisions of Chapter 4.2 of the "Code for Design of Strengthening Concrete Structures" (GB50367-2013); the adhesive shall be Class A adhesive, and the safety performance indicators shall meet the requirements of Chapter 4.4 of the "Code for Design of Strengthening Concrete Structures" (GB50367-2013) and Chapter 3.4 of the "Technical Specification for Post-Anchoring of Concrete Structures" (JGJ145-2013), and the minimum hole depth, hole diameter, spacing and edge distance shall be determined according to the specifications.

[0087] Concrete construction: C40 fine aggregate concrete is used for pouring. During pouring, vibration is strengthened to ensure compaction and avoid defects such as voids. The water-cement ratio and slump of the newly poured concrete need to be controlled. Water curing should begin within 12 hours after pouring and the curing period is 2 weeks. The concrete is cured by covering it with two layers of burlap sacks and watering it regularly.

[0088] In a preferred but non-limiting embodiment of the present invention, in step 1, the requirements for controlling the water-cement ratio and slump of the newly poured concrete are as follows:

[0089] In the construction of the QZ-1 wall segment of the corridor system conversion project, the water-cement ratio and slump control of the newly poured C40 fine aggregate concrete directly affect the concrete strength, the bond performance between the new and old structures, and the workability of construction. Based on the "Code for Acceptance of Construction Quality of Concrete Structures" (GB50204-2015) and the "C40 Fine Aggregate Concrete Pouring" requirements in the document, a complete control plan is provided from four aspects: control basis, specific methods, process monitoring, and anomaly handling.

[0090] Strength requirements: The QZ-1 wall segment needs to bear the load transmitted by the cantilever beam. The concrete strength grade is C40. According to the "Specification for Mix Proportion Design of Ordinary Concrete" (JGJ55-2011), the standard value of the axial compressive strength of C40 concrete is 40MPa. The mix proportion design needs to meet the linear relationship between water-cement ratio and strength.

[0091] Construction scenario: The QZ-1 wall segment is a rebar reinforcement component with a narrow pouring space (requiring the rebar to be wrapped) and needs to be tightly bonded to the original structure. Therefore, the slump needs to balance fluidity (for easy vibration and compaction) and cohesion (to avoid segregation).

[0092] The specifications require that the water-cement ratio of fine aggregate concrete (maximum aggregate size ≤ 15mm) should not exceed 0.55, and the slump should be controlled between 100 and 150mm.

[0093] Construction inspection: Before reinforcement, the reinforced concrete components at the proposed rebar location must be inspected. If any damage is found, it must be repaired first. New rebars must be precisely positioned according to the design drawings. If the original rebars are damaged during construction, the designer must be notified immediately for alternative handling.

[0094] Step 2: After constructing the cantilever beams, the original lower frame structure beams of the corridor system conversion project are suspended and dismantled.

[0095] In a preferred but non-limiting embodiment of the present invention, step 2 specifically includes:

[0096] The original corridor's own bottom beams were used as a support system. The original frame beams were fixed in reverse by steel wire ropes to prevent them from falling during dismantling. The beams were dismantled in sections using a line cutting method, with the middle section being dismantled first and the two ends first: the beams were first divided into three equal parts, the middle section was cut off, and after the middle section was safely lifted off, the two ends were cut off and lifted off in sequence.

[0097] Step 3: After removing the original lower frame structure beams of the corridor, install the jacking system;

[0098] In a preferred but non-limiting embodiment of the present invention, step 3 specifically includes:

[0099] After the original frame structure beams are completely removed, a jacking system is installed above the newly built cantilever beams in step 1; the jacking target is to lift the upper structure of the corridor by about 5cm (the total weight of the upper structure of the corridor is about 100T).

[0100] In a preferred but non-limiting embodiment of the present invention, in step 3, the lifting system is equipped with four jacks (each with a lifting force of 20T). The jacks are arranged at the junction of the cantilever beam and the upper steel beam, with two jacks at each end to ensure balanced force distribution.

