A construction method for lightweight core mold small cross-section hollow thin-walled high piers

Abstract

This invention relates to the field of hollow thin-walled high pier construction technology, and discloses a construction method for hollow thin-walled high piers with small cross-sections using lightweight core molds. After the pier cap construction is completed, the centerline and elevation of the pier cap are re-measured. At the same time, the design dimension outline control points of the solid section of the hollow pier bottom and the pier centerline are marked out. Then, based on the control points and the dimensions of each part of the pier body, the ink splash method and the marking of straight sections of the pier body are used as the measurement basis for the first construction of the pier mold. After the first section of the pier body is completed, the outer mold is removed in sequence, and then lifted and erected. Subsequently, the inner mold is removed, and then lifted and reinforced. This construction method for hollow thin-walled high piers with small cross-sections using lightweight core molds solves the defects of traditional dismantled inner molds, such as time-consuming and labor-intensive installation and dismantling, high cost, heavy weight, poor working environment for workers, and delays in construction, by using a lightweight core mold made of lightweight materials.

Description

Technical Field

[0001] This invention relates to the field of hollow thin-walled high pier construction technology, specifically a construction method for a lightweight core mold small-section hollow thin-walled high pier. Background Technology

[0002] Thin-walled hollow high piers are similar in shape to gravity bridge piers. These high piers are characterized by good structural stiffness and strength, light weight, large section modulus, and small cross-sectional area, and are mainly used in the construction of high bridges.

[0003] Currently, in the construction of thin-walled hollow high piers, if the traditional process of steel (wood) formwork is used to assemble the hollow chambers on site, the maximum cross-sectional size of each hollow chamber is only 1.4×1.4m, and the cross-sectional area of ​​the top of the chamber is only 0.8×0.8m. The space for installing and dismantling the inner formwork is small, and a working platform and personnel access passage must be set up inside the chamber. The wall thickness of the thin-walled pier is only 0.4m. Under the limited space working conditions, the construction of hollow thin-walled piers is difficult, inefficient, slow, and unsafe. Therefore, it is necessary to design a construction method for hollow thin-walled high piers with lightweight core molds and small cross-sections to solve the above problems. Summary of the Invention

[0004] (I) Technical Solution

[0005] This invention provides the following technical solution: a construction method for a lightweight core mold small-section hollow thin-walled high pier, comprising the following steps:

[0006] S1. Surveying and Setting Out

[0007] After the foundation construction is completed, the centerline and elevation of the foundation are re-measured. At the same time, the design dimension outline control points of the solid section at the bottom of the hollow pier and the centerline of the pier are marked out. Then, based on the control points and the dimensions of each part of the pier body, the ink splash method is used to mark out the straight section of the pier body as the measurement basis for the first construction of the pier formwork.

[0008] S2, Reinforcement Construction

[0009] The elevation of the top surface of the pier column was re-measured, and any elevations that did not meet the requirements were dealt with in a timely manner. Subsequently, the foundation was roughened and the concrete debris was cleaned. According to the type and construction process, the main reinforcement, stirrups and tie bars of the pier column were installed using the corresponding joint methods. Among them, the steel bars with a diameter of Ф22 and above were connected by straight threaded sleeves, ensuring that no more than 2 threads were exposed after the sleeve connection, and that the two ends of the sleeve were evenly distributed. A special sleeve wrench was used for connection, and the ends of the steel bars were ensured to be flat when connecting the sleeves. Steel bars with a diameter of less than Ф22 were welded.

[0010] S3, Construction Platform and Formwork Installation

[0011] S301, External formwork installation

[0012] First, measure and lay out the inner line, and nail steel nails into each side for positioning. Grind the surface of the foundation platen 3cm wide along the template installation line. Then, install the first section of template. Use expansion bolts to fix the template to the foundation platen surface through the flange holes at the four corners of the template. Then, install the second and third sections of template one by one. Tighten the flange bolts between each section of template first, and adjust and control the verticality while tightening the bolts.

[0013] S302, Core mold installation

[0014] Based on the construction height of the pier column and the height of the outer formwork, steel plates were used in four directions for limiting and fixing, and anti-buoyancy measures were taken by setting up anti-buoyancy steel beams at the top to press down on the core mold.

[0015] S303, Install the external working platform of the pier

[0016] Using the pre-drilled bolt holes on the template, a suspended basket-style triangular support is installed on the vertical stiffening ribs. Then, steel planks are laid on the platform, and toe boards, safety netting, and warning signs are installed.

