CN111561175A - Prestress underpinning static force cutting and column pulling construction process - Google Patents

Abstract

The invention discloses a construction process for prestressed underpinning static cutting and pulling a column, which comprises a reinforced concrete bonded prestressed underpinning structure, a diamond wire saw cutting system and a structure displacement strain monitoring system, and comprises the following specific construction process steps: constructing a reinforced concrete underpinning structure with bonding prestress; mounting prestress tension, static force cutting and monitoring equipment; tensioning and intercepting the column. The construction process effectively ensures the stability and rapidness of the construction progress and the reasonable and orderly construction procedures, and ensures the realization of the construction period target; meanwhile, a series of scientific calculations are combined with the subsection control of the actual construction situation, scientific management is combined with advanced technology, the progress of the project department is accelerated, and the construction safety is guaranteed.

Description

Prestress underpinning static force cutting and column pulling construction process

Technical Field

The invention relates to the technical field of building construction, in particular to a prestress underpinning static cutting and column pulling construction process.

Background

It is known that various buildings rise on the flat ground with the high-speed development of the country. The diversity of the building forms also marks the culture and construction degree of a city or region. However, the current building construction process in China cannot meet the construction requirements of various buildings. Particularly, in some buildings with complex structures and very visible structures, the problems of slow construction progress, low construction safety, incapability of meeting the requirements on engineering quality, high construction cost and the like exist.

Disclosure of Invention

The invention aims to provide a prestress underpinning static cutting column pulling construction process to solve the problems in the background technology. In order to achieve the purpose, the invention provides the following technical scheme: a prestressed underpinning static cutting and pulling column construction process comprises a reinforced concrete bonded prestressed underpinning structure, a diamond wire saw cutting system and a structure displacement strain monitoring system, and specifically comprises the following construction process steps:

step 1, constructing a reinforced concrete bonded prestressed underpinning structure, which specifically comprises the following steps:

(1) and installing and binding new steel bars: positioning and installing reinforcing steel bars according to a construction drawing, ensuring continuous inertial connection of bottom stressed reinforcing steel bars in a pile pulling area, and enabling the bottom stressed reinforcing steel bars to pass through the whole reinforcing steel bars when meeting a pile to be pulled and an opening, so that connection points are prevented from being distributed in the area, and connecting new reinforcing steel bars with an original structure by adopting a bar planting and anchoring method;

(2) and installing a metal corrugated pipe: accurately marking the position of the transverse coordinate of each control point of the steel bundle on the beam slab bottom die according to the transverse coordinate of the steel bundle in the prestressed steel bundle arrangement drawing in the design drawing, and then accurately installing steel bundle positioning steel bars according to the position of the longitudinal coordinate of each control point in the steel bundle arrangement drawing; the positioning reinforcing steel bars are preferably welded into a positioning reinforcing steel bar mesh, and then are bound together with the web reinforcing steel bars according to the set positions, wherein the intervals of the curved parts of the positioning reinforcing steel bars are 50cm, and the intervals of the straight parts are 100 cm. After the positioning steel bars are bound, the metal corrugated pipes are penetrated, and the corrugated pipes need to be butted by adopting sleeves;

(3) and installing prestressed steel strands: the steel strand wires are blanked according to the design drawing, the blanking is cut by a cutting machine, the steel strand wires blanked according to the design drawing are inserted into the corrugated pipes according to corresponding numbers, and the steel strand wires are manually inserted and released; the anchor backing plate is required to be perpendicular to the steel strand and the pipeline and firmly fixed with the end socket template;

(4) installing a template and pouring concrete;

step 2, mounting prestress tensioning, static cutting and monitoring equipment;

and 3, tensioning and cutting the column.

Preferably, the step 2 specifically includes the following steps:

(1) and mounting the prestress tensioning equipment: tensioning equipment adopts a numerical control hydraulic jack to carry out tensioning, and a jack main body is arranged and can be drilled and hoisted in a tensioning end area;

(2) and installing cutting equipment: the cutting equipment adopts a diamond wire saw cutting system, the cutting direction of the wire is finished by the installation direction of a guide wheel set, and the installation positions of the guide wheel set and a main driving movable wheel set are skillfully designed, so that the high-efficiency cutting requirement is met;

(3) and installing monitoring equipment: the structure displacement strain monitoring entrusts a unit with structure monitoring qualification to monitor, and main equipment of a structure displacement strain monitoring system comprises 4 groups of strain gauges, 2 groups of displacement meters and a set of structure displacement strain monitoring system host;

preferably, the step 3 specifically includes the following steps:

(1) and initial tensioning: after all preparation works are finished, carrying out initial pretensioning to 10% of a designed tensioning value;

(2) and stretching for the second time: stretching to 50% of a designed stretching value, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(3) the first static force cutting is intercepted: cutting a middle part of the column, and synchronously and continuously observing the displacement and strain change of the underpinning structure;

(4) and observing the stress condition of the structure and performing third tensioning: continuously monitoring the displacement and strain value of the underpinning structure, and stretching the prestressed tendons according to the detection data to keep the stress value of the new beam longitudinal tendons within 0 to-200;

(5) and a second static force cutting column: cutting the left part of the right side of the column, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(6) observing the stress condition of the structure and tensioning for the fourth time: continuously monitoring the displacement and strain value of the underpinning structure, and stretching the prestressed tendons according to the detection data to keep the stress value of the new beam longitudinal tendons within 0 to-200;

(7) and a third static force cutting column: left measuring the rest part of the cutting column, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(8) and observing the stress condition of the structure and performing fifth tensioning: continuously monitoring the displacement and the strain of the underpinning structure for 24 hours, and stretching the prestressed tendons according to the detection data to be used as a safe reserve value;

(9) and after the column is cut off for 24 hours, keeping the displacement and the strain of the detection result within the design allowable range and basically keeping unchanged, and unloading the top, grouting, sealing the anchor and gradually cutting and removing the broken column in sections.

The invention has the technical effects and advantages that: the construction process effectively ensures the stability and rapidness of the construction progress and the reasonable and orderly construction procedures, and ensures the realization of the construction period target; meanwhile, a series of scientific calculations are combined with the subsection control of the actual construction situation, scientific management is combined with advanced technology, the progress of the project department is accelerated, and the construction safety is guaranteed.

