The construction plan of the laser leveling machine is as follows
Requirements for the base surface: The base surface must be firm, compacted, without settlement, cracking, no oil stains, no plastic film, no other paint, latex paint, bubble gum and other residues on the ground, and the base surface must be flat without large ups and downs, no bumps, honeycombs, or cement lumps.
Partial treatment of the base
1. Rolling of the bare soil, requiring compaction and flatness error of 2~3cm∕2m.
2. Pad construction: Use C15 fine stone concrete to cast a 6 cm thick pad layer, vibrate with a vibration pump, and the surface does not need to be smoothed. The flatness is maintained at 2cm∕2m. (This item is optional)
Construction of the surface layer
1. Ground treatment
After the general contractor and the relevant construction parties have cleared away the large building materials and garbage in the construction area where the 6 cm cushion layer has been laid and handed it over to us, we will first clean up the dust in this area. If there is paint or other foreign matter that is not easy to combine with concrete on the ground, we must do everything we can to remove it. Then rinse the ground with water, and there must be no floating dust. If the base layer is higher in special places, it should be chiseled off with an electric pick or air compressor.
2. Preliminary measurement of elevation
According to the basic elevation points given by the general contractor or Party A, the elevation of representative locations in the entire area is initially measured with a level to see how much the thickness of the concrete differs from the thickness required by the owner. (This measurement should be as many points as possible, otherwise it is not representative). In most cases, since the flatness of the base layer is not well controlled, once the elevation is measured, it can be seen how thick and thin the thick and thin parts and the thickness of most concrete are. If the thickness of most concrete exceeds the contract thickness, or is much lower than the contract thickness, the situation should be reported to the superior truthfully and a solution should be requested before the next step of construction can be carried out.
3. Rebar binding
For the thicker 20cm thick floor poured in this project, according to the design requirements, double-layer bidirectional reinforcement is generally required. The reinforcement arrangement requires Φ12@150*150, and the upper and lower layers are connected by horse stools. The distance between horse stools is 1 meter. The surface layer reinforcement is 3~4 cm away from the floor elevation. In order to prevent the floor from settling, it is recommended to set up an integral continuous steel mesh. Or pour in separate compartments, but use force transfer rods to connect the plates. The force transfer rods can be Φ20@1000 round steel bars, with a spacing of 400.
4. Formwork
1.) According to the elevation confirmed by Party A, the template position is determined according to the floor drain position and water collection well position listed in the drawings and the slope requirements. This project is in an underground garage, and there may be a slope requirement, so the template can use angle irons of different specifications from Ф6.5*6.5*5 to Ф3*3*2 as the template. Use large specifications for thick concrete and small specifications for thin concrete. According to the designed slope, the compartment casting method is adopted.
2.) The leveling of this project needs to be leveled by a laser leveler. The uniform high-frequency vibration of the laser leveler makes the concrete floor dense and avoids the stress concentration caused by deformation and cracking of the floor. When using a laser leveler for leveling, you only need to make the frame template of each piece. When supporting the formwork, first use an ink fountain to pop up the template control line on the base ground. The line is appropriately wider than the edge of the future compartment seam by 1~2 cm, so that after the formwork is removed, the side seam is not straight due to local damage, and it can also be trimmed. If it can be guaranteed that the side seam after each demolding is a straight line, the template can also be directly supported on the natural seam of the future axis.
3.) On the control line, drill holes on the ground with an electric hammer every one meter or so. Generally, a 12×200 drill bit is used, and the penetration depth is about 14 cm.
4.) Nail the steel bars with a diameter of 12 mm cut into 14 cm each section into the drilled holes. It is required to be firmly driven until it can hardly be driven down.
5.) Place the angle iron near the firmly driven steel bars along the line direction. First, use wood or bricks to pad the two ends of the angle iron. The approximate height is about the same as the elevation. Then one person looks at the level, one person holds the tower ruler, and another person uses a wooden wedge to fine-tune the height of the angle iron at any time according to the elevation. After reaching the same elevation, the electric welder spot welds the angle iron to the top of the steel bar. Then weld the other end of the angle iron in the same way. After both ends are welded, weld the middle part of the angle iron. After welding, check the elevation of one side again.
6) Brush the template oil (waste engine oil) on the supported template to facilitate demoulding.
7) After the compartment formwork is supported, the angle irons are welded around the water collection well. The upper end of the angle iron should be consistent with the floor slope of the compartment, and ensure that water is concentrated to the water collection well from multiple directions.
8) The construction method of the angle irons at the edge of the water collection well for the first floor with only floor drains but no water collection well and car ramp is the same as in Article 7.