[0101] In a preferred but non-limiting embodiment of the present invention, the method of synchronously lifting the upper structure of the corridor by approximately 5 cm in step 3 includes:

[0102] I. Installation and Control Methods of Lifting System

[0103] (a) Step 3-1: Pre-installation preparation and positioning control for the jacking system;

[0104] In a preferred but non-limiting embodiment of the present invention, step 3-1 specifically includes:

[0105] Step 3-1-1: Conduct a load-bearing capacity verification. Based on the "Code for Design of Concrete Structures" (GB50010-2010, 2015 edition), verify the load-bearing capacity of the newly constructed cantilever beam to ensure it can withstand the weight of the upper structure of the corridor (100T) and the self-weight of the jacking system. The verification formula is as follows:

[0106] ;

[0107] in The maximum load on the cantilever beam (including the weight of the superstructure of 100T, the self-weight of the jacks, and additional construction loads, taken as 110T) is... ); The design value of the axial compressive strength of C40 concrete is 19.1 N / mm². The area of ​​the cantilever beam under compression (calculated according to the design dimensions, such as a cross-section of 1000mm × 800mm). ); The design value of tensile strength for HRB400 steel bars (taken as 360 N / mm²). This refers to the total area of ​​the reinforcement in the tension zone of the cantilever beam (calculated according to the design configuration, such as 8 25mm diameter steel bars). If the calculation result satisfies Only if this condition is met can subsequent installation proceed; otherwise, the cantilever beam must be reinforced (e.g., by adding reinforcement in the tension zone).

[0108] Step 3-1-2: Position the jacks. Based on the principle of symmetrical force and uniform distribution, mark the positioning line at the junction of the cantilever beam and the upper steel beam. The positioning deviation should be ≤2mm. Ensure that the center line connecting the four jacks (two at each end) is parallel to the axis of the beam, and that the center of each jack is ≥150mm from the edge of the beam (to avoid stress concentration at the edge of the beam). After positioning, lay a 10mm thick steel plate (the steel plate size is 50mm×50mm larger than the jack base) at the bottom of the jacks. The contact surface between the steel plate and the beam should be ground flat (flatness deviation ≤0.5mm) and a thin layer of grease should be applied (to reduce the friction coefficient of the contact surface and ensure uniform transmission of lifting force).

[0109] (II) Step 3-2: Assemble and debug the lifting system;

[0110] In a preferred but non-limiting embodiment of the present invention, step 3-2 specifically includes:

[0111] First, the jacking system is assembled, which uses a synchronous control system with one main controller and four sub-controllers. The main controller and sub-controllers are connected via wired communication (to avoid wireless signal interference). Each sub-controller controls one jack. A 50mm thick rubber pad (hardness 60±5 Shore A) is installed between the top of the jack and the upper steel beam. The size of the rubber pad is the same as the top of the jack, which is used to buffer the impact force during the jacking process and prevent scratches on the surface of the steel beam.

[0112] Next, start the main controller to control the four jacks to rise 10mm and then fall 10mm simultaneously. Check whether the jacks extend and retract smoothly and whether the displacement data fed back by the sub-controller is consistent with the actual displacement (displacement deviation ≤ 0.1mm). If there is jamming or data deviation, the hydraulic circuit or communication line of the jacks needs to be checked.

[0113] Then, preload 20% (20T) of the weight of the superstructure, control the jacks to synchronously increase the pressure to the preload load, maintain it for 30 minutes, observe whether there are cracks in the cantilever beam (use a crack width meter to check, the crack width must be ≤0.2mm), and whether there is oil leakage from the jacks. Only after the preload is qualified can the formal jacking stage be entered.

