Production process of prestressed middle plate of subway station

Abstract

The invention provides a production process of a prestressed middle plate of a subway station. The construction method comprises the following steps of mold acceptance check, mold cleaning, mold assembly, mold release agent brushing, pre-embedded sliding groove installation, steel reinforcement framework installation, pre-embedded wire box and tool installation, steel pipe truss placement, prestressed tendon installation, pre-tensioning, secondary tensioning, concrete pouring and vibrating, upper surface galling, maintenance, tension releasing, end mold removal and component lifting and placing. The construction method comprises the steps of mold acceptance check, mold cleaning, mold assembly, mold release agent brushing, pre-embedded sliding groove installation, steel reinforcement framework installation, pre-embedded wire box and tool installation, steel pipe truss placement, prestressed tendon installation, pre-tensioning, secondary tensioning, concrete pouring and vibrating, upper surface galling, and inspecting, identifying and warehousing. Maintenance is carried out by adopting electric heating covering, direct exposure in a strong light environment for exposure is avoided, meanwhile, under the covering effect, evaporation can be reduced, humidification equipment is arranged, the humidity is further guaranteed, meanwhile, the temperature difference between the water temperature for humidifying and watering and the component is always kept, and shrinkage and cracking caused by too large temperature difference are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal engineering, and particularly relates to a production process for prestressed middle plates of subway stations. Background Art

[0002] Prestressed middle plates are precast components widely used in construction engineering, and have the characteristics of high bearing capacity, large span, good seismic performance, high construction efficiency, etc., and are applicable to fields such as bridge engineering and subway station construction.

[0003] As an important structural component in subway station construction, the improvement of the production process of prestressed middle plates is of great significance for improving structural performance, reducing costs and increasing production efficiency.

[0004] Traditional production processes have poor control over the quality of finished products, and there may be some defects after the finished products; at the same time, prestressed middle plates are generally produced in the open air. During the curing period, strong sunlight exposure will cause the rapid evaporation of concrete moisture, affecting the hydration of cement. And when maintaining humidity by watering, the temperature difference between the concrete surface and water is relatively large, which is likely to cause shrinkage and cracking. Summary of the Invention

[0005] The present invention provides a production process for prestressed middle plates of subway stations in order to solve the technical problem of poor control over the quality of finished products.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a production process for prestressed middle plates of subway stations, which includes the following steps:

[0008] (1) After the molds are inspected and accepted upon arrival, they are cleaned, assembled, and coated with a release agent, and are protected after the release agent is coated.

[0009] (2) Install embedded chutes.

[0010] (3) Hoist the steel bar cage and place the steel bar cage in the mold.

[0011] (4) Position and place the embedded parts, and fix the embedded parts with tooling.

[0012] (5) Grout the steel pipe truss, and place the steel pipe truss 48 hours after grouting.

[0013] (6) Cut the prestressed tendons into corresponding lengths, and then place the prestressed tendons and hole strengthening bars at the corresponding openings of the end mold.

[0014] (7) Install a coupler at the end of the prestressed tendon, connect it to the spiral tie rod, adjust the position of the jack, and then perform pre-tensioning and secondary tensioning.

[0015] (8) Concrete is poured into the mold and compacted by vibrating with an inserted vibrator; after the initial setting of the concrete, the upper surface of the concrete is roughened;

[0016] (9) The components formed after pouring are covered with electric heating blankets for curing, and humidification equipment is installed to humidify the components during curing. At the same time, the temperature difference between the humidification water temperature and the component surface temperature is always kept below 1°C;

[0017] (10) Prestressing tendons release;

[0018] (11) Remove the end mold and lift the component out of the mold;

[0019] (12) Finished product inspection: check whether the components have quality defects and measure the dimensions of the components. After passing the inspection, a QR code identification card is affixed; unqualified finished products are repaired and then a QR code identification card is affixed;

[0020] (13) Storage.

