Construction method for preventing open web and open web sound of support plate

Abstract

The invention relates to the technical field of railway simply supported beam prefabrication, and discloses a construction method for preventing support plate empty web and empty web sound. Comprising the following steps: S1, pouring a high-performance acrylate structure adhesive or an epoxy resin mixture into a brushing area of the support embedded plate, and uniformly brushing with a scraper; s2, after brushing of the support plate is completed, gravel is evenly scattered on the support plate, and then steel bars with the length equal to the width of the support plate are placed in the long edge direction of the support plate; s3, a high-frequency vibrator is installed on the lower portion of the bottom die of each support plate to assist in vibrating concrete, and the distance between steel bars at the support plates is properly adjusted; and S4, when box girder concrete is poured, a phi 30 vibrating spear is used for directly conducting insertion vibration on the upper portion of the support steel plate from the inner mold hole opening position. According to the method, the adhesive is used for brushing the pre-buried support steel plate, the fine aggregate is pasted, the distance between the reinforcing steel bars above the support plate is properly adjusted, the window is formed above the support for vibration, and meanwhile auxiliary vibration is conducted below the support, so that the empty sound problem of the pre-buried support plate is effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of railway simply supported beam prefabrication, in particular to a construction method for preventing support plates from becoming hollow and causing hollow sound. Background Art

[0002] During the construction of post-tensioned prestressed concrete simply supported box girders (prefabricated box girders) for high-speed railways, it is usually necessary to embed the bearing plate first, install the bridge bearing on the bearing plate of the prefabricated beam, and then fix it to the pad stone by the bearing anchor bolts through the anchor bolt holes on the pad stone by grouting or other methods. In order to ensure the stability of the bearing plate, the traditional construction method requires the installation of reinforcing steel bars above the bearing plate, but this will prevent the vibrator from being inserted above the bearing plate, resulting in insufficient vibration of the concrete on its surface. The bearing steel plate and the concrete have different shrinkage and expansion coefficients, and the shrinkage and expansion are not synchronized, resulting in a tiny gap between the concrete and the bearing steel plate, causing the pre-embedded bearing plate to produce hollow sound.

[0003] The deadweight, second-phase dead load and operational load of the precast beam are all transmitted to the pier through the supports. If there are hollows at the support plates, when the support plates are loaded, sudden or creeping indentations may occur at the supports, which will adversely affect the stability of the beam itself. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention solves the technical problems by adopting a technical solution: a construction method for preventing the hollowing of a support plate and hollowing sound, comprising the following steps:

[0005] S1. Wipe the oil, dust, etc. on the installed bearing embedded steel plate with a dry cotton cloth, pour high-performance acrylic structural adhesive or epoxy resin mixture into the bearing embedded plate painting area, and apply it evenly with a scraper;

[0006] S2. Use the same crushed stone as the beam body. After the bearing plate is painted, evenly spread the crushed stone on it. Then, place steel bars with a diameter of 12mm to 16mm, which is the same length as the plate width, along the long side of the bearing plate. The steel bars are close to the anchor bars of the 5 rows of bearing plates in the middle. After the crushed stone is spread, cover the top of the bearing embedded steel plate with dry and clean geotextile or plastic film and let it stand for 30 minutes until the coating solidifies and the crushed stone is tightly bonded.

[0007] S3. Install a high-frequency vibrator under the bottom formwork of each support plate to assist in vibrating the concrete, and properly adjust the spacing of the steel bars at the support plate so that the coarse and fine materials in the concrete can fully fall on the support plate;

[0008] S4. Drill holes at the corresponding positions near the chamfer of the inner mold and the support steel plate. The holes are in the form of hinged doors. After the vibration at the support plate is completed, close the door firmly. When pouring the box girder concrete, use a φ30 vibrating rod to vibrate directly from the hole in the inner mold to the upper part of the support steel plate to ensure the density of the concrete.

[0009] Preferably, in S1, the high-performance acrylic structural adhesive includes glue A and glue B, and the ratio of glue A to glue B is 1:1.

