Formwork of slabs: instructions for calculation and manufacturing

Construction formwork is used not only for the erection of foundations, concrete walls or collectors. It is successfully used for reinforced concrete floors of various thicknesses and purposes. Monolithic ceilings are well proven in terms of strength, reliability and economy. In those cases where it is not possible to install a finished slab plate on a box of capital walls, a monolithic overlap is made in place by the filling method. The ceiling for the lower room will be the base of the ceiling, and for the upper base of the floor.

To create a strong reinforced monolithic ceiling made of reinforced concrete, a profile formwork is required. Before starting work on the construction of the formwork of slabs, calculations of dimensions and material procurement are carried out. During the preparation of drawings, the communication openings for plumbing and heating pipes and power supply routes are taken into account. Arrangement of the formwork of the floors requires scrupulous compliance with the technology at all stages, from the installation of the formwork to the pouring and drying of the concrete. From this depends the final result and qualitative characteristics of the overlap.

Tools and materials for arrangement of formwork

Formwork for monolithic floors is made collapsible or non-removable. For any of them you need a certain set of materials. The quantity, dimensions and volumes are determined based on the drawing of the overlapping surface.

1. For the foundation of the formwork, it will require a waterproof plywood with a thickness of at least 2 cm, corrugated board or OSB sheets with waterproof impregnation. Telescopic support posts with threaded or pneumatic lifting system. Sometimes you use conventional car jacks or blind, uncontrolled supports.
2. Metal, wooden or reinforced concrete floor beams. Their parameters are determined by the area of ​​the overlapping space. On the profile is used beams formwork I-beam, channel or other configuration.
3. Reinforcement of concrete floor is made by steel reinforcement with a diameter of 8 - 10 mm, for fixing a binding wire or a welded seam is used.
4. High-strength cement 400 or 500, sand, gravel and high-volume concrete mixer are required. During the work you will need a usual set of construction tools: shovel, trowel, kirochka, turbo-grinding machine, spirit level, etc.

Calculation of the

formwork racks The formwork is calculated taking into account the height of the room and the thickness of the reinforced concrete overlay. The exact dimensions of the space to be installed will allow correctly distributing the loads along the plane and distributing the supporting elements in accordance with the technological requirements.

1. Supports are standard sizes from 1.7 to 4.5 meters. At installation from calculation 1 a rack on 1 м.кв.- evenly distributed loads, and provides the required margin of safety. With a thickness of 40 cm overlap, the load on the rack will be 1500 - 2000 kg, which meets the technological requirements.
2. Stability of racks for the formwork of overlap is provided with tripods, which are equipped with each rack individually. The upper part is equipped with unilocks, and for sliding telescopic racks, jacks are provided.
3. The estimated length of beams fastened by univilks is 3.5 linear meters per 1 square meter. The plywood sheets have dimensions of 1220x 2440 mm and to determine the required quantity, the area of ​​the overlapping space is divided by the area of ​​the plywood sheet.
4. When monolithic overlapping at a level of more than 4.5 meters, the racks are equipped with binding horizontal bolts. Two types of bolt connections - wedge or cup / lock, ensure the stability of the structure.

Mounting of non-removable formwork of monolithic floors

The optimal option for pouring concrete is a fixed formwork of ceilings. Such a design is distinguished by reliable joining of walls and overlapping. The reinforcing bars and the joists lie directly on the capital walls and provide the necessary rigidity of the structure.

1. Walls of plywood or other material that will serve as the bottom of the formwork and beams are laid on the walls. For beams, a channel, an I-beam, wooden logs or concrete poles are used and they are fixed tightly to the walls by bolts or staples. Underneath are the support racks of the unilovels which abut against the girder ceilings. On the perimeter of the capital walls laid, for example, in three bricks, a half-brick edge is erected.
2. The space is covered by longitudinal and transverse reinforcement. At the points of intersection, the reinforcement is seized by welding or binding wire. The ends of the reinforcement must go to the plane of the main wall and abut the edge. Then the next layer is laid out in half a brick and is alternated by reinforcement from the reinforcement and so on until the design thickness of the monolithic overlap is reached.

Concrete is poured at a time and is leveled by the Rakley. Raklya is a device similar to a mop. Depending on weather conditions, the concrete is covered with a film from rain or humidified in hot weather for uniform drying. It takes at least a month to completely dry the floor.