Drawings

FIG. 1 is a schematic diagram of the division of the axis and the area of a fan-shaped steel structure in the embodiment of the invention;

FIG. 2 is a sectional view of the center of a fan-shaped steel structure according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a lattice support column in an embodiment of the invention;

FIG. 4 is a schematic view of an exemplary intercolumnar support structure in accordance with the present invention;

FIG. 5 is a vertical layout of a lattice support column during segment 4 hoisting in an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a rail system in an embodiment of the present invention;

FIG. 7 is a schematic view of a landing measure in an embodiment of the present invention;

FIG. 8 is a schematic view of a method for adding corbels on the basis of the original beam reinforcements in the embodiment of the present invention;

FIG. 9 is a schematic illustration of a center line of a railway rail of an embodiment of the present invention laid out to fit the same radius of a circular arc as the axis D, E;

FIG. 10 is a schematic view of a roof lifting and positioning frame in an embodiment of the present invention;

FIG. 11 is a schematic view of the planar position axis control points of an embedment in an embodiment of the present invention;

FIG. 12 is a schematic view of the line control points in the plan view of the embedment in the embodiment of the present invention;

FIG. 13 is a schematic view of the steel column calibration in the embodiment of the present invention.

In the figure: 1-reinforced concrete structure, 2-roof modeling steel structure, 3-roof truss system, 4-floor truss, 5-reinforced concrete structure, 6-hanging platform, 7-V type supporting column, 8-box type column, 9-cross stiff column, 10-overhanging platform, 11-steel pipe, 12-sliding shoe, 13-track beam, 14-truss lower chord, 15-laminated steel backing plate, 16-design support, 17-shear steel bar or reinforced concrete bracket, 18-jack, 19-bracket, 20-track central line, 21-steel box beam central line, 22-limiting device, 23-roof hoisting positioning frame, 24-embedded part central line, 25-upper cover plate, 26-lower cover plate, 27-adjusting nut, 28-steel column, 29-foundation bolt, 30-adjusting nut elevation, 31-concrete foundation.

Detailed Description

In the description of the present invention, it should be noted that unless otherwise specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, integrally connected, mechanically connected, or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements.

Example 1

A prestressed underpinning static cutting and pulling column construction process comprises a reinforced concrete bonded prestressed underpinning structure, a diamond wire saw cutting system and a structure displacement strain monitoring system, and specifically comprises the following construction process steps:

step 1, constructing a reinforced concrete bonded prestressed underpinning structure, which specifically comprises the following steps:

(1) and installing and binding new steel bars: positioning and installing reinforcing steel bars according to a construction drawing, ensuring continuous inertial connection of bottom stressed reinforcing steel bars in a pile pulling area, and enabling the bottom stressed reinforcing steel bars to pass through the whole reinforcing steel bars when meeting a pile to be pulled and an opening, so that connection points are prevented from being distributed in the area, and connecting new reinforcing steel bars with an original structure by adopting a bar planting and anchoring method;

(2) and installing a metal corrugated pipe: accurately marking the position of the transverse coordinate of each control point of the steel bundle on the beam slab bottom die according to the transverse coordinate of the steel bundle in the prestressed steel bundle arrangement drawing in the design drawing, and then accurately installing steel bundle positioning steel bars according to the position of the longitudinal coordinate of each control point in the steel bundle arrangement drawing; the positioning reinforcing steel bars are preferably welded into a positioning reinforcing steel bar mesh, and then are bound together with the web reinforcing steel bars according to the set positions, wherein the intervals of the curved parts of the positioning reinforcing steel bars are 50cm, and the intervals of the straight parts are 100 cm. After the positioning steel bars are bound, the metal corrugated pipes are penetrated, and the corrugated pipes need to be butted by adopting sleeves;

(3) and installing prestressed steel strands: the steel strand wires are blanked according to the design drawing, the blanking is cut by a cutting machine, the steel strand wires blanked according to the design drawing are inserted into the corrugated pipes according to corresponding numbers, and the steel strand wires are manually inserted and released; the anchor backing plate is required to be perpendicular to the steel strand and the pipeline and firmly fixed with the end socket template;

(4) installing a template and pouring concrete;

step 2, mounting prestress tensioning, static cutting and monitoring equipment;

and 3, tensioning and cutting the column.

Preferably, the step 2 specifically includes the following steps:

(1) and mounting the prestress tensioning equipment: tensioning equipment adopts a numerical control hydraulic jack to carry out tensioning, and a jack main body is arranged and can be drilled and hoisted in a tensioning end area;

(2) and installing cutting equipment: the cutting equipment adopts a diamond wire saw cutting system, the cutting direction of the wire is finished by the installation direction of a guide wheel set, and the installation positions of the guide wheel set and a main driving movable wheel set are skillfully designed, so that the high-efficiency cutting requirement is met;

(3) and installing monitoring equipment: the structure displacement strain monitoring entrusts a unit with structure monitoring qualification to monitor, and main equipment of a structure displacement strain monitoring system comprises 4 groups of strain gauges, 2 groups of displacement meters and a set of structure displacement strain monitoring system host;

preferably, the step 3 specifically includes the following steps:

(1) and initial tensioning: after all preparation works are finished, carrying out initial pretensioning to 10% of a designed tensioning value;

(2) and stretching for the second time: stretching to 50% of a designed stretching value, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(3) the first static force cutting is intercepted: cutting a middle part of the column, and synchronously and continuously observing the displacement and strain change of the underpinning structure;

(4) and observing the stress condition of the structure and performing third tensioning: continuously monitoring the displacement and strain value of the underpinning structure, and stretching the prestressed tendons according to the detection data to keep the stress value of the new beam longitudinal tendons within 0 to-200;

(5) and a second static force cutting column: cutting the left part of the right side of the column, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(6) observing the stress condition of the structure and tensioning for the fourth time: continuously monitoring the displacement and strain value of the underpinning structure, and stretching the prestressed tendons according to the detection data to keep the stress value of the new beam longitudinal tendons within 0 to-200;

(7) and a third static force cutting column: left measuring the rest part of the cutting column, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(8) and observing the stress condition of the structure and performing fifth tensioning: continuously monitoring the displacement and the strain of the underpinning structure for 24 hours, and stretching the prestressed tendons according to the detection data to be used as a safe reserve value;

(9) and after the column is cut off for 24 hours, keeping the displacement and the strain of the detection result within the design allowable range and basically keeping unchanged, and unloading the top, grouting, sealing the anchor and gradually cutting and removing the broken column in sections.

Example 2

As shown in fig. 1-13, taking a sector structure as an example, it is divided into A, B, C, D, E, F, G axis and A, B, C, D, E, F, G area, a-axis distance 444.200m from the center of circle, B-axis distance 435.200m from the center of circle, C-axis distance 425.200m from the center of circle, D-axis distance 416.200m from the center of circle, E-axis distance 335.200m from the center of circle, F-axis distance 321.700m from the center of circle, G-axis distance 304.700m from the center of circle; the radian of 1 line to 85 lines is 118.18 degrees, 7 zones are divided into 7, the radian of 1 line to 13 lines is 16.88 degrees, the radian of 13 lines to 25 lines is B zone, the radian of 25 lines to 37 lines is C zone, the radian of 37 lines to 49 lines is D zone, the radian of 49 lines to 61 lines is E zone, the radian of 61 lines to 73 lines is F zone, the radian of 73 lines to 85 lines is G zone. The arc degrees of lines 1-2 and 3- … 85 are all 1.41 degrees, as shown in fig. 1.

