What is the purpose of the grillage in pile foundations. Pile-grillage foundation: classification, advantages and disadvantages, requirements and standards

It is difficult for a non-specialist to figure out which foundation to choose for a house. Traditional tape and slab lay far from all cases - there is whole line restrictions. In addition, they are quite expensive, which is not always economically justified.

A pile foundation with a grillage will require less investment, therefore, if conditions permit, it is more profitable to use it.

It seems that this is a house "on legs" Source sampochinil.ru

What is a pile foundation grillage type

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

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

There are several types of grillage:

• Made. It consists of separate elements, which are a structure of three piles reinforced with a welded frame. To install them, you need a crane.

• Monolithic reinforced concrete. Represents a solid plate or tape. It is poured directly on the construction site.

• Prefabricated monolithic. An intermediate version made from prefabricated parts, which, in turn, are assembled at the factory, and are already embedded in place by means of locks and keyed connections.

Advantages and disadvantages of a pile-grillage foundation

Each of the listed types of foundation has advantages and disadvantages, which are taken into account in the design in order to prevent overspending of materials, deformations and cracks in the supporting structures. Among the most common types of foundation, designers have a choice between strip, slab, pile-grillage and pile. If we compare the pros and cons of a pile-grillage foundation with other types of foundations, then the SRF wins in many ways.

In fact, the advantages of a pile grillage foundation far outweigh the disadvantages. Source lowcarb-ernaehrung.info

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

• applicable to any soil, including mobile and unstable, water-saturated or peaty;
• convenient when building a house in an area with uneven terrain (for example, on a slope);
• does not require a large consumption of materials;
• has a significant service life;
• installation is slightly dependent on weather conditions - work is allowed at air temperatures down to -10 ° C;
• is stable and has a good bearing capacity.

On water-saturated soils, the construction of a foundation requires special skill and accurate calculations. Source termeszetvedelem.hu

• there are limitations related to the bearing capacity: the foundation is used only for one- and two-story buildings;
• the construction of a basement or basement is possible, but is associated with complex and costly design decisions;
• installation requires high precision, so it is strongly recommended to entrust it to specialists;
• installation work involves the use of special equipment.

Types of pile-grillage foundations according to the method of immersion in the ground

• Zabivnaya. The supports are driven into the ground using construction equipment.
• Printed. It involves drilling wells, which are subsequently poured with concrete.
• Screw. It is a method of screwing piles with the help of special equipment.

A special expense item is the use of special equipment Source blog-potolok.ru

On our website you can find contacts of construction companies that offer foundation design and repair services. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

Types of piles used

Depending on the method of immersion, piles are selected:

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

Reinforced concrete piles: if the installation technology is followed, the supports will last for many decades Source block-gbi.ru

• Bored. Formwork and reinforcement are placed in the well for strength, then poured with concrete.
• Drilling. Wells are drilled in advance, in which reinforced concrete supports are then installed.
• Screw. They are hollow pipes, in the lower part of which there are blades and a pointed tip. The supports are screwed into the ground using special equipment.

Piles can have a rectangular or round section. As a material for them, concrete, reinforced concrete, steel of various grades, wood, mainly coniferous species, are used. Of the tree species, larch is considered the most suitable, containing a large amount of resins that protect piles from decay.

Driven metal piles are one of the cheapest and most durable Source blog-potolok.ru

Piles advantages:

• relative cheapness;
• low installation time;
• independence from the level of groundwater;
• reliability (subject to the installation technology).

Screw piles are used even in permafrost conditions Source museblog.ru

All of the above types of piles are used when installing a pile-grillage foundation. When choosing piles, the characteristics of the soil and load are taken into account. For private houses, most often choose bored and screw piles.

Classification by degree of depth

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

• Low or recessed. Its peculiarity lies in the fact that it is installed below ground level, that is, in the ground. The grillage is placed on a sand cushion.
• Ground. Located at surface level.
• Tall or hanging. It is located above ground level on high supports. If groundwater flows close to the surface, this type of grillage is used.