[0021] Preferably, the mold cleaning in step (1) comprises the following steps:

[0022] a. Use a putty knife to remove the residue on the mold surface, and then use an angle grinder with a torque wire wheel or a handheld wire brush to clean the small concrete residue on the template surface;

[0023] b. Use a putty knife to clean the concrete residue on the wooden formwork, and tap it with a small hammer to vibrate the concrete off;

[0024] c. Collect the cleaned waste residues and waste materials in the garbage dumping area.

[0025] Preferably, during the mold assembly in step (1), the mold side mold and the end mold are assembled according to the drawing direction, and the dimensions are reviewed to ensure that the dimensional deviation is within the allowable range.

[0026] Preferably, applying the release agent in step (1) comprises the following steps:

[0027] a. Mix the release agent according to the instructions;

[0028] b. Use a spray pot to evenly spray the release agent to all parts of the mold;

[0029] c. Use a clean mop to evenly apply the release agent;

[0030] d. Cover and protect after painting.

[0031] Preferably, the manufacturing process of the steel skeleton in step (3) is as follows:

[0032] a. After the steel bars are accepted at the site, they are straightened by mechanical and manual methods;

[0033] b. After reviewing the drawing, cut the steel bars according to the size required by the drawing or the length adjusted by the technical department;

[0034] c. After cutting, the semi-finished steel bars are stored in piles according to brand specifications and marked, and are also protected from water and oil pollution;

[0035] d. The semi-finished steel bars are assembled into a fixed frame using end molds for binding.

[0036] Preferably, in step (4), the embedded parts are embedded wire boxes, round tubes, and first-level joint steel bars; and the tooling is positioned square tubes and thin steel bars.

[0037] Preferably, in step (8), the concrete is subjected to raw material inspection, laboratory mix ratio verification, mixing at a mixing station and slump detection before being used for mold casting, wherein the slump of the concrete is controlled at 200-220 mm; and the concrete is sampled, and the sampled test blocks are subjected to a compressive strength test during the prestressed tendon tensioning process.

[0038] Preferably, before pouring the concrete, masking paper is covered on the steel pipes of the steel pipe truss.

[0039] Preferably, the curing in step (9) comprises the following steps:

[0040] a. The component is stopped for 1-4 hours;

[0041] b. Heating, and the heating rate is controlled at 10-20℃ / h;

[0042] c. Maintain at constant temperature for 4-8 hours, and the maximum temperature should be ≤65℃;

[0043] d. Cool down, and the cooling rate is controlled at 10-20℃ / h;

[0044] e. Turn on the electric heating blanket after the temperature difference between the component and the outside of the electric heating blanket does not exceed 20°C.

[0045] Preferably, the finished product repair in step (12) includes exposed reinforcement repair, surface unevenness repair, vibration leakage repair, honeycomb repair, pockmarked surface repair, crack repair, bubble repair, slurry leakage repair, color difference repair, corner chipping repair, bruise repair, flash repair, burr repair and local fracture repair.

[0046] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0047] The positive and progressive effects of the present invention are:

[0048] The above-mentioned prestressed middle plate production process for subway stations adopts electric heating to cover for maintenance to avoid direct exposure to strong light. At the same time, the covering effect can reduce evaporation, and humidification equipment is provided to further ensure the humidity of the components. At the same time, the water temperature of the humidification sprinkler is adjusted synchronously with the maintenance temperature of the components. The water temperature and the components always maintain a low temperature difference to avoid shrinkage and cracking caused by excessive temperature difference; by adding a finished product repair process, in the case that the prestressed middle plate finished product has defects, it can be repaired to avoid the outflow of defective finished products, so that the overall production quality can be controlled; at the same time, the release agent is cleaned before being applied, and protection is provided after application to avoid debris from entering and contaminating the release agent, thereby ensuring the demolding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The present invention is a flow chart of a production process of a prestressed middle plate for a subway station. DETAILED DESCRIPTION

[0050] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0051] Embodiment 1

[0052] like Figure 1 As shown, a production process of a prestressed middle plate for a subway station comprises the following steps:

[0053] (1) After the mold is inspected and accepted, it is cleaned and assembled, and the mold release agent is applied, and then it is protected;

