Bridge deck panel rehabilitation program
Because the bridge has been put into use, so there is a certain degree of difficulty in the construction. According to the actual situation, in order to ensure vehicle traffic, in the construction process only use single width construction single width traffic principle; construction area and traffic area using reflective barrels and reflective tape clear separation, construction personnel are not allowed to move outside the construction area during construction. At 300 meters, 250 meters and 200 meters away from the construction point, obvious warning signs and speed limit signs are placed respectively, and the fixed person is in charge of warning 200 meters away from the construction point; all construction personnel wear reflective clothing, and it is strictly forbidden to laugh and play at work and go out of the isolation zone. Machinery and equipment are parked in an orderly manner, materials are neatly stacked and clearly marked, and are kept away from non-traffic lanes. To ensure the safety of construction and traffic; its layout is shown in Figure 1 below.
Bridge deck refurbishment
Because the bridge deck belongs to the whole plate reinforced concrete structure, in order to ensure the passage of vehicles, in the renovation of the whole block construction by dividing the width.
- Single width correction parts first with a cutting machine will be damaged part and the bridge deck panel longitudinal, transverse cut into a straight line to ensure the straightness of the plate, cutting can not damage the original reinforcement, and do not damage other intact parts. If the original reinforcement is damaged and destroyed during cutting, it should be replaced to ensure the structural integrity of the deck reinforcement.
Breaking using wind or electric impact drill chiseling, chiseling to the original grass-roots position; in the chiseling construction shall not damage the structure of the grass-roots level; chiseling after the use of manual excavation. Construction garbage is piled up and transported away in a unified manner, and shall not intrude into the traffic lane when placed. Because of the breaking construction process to retain the original steel structure, the local fracture and damage to the full lap welding method to complete. Clean up the chiseled parts and flush them with water.
- Concrete pouring
During the concrete pouring, the pouring part can be painted with waterproof adhesive. The concrete is directly adopted from commercial concrete, and the concrete tanker is backed up to the pouring part with a hand truck upon arrival.
After the concrete enters the chiseled area, the concrete is spread out and flattened by hand with a shovel, and is first pounded with an insertion-type concrete vibrator, and then pounded and flattened with a plate-type concrete vibrator. Then the concrete surface is smoothed and calendered with rollers and manual tapping boards. After the concrete has had a certain amount of time, the concrete is then embossed with the original grain to form a standard concrete pavement.
- Concrete maintenance
After the concrete is poured and formed, the maintenance should be strengthened by sending special personnel to sprinkle water and cover with sacks of wet water for maintenance. After 28 days of maintenance, the pavement can be cleaned and another one can be constructed.
- Construction flow
This construction adopts flowing operation, and the construction sequence is as follows: before left line left – after left line left – before right line left – after right line left – before left line right – after left line right – before right line right – after right line right. The sequence ensures both the continuity of construction and the time of concrete maintenance.
All the steel and concrete used are first quality checked and the physical properties of the steel are tested before use.
Each process is inspected by quality inspectors during construction and agreed by the supervisor before the next process is carried out. There are quality inspectors and supervisors present to control the concrete pouring process.
- the traditional practice of large area concrete flooring expansion joints is, after the grass-roots leveling, according to the thickness of the concrete flooring fixed expansion joints grid formwork, and then pouring concrete, after the concrete reaches a certain strength, remove the grid formwork, and finally pour hot asphalt in the joints.
- The disadvantage of this practice is that due to the construction machinery and the construction personnel’s traffic and other reasons, it will cause the deformation and displacement of the grid formwork, so there will be expansion joints are not straight, both sides of the seam mouth is not flat and jagged on both sides of the seam mouth and other phenomena, which affects the quality and appearance of the whole flooring.
- In the process of large area concrete flooring construction in recent years, the traditional construction method has been changed and concrete pavement cutting machine has been used to cut concrete flooring to form expansion joints, which has achieved good results.
The specific construction method is: no expansion joints are left in the concrete flooring construction, and the concrete is poured at one time to smooth and calendering, and then the concrete reaches
after a certain strength, in the flooring according to the design requirements of the location of the expansion joint line, and then use the concrete pavement cutting machine along the line to cut out the expansion joint. Finally, fill in the joints with construction oil paste.
With this method of construction, the expansion joints are straight and beautiful, with the same height and no jaggedness, and also can save part of the labor and wood. This method is simple and easy to use, avoiding the problems of traditional construction methods.
The expansion joints are set in relation to the length of the wall and must be set every 45 meters or more. The width of the expansion joints is set at about 100 mm and the reinforcement and concrete in the expansion joints must be completely disconnected, but the foundation part (floor beams, strip foundation, etc.) does not need to be disconnected. If it is a settlement joint, it has to be disconnected from top to bottom.
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