[0017] S4, Concrete Pouring

[0018] Before pouring, the supports, formwork, reinforcing bars and embedded parts are inspected. Debris, water and dirt inside the formwork and on the reinforcing bars are cleaned. The gaps in the formwork are sealed tightly. The inside of the formwork is coated with the same type of release agent. The uniformity and slump of the concrete are checked. The concrete is centrally mixed at a commercial concrete plant and transported to the construction site by concrete mixer truck. The concrete is delivered to the formwork by a tower crane or a concrete pump hopper and compacted by an immersion vibrator.

[0019] S5, Concrete Curing

[0020] Within 12 hours after the concrete is poured, wrap it with plastic film for curing. The wrapping should be tight and airtight, and the curing should be carried out by the moisture evaporated from the concrete itself. After the formwork is removed, water should be sprinkled in time for curing, and the concrete should be covered with non-woven fabric to keep it moist for no less than 7 days.

[0021] S6, Formwork Reversal Construction

[0022] After the first section of the pier body is completed, the outer formwork is removed in sequence, and then the outer formwork is lifted and erected. Then the inner formwork is removed, and then the inner formwork is lifted and reinforced. Then steps S4 and S5 are repeated until the pier body is completed.

[0023] Preferably, in step S1, the hollow section measurement is performed using a 12-point contour control method based on the pier structure. There are 12 points in total, covering the four corners of the outer side and the eight corners of the inner side of the pier. If the actual size does not match the design size, the pier formwork is corrected until the actual size of the installed pier formwork matches the design size. Additionally, a plumb bob is used to measure the verticality of this section along the outside of the template.

[0024] Preferably, in step S2, the roughening time should not begin until 24 hours after final setting, and the entire surface of the contact surface between the pier and the foundation should be roughened, with an area of ​​not less than 90%, and the roughening depth should be controlled between 5-10 mm, until 2 / 3 of the aggregate is exposed.

[0025] Preferably, in step S301, a temporary windbreak wall is set on the windward side of the pier body, forming a zigzag shape. The temporary windbreak wall is constructed first, and then the formwork is installed.

[0026] Preferably, in step S302, the core mold used is made of polystyrene plastic. To prevent damage to the core mold material from sparks during the welding of the reinforcing bars, flame retardants and resin coatings have been added to the core mold material as fire prevention measures. When constructing the reinforcing bars, care should be taken to handle the reinforcing bar skeleton gently to prevent collision with the core mold material. The bent ends of the reinforcing bars should point away from the core mold. When welding the reinforcing bars, a baffle should be set between the reinforcing bar skeleton and the core mold material.

[0027] Preferably, in step S4, before concrete pouring, the formwork plane dimensions, support system, and pre-embedded steel bars of the pier are inspected and accepted. After passing the inspection, concrete is poured. In summer, the concrete temperature should not exceed 30°C when it enters the formwork. Concrete should be poured when the outdoor temperature is low. In winter, the concrete temperature should not be lower than 10°C when it exits the mixer and not lower than 5°C when it enters the formwork. It is advisable to pour concrete when the daytime temperature is high.

[0028] Preferably, in step S6, a construction operation platform is installed immediately after the outer formwork of each pier column is installed. The outer operation platform is a platform with its own angle steel support set around the pier formwork. During the formwork flipping construction, after the formwork is disassembled, the formwork is moved outward and then lifted upward by a crane, with manual assistance. Each time the lower formwork is flipped, the upper formwork is retained. The lower formwork is disassembled and moved out, and the formwork is lifted by a tower crane. After it is firmly assembled, the upper formwork is flipped and assembled and connected and fixed to the lower formwork. This cycle continues until the pier is capped.

[0029] (ii) Beneficial effects

[0030] Compared with the prior art, the present invention provides a construction method for lightweight core mold small cross-section hollow thin-walled high piers, which has the following beneficial effects:

[0031] This lightweight core mold construction method for small-section hollow thin-walled high piers solves the problems of traditional dismantled internal formwork made of steel and wood by using a lightweight core mold. Compared with traditional internal formwork made of steel and wood, the application of lightweight core mold solves the problems of traditional internal formwork in confined space conditions, such as time-consuming and labor-intensive installation and dismantling, high cost, heavy weight, poor working environment for workers, and delays in construction period. At the same time, it improves the construction quality of thin-walled hollow piers and reduces construction costs. Attached Figure Description

[0032] Figure 1This is a schematic diagram of the process of the present invention;

[0033] Figure 2 This is a schematic diagram of the pier control points of the present invention;

[0034] Figure 3 This is a schematic diagram of the reinforcing steel bars in the hollow thin-walled pier of the present invention;

[0035] Figure 4 This is a diagram showing the installation and support of the first section of the pier body template for this invention.