Recessed grillages are used only in case of emergency, since their installation is comparable in complexity to the installation of a shallow strip foundation: it is necessary to dig a foundation pit, equip a draining sand cushion, make a formwork, but also install piles.

Unlike buried and ground grillages, hanging grillages are not as labor-intensive and, as a result, less expensive.

Stages of installation of a pile foundation with a grillage

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

Preliminary work

• For the construction of the foundation, first of all, it is necessary project, which is created on the basis of load calculations, the estimated depth of piles, what materials the foundation is planned from.

A project from a professional is a guarantee of safety, long service life, as well as savings in materials and finances Source nl.decorexpro.com

• Then site is being prepared: debris, topsoil and plant roots are removed.
• Held territory marking: mark the location of supports, grillage, load-bearing structures of partitions.

Attention! Deviation from the project is always the cause of negative consequences, such as the curvature of the foundation, the occurrence of unforeseen items of expenditure, and more. Therefore, it is important that the project is drawn up by professionals and is tied to the area.

The work of a "professional" is immediately visible Source blog-potolok.ru

• A trench is dug under the grillage. Its walls and bottom are checked for evenness with a level. After that, a sand cushion is laid and compacted.
• Drilling wells for supports, on the bottom of which a pillow of sand is also laid. Waterproofing is laid in the pit: you can use a special film, several layers of roofing material, plastic pipes.

Installation technology of pile-grillage foundation

• For the grillage, reinforced concrete beams are used or a monolithic tape is poured. A wooden rectangular formwork is prepared for it, which is fixed with supports and lintels. At this stage, it is also worth taking care of sewers and pipelines.

Photo of a pile grillage foundation - after the concrete dries, the formwork is removed Source bestroof.ru

• 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.
• Next, concrete is poured first into the wells, then into the formwork. The setting of concrete will take at least 10 days, after which the formwork is dismantled.

How is the need for foundation materials calculated?

An accurate calculation can only be performed by a specialist - a civil engineer, who will rely on the requirements of SNiP and a number of indicators such as the strength of the supports, grillage, the bearing capacity of the foundation, the soil resistance force, the degree of shrinkage of the support under the influence of a vertical load, etc. The specialist will determine the depth of immersion of the supports, their diameter, number, type of grillage and develop a diagram.

For a person without a specialized education, the calculations of a pile grillage foundation look something like this Source ask.fm

When calculating the number of supports, they proceed primarily from the load on the foundation, which consists of several indicators. Here it is necessary to know the mass of load-bearing walls, partitions, roofs, floor slabs, i.e., the entire mass of the building above the foundation. The payload produced by residents, household items and all other things is also taken into account. In calculations for private houses, an indicator equal to 150 kg / m² is used.

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

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

Video description

An example of an online calculator, see the video:

Installing additional items

When erecting a pile-grillage foundation, it is necessary to equip ventilation holes in the foundation and lay pipes that can be used for heating, sewer, plumbing systems and other communications. If you do not take care of the engineering and technical equipment of the house in time, later you will have to partially destroy the grillage to install them.

For the preservation of the foundation, it is imperative to provide vents for ventilation Source repairstroy.net

Requirements for creating a high-quality grillage foundation

Since the main loads on the grillage are bending forces, one of the key points when creating a grillage foundation, reinforcement is used, which significantly increases the strength of the structure.

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

Possible errors in the arrangement of the foundation

• The piles are not firmly fastened to the grillage - thermal expansion with seasonal temperature fluctuations will soon loosen the attachment point.
• The piles are laid too shallow. Here, both excessive shrinkage of the foundation and extrusion of piles that are not fixed in the layer below the freezing of the ground by the forces of soil heaving are not ruled out. All this can lead to the destruction of the building.
• Inaccurate calculations. It's just a powder keg - you never know what might happen.