[0114] II. Synchronous Lifting (5cm) Control Method

[0115] (a) Step 3-3: Implement the graded lifting control scheme;

[0116] In a preferred but non-limiting embodiment of the present invention, step 3-3 specifically includes:

[0117] The jacking height of 5cm is divided into 5 levels, with each level having a jacking height of 10mm. The jacking time for each level is controlled at 10-15 minutes (to avoid sudden changes in structural stress caused by excessively rapid jacking speed). The jacking process for each level is as follows: start the main controller → synchronously pressurize the jacks (pressurization speed ≤ 0.5MPa / s) → reach the jacking height of that level (displacement data is fed back in real time by the sub-controllers) → pause jacking → stabilize pressure for 3 minutes → check the structural condition (cracks in the crossbeams, displacement of the steel beams) → proceed to the next level of jacking after confirmation of compliance. Synchronization control is implemented using a dual-parameter control strategy of displacement priority and pressure assistance. The main controller collects the displacement data of the four jacks in real time (sampling frequency 10Hz). When the deviation of a single jack from the average displacement is ≥ 0.5mm, the main controller automatically adjusts the output pressure of the corresponding sub-controller (reducing the pressure of the jack with the deviation or increasing the pressure of other jacks) until the displacement deviation is ≤ 0.3mm. The synchronization control formula is shown below:

[0118] ;

[0119] in For the first The displacement deviation of the jack =1,2,3,4; For the first The actual displacement of each jack (mm); The average displacement of the four jacks ( mm).

[0120] (ii) Steps 3-4: Implement load and displacement monitoring and control;

[0121] In a preferred but non-limiting embodiment of the present invention, steps 3-4 specifically include:

[0122] Step 3-4-1, Perform load monitoring: The sub-controller of each jack collects pressure data in real time (sampling frequency 5Hz) and calculates the actual load of a single jack. ,in For the first The pressure value of a jack, MPa; The effective area of ​​the jack piston is in mm².

[0123] The load distribution deviation of the four jacks must be ≤5%, that is: ,in For the first The load distribution deviation of each jack; For the first The actual load (N) of each jack; The average load of 4 jacks ( If the load distribution deviation exceeds 5%, the main controller will automatically reduce the pressure of the overloaded jack to avoid overloading of a single jack (maximum load of a single jack ≤ 20T).

[0124] Step 3-4-2, perform displacement monitoring: In addition to the displacement sensor built into the jack, laser displacement gauges (measurement accuracy ±0.05mm) are installed at the four corner points of the upper steel beam of the corridor (within 1m of the jack) to monitor the overall displacement of the steel beam in real time, ensuring that there is no horizontal deviation during the lifting process (horizontal deviation ≤1mm). That is, when the laser displacement gauge detects a horizontal deviation of more than 1mm, the lifting is stopped immediately, and the horizontal position of the jack is adjusted (by placing a thin steel plate at the bottom of the jack, the thickness of the steel plate is calculated according to the deviation) until the horizontal deviation is ≤0.5mm, and then the lifting continues.

[0125] (III) Steps 3-5: Perform pressure stabilization control after the jacking is in place.

[0126] In a preferred but non-limiting embodiment of the present invention, steps 3-5 specifically include:

[0127] When the average displacement of the four jacks reaches 50mm (5cm), stop lifting and enter the pressure stabilization stage (pressure stabilization time 30 minutes). During the pressure stabilization period, record the pressure and displacement values ​​of the jacks every 5 minutes. The pressure fluctuation must be ≤0.2MPa and the displacement change must be ≤0.1mm. If there is a sudden drop in pressure or a significant change in displacement, it is necessary to check whether there is a problem with the structural contact or leakage of the jacks. After the problem is resolved, re-stabilize the pressure until the requirements are met.

[0128] The technical effects of the method of simultaneously lifting the upper structure of the corridor by about 5cm according to the present invention are as follows:

[0129] (a) Ensuring structural safety and stability

[0130] By verifying the load-bearing capacity and conducting pre-stressing tests, potential stress hazards in the cantilever beams were identified in advance to prevent cracks or deformations from occurring during the lifting process. Actual engineering tests showed that the maximum crack width of the beams after lifting was ≤0.1mm, which is far less than the standard limit (0.2mm), and the structural safety meets the requirements.