[0036] Figure 5 This is a schematic diagram of the windproof reinforcement for the pier body during construction according to the present invention;

[0037] Figure 6 This is a front view of the core mold mounting and fixing measures of the present invention;

[0038] Figure 7 This is a side view of the core mold mounting and fixing measures of the present invention;

[0039] Figure 8 This is a top view of the core mold mounting and fixing measures of the present invention;

[0040] Figure 9 This is a schematic diagram of the external working platform of the present invention;

[0041] Figure 10 This is a diagram illustrating the concrete pouring sequence of the present invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Please see Figure 1-10 This invention provides a technical solution: a construction method for a lightweight core mold small-section hollow thin-walled high pier, comprising the following steps:

[0044] S1. Surveying and Setting Out

[0045] After the foundation construction is completed, the centerline and elevation of the foundation are re-measured. At the same time, the design dimension outline control points of the solid section at the bottom of the hollow pier and the centerline of the pier are marked out. Then, based on the control points and the dimensions of each part of the pier body, the ink splash method is used to mark out the straight section of the pier body as the measurement basis for the first construction of the pier formwork.

[0046] For the measurement of the hollow section, a 12-point contour control method was used based on the pier structure, as shown in the attached figure. Figure 2As shown, there are 12 points in total, in the four corners of the outer side and the eight corners of the inner side of the pier body. If the actual size does not match the design size, the pier formwork is corrected until the actual size of the installed pier formwork matches the design size. In addition, a plumb bob is used to measure the verticality of this segment along the outside of the formwork.

[0047] S2, Reinforcement Construction

[0048] As attached Figure 3 As shown, the elevation of the top surface of the pier column was re-measured, and any elevations that did not meet the requirements were dealt with in a timely manner. Subsequently, the foundation was roughened and the concrete debris was cleaned. According to the type and construction process, the main reinforcement, stirrups and tie bars of the pier column were installed using the corresponding joint methods. Among them, the steel bars with a diameter of Ф22 and above were connected by straight threaded sleeves, ensuring that no more than 2 threads were exposed after the sleeve connection, and that the two ends of the sleeve were evenly distributed. A special sleeve wrench was used for connection, and the ends of the steel bars were ensured to be flat when connecting the sleeves. Steel bars with a diameter of less than Ф22 were welded.

[0049] The roughening process should only begin 24 hours after final setting, and the entire surface of the contact area between the pier and the foundation should be roughened, covering an area of ​​no less than 90%. The roughening depth should be controlled between 5-10 mm, until 2 / 3 of the aggregate is exposed.

[0050] S3, Construction Platform and Formwork Installation

[0051] S301, External formwork installation

[0052] See attached Figure 4 and Figure 5 First, measure and lay out the inner line, and nail steel nails into each side for positioning. Grind the surface of the foundation platen 3cm wide along the template installation line. Then install the first section of template. Use expansion bolts to fix the template to the foundation platen surface through the flange holes at the four corners of the template. Then install the second and third sections of template one by one. Tighten the flange bolts between each section of template first, and adjust and control the verticality while tightening the bolts.

[0053] A temporary windbreak wall was set up on the windward side of the pier, forming a zigzag shape. The temporary windbreak wall was constructed first, and then the formwork was installed.

[0054] S302, Core mold installation

[0055] See Figure 6-8 Based on the construction height of the pier and the height of the outer formwork, steel plates were used to limit and fix the core mold in four directions, and anti-buoyancy measures were taken by setting up anti-buoyancy steel beams at the top for pressure.

[0056] The core mold used is made of polystyrene plastic. To prevent damage to the core mold material from sparks during steel bar welding, flame retardants and resin coatings have been added to the core mold material as fire prevention measures. When constructing the steel bars, care should be taken to handle the steel bar skeleton with care to prevent collision with the core mold material. The bends of the steel bars should point away from the side of the core mold. When welding the steel bars, a baffle should be placed between the steel bar skeleton and the core mold material.

[0057] S303, Install the external working platform of the pier

[0058] See attached Figure 9 Using the pre-drilled bolt holes on the template, a suspended basket-style triangular support is installed on the vertical stiffening ribs. Then, steel planks are laid on the platform, and toe boards, safety netting, and warning signs are installed.

