The foundation foundation performs the critical tasks of receiving and distributing the load coming from the building frame. In most cases, a concrete pillow is used for the bearing part, which, in various configurations, is arranged on the work site. But such a foundation itself is unreliable, and foundation reinforcement with special rods is used as additional reinforcement. Metal rods fasten the concrete slab, endowing it with high strength and resistance to natural destructive processes. Accordingly, the reliability of the building as a whole will depend on the quality of reinforcement, therefore, during installation activities it is important to follow the technical instructions.
Required Tools and Materials
The foundation itself is made of cement of the M250 brand, sometimes with the addition of crushed stone, and the medium sand will be the basis. Work operations may require the use of an angle grinder, shovel and pliers. Mostly the tool will be used in the processing of the reinforcement itself.
For the preparation of cement, a container, an electric mixer and a construction sieve will also be required. Particular attention is paid to the selection of rods. In capital construction, steel rods with a smooth or corrugated surface are used. So, the reinforcement of the foundation of a multi-storey building is carried out by smooth rods, and for cottages they use sickle-shaped rods. A universal option for low-rise construction will be reinforcement with a discontinuous ribbed surface. This option is advantageous in that it provides a good hitch regardless of the type of concrete base and the design of the carrier pillow.
Preparing for work
The work site is freed from unnecessary building materials, equipment and consumables. At this stage, it is important to prepare and clear the zone for the future foundation foundation pouring. If you plan to use a power tool, an energy supply system should be provided. Alternatively, a battery pack that does not require a direct network connection may be suitable. In order for the reinforcement of the foundation with reinforcement to be better and more durable, it is necessary to initially degrease and dry the surfaces of the rods. There should be no foreign particles or exfoliating coatings on them. Elements with corrosive damage should be eliminated and replaced with new clean fittings.
Foundation reinforcement calculation
At this stage, the number of rods that will be used during the strengthening of the structure is determined. But before that, several requirements for the frame parameters should be taken into account:
- The square cell of the reinforcement mesh should have a size of 20 to 30 cm.
- If the length of the section is exceeded 3 m, the diameter of the rods should be at least 12 mm.
- Cross rods are selected with the expectation that their length will be 100 mm shorter than the shuttering width. This is necessary to ensure free filling along the edges.
- If the height of the frame exceeds 80 cm, then the diameter of the transverse reinforcement should be at least 8 mm.
- Overlap nodes do a runaway that will increase the reliability of fasteners.
The calculation of the number of rods is made based on the grid pitch, the number of tiers, the length of the rods and the actual linear meters at the construction site. For a visual representation of the optimal reinforcement of the foundation, it is desirable to draw up a plan and diagram. A concrete calculation example for a tape base can be represented as follows:
- The foundation cross section is 0.4 × 1 m or 4000 cm 2 .
- The reinforced area is 4000 × 0.001 = 4 cm 2 .
- According to the technological recommendations from the regulatory documentation, 8 rods with a diameter of 8 mm are obtained.
- For ease of placement, you can choose half of the rods with a tolerance of up to 12 mm.
Installation of rods in a monolithic foundation
This type of carrier base assumes that the loads will be distributed over the entire area. The optimal type of rods is with a corrugated surface with a diameter of 8-14 mm. At the first stage, the draft base is assembled with the formation of the lower level of the grid of rods. Squares are created with sides of 20-30 cm. Vertical posts are also made to strengthen the initial harness belt. For such purposes, a larger diameter rod is used, and the step between the racks is maintained with a distance of up to 40 cm. It is important to consider that reinforcing the foundation slab will require more fastening consumables. Therefore, welding is often used to simplify joining operations. This option of fasteners is less time consuming than strapping, but it can be inferior in terms of reliability - it depends on the type of welding used.
Installation of rods in the strip foundation
In this case, the formwork will be performed linearly along the contours of the construction site. The foundation tapes are about 50 cm thick, so the maximum width of the mesh can be 40 cm. When laying, it is important to withstand 5 cm of space to the wall. To form the frame, lengths of the order of 40-60 cm are made. Vertical rods should be longer, which will allow completing an additional upper strapping without side rods upon completion. Also, the reinforcement of the strip foundation provides for the integration of full rods, capturing the entire length of the box. But even in this case, up to 10 cm of free space to the extreme walls should remain at the ends. At the bottom of the formwork, plastic rod clamps are also installed, which will act as temporary supporting devices. Next, you can start strapping.
Knitting rods
Again, the wire connection can be replaced by welding, but burning metal as such will reduce the quality of the fasteners. The main strapping is performed at the corners of the joints of the wire in the cells of the structure. The laborious reinforcement of a monolithic foundation is preferably performed with a special knitting gun. If the amount of work is small, then the operations are carried out with a crochet hook. This is a special device that allows you to manually make wire connections with a diameter of up to 1.4 mm.
The optimal length of the fastening segments is 40 cm. Previously, they are folded in half, and then they are twisted diagonally in a crosswise manner. The endings are hooked and rotated until a reliable connection is made. If the reinforcement of the strip foundation is carried out, then the so-called rigid foot should also be used as an addition. In such a system, a bend is formed at the end of the rod, capturing another hook from the perpendicular line. Using this fastener, in particular, a styling is formed at the points of abutment of the frame walls to each other.
Clamping
An alternative method of fastening, also used in mixing and fixing critical parts of the frame, experiencing heavy loads. Two types of clamps can be used: L-shaped and P-shaped. In the first case, one side of the element is attached to the wall of the frame, and the second to it, but perpendicularly. The grip length is calculated based on the diameter of the rod. U-shaped devices are used in the reinforcement of foundation plates as a consumable for welding. The clamps are joined to two parallel running rods, closing in the node and one perpendicular line.
Common Reinforcement Errors
Most often, errors are made during settlement operations. Moreover, this concerns initially incorrect data on the construction of the foundation foundation from the point of view of interaction with the soil. For example, seismic activity can ultimately deform a structure assembled using too thin rods. Under such conditions, reinforcing the columnar foundation on which loads are placed pointwise without affecting the tiled array is most advantageous, as is the case with a monolithic platform. A lot of mistakes are made when connecting parts of the frame and individual rods. When using the same wire, it is important to maintain the optimum tightening force so that the assembly does not deform due to internal overload.
Conclusion
To date, the construction industry offers not so many fundamentally new reinforcement methods that can replace traditional technologies. Only innovative glass composite rods are beginning to be widely used, but this option, due to its high price, does not always withstand competition with metal. The experts still consider the tape configuration with a wire harness to be the best option for reinforcing the foundation of a private house. This is a rather laborious way to strengthen the structure, but it is profitable both in financial costs and in the quality of the result. A correctly assembled foundation base with such a strapping of the rods will provide the average building with a high degree of reliability and durability under natural loads.