[0010] Preferably, the raw materials of the glue A include the following components in parts by weight: 30-40 parts of methyl methacrylate, 40-50 parts of acrylic acid, 10-20 parts of nitrile rubber, 30-40 parts of phosphorus-containing acrylate emulsion, and 20-30 parts of initiator; the raw materials of the glue B include the following components in parts by weight: 30-40 parts of methyl methacrylate, 20-30 parts of epoxy acrylate, and 10-20 parts of inhibitor.

[0011] Preferably, in S1, the epoxy resin mixture is prepared by taking 1 kg of epoxy resin and then measuring 100 mL of dibutyl ether and 60 mL of ethylenediamine, mixing them together and stirring them evenly. After stirring evenly, it can be used only when there are no bubbles or color difference, and it must be used up within 30 minutes. The mixture is weighed once before and after pouring out to determine the amount.

[0012] Preferably, the amount of mixed material for a single piece of the support embedded steel plate is controlled at 0.3±0.02kg.

[0013] Preferably, in S2, the gravel is first sieved with a 10 mm sieve, and the sieved gravel is sieved with a 5 mm sieve, and the 5 mm to 10 mm gravel on the sieve is taken, rinsed with water, and spread in a ventilated place to dry or dried with a hair dryer.

[0014] Preferably, the area occupied by the crushed stones in S2 is about 80% of the mixed material coating area, and the weight of the stones spread on each embedded support is about 2 kg.

[0015] Preferably, in S3, the slump of the concrete is controlled to be between 180 mm and 200 mm.

[0016] Preferably, the diameter of the opening in S4 is 150 mm.

[0017] Preferably, the specific process of pouring and vibrating is as follows: first, use a φ30mm vibrating rod to induce tamping, and after the concrete covers all the embedded steel bars at the bearing plate, turn on the bottom plate attached vibrator for vibrating. The attached vibrator is turned on intermittently, and the vibration is generally for about 15 seconds. Then continue pouring concrete, and the bridge deck inserted φ50mm vibrating rod, the inner cavity φ30mm vibrating rod and the bottom plate attached vibrator cooperate to vibrate. After the chamfered concrete of the beam body is filled, stop turning on the bottom plate attached vibrator, and insert the vibrating rod above the bearing plate.

[0018] The beneficial effects of the present invention are as follows:

[0019] A series of measures have been taken to address the cause of the hollow sound of the embedded bearing plate due to the defects of traditional construction methods. The use of adhesive to paint the embedded bearing steel plate and paste fine aggregate can prevent the coarse aggregate from being difficult to fall when pouring concrete, resulting in too little stone and too much and thick cement slurry, causing excessive shrinkage of the concrete in this area. The shrinkage and expansion of the bearing steel plate and concrete are synchronized to avoid tiny gaps between the concrete and the bearing steel plate; appropriately adjust the spacing of the reinforcing steel bars above the bearing plate and open a window above the bearing for vibration while performing auxiliary vibration below, so that the concrete on its surface is fully vibrated, effectively improving the hollow sound problem of the embedded bearing plate. DETAILED DESCRIPTION

[0020] The following specific embodiments further illustrate the present invention in detail:

[0021] A construction method for preventing hollowing and hollowing sound of a support plate comprises the following steps:

[0022] S1. Wipe the oil, dust, etc. on the installed bearing embedded steel plate with a dry cotton cloth, pour high-performance acrylic structural adhesive or epoxy resin mixture into the bearing embedded plate painting area, and apply it evenly with a scraper;

[0023] S2. Use the same crushed stone as the beam body. After the bearing plate is painted, evenly spread the crushed stone on it. Then, place steel bars with a diameter of 12mm to 16mm, which is equal to the width of the plate, along the long side of the bearing plate. The steel bars are close to the anchor bars of the 5 rows of bearing plates in the middle. After the crushed stone is spread, cover the top of the bearing embedded steel plate with dry and clean geotextile or plastic film and let it stand for 30 minutes. Do not touch the stones at will during the standing process. Wait until the coating solidifies and the crushed stone is tightly bonded;

[0024] S3. Install a high-frequency vibrator under the bottom formwork of each support plate to assist in vibrating the concrete to ensure that the concrete is tightly bonded to the support steel plate, and properly adjust the spacing between the steel bars at the support plate so that the coarse and fine materials in the concrete can fully fall on the support plate;

[0025] S4. Drill holes (diameter of the holes is 150mm) at the corresponding positions near the chamfer of the inner mold and the support steel plate. The holes are in the form of hinged doors. After the vibration at the support plate is completed, close the door firmly. When pouring the box girder concrete, use a φ30 vibrating rod to vibrate directly from the hole of the inner mold to the upper part of the support steel plate to ensure the density of the concrete.