[0054] (2) Install the embedded chute;

[0055] (3) Lift the steel bar skeleton and place it in the mold;

[0056] (4) Position and place embedded parts, and use tooling to fix the embedded parts;

[0057] (5) Grouting the steel tube truss and placing the steel tube truss 48 hours after grouting;

[0058] (6) Cut the prestressed tendons into the corresponding length, and then place the prestressed tendons and the opening reinforcement bars at the corresponding openings of the end mold;

[0059] (7) Install connectors at the ends of prestressed tendons, connect them to the spiral tie rods, adjust the position of the jacks, and then perform pre-tensioning and secondary tensioning;

[0060] (8) Concrete is poured into the mold and compacted by vibrating with an inserted vibrator; after the initial setting of the concrete, the upper surface of the concrete is roughened;

[0061] (9) The components formed after pouring are covered with electric heating blankets for curing, and humidification equipment is installed to humidify the components during curing. At the same time, the temperature difference between the humidification water temperature and the component surface temperature is always kept below 1°C;

[0062] (10) Prestressing tendons release;

[0063] (11) Remove the end mold and lift the component out of the mold;

[0064] (12) Finished product inspection: check whether the components have quality defects and measure the dimensions of the components. After passing the inspection, a QR code identification card is affixed; unqualified finished products are repaired and then a QR code identification card is affixed;

[0065] (13) Storage.

[0066] The mold cleaning in step (1) comprises the following steps:

[0067] a. Use a putty knife to remove the residue on the mold surface, and then use an angle grinder with a torque wire wheel or a handheld wire brush to clean the small concrete residue on the template surface;

[0068] b. Use a putty knife to clean the concrete residue on the wooden formwork, and tap it with a small hammer to vibrate the concrete off;

[0069] c. Collect the cleaned waste residues and waste materials in the garbage dumping area.

[0070] During the mold assembly in step (1), the mold side mold and the end mold are assembled according to the drawing direction, and the dimensions are checked to ensure that the dimensional deviation is within the allowable range.

[0071] The step (1) of applying the release agent comprises the following steps:

[0072] a. Mix the release agent according to the instructions;

[0073] b. Use a spray pot to evenly spray the release agent to all parts of the mold;

[0074] c. Use a clean mop to evenly apply the release agent;

[0075] d. Cover and protect after painting.

[0076] The manufacturing process of the steel frame in step (3) is as follows:

[0077] a. After the steel bars are accepted at the site, they are straightened by mechanical and manual methods;

[0078] b. After reviewing the drawing, cut the steel bars according to the size required by the drawing or the length adjusted by the technical department;

[0079] c. After cutting, the semi-finished steel bars are stored in piles according to brand specifications and marked, and are also protected from water and oil pollution;

[0080] d. The semi-finished steel bars are assembled into a fixed frame using end molds for binding.

[0081] In the step (4), the embedded parts include embedded wire boxes, round tubes, and first-level joint steel bars; and the tooling includes positioning square tubes and thin steel bars.

[0082] In the step (8), the concrete is subjected to raw material inspection, laboratory mix ratio verification, mixing at a mixing station, and slump detection before being used for mold casting, wherein the slump of the concrete is controlled at 200-220 mm; and the concrete is sampled, and the compressive strength test of the sampled test blocks is performed under the prestressed tendon tensioning process.

[0083] Before the concrete is poured, masking paper is covered on the steel pipe truss steel pipe.

[0084] The curing in step (9) comprises the following steps:

[0085] a. The component is stationary for 4 hours;

[0086] b. Heating, and the heating rate is controlled at 10°C / h;

[0087] c. Maintain at constant temperature for 8 hours, and the maximum temperature shall be ≤65℃;

[0088] d. Cool down, and the cooling rate is controlled at 10℃ / h;

[0089] e. Turn on the electric heating blanket after the temperature difference between the component and the outside of the electric heating blanket does not exceed 20°C.