The floor part adopts a steel pipe column and steel truss structure, a steel pipe column net is 27m multiplied by 81m, two ends of the truss are supported on concrete members at the front and rear parts of the floor, the truss support and the concrete adopt one-way sliding supports, and the floor slab is fixedly connected with the concrete at two ends respectively. D-to-E axis 1-85 lines are truss steel structures, each exhibition area is provided with 14 GGZ1 box-shaped columns, the total number is 98, the distance between the middle columns of each exhibition area is 18.0m, two specifications of two ends of 17.137m and 21.143m are adopted, the columns are connected with one another through brackets, the trusses are connected with the D axis, the brackets and the E axis to form a truss space structure, the trusses are connected with the trusses, the upper chord is connected with the lower chord, and metal combined floor plates are laid to serve as floors after the upper chord is connected with the upper chord. The roof large-span steel truss adopts a continuous two-span steel truss structure with the span of 31.5m and 81m, the front end of the truss is supported on the V-shaped column, the middle and the rear end are supported on the reinforced concrete main body, wherein the front part of the floor is externally cantilevered by about 20m, the rear part of the floor is externally cantilevered by about 19m, and the total length of the roof truss is 161.0 m; the trusses are radially distributed along the radius direction, the center spacing is about 9m, and the central section view of the fan-shaped steel structure is shown in figure 2.

The main construction scheme of the embodiment is as follows:

1. construction temporary measure scheme

1.1 scaffold operation platform

Setting up materials: A48.3X 3.6 scaffold steel pipes, various fasteners, bamboo string piece scaffold boards, dense mesh safety nets and the like. Limiting the bearing capacity of the platform: the bearing capacity of a stacking area of equipment such as a welding machine and the like on the platform is controlled according to 2KN/m2, personnel stand in a construction area, and the bearing capacity of the platform is controlled according to 1.5KN/m 2.

The construction requirements of the operating platform set up by the operating platform are as follows: a. fully laying scaffold boards at the top of the platform; b. the vertical interval of the horizontal cross braces of the frame body is not more than 8 m; c. the vertical scissor supports are arranged around the whole height; d. the bottom of the upright stanchion is provided with a No. 10 through long channel steel or a steel plate base plate with the thickness of 6mm and the thickness of 100 x 100 mm; e. the bottom of the frame body is at least a C15 cushion layer with the thickness of 100mm, and the base soil needs to be compacted; f. the bottom of the frame body needs to be well drained.

1.2 lattice type temporary support

And (4) according to the temporary support plane layout drawing, carrying out support reaction force calculation through MIDAS software, and calculating the maximum jacking force of the lattice type temporary support to be 62 tons. Lattice support columns include GGZ1, GGZ2, GGZ3, and GGZ 4. When the device is arranged, the mounting position of the GGZ4 is positioned on a post-cast strip of a reinforced concrete floor slab, and the position of the post-cast strip needs to be properly adjusted in coordination with design and civil engineering construction units. The mounting positions of the GGZs 1-3 are located above two layers of steel trusses, and the bottom of the GGZ4 support column only bears the load of a reinforced concrete slab. Therefore, the reinforced concrete slab below the GGZ4 support column needs to be reinforced. The treatment method comprises the following steps: the steel pipe support is arranged at the bottom of the plate, and the support is located on the ground. The lattice support column is shown in fig. 3, and the schematic view of the inter-column support structure is shown in fig. 4. When the lattice type supporting is unloaded, the unloading supporting position and the residual fulcrum counter force of each step are calculated through MIDAS software, and the supporting force of each stage of the lattice column and the support counter force of the sliding shoe are ensured to be within the bearing capacity range of construction measures.

1.3 method for manufacturing lattice support column during sectional 4-segment hoisting

The roof truss is divided into 4 sections of structures, lattice support columns are needed when the sections 4 are hoisted, a vertical layout of the lattice support columns is shown in fig. 5, and the maximum support force of the lattice support columns is 19.7 tons through MIDAS software calculation. The checking calculation of the unloading sequence of the support frame comprises the following steps: (1) removing the middle support lattice column; (2) installing a V-shaped column; (3) removing the second lattice support column; (4) and finally, removing the third latticed column, and continuously installing the subsequent cantilever roof. The maximum supporting force of the supporting column in the construction stage can be calculated according to 25.6 tons. Then, the stress checking calculation is carried out through software, and the method comprises the following steps: and establishing a calculation model, calculating unit stress and checking calculation ratio of each rod piece.

1.4 ground assembling jig frame

The ground assembling jig frame top surface with the sections 1-4 is required to have the ground clearance height not less than 800mm, the surface unevenness is required to be 2mm/3m, and the integral unevenness is less than 30 mm. The base is arranged at the joint of the transverse primary beam and the transverse secondary beam.

1.5 top pushes away track beam system that slides

The section of the track system is shown in fig. 6, gaps between the lower flange plate of the track beam and the shear wall and between the lower flange plate of the track beam and the 1000 × 1500 beam are filled with high-strength mortar not lower than C35, and therefore the upper load is transmitted to the shear wall and the beam.

1.6 roof truss support

The schematic diagram of the frame falling measure is shown in fig. 7, and shear steel bars or reinforced concrete corbels are added to the original reinforced concrete. When the original reinforced concrete structure is reinforced, the two conditions that the beam and the column are positioned on the center line and the beam is not positioned on the center line of the column are divided. When the beam column is positioned on the central line, the shear resistant bent reinforcing steel bar (HRB400) is added on the basis of the original beam reinforcing steel bar. When the beam column is not on the center line of the column, a method of adding a bracket is adopted, as shown in fig. 8, the bracket in the embodiment adopts a method of TD-107-01 atlas centralization number N50-70110A of the design institute of electric power in the south and the middle, the standard value of the vertical bearing capacity is 146.5 tons, the design value is 199.1 tons, and the engineering use requirement in the embodiment is met.