[0131] The staged jacking and dual-parameter (displacement and pressure) synchronous control ensure that the displacement deviation of the four jacks is ≤0.3mm and the load deviation is ≤5%, the upper steel beam of the corridor is not tilted or horizontally offset, and the deviation between the steel beam axis and the original axis after jacking is ≤0.8mm, so as to avoid local damage to the steel beam due to uneven force.

[0132] (II) Improve construction precision and efficiency

[0133] The synchronous control system, consisting of a main controller and sub-controllers, combined with the auxiliary monitoring of laser displacement gauges, achieves a lifting accuracy of ±0.1mm, far exceeding that of traditional manual control (accuracy ±2mm). This ensures that the steel beams can be accurately positioned on the permanent supports during subsequent beam lowering, reducing the workload of support adjustment.

[0134] The tiered jacking process is clear, and the jacking and stabilization time for each stage is controllable. The entire 5cm jacking process can be completed in 2-2.5 hours (including monitoring time). Compared with the traditional method of "single jacking + multiple adjustments" (which takes 4-5 hours), the efficiency is increased by more than 50%, and the construction period is shortened.

[0135] (III) Reduce construction risks and costs

[0136] The system monitors pressure and displacement data in real time throughout the process, enabling timely detection and handling of issues such as jack leakage and structural displacement, thus avoiding the risk of structural collapse due to sudden malfunctions. No safety accidents have occurred in actual projects.

[0137] No additional lifting support platform is required (using newly built cantilever beams as support), and the synchronous control system can be reused. Compared with traditional lifting solutions, it saves platform construction costs (about 20,000 yuan) and equipment procurement costs (about 50,000 yuan), reducing overall construction costs by 15%-20%.

[0138] Step 4: After installing the jacking system, remove the original lower frame structure columns of the corridor system conversion project;

[0139] In a preferred but non-limiting embodiment of the present invention, step 4 specifically includes:

[0140] After the upper structure of the corridor is stably raised to the designated height by the jacking system, the columns on both sides are erected and fixed by a truck crane. The columns are then separated from the foundation by cutting. After the cutting is completed, the columns are lifted away from the construction area by the truck crane to avoid collision with the already jacked upper structure or the newly built cantilever beams during the dismantling of the columns.

[0141] Step 5: After removing the original lower frame structure columns of the corridor, lower the beams and complete the system conversion.

[0142] In a preferred but non-limiting embodiment of the present invention, step 5 specifically includes:

[0143] After the columns are removed, permanent supports are installed at the designated locations on the cantilever beams. The lifting force of the jacks is slowly released, allowing the upper steel beams of the corridor to slowly fall vertically until they are stably seated on the permanent supports. Once the steel beams are tightly fitted to the permanent supports and are under stable stress, the temporary lifting system is removed, completing the system conversion of the entire corridor structure.

[0144] A specific example of the present invention is shown below:

[0145] Taking the conversion project of the approach bridge corridor system of a certain wharf as an example, the specific implementation process is as follows:

[0146] 1. Construction Preparation

[0147] Material preparation: HRB400 hot-rolled ribbed steel bars (diameter as per design requirements), Grade A rebar adhesive, C40 fine aggregate concrete, concrete interface bond, four 20T jacks, steel wire rope, cutting equipment, etc.

[0148] Equipment preparation: truck crane (rated lifting capacity not less than 1.2 times the weight of the column), steel pipes and fasteners required for the cantilever construction platform, vibrating equipment, burlap sacks and watering equipment for curing, etc.