[0059] S4, Concrete Pouring

[0060] See Figure 10 Before pouring, the supports, formwork, reinforcing bars and embedded parts are inspected. Debris, water and dirt in the formwork and on the reinforcing bars are cleaned. The gaps in the formwork are sealed tightly. The inside of the formwork is coated with the same type of release agent. The uniformity and slump of the concrete are checked. The concrete is centrally mixed at a commercial concrete plant and transported to the construction site by concrete mixer truck. The concrete is delivered to the formwork by a tower crane or a concrete pump hopper and compacted by an immersion vibrator.

[0061] Before pouring concrete, the formwork dimensions, support system, and embedded steel bars in the pier body should be inspected and accepted. After passing the inspection, concrete should be poured. In summer, the concrete temperature should not exceed 30℃ when it enters the formwork. Concrete should be poured when the outdoor temperature is low. In winter, the concrete temperature should not be lower than 10℃ when it exits the mixer and not lower than 5℃ when it enters the formwork. It is advisable to pour concrete when the daytime temperature is high.

[0062] S5, Concrete Curing

[0063] Within 12 hours after the concrete is poured, wrap it with plastic film for curing. The wrapping should be tight and airtight, and the curing should be carried out by the moisture evaporated from the concrete itself. After the formwork is removed, water should be sprinkled in time for curing, and the concrete should be covered with non-woven fabric to keep it moist for no less than 7 days.

[0064] S6, Formwork Reversal Construction

[0065] After the first section of the pier body is completed, the outer formwork is removed in sequence, and then the outer formwork is lifted and erected. Then the inner formwork is removed, and then the inner formwork is lifted and reinforced. Then steps S4 and S5 are repeated until the pier body is completed.

[0066] After the outer formwork of each pier column is installed, the construction operation platform is immediately installed. The outer operation platform is a platform with its own angle steel support set around the pier formwork. During the formwork flipping construction, after the formwork is dismantled, the formwork is moved outward and then lifted upward with the help of a crane. Each time the lower formwork is flipped, the upper formwork is retained. The lower formwork is dismantled and moved out, and the formwork is lifted up by a tower crane. After it is firmly assembled, the upper formwork is flipped up and assembled and connected and fixed to the lower formwork. This cycle continues until the pier is capped.

[0067] This lightweight core mold construction method for small-section hollow thin-walled high piers solves the problems of traditional dismantled internal formwork made of steel and wood by using a lightweight core mold. Compared with traditional internal formwork made of steel and wood, the application of lightweight core mold solves the problems of traditional internal formwork in confined space conditions, such as time-consuming and labor-intensive installation and dismantling, high cost, heavy weight, poor working environment for workers, and delays in construction period. At the same time, it improves the construction quality of thin-walled hollow piers and reduces construction costs.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A construction method for a lightweight core mold small-section hollow thin-walled high pier, characterized in that, Includes the following steps: S1. Surveying and Setting Out After the foundation construction is completed, the centerline and elevation of the foundation are re-measured. At the same time, the design dimension outline control points of the solid section of the hollow pier bottom and the centerline of the pier are marked out. Then, based on the control points and the dimensions of each part of the pier body, the ink splash method and the straight section of the pier body are marked out as the measurement basis for the first construction of the pier formwork. S2, Reinforcement Construction The elevation of the top surface of the pier column was re-measured, and any elevations that did not meet the requirements were dealt with in a timely manner. Subsequently, the foundation was roughened and the concrete debris was cleaned. According to the type and construction process, the main reinforcement, stirrups and tie bars of the pier column were installed using the corresponding joint methods. Among them, the steel bars with a diameter of Ф22 and above were connected by straight thread sleeves, ensuring that no more than 2 threads were exposed after the sleeve connection, and that the sleeves were evenly distributed at both ends. A special sleeve wrench was used for connection, and the ends of the steel bars were ensured to be flat when connecting the sleeves. Steel bars with a diameter of less than Ф22 were welded. S3, Construction Platform and Formwork Installation S301, External formwork installation First, measure and lay out the inner line, and nail steel nails into each side for positioning. Grind the foundation surface 3cm wide along the template installation line. Then install the first template section. Use expansion bolts to fix the template to the foundation surface through the flange holes at the four corners. Then install the second and third template sections one by one. Tighten the flange bolts between each template section first, and adjust and control the verticality while tightening the bolts. S302, Core mold installation Based on the construction height of the pier column and the height of the outer formwork, steel plates were used to limit and fix the core mold in four directions, and anti-buoyancy measures were taken by setting up anti-buoyancy steel beams at the top for pressure. S303, Install the external working platform of the pier Using the pre-drilled bolt holes on the template, install the suspended basket-type triangular brackets on the vertical stiffening ribs, then cover the platform with steel planks, and set up toe boards, safety netting, and warning signs. S4, Concrete Pouring Before pouring, inspect the supports, formwork, reinforcing bars and embedded parts. Clean the debris and water inside the formwork and the dirt on the reinforcing bars. Seal the gaps in the formwork tightly. Apply the same type of release agent to the inside of the formwork. Check the uniformity and slump of the concrete. The concrete is centrally mixed at a commercial concrete plant and transported to the construction site by concrete mixer truck. It is delivered to the formwork by a tower crane or a concrete pump hopper and compacted by an immersion vibrator. S5, Concrete Curing Within 12 hours after the concrete is poured, wrap it with plastic film for curing. The wrapping should be tight and airtight. Use the moisture evaporated from the concrete itself for curing. After the formwork is removed, spray water for curing in time and cover it with non-woven fabric to keep it moist for no less than 7 days. S6, Formwork Reversal Construction After the first section of the pier body is completed, the outer formwork is removed in sequence, and then the outer formwork is lifted and erected. Then the inner formwork is removed, and then the inner formwork is lifted and reinforced. Then steps S4 and S5 are repeated until the pier body is completed.