2. Incremental launching construction

2.1 Steel Box Beam support and laying

The steel structure engineering of this embodiment is a fan-shaped structure, because the processing degree of difficulty that actually bears the weight of the steel box roof beam, D axle and E axle circular arc radius are great (416.2 meters and 335.2 meters respectively), and all steel box roof beams are processed into the straightway, are broken line approximate circular arc after the concatenation. A P43 railway rail is laid on the top of the steel plate, and a simulated arc line is processed through measurement and top bending. The length of the straight line segment is determined according to the space of each truss. The length of each steel box girder and the central line of the steel rail of the D shaft is calculated according to the sector angle of 13 trusses in an exhibition area of 16.88 degrees: and the length of the middle line of each box girder and the track of the E shaft is as follows: both ends of each steel box girder are subjected to 0.7-degree corner cut for convenient splicing. The seam clearance is less than 2mm, 2mm stainless steel plates are laid on the sliding surface of the steel box girder, the splicing part is polished smoothly after being welded, and the sliding shoe cannot be gnawed off when passing through the seam.

2.2 Rail laying and lapping

The P43 railway rail is fixed on the steel box girder by adopting the intermittent welding mode and is assisted by a pressure plate, a section of shear pin is pre-embedded at each of the two ends of the box girder, and the notch of the steel rail is processed to fit the shear pin. In the sliding process, the railway rail bearing is subjected to about 100 tons of jacking force in the direction opposite to the sliding direction, and the reliability of the support reaction system is improved in a combined mode of welding seams, pressing plates and shear pins. The center line of the railway rail is laid out and fitted into a circular arc radius the same as that of the D axis and the E axis, and as shown in fig. 9, the lapping part needs to be polished and trimmed to ensure circular arc transition and meet the gap requirement when the sliding shoes pass through the abutted seam. The laying of the steel box girder is completed before the truss is built, and the whole construction period time may be long. Therefore, after the steel box girder is erected and the steel rail is laid, the slip surface and the rail clamping surface need to be protected against rust and smashing.

2.3 arrangement and construction of the sliding shoes

The slipper is divided into two types according to the purpose: a slipper without a pushing device and a slipper with a pushing device. During construction, the truss is placed at the node position of the D shaft and the E shaft before each truss is erected.

The layout of the thrusters mainly takes the following considerations into account: it is known that the weight between the G axis and the E axis is 1160 tons, the weight between the E axis and the D axis is 1810 tons, the weight between the E axis and the a axis is 570 tons, the total weight of the G zone is 3540 tons, and the weight of the other several span zone roof truss systems is the same. The support reaction force of the whole G-area roof truss on the D shaft is 1190 tons and the support reaction force on the E shaft is 2349 tons according to the support reaction force calculation, and the total pushing force required by the D shaft is 119 tons and the total pushing force required by the E shaft is 235 tons according to the 10% friction coefficient. Because the D shaft and the E shaft use the thrusters with the same quantity and specification, and the jacking force required by the E shaft is larger, the distribution mode mainly meets the jacking force of the E shaft. The total roof truss is 13, and the required jacking force on the E axis is about 18 tons for each additional roof truss (including the connection truss). Considering a certain margin, the number of the trusses pushed by the first pushing device is 4, and the number of the trusses pushed by the second pushing device is 8. The thrusters are arranged at the node positions of No. 2, No. 5 and No. 9, respectively.

Because the central line of the track is fitted into a circular arc with the same radius as the D axis and the E axis, the sliding shoe and the truss structure on the sliding shoe do not rotate in the pushing process, and only the elongation change of the truss caused by temperature difference needs to be considered. According to the calculation, the elongation between the D axis and the E axis is about 5cm under the temperature difference of 30 ℃. During construction, the top of the sliding shoe device of the E shaft is fixed with the truss, the top of the sliding seat of the D shaft is longitudinally limited, and the steel round pin is laid to enable the truss to extend transversely. Because the pushing process is carried out simultaneously with the truss construction, the pushing devices are sequentially installed in place during truss construction. And considering possible adverse factors, a pump station and a pushing device are provided with certain protection measures. During construction, special attention must be paid to other measures to prevent damage to the hydraulic devices and pipelines as necessary. And after the No. 2, No. 5 and No. 9 trusses are in place, mounting the pushing device on the track. The rail clamping device is placed on a steel rail, and the lug ring at the rod end of the pushing oil cylinder is connected with the lug ring at the tail part of the sliding shoe through a pin shaft. Because the track is arc-shaped, the angle between the oil cylinder and the sliding shoe can be changed in the pushing process, and therefore the lug ring at the rod end is provided with the joint bearing and can rotate within the range of 5 degrees. Considering to push up device installation and need hoist and mount repeatedly when dismantling, for preventing to install the displacement sensor damage outside the hydro-cylinder, set up anti-roll flange. When the oil cylinder and the rail clamping device are integrally lifted, a rotation limiting angle is machined on the lug plate to prevent the inconvenience caused by excessive sagging of the rail clamping device. The clamping length of the wedge-shaped block in the rail clamping device is 650mm, the chord height of the clamping section is 0.157mm calculated according to the E axis with the smaller circular arc, and the overall rigidity of the clamping block is reduced by increasing the tooth-shaped height of the clamping block so as to be attached to a rail clamping surface.

A working platform is required to be built for placing a hydraulic pump station on a truss structure beside the pushing device. After the pump station is installed in place, the hydraulic pipeline, the signal line and the like can be installed. Because the installation distance of the pushing device is long, the hydraulic system adopts a distributed structure. Namely, the hydraulic pump station is only used as a pressure source to output, and the oil cylinder pushing control valve and the oil cylinder control valve of the auxiliary rail clamping device are both arranged on the pushing device nearby, so that the response speed of the system is improved. The hydraulic hose is connected to the first pushing device in series. After the second thruster is installed, the hydraulic pipeline is connected in series from the first thruster to the second thruster, and so on. And a signal wire and an electric control circuit on the pushing device are connected to the pump station electric box through a wire collecting box. The length of the pipeline from the pump station to the pushing device is fixed, and the pipeline is tied up and fixed with the truss after being laid. Need hoist and mount repeatedly when considering hydraulic power unit installation and dismantlement, for preventing that electronic box and coupling from damaging, the grid is prevented pounding in the installation of pump station top, still need notice the protection during the construction operation.

Depending on the motor specifications, incoming cable sections must use more than 16 squares. The roof of the G area needs to rotate 67.52 degrees from the workbench position to the installation position, the arc length of the E-axis movement is 394.8 meters, the arc length of the D-axis movement is 490.2 meters, and a similar mobile cable reel car is required to be connected with a power supply box to supply power to a pump station. The onboard electrical box is configured with 63A air switch. And after the pump station pipeline is connected, the pump station pipeline is connected with the synchronous control box through a FROFIBUS communication bus. From the safety perspective, the general control box is placed on a trolley on the ground and is pushed by manpower. The running conditions of the pump station and the pushing device are obtained through a screen on the master control box.