[0090] The finished product repair in step (12) includes exposed reinforcement repair, surface unevenness repair, vibration leakage repair, honeycomb repair, pockmarked surface repair, crack repair, bubble repair, slurry leakage repair, color difference repair, corner loss repair, bruise repair, flash repair, burr repair and local fracture repair.

[0091] The above-mentioned embodiment is suitable for the production of prestressed middle plates in a low temperature environment in winter.

[0092] Embodiment 2

[0093] like Figure 1 As shown, a production process of a prestressed middle plate for a subway station comprises the following steps:

[0094] (1) After the mold is inspected and accepted, it is cleaned and assembled, and the mold release agent is applied, and then it is protected;

[0095] (2) Install the embedded chute;

[0096] (3) Hoist the steel bar cage and place it in the mold.

[0097] (4) Locate and place the embedded parts, and fix the embedded parts using tooling.

[0098] (5) Grout the steel pipe truss, and place the steel pipe truss 48 hours after grouting.

[0099] (6) Cut the prestressed tendons into corresponding lengths, and then place the prestressed tendons and the opening reinforcement bars at the corresponding openings of the end mold.

[0100] (7) Install a coupler at the end of the prestressed tendon, connect it to the spiral tie rod, adjust the position of the jack, and then perform pre-tensioning and secondary tensioning.

[0101] (8) Pour the concrete into the mold and vibrate it thoroughly with an insertion vibrator; after the concrete begins to set, roughen the upper surface of the concrete.

[0102] (9) Cover the formed component with an electric heating blanket for curing, and set up a humidifying device to humidify the component during curing. At the same time, the temperature difference between the humidifying water temperature and the surface of the component should always be kept below 1°C.

[0103] (10) Relax the prestressed tendons.

[0104] (11) Remove the end mold and hoist the component out of the mold.

[0105] (12) Conduct final inspection on the finished product, check whether there are any quality defects in the component, and measure the dimensions of the component. After passing the inspection, paste a QR code identification card; for unqualified finished products, repair them and then paste a QR code identification card.

[0106] (13) Store in the warehouse.

[0107] The mold cleaning in step (1) includes the following steps:

[0108] a. Use a putty knife to remove the residues on the surface of the mold, and then use an angle grinder with a torsion wire wheel or a hand-held wire brush to clean the small concrete residues on the surface of the formwork.

[0109] b. Use a putty knife to clean the concrete residues on the wooden formwork, and gently tap with a small hammer to make the concrete fall off.

[0110] c. Collect the waste residues and waste materials cleaned up to the garbage stacking area.

[0111] When assembling the mold in step (1), the side mold and the end mold of the mold are assembled according to the drawing direction, and the dimensions are rechecked to ensure that the dimensional deviation is within the allowable range.

[0112] The application of the mold release agent in step (1) includes the following steps:

[0113] a. Mix the mold release agent according to the instruction manual;

[0114] b. Evenly spray the mold release agent onto all parts of the mold through a sprayer;

[0115] c. Evenly brush the mold release agent with a clean mop;

[0116] d. Carry out covering protection after brushing.

[0117] The manufacturing process of the steel bar framework in step (3) is as follows:

[0118] a. After the steel bars pass the on-site acceptance, straighten them by mechanical means in cooperation with manual labor;

[0119] b. After reviewing the drawings, cut the steel bars according to the dimensions required by the drawings or the length adjusted by the technical department;

[0120] c. Stack the semi-finished steel bars after cutting according to the brand and specification, make marks, and at the same time carry out waterproof and anti-oil pollution protection;

[0121] d. Assemble the semi-finished steel bars into a fixed frame using the end mold and tie them up.

[0122] In step (4), the embedded parts adopt embedded wire boxes, round pipes, and grade-1 joint steel bars; the tooling adopts positioning square pipes and thin steel bars.

[0123] In step (8), after the raw materials of the concrete are inspected, the laboratory mix ratio is verified, the mixing station discharges materials for mixing, and the slump is detected, it is supplied for mold pouring. Among them, the slump of the concrete is controlled at 200 - 220 mm; and the concrete is sampled, and under the prestressed tendon relaxation process, the compressive strength test is carried out on the sampled test blocks.