[0149] Preliminary inspection: Check the concrete strength of the frame beams of the transfer station (must meet the design requirements), the load-bearing capacity of the original corridor bottom beams (must be able to withstand the weight of the reverse-hanging beams), and the distribution of the original structural steel bars at the proposed rebar installation locations (to avoid damaging the original steel bars when drilling for rebar installation).

[0150] 2. Step 1 Implementation (Cantilever Beam Construction)

[0151] Rebar installation: Drill holes at the designed spacing on the outside of the frame beam of the transfer station, clean the dust and debris in the holes, inject Class A adhesive, insert HRB400 steel bars, and let stand until the adhesive cures (curing time is as required by the adhesive instructions).

[0152] Platform construction: Using rebar anchors as the load-bearing points, a cantilevered construction platform is erected using steel pipe couplers. The height of the platform railing is not less than 1.2m, and anti-slip scaffolding boards are laid.

[0153] Reinforcement binding and formwork erection: Bind the reinforcing bars of the cantilever beams according to the design drawings (ensure that the spacing of the reinforcing bars and the thickness of the protective layer meet the requirements), and erect the formwork using steel formwork (seal the joints of the formwork to prevent grout leakage).

[0154] Concrete pouring and curing: Pour C40 fine aggregate concrete and compact it with a vibrator (the vibration time is based on the time when no air bubbles overflow from the concrete surface); cover it with two layers of burlap sacks within 12 hours after pouring, and water it regularly every day (keep the burlap sacks moist) for curing. The curing period is 2 weeks. During the curing period, it is forbidden to pile heavy objects on the beam.

[0155] 3. Step 2 is carried out (the original crossbeam is removed).

[0156] Reverse suspension and fixation: Weld suspension points on the bottom beam of the corridor, connect the original frame beam to the suspension points with steel wire ropes, and adjust the tension of the steel wire ropes to keep the beam in a horizontal state;

[0157] Wire cutting segmentation: The original crossbeam is divided into three equal parts using a diamond wire saw, and the cutting lines are marked. The middle section is cut first, and the tension of the wire rope is monitored in real time during the cutting process. After the middle section is cut, it is lifted off by a truck crane. Then the two end sections are cut in sequence and lifted off by a truck crane in the same way.

[0158] 4. Step 3 Implementation (Lifting System Installation and Lifting)

[0159] Jack installation: Mark the position at the junction of the cantilever beam and the upper steel beam, place 4 jacks (2 at each end) at the positioning point, and adjust the height of the jacks so that the top is in contact with the steel beam;

[0160] Synchronous jacking: The jacks are started using a unified control system. The upper structure is jacked to 5cm according to the principle of "stage jacking" (each stage of jacking height does not exceed 1cm). After each stage of jacking, the jacks are paused for 5 minutes to check whether the force on the jacks is offset from the upper structure, so as to ensure synchronization.

[0161] 5. Step 4 (Column Removal)

[0162] Lifting and fixing: After the truck crane is in place, wrap the column with steel wire rope (the wrapping position is 1 / 3 of the height from the top of the column), and slowly lift it to put the steel wire rope under tension.

[0163] Cutting and dismantling: The bottom of the column is cut using an oxy-acetylene cutting device (the cutting position is 5cm away from the top surface of the foundation). During the cutting process, a dedicated person monitors the angle of the crane boom and the stability of the column. After the cutting is completed, the crane lifts the column to the designated stacking area.

[0164] 6. Step 5 Implementation (Beam Dropping and System Conversion)

[0165] Support installation: Install permanent supports on the cantilever beam according to the design coordinates, and level the bottom of the supports with cement mortar;

[0166] Slowly lower the beam: Depressurize slowly through the jack control system, with the depressurization rate controlled so that the beam falls no more than 2 cm per hour, while observing the contact between the steel beam and the support.

[0167] System dismantling: After the steel beams are lowered to the permanent supports, the structure is left to stand for 24 hours to observe the settlement (the settlement must meet the design requirements). Once stability is confirmed, the jacks and temporary supports are removed to complete the system conversion.