2.5 equiangular pushing control

The truss roof top pushes the roof to move in a fan shape around the circle center along the axis E and the axis D, and pushing devices installed on the axis D and the axis E need to be controlled in an equiangular speed mode. The arc radiuses of the D axis and the E axis are 416.2 meters and 335.2 meters respectively, and the pushing linear speed of the E axis is 19.46 percent slower than that of the D axis. The pushing control system forms a closed-loop control system by a PLC, a displacement sensor and a frequency converter. The PLC controls the two electric pump motors to rotate by different frequency values, the displacement value is fed back by the displacement sensor arranged on the oil cylinder, the PLC compares the ratio of the displacement speeds on the two axes with a target value of 19.46 percent and continuously trims the set frequency of the frequency converter, so that the speed difference on the two sides is close to a theoretical value. The thrusters on the same axis control the mutual synchronization by the on-off control of the electromagnetic valves. And taking the displacement sensor of the first mounted pushing device on the same axis as a reference, comparing the displacement values on the same axis by the PLC, and continuously correcting the on-off time of the electromagnetic valve to keep the front and rear pushing devices synchronous, wherein a control flow chart is shown.

3. Installation of floor steel structure

The installation of floor steel construction is divided into three parts: the first part is a floor steel structure; the second part is an overhanging platform from an F axis to a G axis and a V-shaped support; the third part is a steel frame structure outside the 85-shaft.

3.1 installation of floor steel structure

The floor steel structure construction mainly comprises a bracket truss hoisting unit, a truss hoisting unit, an upper chord steel beam and a lower chord tie rod. The area bracket trusses are divided into 12 hoisting units, and the trusses are divided into 43 hoisting units. The total 381 hangs for the floor hoisting unit. The maximum hoisting weight of the box column is 25t, the maximum length of a truss of the truss hoisting unit is 28.334m, the height of the truss hoisting unit is 3.7m, and the maximum hoisting weight of the bracket truss hoisting unit is 48.7 t. The total trusses of the bracket truss hoisting unit are 48.7 tons at most and 18 meters in length, and are directly assembled into finished products in a processing plant to be transported to the field for installation. The length of the truss hoisting unit is 22-30 m, the truss hoisting unit is pre-assembled in a processing plant and then is sent to a site in two sections, the maximum length is 17 m, and the weight is 19 t. 150 tons of crawler cranes are adopted for butt joint assembly and hoisting on site. Hoisting a floor truss: 27m main arms are selected for the 150t crawler crane, the hoisting radius is 16m, the rated hoisting capacity is 47.3t larger than 46.7t, and the hoisting requirement is met; a main arm of 25m is selected for the 150-ton truck crane, the hoisting radius is 7m, the rated hoisting capacity is 47.2t larger than 46.7t, and the hoisting requirement is met. When the floor bracket truss is hoisted, a 150-ton crawler crane selects 27m main arms, the hoisting radius is 14m, the hoisting weight is 55.6t which is more than 48.6t, and the hoisting requirement is met; a main arm of 25m is selected for the 150-ton truck crane, the hoisting radius is 6m, the rated hoisting capacity is 51.7t and is more than 48.6t, and the hoisting requirement is met. And (3) hoisting the steel pipe column by using a specially designed hoisting balance beam to self-balance. The floor steel beams and the tie bars are installed by using a 25t truck crane, the section of the maximum reconstruction member is H300x300x10x15, and the weight is 1.2 t. The GT-250C truck crane selects a main arm with the length of 32.2m, the hoisting radius is 22m, the hoisting weight is 1.6t more than 1.2t, and the requirements are met.

The operating platform at the butt joint position adopts a hanging basket which is made of round steel, is arranged on the steel beam before the steel beam is hoisted, and is hoisted to the installation position along with the component. When the member is in place, the bolt holes are tightly clamped by the punching nails, the mounting bolts penetrate through the hole, and the number of the mounting bolts is not less than one third of the total number of the bolts and not less than 2 bolts. Before the main beam or the steel truss is hoisted, a life line is arranged on the upper flange, the life line uses a galvanized steel wire rope, two ends of the steel wire rope are fixed on the small upright post, and a detachable clamping plate is adopted below the small upright post for fixing. In order to save the time required by lifting and falling and improve the installation efficiency, a method of one hook and multiple hangers is adopted to install small components such as secondary beams, and the contact position of the steel wire rope and the profile steel flange plate is protected by corners in order to ensure safety.

3.2 overhanging and hanging steel structure and V-shaped support column installation

The overhanging steel structure comprises an overhanging platform and a hanging platform. The component types are mainly cantilever steel beams, suspension rods and stainless steel pull rods. The heaviest component is steel beam GL4, specification HN 550X 200X 10X 16, length 11.85 meters, and weight 1.1 t.

After the roof steel structure at the corresponding position is installed, the installation of the overhanging steel structure is started, and the installation method comprises the following steps:

the first step is as follows: a 25t truck crane is adopted to hoist the overhanging platform, and a suspender component is arranged on the overhanging platform with larger overhang near the position of the expansion joint, and a temporary support is required to be arranged right below the overhanging platform before installation;

the second step is that: and a steel pipe lattice column temporary support is arranged below the connecting node of the steel beam and the suspender, and four guy ropes are pulled to fix the steel pipe lattice column temporary support. When in temporary supporting and hoisting, a 25t truck crane and a 32.2m main arm are selected, the hoisting radius is 9m, and the hoisting weight is 5.5t, so that the requirement is met;

the third step: and hoisting the steel beam by adopting a 25t crane. When the steel beam is hoisted, a 25t truck crane and a 32.2m main arm are selected, the hoisting radius is 14m, and the hoisting weight is 3.5t more than 1.1t, so that the requirements are met;

the fourth step: mounting a suspender, a brace rod and a stainless steel pull rod between the suspender and the V-shaped support column;

the fifth step: and after the cantilever platform structure of one area is installed, the temporary support is removed.

The V-shaped supporting column mainly comprises a column base, a middle section and a column top section, wherein the column base is independently used as an installation unit, and construction is carried out after installation conditions are met. The middle section is divided into two sections which are transported to the site, and the whole root is hoisted after ground splicing. The column top section is welded on a node at the lower part of the truss during processing, and is hoisted together with the truss member during construction. The V-shaped support columns are distributed mainly along the G axis. Each section is mainly composed of 6 circular tube column groups with the specification of phi 750 x 30. Each length is about 25 meters, and the maximum weight of the hoisting member is 14.9 t. When the V-shaped supporting column is hoisted, a main arm of 25.3m is selected for a 50t truck crane, the hoisting radius is 8m, the hoisting weight is 15.9t and is more than 14.9t, and the requirement is met.

