A preliminary calculation of the loads on the building foundation should be comprehensive. Many mistakenly focus on the static load of the frame, adjusting the base structure for it. But this is only part of the total pressure force that affects the foundation. Dynamic loads and overall ground movements can lead to more sad consequences than minor miscalculations in the supporting racks of the frame. If these nuances were not taken into account during construction, then as part of the scheduled maintenance of the house, it will be necessary to strengthen the foundation in one of the following ways.
How to strengthen the strip foundation?
In private housing construction, a tape carrier is one of the most popular ways of building a foundation. But its design has many vulnerabilities. The basic method of amplification in this case involves the implementation of shotcrete. A trench is digging along the concrete strip laying line, which gives access to the surface of the structure. Then, throughout the entire lower region, rows of notches are made, along which concrete is subsequently sprayed. For this operation, it is necessary to use a heat construction gun.
Another way to increase the durability of the foundation using an adhesion solution is cementation. Unlike the previous method, this technology does not require excavation of the foundation pit. To strengthen the strip foundation with cementation, a special injector unit is used, through which concrete mortar is supplied to problem surfaces through the ground. But first you need to create pits with a depth of 50-100 cm. This technology allows you to fill the cracks and voids of the foundation, increasing the density of the ligament with the adjacent soil.
Pile foundation reinforcement options
It is also a popular version of the supporting structure of the house, which due to technical features gives more room for the implementation of various options for strengthening. In particular, experts recommend the following technologies:
- Girth application. For load-bearing racks, a reinforced concrete ferrule suitable in size is selected, which the rod is captured. For a medium-sized house, it is advisable to use a structure with a thickness of at least 10 cm, which allows for immersion in the ground at 100 cm
- Technology "concrete shirt". In a sense, this approach is similar to the methods described above for tape design. Point reinforcement of the foundation for each pile is realized by pouring the solution into the created wells and trenches.
- Strengthen with additional columns. A more complex operation requiring detailed calculation. Near the existing problem pile, another auxiliary support rod is installed. The pillar insertion technique can be driven or bored.
- Strengthening grillage. Concrete injection by shotcreting. This is not about the part of the foundation immersed in the ground, but rather about the upper tier, where the transition to the lower floor of the house begins.
And in the case of the tape, and with the column design, combined approaches are possible and even recommended to increase the strength of the bearing base.
Features of strengthening tile foundations
Monolithic reinforced concrete construction is the most reliable and durable, but also the most problematic in terms of its strengthening. The difficulty lies in the lack of access to the central zone of the structure, which connects the soil and grillage. The master can only deal with the edges of the structure, preventing the frame from creeping out and the structure to slowly peel off.
The main methods for reinforcing foundations on a monolithic reinforced concrete slab are reduced to creating a prefabricated holder covering the entire perimeter of the structure. In other words, a reinforcing belt is formed in a circle around the house at the foundation laying level. It should enter the soil to the same depth as the slab. As for reinforcement materials, it is best to use wood. It is more flexible in installation, holds dynamic loads and in case of serious damage is easily updated. Fastening is performed by anchor joints and strong steel brackets at the corners.
Now we can move on to universal reinforcement technologies, which in different variations can be applied to one or another type of foundation.
The increase in the reference area
This method is based on the principle of increasing the density of the mutual load of the foundation-soil. Often problems with structural failure arise precisely because of the lack of reliable external support. The task is to artificially increase the width of the foundation towards the ground. To do this, a new formwork is formed, which will temporarily crush the space between concrete and adjacent ground. Construction jacks will perform this task. In the process of holding, it is necessary to strengthen the foundation of the building with concrete castings. Moreover, for greater reliability, they should be introduced with additional fixation with metal rods extending from the foundation niche. For reinforcing rods, holes are pre-drilled, followed by cement or other bonding high-strength mixtures. At the final stage, after solidification of the tides, the jacks are removed, and the space is filled with dense soil.