[0026] In S1, the high-performance acrylic structural adhesive includes glue A and glue B, the ratio of glue A to glue B is 1:1, wherein the raw materials of glue A include the following components in parts by weight: 30-40 parts of methyl methacrylate, 40-50 parts of acrylic acid, 10-20 parts of nitrile rubber, 30-40 parts of phosphorus-containing acrylic emulsion, and 20-30 parts of initiator; the raw materials of glue B include the following components in parts by weight: 30-40 parts of methyl methacrylate, 20-30 parts of epoxy acrylate, and 10-20 parts of inhibitor; methyl methacrylate, butyl acrylate, and acrylic acid are mixed uniformly to obtain drops, wherein the weight ratio of methyl methacrylate, butyl acrylate, and acrylic acid is 1:1:0.02, methacrylate-based alkoxy phosphate and emulsifier are added to water, stirred uniformly, and obtained. to a mother liquor, and dropwise adding the dropwise liquid into the mother liquor, stirring and dispersing for 20 minutes to obtain a pre-liquid, wherein the mass fraction of methacrylate-based alkoxy phosphate in the mother liquor is 3wt%, the mass fraction of the emulsifier is 2wt%, and the emulsifier comprises a mixture of sodium dodecylbenzene sulfonate and polyoxyethylene ether, and the weight ratio of sodium dodecylbenzene sulfonate to polyoxyethylene ether is 2:1; the buffer is added into water to obtain a buffer solution, wherein the buffer is sodium bicarbonate, and the mass fraction of sodium bicarbonate is 6wt%; potassium persulfate is added into water to obtain an initiator aqueous solution, wherein the weight of potassium persulfate is 0.6% of the total weight of methyl methacrylate and butyl acrylate; the pre-liquid and the initiator aqueous solution are dropwise added into the buffer solution at 80°C, and emulsified for 1.5h to obtain a phosphorus-containing acrylate structural adhesive.

[0027] In S1, the epoxy resin mixture is prepared by taking 1 kg of epoxy resin and then measuring 100 mL of dibutyl ether and 60 mL of ethylenediamine, mixing them together and stirring them evenly. It can be used only when there are no bubbles or color differences after stirring evenly, and it must be used up within 30 minutes. The mixture is weighed once before and after pouring out to determine the amount. The amount of mixture for a single support embedded steel plate is controlled at 0.3±0.02 kg.

[0028] In S2, the crushed stone is first sieved with a 10mm sieve, and then sieved with a 5mm sieve. The 5mm to 10mm crushed stone on the sieve is taken, and then rinsed with water and spread in a ventilated place to dry or dried with a hair dryer; the area occupied by the crushed stone is about 80% of the mixture coating area, and the weight of the stone spread on each embedded support is about 2kg.

[0029] In S3, the slump of concrete is controlled at 180mm to 200mm, and the mixing quality of concrete is enhanced so that it can fill the smaller gaps between steel bars and increase bonding strength.

[0030] In S4, the specific process of pouring and vibrating is as follows: the bearing plate position is the first place where concrete is poured. First, use a φ30mm vibrator to induce tamping. After the concrete covers all the embedded steel bars at the bearing plate (after reaching 20cm), turn on the bottom plate attached vibrator for vibrating. The attached vibrator is turned on intermittently, and the vibration is generally about 15s. Then continue pouring concrete, and the bridge deck inserted φ50mm vibrator and the inner cavity φ30mm vibrator and the bottom plate attached vibrator cooperate to vibrate. After the chamfered concrete of the beam body is filled, that is, the concrete thickness is about 60mm, stop turning on the bottom plate attached vibrator, and insert the vibrator as far as possible above the bearing plate. Since the steel bars at the bearing plate are dense, it is difficult to estimate whether it is in place due to obstruction during insertion. For this reason, we can mark the vibrator to measure whether the vibrator reaches above the bearing plate.