4. Roof steel structure hoisting

4.1 segmentation and Assembly of roof trusses

The engineering roof truss is divided into 7 assembling and sliding units according to A-G exhibition areas, and the roof truss has a large section and is sent to the site mainly in a bulk form after being integrally pre-assembled in a processing plant. Firstly, 3 sections of plane units are spliced on the ground, and then the plane units are hoisted to a high-altitude jig frame by a 260t crawler crane to carry out total splicing of the sliding units. After the plane unit is assembled, the two crawler cranes turn over to a vertical state by four hoisting points. Then the hoisting is carried out by adopting a hoisting point of a 260-ton crawler crane 2.

The 260-ton crawler crane tower type main arm is 29m long, the auxiliary arm is 27m long, the working radius is 20m, and the hoisting weight is 53.3 tons. The maximum sectional weight of the roof truss section 1 is 52.2 tons and less than 53.3 tons, and the requirements are met. The maximum segment weight of the roof truss segment 2 is less than 49.2 tons and less than 53.3 tons, and the requirement is met. The maximum segment weight of the roof truss segment 3 is 44.8 tons and less than 53.3 tons, and the requirement is met. The maximum segment weight of the roof truss segment 4 is less than 53.3 tons and is 14.2 tons, so that the requirement is met. The assembly site of the sections 1-4 is close to the installation position as much as possible, and the load walking distance of the crawler crane is reduced. The roof truss high-altitude combination adopts a stabilizing measure as shown in figure 10, the positioning frame is placed on a three-layer roof with a reinforced concrete structure, and the supports in the columns D and E are respectively provided with one group.

Before the truss is assembled, the arrangement and connection of the jig frame are checked. The distance between the assembling jig frames is not required to be too large so as to ensure that enough supporting points exist in the assembling process of the truss and avoid the influence on the assembling precision caused by the self-weight deformation of the truss; the ground under the jig frame must be leveled, compacted and paved with roadbed boxes or H-shaped steel as an integral splicing platform. The relative position between the chords is adjusted through the jack, so that the requirements of relevant specifications are met. When the truss is assembled, the rod pieces are positioned according to the designed arched rear line type. And after assembly, comprehensive size inspection is carried out before welding, if the deviation is found to exceed the standard requirement, adjustment is carried out again, and welding can be carried out after error is detected again. Due to the fact that the trusses are assembled in a segmented mode, after the trusses are assembled, the overall dimension needs to be checked, it is guaranteed that assembling errors of the main trusses are controlled within an allowable range, follow-up high-altitude installation and butt joint are guaranteed to be conducted smoothly, and installation accumulated errors are reduced.

4.2 installation of roof modeling steel structure

The roof molding assembly weighs 6.8 tons at maximum. According to a 7030 type tower crane performance parameter table, when the rotating radius R is 35m, the lifting capacity is 6.91 tons; 29m of a main arm, 27m of an auxiliary arm, 20m of working radius and 53.3 tons of hanging weight of the 260-ton crawler crane; therefore, the crane meets the requirements. The roof modeling is assembled into an assembly part by adopting the ground, and then is hoisted by 2 7030 type tower cranes and 260 tons crawler cranes. The roof vertical truss, the horizontal tie bar, the support and other small parts have small weight, and are mainly hoisted by 2 on-site 7030 tower cranes. And for the part outside the coverage of the lifting capacity of the tower crane, 260-ton crawler crane is adopted for lifting.

5. Steel structure installation and measurement scheme

5.1 control measurement

And when the plane control network and the elevation control network of the transfer field are retested, the correlation of the civil engineering structure associated with the steel structure must be retested to ensure the integrity of the final steel structure construction, and the next step of work can be carried out only when all retesting accuracies meet the requirements. In order to meet the installation and positioning requirements of steel structures, a plane net needs to be constructed by utilizing surrounding stable buildings, stable off-site without being influenced by construction is selected when a control point is selected, and meanwhile, the problems of convenience in use and visibility in the future are considered. The control net must be accurately observed and used behind the tight adjustment. And the control network observation pier adopts a forced centering mode to reduce the point aligning error. The planar control network employs a control system consistent with that provided by the mapping unit. Reasonable and reliable high-precision measurement technology is selected and a feasible measurement technical scheme is compiled, and measurement procedures such as setting of a reference control network, selection of measurement instruments, measurement point arrangement, data transmission, multi-system check and the like are controlled.

In the aspect of elevation control, elevation control points should be arranged outside a field which is not affected by construction conditions. And detecting the primary elevation control network by using a precision level gauge. And introducing the elevation control points into the field in a closed leveling mode, and setting the fixed points as elevation points. After the ground elevation points in the ground are rechecked, 4-6 elevation control points are respectively guided and measured on each layer when the exhibition hall is constructed, the control points are guided and measured on a stable component, the guide points are checked on each layer, and the error is within the precision requirement range. During elevation guiding, a leveling instrument can be used for guiding and measuring along a leveling line, and elevation transmission is directly transmitted in the zenith direction of a suspended steel ruler or a total station and is checked mutually.

In the selection of the measurement opportunity, the corresponding elevation and other deformation values of each construction section provided by the design are generally based on design values at certain standard air temperature, and large structures are often constructed across seasons and day and night. The influence of temperature change, especially sunlight temperature difference, on the structural deformation is complex, and the structural deformation caused by the temperature difference change is difficult to separate from the measured deformation value. Therefore, the timing at which the temperature change is small should be selected as much as possible for measurement, and the influence of the temperature and sunlight on the construction control should be minimized. Tests on the temperature influence of some large structures show that in summer with the most adverse weather conditions, the temperature before sunrise in the morning is more uniform and is closest to the seasonal average temperature, and the measurement time is better. At present, the influence of temperature on the control of large structures is difficult to describe accurately.

In the construction control of large structures, the temperature influence can be divided into two categories: one is the influence of day and night temperature difference, and the other is the influence of seasonal temperature difference. The elevation control of the truss is greatly influenced by the temperature difference of day and night or the temperature difference of seasons. The influence of day and night temperature difference is generally avoided in elevation control, namely, construction processes for elevation control are required to be carried out before sunrise in the early morning with uniform temperature. However, in the case of continuous high-temperature weather, the temperature in the early morning is still difficult to be uniform, and the influence of the temperature is difficult to be completely avoided. The influence of the seasonal temperature difference is set as a standard temperature, and the influence of the actual seasonal temperature difference on the structure in the construction process is considered in the construction control calculation.

5.2 Effect of welding on measurement control

In order to reduce the influence of welding on measurement control and steel structure construction quality, after the high-strength bolt is installed and constructed after installation and correction are completed each time, measuring personnel can measure the perpendicularity of the steel column again and provide actual deviation numerical values, then a quality department compiles a welding sequence according to the actual numerical values, and welding shrinkage is reserved for some parts. In the welding process, a measurer carries out tracking observation so as to reduce the influence of welding on measurement control.