Video description

About the features of the pile strip foundation, see the video:

These are typical, but far from all, oversights that unskilled builders make. There are many stories on the Internet about what went wrong during self-construction, but even knowing other people's mistakes often does not compensate for the presence of real skills and experience. As a result, everyone should mind their own business.

Calculate and build must be qualified specialists Source pinterest.com

What determines the cost of srf

If the project provides for the installation of a pile grillage foundation, then what determines the cost of the cff is determined by a whole group of factors:

• the scale of the building;
• type and number of supports, their diameter and length;
• dimensions of the foundation tape;
• use of special equipment;
• region;
• construction company policy.

Online foundation calculator

To find out the approximate cost of a "grillage on piles" foundation, use the following calculator:

Video description

Visually about the cost of a pile-grillage foundation, see the video:

Conclusion

A pile-grillage foundation is considered more reliable than a pile foundation, and more profitable than a strip one, and in some situations it is the only possible one. But competently make calculations and equip it only by qualified specialists. Otherwise, such a foundation will have insufficient strength or excess cost, which equally levels out all its advantages.

Under certain conditions, the construction of a pile foundation becomes beneficial. The pros and cons of this design make it ideal for a private house on difficult soils.

The installation of a pile-grillage foundation requires, in most cases, lower costs. This is due to a decrease in the volume of earthworks. Before making piles, you need to study their advantages and disadvantages, scope, technology description.

Types of piles

There are several ways to make such a pile-grillage foundation. The pros and cons in this case will depend on the technology and materials used.

According to the material of the support are divided into:

• wooden;
• reinforced concrete;
• metal.

The former are rarely used, since their main drawback will be their low durability. The tree is destroyed by moisture, decay, microorganisms.

Reinforced concrete piles have a high bearing capacity. Usually, the laying depth for your house is 1.5-3 m. The dimensions of the section are chosen depending on the characteristics of the soil on the site.

Metal supports of pile foundations - an option for private housing construction. They are not designed for high loads, therefore they are used for wooden or frame buildings.

The following classification is performed depending on the element immersion technology. The pile foundation can be installed in three ways:

• driving;
• bored;
• screw.

To make a pile-grillage foundation with your own hands, the driving method is not always suitable. It allows you to build powerful structures, but has a significant drawback - the need for special equipment (heavy duty, pile drivers). Another disadvantage of a pile-rammed foundation is a strong impact on the surrounding buildings. During the operation of the mechanisms, impacts on the ground occur, which can cause damage to nearby buildings.

pouring concrete

Pile foundation technology involves the use of concrete classes B15-B20, depending on the load. Using a material with greater strength is not economically viable. Concrete can be made independently or ordered at the factory. The second option is preferable, since in this case you can be sure that the resulting mixture has a certain strength. When mixing concrete by hand, be sure to study the manual for this process. Usually the instructions are on the package with cement.

Piles should preferably be poured in one go. Interruptions in the production of one element will lead to its weakening. Concrete pouring is recommended to be carried out at an outdoor temperature of 15-25 degrees Celsius. In this case, the concrete will gain strength faster and be durable. After every 30-50 cm of pouring in height, a short break is made, during which the solution is compacted with a vibrator or bayonet.

The hardening of the material takes an average of 4 weeks. In rainy and cold weather, more time is required. You can make a monolithic grillage after the concrete has gained 50-70% of its strength.

Do-it-yourself screw pile foundation step by step instructions

Do-it-yourself pile-tape foundations are easy to do in this way. The work is carried out in the following order:

1. clearing the site and preparing building materials;
2. marking the territory for the building;
3. screwing piles with a manual or mechanized drill to the desired depth;
4. cutting supports at one level, on which the grillage on piles will be located;
5. filling pipes with concrete class B15;
6. arrangement of grillage on pile foundations.

Do-it-yourself construction of a pile foundation in this case does not require time for the curing of concrete. You can start the next stage of work immediately.