[0031] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention are implemented according to the conventional means in the field unless otherwise specified and limited.

Claims

1. A construction method for preventing hollowing and hollowing sound of a support plate, characterized in that: The following steps are involved: S1. Wipe the oil, dust, etc. on the installed bearing embedded steel plate with a dry cotton cloth, pour high-performance acrylic structural adhesive or epoxy resin mixture into the bearing embedded plate painting area, and apply it evenly with a scraper; S2. Use the same crushed stone as the beam body. After the bearing plate is painted, evenly spread the crushed stone on it. Then, place steel bars with a diameter of 12mm to 16mm, which is the same length as the plate width, along the long side of the bearing plate. The steel bars are close to the anchor bars of the 5 rows of bearing plates in the middle. After the crushed stone is spread, cover the top of the bearing embedded steel plate with dry and clean geotextile or plastic film and let it stand for 30 minutes until the coating solidifies and the crushed stone is tightly bonded. S3. Install a high-frequency vibrator under the bottom formwork of each support plate to assist in vibrating the concrete, and properly adjust the spacing of the steel bars at the support plate so that the coarse and fine materials in the concrete can fully fall on the support plate; S4. Drill holes at the corresponding positions near the chamfer of the inner mold and the support steel plate. The holes are in the form of hinged doors. After the vibration at the support plate is completed, close the door firmly. When pouring the box girder concrete, use a φ30 vibrating rod to vibrate directly from the hole in the inner mold to the upper part of the support steel plate to ensure the density of the concrete.

2. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 1, characterized in that: In S1, the high-performance acrylic structural adhesive includes adhesive A and adhesive B, and the ratio of adhesive A to adhesive B is 1:

1.

3. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 2, characterized in that: The raw materials of the A glue include the following components in parts by weight: 30-40 parts of methyl methacrylate, 40-50 parts of acrylic acid, 10-20 parts of nitrile rubber, 30-40 parts of phosphorus-containing acrylate emulsion, and 20-30 parts of initiator; the raw materials of the B glue include the following components in parts by weight: 30-40 parts of methyl methacrylate, 20-30 parts of epoxy acrylate, and 10-20 parts of inhibitor.

4. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 1, characterized in that: In S1, the epoxy resin mixture is prepared by taking 1 kg of epoxy resin, measuring 100 mL of dibutyl ether and 60 mL of ethylenediamine, mixing them together, and quickly stirring them evenly. After stirring evenly, it can be used only when there are no bubbles or color differences, and it must be used up within 30 minutes. The mixture is weighed once before and after pouring it out to determine the amount.

5. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 4, characterized in that: The amount of mixed material for a single piece of the support embedded steel plate is controlled at 0.3±0.02kg.

6. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 1, characterized in that: In S2, the crushed stones are first sieved with a 10 mm sieve, and the sieved crushed stones are sieved with a 5 mm sieve, and the 5 mm to 10 mm crushed stones on the sieve are taken, rinsed with water, and spread in a ventilated place to dry or dried with a hair dryer.

7. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 1, characterized in that: The area occupied by the crushed stones in S2 is about 80% of the mixed material coating area, and the weight of the stones spread on each embedded support is about 2kg.

8. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 1, characterized in that: In S3, the slump of the concrete is controlled to be between 180 mm and 200 mm.

9. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 1, characterized in that: The diameter of the opening in S4 is 150 mm.

10. A construction method for preventing hollowing and hollowing sound of a support plate according to claim 9, characterized in that: The specific process of pouring and vibrating is as follows: first, use a φ30mm vibrating rod to induce tamping. After the concrete covers all the embedded steel bars at the bearing plate, turn on the bottom plate attached vibrator for vibrating. The attached vibrator is turned on intermittently, and the vibration is generally for about 15 seconds. Then continue pouring concrete, and the bridge deck inserted φ50mm vibrating rod, the inner cavity φ30mm vibrating rod and the bottom plate attached vibrator cooperate to vibrate. After the chamfered concrete of the beam body is filled, stop turning on the bottom plate attached vibrator and insert the vibrating rod above the bearing plate.