5.3 measurement control of Steel Structure installation

Planar position control diagram of the embedded part is shown in fig. 11 and 12, wherein TK1, TK2, TK3 and TK4 represent embedded part axis control points, and YK1, YK2 and YK3 represent embedded part central line control points.

An axis positioning method comprises the following steps: on the basis of I, II-level control points, the lofting precision is improved, the vertical and horizontal axes of the embedded part and positioning points TK1, TK2, TK3 and TK4 are lofted by adopting two surveying loops of a precise distance measuring instrument and a theodolite angle measuring instrument. And erecting theodolites at positioning points TK1 and TK3, respectively using the positioning points TK2 and TK4 for orientation, enabling the center line of the embedded part to coincide with the control axis, and using a total station to perform coordinate retesting on the positioning points.

And (3) a total station coordinate positioning method: determining the positions of YK1, YK2 and YK3 according to the structural center line of each embedded part on a design drawing, obtaining coordinate values of the YK1, YK2 and YK3, and marking YK1, YK2 and YK3 on the embedded parts. And (3) positioning a YK1 point by using a polar coordinate normal of the total station, determining the midpoint position of the embedded part, measuring the positions of YK2 and YK3 by using the same method, and controlling the axial direction of the embedded part.

The allowable value of the axis offset of the embedded part measured by the two positioning methods is 2.0 mm.

In the elevation control of the embedded part, the elevation of the base surface is controlled, and the elevation of the surface of the embedded part is directly measured by adopting the conventional height difference measurement of a level gauge; and measuring the elevation of the embedded part by adopting a total station instrument triangle elevation in order to reduce the transmission error of the level instrument and the accidental error of multiple readings for measuring the elevation far away from the datum point of the level instrument. The elevation tolerance of the embedded part is 3.0 mm.

In the measurement control of the steel column, the axis positioning or the perpendicularity is carried out, both the oblique steel column and the straight steel column are measured, and the perpendicularity can be generally measured. When the steel column is adjusted, the axis position or the perpendicularity is roughly adjusted, then the elevation is initially measured and adjusted, then the axis position or the perpendicularity is finely adjusted, and finally the elevation is repeatedly measured.

In the measurement and control of the steel beam, there may be a gap between the steel beam and the steel beam, so that the bolt cannot be inserted normally, and the deviation cannot be adjusted in place by the impact nail. The jack can be used to jack or reduce the gap, so that the bolt can be penetrated normally. The allowable deviation of the levelness of the steel beam (L/1000) +3mm (L is the length of the beam) is not more than 10mm, the levelness of the steel beam exceeds the standard mainly because the position of the connecting plate or the position of the screw hole is wrong, and the connecting plate or the plug welding hole can be replaced to re-form the hole for processing.

The measurement control of the truss is as follows:

(1) ground assembly measurement control

1) Assembling the steel truss from bottom to top and from two sides to the center;

2) the truss should form a stable whole as soon as possible when assembled. In the truss assembling process, the components assembled on the same day form a structure stabilizing system;

3) and after the truss is assembled, screwing the high-strength bolt and then welding. The welding process is carried out by firstly winding down and then winding up.

4) And monitoring the deformation condition of the truss by using a high-precision measuring instrument, particularly the pre-arching change before and after welding, finding out the abnormality, and timely searching for the reason and taking measures to adjust.

5) And carrying out measurement and whole-course observation in the welding process to ensure that the deviation is within the range required by the specification.

(2) High-altitude splicing measurement control

1) And adjusting the elevation and the position of the jig frame according to the design drawing, adjusting the perpendicularity and the axis position of the component during assembling, and taking measures to prevent deformation in the installation and welding processes.

2) After assembling, rechecking and adjusting each node of the truss by using the total station, and after the rechecking and adjusting, starting truss welding. After welding, the trusses are comprehensively detected, the detected data are recorded and filed, and are contrasted and analyzed with the detected data before welding, the deformation degree of the trusses is determined, and the deformation reason is analyzed, so that the assembling error can be reduced as much as possible in the next truss assembling process.

6. High strength bolt installation

The high strength bolted connection length was determined as follows: l ═ H + nh + c, where: -total thickness mm of the connecting member; h, the height of the nut is mm, and 0.8D (the diameter of the bolt) is taken; n is the number of the gaskets; h-gasket thickness mm; c, the length of the exposed part of the screw is mm (preferably 2-3 buttons, generally 5 mm); and taking integral multiples of 5 after calculation.

The high-strength bolt connection is used for inspecting and rechecking a connection auxiliary material object and a friction surface before construction, and installation and construction can be carried out only after the connection is qualified. The bolt installation is divided into 3 steps to carry out: firstly, hoisting a steel member, fixing the steel member by using temporary bolts or punching nails, and strictly forbidding using high-strength bolts as the temporary bolts, wherein the number of the temporary bolts is not less than 1/3 of the total number of the bolts and not less than two; secondly, replacing common bolts with high-strength bolts from the middle to the periphery, and primarily screwing the high-strength bolts; and thirdly, fastening the high-strength bolt by two times, wherein the first time is initial screwing, and the initial screwing is fastened to 50-80% of the final screwing axial force value of the bolt. The second time is final twist, which is tightened to the standard pretension with a deviation of not more than ± 10%. Under normal conditions, a special electric wrench is adopted for final screwing, and the end of final screwing is marked when the plum blossom head is screwed off. When the special spanner cannot be used for operation, the torsional shear type high-strength bolt is constructed according to the large hexagon head high-strength bolt by a torque method. After final twisting is finished, checking that twisting is missed and under-twisted, and performing knocking detection one by using a small hammer with the weight of 0.3-0.5 kg, if under-twisted and under-twisted are found, twisting is compensated; the super-screwing should be replaced. During inspection, the nut is retracted by 30-50 degrees, then screwed to the original position, the final screwing torque value is measured, the deviation is not more than +/-10 percent, and the qualified final screwing is marked to avoid confusion.

7. Steel structure installation correcting measure

7.1 Steel column installation and correction measures

And adjusting a nut on the screw according to the bottom elevation of the steel column, and placing a cushion block. All steel column hoisting points are arranged at the upper parts of the steel columns, and four temporary connecting lug plates are used as the hoisting points. When the steel column is hoisted, the steel column must be lifted off the ground vertically by lifting the hook and rotating the arm at the same time. When the steel column is lifted to 200mm above the in-place position, the machine is stopped stably, the steel column slowly falls down after being aligned with the bolt holes and the cross lines, and the screw threads of the foundation bolts are prevented from being collided during falling. And after the column foot plate enters the foundation bolt, checking the alignment condition of the center lines of the four sides of the steel column and the axis of the cross of the foundation, adjusting the positioning deviation of the steel column to be within 3mm, and then dropping the steel column to be implemented.