[0124] Before the concrete pouring, cover the steel pipes of the steel pipe truss with masking paper.

[0125] The curing in step (9) includes the following steps:

[0126] a. The component is statically stopped for 1 h;

[0127] b. Heat up, and the heating rate is controlled at 20 °C / h;

[0128] c. Keep the temperature constant for 4 h, and the maximum temperature ≤ 65 °C;

[0129] d. Cool down, and the cooling rate is controlled at 20 °C / h;

[0130] e. After the temperature difference between the component and the electric heating blanket does not exceed 20 °C, open the electric heating blanket.

[0131] The finished product repair in step (12) includes exposed reinforcement repair, surface unevenness repair, vibration leakage repair, honeycomb repair, pockmarked surface repair, crack repair, bubble repair, slurry leakage repair, color difference repair, corner loss repair, bruise repair, flash repair, burr repair and local fracture repair.

[0132] The above-mentioned embodiment is suitable for producing prestressed middle plates in a high temperature environment in summer.

[0133] During the specific implementation, during the exposed steel bar repair process, an angle grinder is installed with a cutting disc to cut off the excess exposed steel bar so that the steel bar is 3-5mm lower than the concrete surface after cutting. Then it is repaired with repair material and smoothed with sandpaper.

[0134] During the repair process of uneven surface, use an angle grinder with a diamond grinding wheel to grind off the protruding parts.

[0135] During the repair process of leakage and honeycomb, first use a hand hammer and iron chisel to remove the stones and residues that have not been compacted, then fill the uncompacted part with mortar of the same proportion, and press it flat with sand and iron trowel. The repair should be 1-3mm lower than the surface of the component, and then repair with repair material and polish.

[0136] In the process of roughness, cracks, bubbles and slurry leakage, the damaged parts are covered and scraped flat with repair material, and then polished smooth with sandpaper.

[0137] During the color difference repair process, use 500-600 mesh fine sandpaper to polish the parts with bad color difference on the surface. Be careful not to polish too hard to avoid sanding.

[0138] During the process of repairing chipped corners and bumps, moisten with cement slurry, then use mortar to make it smooth. The repair should be 1-3mm lower than the surface of the component, and the surface should be treated and polished with repair material.

[0139] During the repair process of flash and burrs, use a hand hammer to knock them inward from the flat surface, grind the protrusions at the damaged edges and corners with a diamond grinding wheel, and repair the concave ones with repair material and then polish them with sandpaper.

[0140] During the repair process of local fractures and severe damage, all the broken and damaged concrete parts are smashed, and the parts with steel bars are re-tied and installed for correction. Then, the formwork is supported and the concrete is poured and vibrated to make it dense. After the concrete has initially set, the formwork is removed and the construction joints between the newly poured concrete and the original concrete are smoothed with diamond grinding wheels or sandpaper.

[0141] The present invention is not limited to the above embodiments. No matter what changes are made in its shape or structure, they all fall within the protection scope of the present invention. The protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A production process for prestressed middle slabs of subway stations, characterized in that, The production process of the prestressed middle slab of a subway station includes the following steps: (1) After the molds are inspected and accepted upon arrival, they are cleaned, assembled, and a release agent is applied. After applying the release agent, protection is carried out. (2) Install the embedded chutes. (3) Hoist the steel bar cage and place it inside the mold. (4) Position and place the embedded parts and fix the embedded parts using tooling. (5) Grout the steel pipe truss, and place the steel pipe truss 48 hours after grouting. (6) Cut the prestressed tendons into corresponding lengths, and then place the prestressed tendons and the opening reinforcement bars at the corresponding openings of the end mold. (7) Install a coupler at the end of the prestressed tendon, connect it to the spiral tie rod, adjust the position of the jack, and then perform pre-tensioning and secondary tensioning. (8) Pour the concrete into the mold and vibrate it thoroughly with an inserted vibrator; after the concrete begins to set, roughen the upper surface of the concrete. (9) The formed components after pouring are cured by covering with electric heating blankets, and humidifying equipment is set up to humidify the components during curing. At the same time, the temperature difference between the humidifying water temperature and the surface of the components is always kept below 1°C. (10) Relax the prestressed tendons. (11) Remove the end mold and hoist the components out of the mold. (12) Conduct finished product inspection, check whether there are quality defects in the components, and measure the dimensions of the components. After passing the inspection, paste a QR code identification card; for unqualified finished products, repair them and then paste a QR code identification card. (13) Store in the warehouse.

