Pile foundation foundation: the pros and cons of technology

0 Traditional tape and slab lay not in all cases - there are a number of limitations. In addition, they are quite expensive, which is not always justified economically.

Pile foundation with a grillage will require less investment, therefore, if conditions allow, it is more profitable to use it.

It seems that this is a “legged” house

What is a pile foundation of a spade type

Such a foundation It is a structure of piles embedded in the soil below the depth of soil freezing, and connected at the top with a metal or concrete tape (grillage). The supports can be combined with one common plate, located at ground level or slightly higher. The construction, built according to the rules, is reliable and has a long service life - several decades.

Concrete grillage

Here you can clearly see what a grillage of the foundation is the entire upper part of any pile foundation, which is also called " cap ". The task of the grillage is to evenly distribute the load from the structural elements on the piles and, accordingly, on the ground.

There are several types of grillage:

• National. Consists of individual elements, which are a construction of three piles reinforced with a welded frame. To install them, you need a tap.

Precast grillage from beams

• Monolithic reinforced concrete. It is a solid plate or ribbon. Poured directly on the construction site.

Monolithic reinforced concrete grillage

• Precast monolithic . An intermediate variant, made of prefabricated parts, which, in turn, are assembled in factory conditions, and are already monolithic in place by means of locks and keyed joints.

Advantages and disadvantages of the pile-grillage foundation

Each of the above types of foundation has advantages and disadvantages that are taken into account in the design, in order to prevent waste supporting structures. Among the most common types of basement, designers have a choice between tape, slab, pile-cap and pile. If you compare the pros and cons of the pile-grillage foundation, with other types of bases, then sfr largely benefits.

In reality, the advantages of the pile-grillage foundation far outweigh the disadvantages.

The properties of the foundation with the grillage determine the following advantages of its use:

• is applicable for any soils, including mobile and unstable, water-saturated or peaty; );

• does not require a large consumption of materials;

• has a significant service life;

• performance installation depends slightly on weather x conditions - work is allowed at air temperature up to -10 ° C;

• is stable and has a good bearing capacity.

On water-saturated soils, building a foundation requires special skill and accurate calculations

Cons:

• there are limitations related to bearing capacity: the foundation is used only for one and two-story buildings;

• the construction of the basement or basement is possible, but associated with costly design solutions;

• installation requires high accuracy, so it is strongly recommended to entrust it to specialists;

• installation work involves the use of special equipment .

Types of pile-rost foundation foundations by the method of diving into the ground

• Zabivnaya. The supports are driven into the ground with the help of construction equipment.

• Padded. Assumes drilling, which are subsequently poured with concrete.

• Screw. It is a method of screwing in piles using special equipment.

A special item of expenditure - the use of special equipment

On our site you can find contacts of construction companies that offer the service of designing and repairing the foundation. Directly to communicate with representatives, you can visit the exhibition of houses "Low-rise Country".

Pile Types Used

Piles are selected depending on the diving method:

• Zabivny. For them, wells are prepared in advance, with a depth of 1/3 of the pile height. A special construction equipment is used for the installation: the pressing machine, the vibrating hammer, the vibratory driver.Wooden, steel, reinforced concrete and hollow supports are used as roadheads.

Reinforced concrete piles: if the technology of installation is observed, the supports will last for many decades

• Bored. Formwork and reinforcement are placed in the well for strength, then poured with concrete.

• Drilling. Boreholes are drilled in advance, into which the reinforced concrete supports are then installed.

• Screw. They are hollow tubes, in the lower part of which there are blades and a pointed tip. The supports are screwed into the ground with the help of special equipment.

UBM-85 for tightening screw piles

Piles can have a rectangular or circular cross-section. Concrete, reinforced concrete, steel of various grades, wood, mainly coniferous, are used as materials for them. Of the tree species, larch is considered to be the most suitable, containing a large amount of resin that protects the piles from rotting.

Metal driven piles are one of the cheapest and most durable

It can be interesting! In the article on the following link read about how to knit reinforcement for the foundation.

Pile benefits:

• relative cheapness;

• low installation time;

• independence from the level of groundwater;

• reliability (subject to the installation technology).

Screw piles are used even in permafrost

All of the above types of piles are used when installing the pile grillage foundation. When choosing piles take into account the features of the soil and load. For private homes most often choose bored and screw piles.

Classification according to the degree of depth

Depending on the position relative to the ground, there are 3 types of grillage:

• Low or recessed. Its feature is that it is installed below ground level, that is, into the ground. Rostverk placed on a sandy pillow.

• Ground. Located at surface level.

• Tall or trailing. It is located above the ground at high supports. If groundwater flows close to the surface, use this type of grillage.

In-depth grillage

The in-depth grillages are used only when absolutely necessary, since their installation is by complexity compare with the installation of shallow strip foundations: it is necessary to dig a pit, arrange a drainage sand cushion, make formwork, but also install piles.

In contrast to the buried and terrestrial, the hanging grillages are not so laborious and, as a result, less expensive.

It might be interesting! In the article on the following link read about draining water from the foundation of the house.