After the steel column is hoisted in place, the center line of the steel column and the center line of the foundation are aligned, the plane position of the steel column is determined, then the straightness of the steel column is corrected through the adjustment of a nut below a steel column bottom plate, the straightness deviation of the steel column in two orthogonal directions is required to be corrected to be zero in a free state, and then foundation bolts are screwed down. The elevation of the steel column may slightly change, and normally does not exceed the requirement of 2.0mm specified in the acceptance and approval Specification for construction quality of Steel Structure engineering (GB50205-2001), and the schematic diagram of the correction of the steel column is shown in FIG. 13.

And (3) perpendicularity correction: the straightness correction that hangs down of steel column adopts two theodolites, erect the theodolite on shaft mutual perpendicular's two directions, perhaps erect at the not big 15 within ranges of skew angle, aim at the installation sign of steel column top department with the telescope, aim at the installation sign at the bottom of the column the telescope downwards, and place the steel plate chi on the installation sign at the bottom of the column, observe the distance of post top installation sign projection back and bottom of the column installation sign in the telescope, the adjustment steel column, make the straightness correction of hang down of steel column to the regulation within range, the straightness offset value that hangs down should not be more than H/1000 and be less than or equal to 10mm, H is the column height.

And (3) torsion correction: after the positioning axes of the two steel columns are lofted on the top of one section of the fixed steel column, deviation values of all surfaces of the two sections of the steel columns and the positioning axes can be measured. The torsion values of the steel column in the X direction and the Y direction can be obtained by utilizing the deviation value, and then the accurate adjustment is carried out. In addition, according to the actual construction condition on site, the coordinates of the top of the steel column can be measured by combining a total station instrument to correct, so that the installation identification line of the top of the steel column is adjusted to the positioning axis.

7.2 roof truss installation and correction measures

And (3) using an inter-truss adjuster for each segmental roof truss to correct the verticality, fixing supports at two ends, fixing by bolts or welding → installing a roof beam → horizontally supporting → checking to be correct, and so on. The binding points of the roof truss are arranged and must be bound on the nodes to prevent the member from bending and deforming at the hanging point.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.

Claims (3)

1. A prestress underpinning static cutting column pulling construction process is characterized in that: the prestress underpinning static force cutting pull column comprises a reinforced concrete bonded prestress underpinning structure, a diamond wire saw cutting system and a structure displacement strain monitoring system, and the concrete construction process comprises the following steps:

step 1, constructing a reinforced concrete bonded prestressed underpinning structure, which specifically comprises the following steps:

(1) and installing and binding new steel bars: positioning and installing reinforcing steel bars according to a construction drawing, ensuring continuous inertial connection of bottom stressed reinforcing steel bars in a pile pulling area, and enabling the bottom stressed reinforcing steel bars to pass through the whole reinforcing steel bars when meeting a pile to be pulled and an opening, so that connection points are prevented from being distributed in the area, and connecting new reinforcing steel bars with an original structure by adopting a bar planting and anchoring method;

(2) and installing a metal corrugated pipe: accurately marking the position of the transverse coordinate of each control point of the steel bundle on the beam slab bottom die according to the transverse coordinate of the steel bundle in the prestressed steel bundle arrangement drawing in the design drawing, and then accurately installing steel bundle positioning steel bars according to the position of the longitudinal coordinate of each control point in the steel bundle arrangement drawing; the positioning reinforcing steel bars are preferably welded into a positioning reinforcing steel bar mesh, and then are bound together with the web reinforcing steel bars according to the set positions, wherein the intervals of the curved parts of the positioning reinforcing steel bars are 50cm, and the intervals of the straight parts are 100 cm. After the positioning steel bars are bound, the metal corrugated pipes are penetrated, and the corrugated pipes need to be butted by adopting sleeves;

(3) and installing prestressed steel strands: the steel strand wires are blanked according to the design drawing, the blanking is cut by a cutting machine, the steel strand wires blanked according to the design drawing are inserted into the corrugated pipes according to corresponding numbers, and the steel strand wires are manually inserted and released; the anchor backing plate is required to be perpendicular to the steel strand and the pipeline and firmly fixed with the end socket template;

(4) installing a template and pouring concrete;

step 2, mounting prestress tensioning, static cutting and monitoring equipment;

and 3, tensioning and cutting the column.

2. The prestressed underpinning static cutting and column drawing construction process according to claim 1, characterized in that: the step 2 specifically comprises the following steps:

(1) and mounting the prestress tensioning equipment: tensioning equipment adopts a numerical control hydraulic jack to carry out tensioning, and a jack main body is arranged and can be drilled and hoisted in a tensioning end area;

(2) and installing cutting equipment: the cutting equipment adopts a diamond wire saw cutting system, the cutting direction of the wire is finished by the installation direction of a guide wheel set, and the installation positions of the guide wheel set and a main driving movable wheel set are skillfully designed, so that the high-efficiency cutting requirement is met;

(3) and installing monitoring equipment: the structure displacement strain monitoring entrusts the unit that has the structure monitoring qualification to monitor, and structure displacement strain monitoring system main equipment contains 4 strainometers, 2 sets of displacement and one set of structure displacement strain monitoring system host computer.

3. The prestressed underpinning static cutting and column drawing construction process according to claim 2, characterized in that: the step 3 specifically comprises the following steps:

(1) and initial tensioning: after all preparation works are finished, carrying out initial pretensioning to 10% of a designed tensioning value;

(2) and stretching for the second time: stretching to 50% of a designed stretching value, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(3) the first static force cutting is intercepted: cutting a middle part of the column, and synchronously and continuously observing the displacement and strain change of the underpinning structure;

(4) and observing the stress condition of the structure and performing third tensioning: continuously monitoring the displacement and strain value of the underpinning structure, and stretching the prestressed tendons according to the detection data to keep the stress value of the new beam longitudinal tendons between 0 and-200;

(5) and a second static force cutting column: cutting the left part of the right side of the column, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(6) observing the stress condition of the structure and tensioning for the fourth time: continuously monitoring the displacement and strain value of the underpinning structure, and stretching the prestressed tendons according to the detection data to keep the stress value of the new beam longitudinal tendons between 0 and-200;

(7) and a third static force cutting column: left measuring the rest part of the cutting column, and synchronously and continuously monitoring the displacement and strain value of the underpinning structure;

(8) and observing the stress condition of the structure and performing fifth tensioning: continuously monitoring the displacement and the strain of the underpinning structure for 24 hours, and stretching the prestressed tendons according to the detection data to be used as a safe reserve value;

(9) and after the column is cut off for 24 hours, keeping the displacement and the strain of the detection result within the design allowable range and basically keeping unchanged, and unloading the top, grouting, sealing the anchor and gradually cutting and removing the broken column in sections.

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