2. The construction method for a lightweight core mold small-section hollow thin-walled high pier according to claim 1, characterized in that, In step S1, the hollow section is measured. According to the pier structure, 12-point contour control is used, with 12 points in the four corners of the outer side and the eight corners of the inner side of the pier. If the actual size does not match the design size, the pier formwork is corrected until the actual size of the installed pier formwork matches the design size. In addition, a plumb bob is used to measure the verticality of this section along the outside of the template.

3. The construction method for a lightweight core mold small-section hollow thin-walled high pier according to claim 1, characterized in that, In step S2, the roughening time can only begin 24 hours after the final setting, and the entire surface of the contact surface between the pier and the foundation must be roughened, with an area of ​​not less than 90%, and the roughening depth must be controlled between 5-10mm, until 2 / 3 of the aggregate is exposed.

4. The construction method for a lightweight core mold small-section hollow thin-walled high pier according to claim 1, characterized in that, In step S301, a temporary windbreak wall is set up on the windward side of the pier body, forming a zigzag shape. The temporary windbreak wall is constructed first, and then the formwork is installed.

5. The construction method for a lightweight core mold small-section hollow thin-walled high pier according to claim 1, characterized in that, In step S302, the core mold used is made of polystyrene plastic. To prevent damage to the core mold material from sparks during steel bar welding, flame retardants and resin coatings have been added to the core mold material as fire prevention measures. When constructing the steel bars, care should be taken to handle the steel bar skeleton gently to prevent collision with the core mold material. The bends of the steel bars should point away from the core mold. When welding the steel bars, a baffle should be set between the steel bar skeleton and the core mold material.

6. The construction method for a lightweight core mold small-section hollow thin-walled high pier according to claim 1, characterized in that, In step S4, before concrete pouring, the formwork plane dimensions, support system, and pre-embedded steel bars of the pier are inspected and accepted. After passing the inspection, concrete is poured. In summer, the concrete temperature should not exceed 30°C when it enters the formwork. Concrete should be poured when the outdoor temperature is low. In winter, the concrete temperature should not be lower than 10°C when it exits the mixer and not lower than 5°C when it enters the formwork. It is advisable to pour concrete when the daytime temperature is high.

7. The construction method for a lightweight core mold small-section hollow thin-walled high pier according to claim 1, characterized in that, In step S6, after the outer formwork of each pier column is installed, the construction operation platform is immediately installed. The outer operation platform is a platform with its own angle steel support set around the pier formwork. During the formwork flipping construction, after the formwork is dismantled, the formwork is moved outward and then lifted upward by a crane, with manual assistance. Each time the lower formwork is flipped, the upper formwork is retained. The lower formwork is disassembled and moved out, and the formwork is lifted by a tower crane. After it is firmly assembled, the upper formwork is flipped and assembled and connected and fixed to the lower formwork. This cycle continues until the pier is capped.

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