Stages of installation of a pile foundation with a grillage

The equipment of the pile-rost foundation is divided into the preparatory stage and the installation itself. At each stage, we have to perform several types of work:

Preliminary works

1. For the construction of the foundation, a project that is created based on calculations loads, the estimated depth of the pile, from which materials the foundation is planned.

The project from a professional is a guarantee of safety, long service life, and also savings in materials and finance

1. Then a plot of is prepared: trash, topsoil and plant roots are removed.

2. A marking of the territory is carried out: note the location of the supports, the grillage, the supporting structures of the partitions.

Attention! Deviation from a project is always a cause of negative consequences, such as curvature of the foundation, the occurrence of unforeseen items of expenditure and not only. Therefore, it is important that the project was drawn up by professionals and was tied to the locality.

The work of a “professional” is immediately visible

1. A trench is digged under the grillage. Its walls and bottom are checked for evenness by level. After that the sand cushion is laid and compacted.

2. Wells are drilled for supports , at the bottom of which a sand cushion is also placed. Waterproofing is installed in the pit: a special film, several layers of roofing material, plastic pipes can be used.

Technology of installation of the pile-rover foundation

1. For the grillage, use reinforced concrete beams or pour monolithic tape. For her prepare the wooden rectangular formwork, which is fixed with struts and lintels. At this stage it is also worth taking care of the sewage system and the pipeline.

Photo of the pile-grillage foundation - after the concrete has dried the formwork is removed

1. To increase the strength of the structure, a reinforced frame is placed in the well - 4 metal rods each, tied with wire. Then the concrete is poured. The tape is also reinforced.

2. Next, concrete is poured, first into the wells, then into the formwork. Seizing concrete will take at least 10 days, after which the formwork is dismantled.

How the need for materials for the foundation is calculated

Accurate calculations can only be carried out by a specialist engineer who will build on the requirements of building codes and a number of indicators such as the strength of the supports, the grillage, the bearing capacity of the foundation, the resistance of the soil, the degree of shrinkage of the support under the influence of vertical load, etc. The specialist will determine the depth of the supports, their diameter, number, type of grillage and develop a scheme.

For a person without specialized education, calculations of a pile-rover foundation look like this

When calculating the number of supports, it is primarily based on the load on the foundation which consists of several indicators. Here it is necessary to know the mass of supporting walls, partitions, roofs, floor slabs, i.e. the whole mass of the building above the foundation. It also takes into account the payload that tenants, household items and all other things produce. In the calculations for private homes using an indicator equal to 150 kg / m².

The last parameter to determine the total load is the weight of the snow mass that can accumulate on the roof in winter. Mostly used is 180 kg / m², but for some regions of the country it is slightly different. The resulting amount of load is multiplied by the safety factor, which is 1.1 (1.2 is sometimes used). Next, you can calculate the load on one pile.

It would be nice to add that the online calculators for calculating materials that are common on the web should be treated very carefully. They may not take into account a number of important parameters.

For an online calculator example, see the video:

Installation of additional elements

When erecting piles -strooped foundation must be equipped with holes for ventilation in the foundation and lay pipes that can be used for heating, sewer, plumbing systems and other utilities. If time does not take care of the engineering and technical equipment of the house, later to install them will have to partially destroy the grillage.

For the preservation of the foundation, it is necessary to provide a vent to ventilate

Requirements for creating high-quality gravel foundation

Since the main loads on the grillage are forces aimed at bending, then one of the key points in creating the foundation foundation is reinforcement, which significantly increases the strength of the structure.

Reinforcement scheme

The second significant point concerns the hardening time of the concrete structure - and this is a whole month. Rostverk will be able to withstand proper loads only after the concrete has completely hardened.

Possible errors during construction of the foundation

• The piles are not tightly fastened to the grillage - the temperature expansion due to seasonal fluctuations in temperature will soon loosen the attachment point.

• The piles are laid too deep. Both excessive shrinkage of the foundation and squeezing of piles of loose soil in the layer below the freezing of the ground are not excluded here. All this can lead to the destruction of the building.

• Inaccurately calculated. It's just a powder keg - you never know what might happen.

For the pros and cons of the pile foundation, see the video:

These are typical but far from all the mistakes that unskilled builders make. There are a lot of stories on the Internet, what went wrong with independent construction, but even knowing the mistakes of others often does not compensate for the presence of real skills and experience. As a result - everyone should do their own thing.

It should be calculated and built by qualified specialists

What determines the cost of construction work

foundation, then the whole group of factors determines the cost of the SRF:

• construction scale;

• type and number of supports, their diameter and length;

• dimensions of the base strip;

• use of special equipment;

• region;

• construction firm policy.

You can clearly see the cost of the pile-grillage foundation on the video:

It can be interesting! In the article on the following link read about replacing crowns and repairing the foundation of a wooden house.

Conclusion

The pile-pile foundation is considered to be more reliable than the pile foundation and more profitable compared to the strip foundation, and in some situations it is the only possible one. But competently make calculations and equip it under the force of only qualified professionals. Otherwise, such a foundation will not have enough strength or excess value, which equally levels all its advantages.