Increase the depth of the foundation
The technology is applicable only to lightweight platforms that are commonly used for timber frame houses. The bottom line is to transfer the support sole to the underlying subsoil. For the construction of a new platform, the formation of a system of concrete blocks will be required. The unloading of the previous foundation structure is carried out using hydraulic jacks and random beams. Power equipment raises the walls of the structure, after which approximately 2-meter pits are dug up along the perimeter of the bookmark.
The bottom and walls of the formed ditches are reinforced with wooden blockings. The foundation is directly reinforced by the support base under which the well is digging. Its depth should correspond to the height of the recess of the base. When the well concreting has hardened, it is possible to place the hydraulic equipment under the walls already in the new home placement configuration. The well is crimped, the remaining gap is concreted and sprinkled with dense soil.
Sole support structures
The optimal solution for a shallow foundation, which allows you to strengthen the supporting structure without building up the platform. A reinforced concrete element or a group of columns can act as a nested element. The choice of a particular tool will depend on the local conditions of the bookmark. Technically, reinforcement of foundations and foundations with eyeliner can be realized without special equipment. In a simple configuration with racks, you can dig a trench around the perimeter and install screw piles by screwing in. They will be based on a reinforcing belt made of a concrete platform, metal or even wood pre-treated with protective impregnations.
Pillar Reinforcement
As you can see, pile elements are one of the most popular means of supporting the foundation. In this case, we consider a universal method of using columnar discharge. The advantages of this technology include the complete exclusion of earthworks. Neither digging trenches nor creating wells is required. In a bored way, a rod 10-15 cm thick is placed either close to the existing supports, or behind the perimeter of the base line. The traditional reinforcement of the foundations with piles involves the direct unloading of the bearing base. In this case, the possibility of transferring part of the pressure from the grillage to additional piles is also allowed. Again, it is advisable to use not one column, but several - this is necessary so that the unloading of the mass is uniform and without distortions.
Foundation reconstruction
Sometimes, due to the obsolescence of the structure, the support aids for the foundation no longer help. In this case, you can not do without a major review of the structure. The work is carried out in two stages - dismantling with cleaning the previous base and the device of a new design. Accordingly, the use of special equipment with a crane and hydraulic equipment will be required, which will allow to lift the structure with minimal damage to the frame. Further, the current platform is liquidated. After reconstruction, a new sole is created by pouring a monolithic screed. Moreover, strengthening the foundation of the house in such a scheme can be thought out and implemented even before the installation of the frame. The most effective way is tight reinforcement both inside the monolithic base with metal rods, and by laying on the grillage of the mesh.
Methods of strengthening the soil around the perimeter
The low density of the soil surrounding the foundation often causes the destruction of the supporting structure. The following methods will help to improve the stability of the adjacent land structure:
- The introduction of solutions. This is an extensive group of technologies involving the strengthening of soil with cements, silicate mixtures, bitumen and other building binders that are brought into the ground through the same pits and trenches.
- Increased strength by backfill. If you plan to strengthen the foundation in an indirect way around the perimeter and without the use of special building materials, then you can limit yourself to adding crushed stone with sand. With small indentations from the building, wells are made with a depth of 1.5-2 m and filled with the aforementioned combination of bulk materials. The main thing is then to make a hard ramming.
- Installation of piles. Another way of deep reinforcement. Concrete or metal rods are introduced into the ground along the foundation line.
Foundation insulation
Exposure to moisture, frost and condensation negatively affects the concrete structure of any foundation. Complex insulation will help to protect the structure from such processes. If you plan to strengthen the foundation of a private building, then you can limit yourself to a standard set of means of heat and water protection. For insulation on the ceiling of the grillage, you can use expanded clay embankment, expanded polystyrene boards or mineral wool. On the sides outside, for waterproofing, geotextiles, bituminous tar or traditional laying of a two-layer roofing material are usually used.
Finally
There are various methods to strengthen the platform on which the house stands. The simplest ones do not require the use of special equipment and machinery. For example, for a small building, you can use the methods of strengthening foundations due to piles or compacting bedding in the ground. They will cost cheaply and do not require much physical effort. Difficulties can arise except with the reconstruction of the tile foundation or with the complete replacement of the bearing base. But in such cases it is better to turn to professionals for help.