[0168] The beneficial effects of the present invention are as follows, compared with the prior art:

[0169] 1. Significantly reduce project workload and construction costs

[0170] Without the need for traditional procedures such as building new foundations, pile caps, and piers, the cantilever beams are constructed by using the frame beams of the transfer station to install rebar, reducing the amount of new structural work by more than 70% and saving a lot of material costs such as concrete and steel bars.

[0171] When demolishing the old structure, there is no need to build a special demolition platform. The crossbeam at the bottom of the corridor is used as a reverse support, which saves the labor and equipment costs of platform construction and reduces the overall construction cost by 40%-50%.

[0172] 2. Simplify construction techniques and shorten the construction period.

[0173] The construction process is integrated into five core steps: building the transfer beam, dismantling the crossbeam, jacking up, dismantling the column, and lowering the beam. The process is closely linked, avoiding the redundancy of the process of separate construction and demolition in traditional construction.

[0174] Taking a wharf approach bridge project as an example, traditional construction requires 60 days to complete the system conversion, while this invention only requires 25-30 days, shortening the construction period by more than 50% and meeting the needs of rapid project expansion and renovation.

[0175] 3. Improve construction safety and structural stability

[0176] The demolition of the old structure adopted a reverse hoisting + segmented cutting method to avoid the risk of beams and columns falling; the jacking system adopted four symmetrically arranged jacks to ensure that the upper structure was raised and lowered synchronously and to prevent the structure from deforming due to uneven stress.

[0177] The integration of rebar and freshly poured concrete strictly followed the specifications, and the installation of permanent supports ensured the long-term stability of the structure after the conversion. After testing, the settlement of the upper structure of the corridor after the conversion was less than 2mm, which met the design safety standards.

[0178] 4. Highly applicable and can be extended to various scenarios.

[0179] It is not only applicable to wharf approach bridge corridors, but can also be extended to road interchanges, yard transfer stations, industrial plants and other projects that require beam-column system conversion. It is especially suitable for scenarios that require the preservation of the superstructure and only the removal of the obstructing lower structure.

[0180] The construction process has minimal impact on the normal passage of surrounding engineering equipment (only temporarily occupying a local area when the columns are removed), solving the problem of traffic interruption caused by fully enclosed operations in traditional construction.

[0181] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention without departing from the spirit and scope of the present invention. Any modifications or equivalent substitutions should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for converting a gallery structure system, characterized by, Comprise: Step 1: Perform the construction cantilever beam of the corridor structure system transformation construction; Step 2: After the construction cantilever beam, suspend the removal of the original corridor lower row of corridor system transformation project structure beam; Step 3: After the removal of the original corridor lower row of corridor structure system, install the jacking system; Step 4: After installing the jacking system, remove the original corridor lower row of corridor structure system of the corridor system transformation project; Step 5: After removing the original corridor lower row of corridor structure, beam falling and completing the system transformation.

2. The gallery structure system conversion construction method according to claim 1, characterized by, Step 1 specifically includes: Chemical anchoring method is used to implant steel bars outside the frame beam of the conversion station; then the cantilever construction platform is erected with anchoring as support; the steel bars of the beam are bound and the formwork is erected on the cantilever construction platform, and finally the concrete is poured to form the cantilever beam; In step 1, the method of implanting steel bars by chemical anchoring includes: Anchoring range: the bottom, top and column side of the newly added QZ-1 wall limb need to be anchored; Pre-treatment: first, chisel the concrete around the position of the proposed QZ-1 wall limb to make the surface concave and convex difference not less than 4mm, then wash it with water and apply a layer of concrete interface bonding agent before pouring the concrete; Material requirements: the steel bars used for anchoring are HRB400 hot-rolled ribbed steel bars; the adhesive is A-grade adhesive, and the minimum hole depth, hole diameter, spacing and edge distance are determined according to the specification; Concrete construction: C40 fine stone concrete is used for pouring, and vibration is strengthened to ensure compactness; the water-cement ratio and slump of the newly poured concrete need to be controlled, and the water curing starts within 12 hours after pouring, with a curing period of 2 weeks; the curing method is to cover the concrete with 2 layers of burlap and water regularly.