2. The production process of the prestressed middle slab of a subway station according to claim 1, characterized in that: The mold cleaning in step (1) includes the following steps: a. Use a putty knife to remove the residue on the surface of the mold, and then use a angle grinder with a torsion wire wheel or a hand-held wire brush to clean the small concrete residues on the surface of the formwork. b. Use a putty knife to clean the concrete residues on the wooden mold, and gently tap with a small hammer to make the concrete fall off. c. Concentrate the cleaned waste residues to the garbage stacking area.

3. The production process of the prestressed middle slab of a subway station according to claim 1, characterized in that: When assembling the molds in step (1), the side molds and end molds of the molds are assembled according to the drawing directions, and the dimensions are rechecked to ensure that the dimensional deviations are within the allowable range.

4. The production process of the prestressed middle slab of a subway station according to claim 1, characterized in that: The application of the release agent in step (1) includes the following steps: a. Prepare the release agent according to the instruction manual. b. Evenly spray the release agent onto all parts of the mold through a spray bottle. c. Use a clean mop to evenly apply the release agent. d. Carry out covering protection after application.

5. The production process of the prestressed middle plate of a subway station according to claim 1, characterized in that: The production process of the steel bar cage in step (3) is as follows: a. After the steel bars are inspected and accepted upon arrival, they are straightened by mechanical means in cooperation with manual labor. b. After reviewing the drawings, cut the steel bars according to the dimensions required by the drawings or the lengths adjusted by the technical department. c. The cut semi-finished steel bars are stacked separately according to the brand specifications and marked, and at the same time, waterproof and anti-oil pollution protection is carried out. d. The semi-finished steel bars are assembled into a fixed frame using the end mold for binding.

6. The production process of a prestressed middle slab of a subway station according to claim 1, characterized in that: In step (4), the embedded parts use embedded wire boxes, round pipes, and grade 1 joint steel bars; the tooling uses positioning square pipes and thin steel bars.

7. The production process of the prestressed middle slab of a subway station according to claim 1, characterized in that: In step (8), after the raw materials of the concrete are inspected, the laboratory mix ratio is verified, the mixing plant discharges and mixes, and the slump is detected, it is supplied for pouring into the mold. Among them, the slump of the concrete is controlled at 200 - 220 mm; and the concrete is sampled, and under the process of relaxing the prestressed tendons, the compressive strength test is carried out on the sampled test blocks.

8. The production process of the prestressed middle slab of a subway station according to claim 1, characterized in that: Before the concrete pouring, masking paper is covered on the steel pipes of the steel pipe truss.

9. The production process of the prestressed middle slab of a subway station according to claim 1, characterized in that: The curing in step (9) includes the following steps: a. The component stands still for 1 - 4 h; b. The temperature is raised, and the heating rate is controlled at 10 - 20 °C / h; c. The component is cured at a constant temperature for 4 - 8 h, and the maximum temperature ≤ 65 °C; d. The temperature is lowered, and the cooling rate is controlled at 10 - 20 °C / h; e. After the temperature difference between the component and the electric heating blanket does not exceed 20 °C, the electric heating blanket is opened.

10. The production process of the prestressed middle slab of a subway station according to claim 1, characterized in that: The finished product repair in step (12) includes exposed reinforcement repair, surface unevenness repair, vibration leakage repair, honeycomb repair, pitted surface repair, crack repair, air bubble repair, grout leakage repair, color difference repair, corner chipping repair, impact repair, flash repair, burr repair, and local fracture repair.

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