Quite often, during the operation of buildings or if you want to expand the living space of the house, you have to take any measures to strengthen the old foundation. Since the increase in the weight of the structure, the old foundation can burst and collapse, and this can lead to cracks on the walls and, accordingly, destroy them. To prevent this, you need to correctly plan the reinforcement of the strip foundation.
First, it will be necessary to analyze the current state of the building, to assess the possibility.
These works can be done by hand or by professional craftsmen.
Strengthening the foundation prevents its complete replacement, which costs the owners a lot of money and time. For a well-performed work, it is necessary to identify all the reasons that influenced its deformation and take appropriate measures to eliminate them.
Highlight the main reasons that lead to the need for reconstruction of the foundation:
A frequent phenomenon that destroys the base is considered to be fluctuations in groundwater occurring due to large precipitation, floods, which lead to swelling of the soil. In this case, the soil swells and, as a result, the foundation is skewed.
The solution here can be the use of drainage and waterproofing of the foundation. It is necessary to start any work on strengthening the foundation only after the destructive factor is completely eliminated. If this is not taken into account, destruction will continue to occur.
First, an external examination is carried out, which is aimed at analyzing the size of the structure, assessing the condition of the supporting structure, as well as the presence of cracks and bevels on the foundation. Next comes an underground survey, where the depth of the base, strength and quality of the material of manufacture are assessed.
There are situations when there are no visible deformations, and strengthening of the foundation is needed:
Another preparatory moment is the unloading of the foundation. It can be partial and complete. It is an important step and does not allow any distortions.
Partial can be carried out using the support device.
They can be wooden or metal. Supports are installed in the basement, logs are placed on top and secured with racks. These elements are then connected using beams and wedges.
For complete unloading, metal beams are installed. The punches are punched in the wall, they are placed in them and fastened to the bolts with periodicity of the beams, which are further fastened by welding.
The formed space is covered with a mixture of sand and cement. Holes are made at the bottom of the wall, beams are inserted into them.
Walls are supported by perpendicular beams.
First, the degree of complexity of the work carried out depends on the general position of the structure. Under some circumstances, the restoration of the heat and waterproofing layer will be sufficient, in others it will be necessary to expand the foundation.
The most common method of strengthening is the regeneration of the soil under the foundation. This is done in cases of structural changes in the soil or when it is weakened.
There are also the following methods of strengthening:
Note: Shotcrete is a method of applying a concrete mixture to a structure by the action of compressed air, due to which the cement layer tightly fills cracks and small pores on the structure's surface.
It fills in empty spaces and cracks, as well as the distance between the base and the ground.
Note: The cementation method is also called injection. This method differs from others by installing hollow pipes in the base. They are installed and fixed with a mixture. The pipe cavities are filled with a non-thick cement mortar.
The work is carried out with precise methodicality: creating a cage, after it has solidified, the installed tubes are filled;
Important: Cementation can be used only on condition that the maximum bearing capacity of the foundation is preserved.
With the use of this method, strengthening occurs throughout the thickness of the base, due to the fact that all defects are filled with a solution. First you need to dig out a section of the old foundation about 3m long. It is deepened by 1.5 m, and it should be 1 m wide. Through holes are made on both sides.
Steel rods from fourteen to twenty millimeters are inserted into these holes, on which the frame is fixed. The frame consists of cells with a size of 150 * 150 mm. Then they arrange the formwork and the formed gap is filled with concrete;
Then the pile and base reinforcement is laid and bandaged.
After all this is poured with concrete and compacted;
This method is used if it is necessary that the load is transferred to deeper solid ground. For good joining of the foundation with the piles, beams are arranged;
They are installed on both sides of the foundation and tied with reinforced concrete beams;
Important: When carrying out reinforcement work, an accurate calculation of the load on the foundation is required. If this is not taken into account, after a certain period of time, shrinkage and destruction of the structure is possible.
Here you will need reinforcement from sixteen to eighteen millimeters in diameter and concrete M400. A trench is dug, starting from the corners, more than fifty centimeters wide than the old base. Next, a reinforcing cage is created, which must take on the main load, for which it is attached to the foundation with anchors. The final stage is wooden formwork, which runs along the entire perimeter of the frame, and concrete is poured. After hardening, backfilling is carried out and slopes are created to prevent moisture from entering the structure;
The sole is a reinforced concrete cushion for the foundation. First, mark the base with a frequency of two and a half to three meters. Then, in the lateral places of the base and under it, recesses are made in the soil. Make a screed. The mixture should be as homogeneous as possible and free of air bubbles.
This work can be done with a concrete mixer;
The formed space is filled with concrete mixture. Thanks to this, the base is strengthened not only by the ebb, but also by this concrete layer.
Then pits are dug around below the foundation by 1m. A well is pulled out under the support of the base. Next, it is concreted, the trench is filled up.
There is also another way to strengthen the base with the help of a release well, which is a construction of reinforced concrete slabs, which is used to compress the soil around the perimeter of the base. This method is used for critical deformation changes that cannot be prevented by other methods.
Poor soil density is considered the main provoking factor of foundation shrinkage. In such a situation, together with the strengthening of the foundation, it is necessary to reinforce the soil.
The following methods are distinguished:
From the above, you can see how many possible options for strengthening the strip foundation exist.
It is possible to choose the option that suits your case.
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