3. The gallery structure system conversion construction method according to claim 2, characterized by, In step 1, the requirements for the water-cement ratio and slump of the newly poured concrete are: Strength requirements: the QZ-1 wall limb needs to bear the load transferred by the cantilever beam, and the concrete strength grade is C40; according to the "Ordinary Concrete Mix Design Specification" (JGJ55-2011), the standard value of the axial compressive strength of C40 concrete is 40MPa, and the mix design needs to meet the linear relationship between water-cement ratio and strength; Construction scene: the QZ-1 wall limb is a reinforced component with anchoring, the pouring space is narrow, and it needs to be closely bonded with the original structure, so the slump needs to consider both fluidity and cohesiveness; Specification requirements: the water-cement ratio of fine stone concrete should not be greater than 0.55, and the slump should be controlled between 100-150mm. Construction inspection: before reinforcement, the steel reinforced concrete component at the proposed anchoring position needs to be inspected, and if there is damage, it needs to be repaired first; the newly added steel bars need to be accurately positioned according to the design drawings, and if the original steel bars are damaged during construction, the design party needs to be notified immediately for separate treatment.

4. The gallery structure system conversion construction method according to claim 3, characterized by, Step 2 specifically includes: Using the bottom beam of the original corridor as a support system, the original row of beams is fixed by steel wire rope; the beams are removed by segmenting with wire cutting method, and the removal sequence is from the middle to the two ends: first, divide the beam into three equal parts, cut off the middle section, and then cut off and lift off the two end sections in turn after the middle section is safely lifted off; Step 3 specifically includes: After the original row of structure beams are completely removed, install the jacking system above the newly built cantilever beam; the jacking target is to simultaneously jack up the corridor upper structure by 5cm; In step 3, the jacking system is configured with 4 jacks, which are arranged at the junction of the cantilever beam and the upper steel beam, with 2 jacks at each end.

5. The gallery structure system conversion construction method according to claim 4, characterized by, In step 3, the method for synchronously jacking up the gallery superstructure by 5 cm includes: Step 3-1: Installation preparation and positioning control for the jacking system; Step 3-2: Assembly and debugging control of the jacking system; Step 3-3: Execution of the staged jacking control scheme; Step 3-4: Execution of load and displacement monitoring control; Step 3-5: Execution of pressure stabilization control after jacking into position.

6. The gallery structure system conversion construction method according to claim 5, wherein Step 3-1 specifically includes: Step 3-1-1: Review the bearing capacity of the newly built cantilever beam, the review formula is as follows: ； wherein is the maximum force of the cantilever beam; is the design value of the axial compressive strength of C40 concrete; is the compressive section area of the cantilever beam; is the design value of the tensile strength of HRB400 steel; is the total area of the steel in the tensile zone of the cantilever beam, and if the calculation result satisfies , the subsequent installation can be carried out; otherwise, the cantilever beam needs to be reinforced. Step 3-1-2: Positioning control for the jacks, i.e. positioning by elastic line at the junction of the cantilever beam and the upper steel beam according to the principle of symmetrical stress and uniform distribution, with a positioning deviation of ≤2 mm, ensuring that the center line of the 4 jacks is parallel to the beam axis, and the center of each jack is ≥150 mm from the edge of the beam. After positioning, a 10 mm thick steel plate is laid at the bottom of the jack, the contact surface between the steel plate and the beam should be smooth and coated with a thin layer of butter.

7. The gallery structure system conversion construction method according to claim 6, wherein Step 3-2 specifically includes: First, assemble the jacking system, i.e. use a synchronous control system with 1 master controller and 4 sub-controllers, the master controller is connected to the sub-controllers through wired communication, and each sub-controller controls 1 jack; A 50mm thick rubber pad is placed between the top of the jack and the upper steel beam, the size of the thick rubber pad is consistent with the size of the top of the jack, which is used to buffer the impact force during jacking to prevent scratches on the surface of the steel beam: Then start the master controller to control the 4 jacks to rise and fall by 10mm synchronously, check whether the jack extension is smooth and the displacement data feedback by the sub-controller is consistent with the actual displacement, if there is a jam or data deviation; Then press 20% of the weight of the upper structure, control the jacks to press to the pre-press load, keep for 30 minutes, observe whether there are cracks in the cantilever beam and whether there are oil leakage phenomena in the jacks, and only after the pre-pressing is qualified can the formal jacking stage begin.

8. The gallery structure system conversion construction method according to claim 7, wherein Step 3-3 specifically includes: Divide the 5cm jacking height into 5 levels, each level is 10mm, and the jacking time of each level is controlled within 10-15 minutes, and the synchronicity control is carried out synchronously, which adopts a double-parameter control strategy of displacement priority and pressure assistance, the master controller collects the displacement data of the 4 jacks in real time, when the deviation of a single jack and the average displacement is ≥0.5mm, the master controller automatically adjusts the output pressure of the corresponding sub-controller, until the displacement deviation is ≤0.3mm, the synchronicity control formula is as follows: ； in For the first The displacement deviation of the jack =1,2,3,4; For the first The actual displacement of the jack; This represents the average displacement of the four jacks. Step 3-4 specifically includes: Step 3-4-1, perform load monitoring: the sub-controller of each jack real-time collects pressure data, and calculates the actual load of a single jack wherein is the pressure value of the j th jack; is the effective area of the jack piston; The load distribution deviation of the four jacks must be ≤5%, that is: ,in For the first The load distribution deviation of each jack; For the first The actual load of the jack; The average load of the four jacks is calculated. If the load distribution deviation exceeds 5%, the main controller will automatically reduce the pressure of the jack with the excessive load to prevent individual jacks from being overloaded. Step 3-4-2, displacement monitoring: In addition to the displacement sensor provided by the jack, a laser displacement meter is installed at the 4 corner points of the gallery upper steel beam to monitor the overall displacement of the steel beam in real time, ensuring that there is no horizontal deviation during the jacking of the steel beam, i.e. when the laser displacement meter detects that the horizontal deviation exceeds 1mm, the jacking is immediately stopped, the horizontal position of the jack is adjusted, and the jacking is continued after the horizontal deviation is ≤0.5mm; Step 3-5 specifically includes: When the average displacement of the four jacks reaches 50 mm, the jacking is stopped and the stable pressure stage is entered. During the stable pressure stage, the pressure value and displacement value of the jacks are recorded every 5 minutes. The pressure fluctuation needs to be ≤0.2 MPa, and the displacement change needs to be ≤0.1 mm. If there is a sudden drop in pressure or a significant change in displacement, it needs to be checked whether there is a problem of structural contact or jack leakage. After the problem is handled, the stable pressure is re-established until the requirements are met.

9. The gallery structure system conversion construction method according to claim 8, wherein Step 4 specifically includes: After the upper structure of the corridor is stably lifted to the specified height by the jacking system, the car hoist is used to hoist and fix the two side columns. The columns are separated from the foundation by cutting, and after the cutting is completed, the columns are hoisted away from the construction area by the car hoist.

10. The gallery structure system conversion construction method according to claim 9, wherein Step 5 specifically includes: After the column removal is completed, permanent supports are installed at the specified positions of the cantilever beam. The jacking force of the jacks is released, and the steel beam of the corridor upper structure falls along the vertical direction until it is stably seated on the permanent supports. After the steel beam is closely attached to the permanent supports and the stress is stable, the temporary jacking system is removed, and the system conversion of the entire corridor structure is completed.

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