Strip foundation on piles

The pile-strip foundation is a structure of free-standing supports rigidly connected to each other. The grillage prevents the structure from sagging unevenly. Tape can be made from:

• wood (only for a wooden or frame house);
• metal;
• reinforced concrete.

Each strip foundation has its pros and cons. When choosing a material for a strip foundation with piles, you should pay attention to the material of the supports and walls of the building. For wooden house- wooden grillage. For metal piles, it is reasonable to make a structure from rolled metal or wood, for reinforced concrete - from concrete.

Strapping completes column-strip foundation. First of all, the depth of the grillage is determined. He can be:

• buried;
• ground;
• hanging.

The choice largely depends on the characteristics of the soil. Particular attention should be paid to the do-it-yourself column-strip foundation on heaving soil. In this case, the probability of damage to the structure during frost heaving is high. The grillage should not come into contact with the soil. Two methods are used:

• hanging harness (for this, 10-15 cm of sand is poured onto the ground, an element is poured over it, after which the bulk material is removed);
• recessed piping with low density foam cushion.

The device of a pile foundation and a monolithic grillage is not very complex. Even a non-professional can cope with the work, provided that the calculations are performed correctly and the technology is observed.

When it comes to such a building structure as a pile-grillage foundation, it must be understood that this is a symbiosis of two types of foundations: columnar and tape. In this case, the grillage tape rests on the pillars of the piles.

It bears the loads from the weight of the building and evenly distributes them over all the supporting pillars. The design is reliable, stable, so it is used on any type of soil.

Varieties of pile-grillage foundations

Basically, in this foundation structure, piles differ from each other. In civil and industrial construction, three types of them are used today:

1. Bored foundation with grillage. This is when wells are drilled in the ground, a reinforcing frame is installed in them, they are poured with concrete mortar.
2. Drop-in. These are prefabricated piles made of reinforced concrete. They are hammered into the ground with the help of special equipment.
3. Screw. These are steel pipes, at the end of which a drill is installed. They are simply screwed into the ground and filled with concrete.

The second technology is complicated in that it requires machinery to drive piles. Hence the high cost of the ongoing processes.

Advantages and disadvantages of the design

Considering the pros and cons of a pile-grillage foundation, it is necessary first of all to indicate the complexity of the design calculation. This is a big minus for those who are not specialists in the construction business. Therefore, a specialist should deal with the project and calculation of the pile foundation.

He can calculate not only the dimensions of the elements, but also the depth of the support pillars. The last factor is very important, because according to SNiP, foundations must be laid below the level of soil freezing. The disadvantages of the device pile-grillage foundation can also include:

• organization complexity basement or basement;
• it is recommended to pour such a foundation for a house built from lightweight materials.

As for the advantages of the foundation on piles with a grillage, first of all it is necessary to indicate a small amount of work being carried out, which affects the cost of construction. Here we will add the possibility of building on plots with a slope.

Construction rules

Consider the technology of pouring a strip pile foundation with bored piles as the most commonly used.

Site preparation and marking

The construction site is cleared of vegetation and debris. In some cases, the top layer is removed. Now the main stage is markup. The best option for setting the exact location of the piles is to invite a specialist with a laser level.

With the help of this tool, the places of supports and their exact location relative to the boundaries of the site are determined directly on the ground. Pegs are hammered into them, which are interconnected with twine or twine.

Now you need to set aside half the width of the foundation structure along the laid axis in two directions from the stretched thread. For example, if the width of the grillage is 40 cm, then from the axis it is necessary to set aside 20 cm on both sides. According to these dimensions, a trench is dug 30-40 cm deep.

pile construction

Wells are drilled at the place of installation of the pegs. Their diameter, the distance between the piles, the amount of penetration, the layout is determined by the design of the house. By the way, you can drill with a garden drill, the main thing is to choose it according to the diameter of the piles.

1. Falling asleep in wells sand 20-30 cm thick. it must be rammed.
2. Inserted inside metal carcass from steel fittings with a diameter of 8-16 mm. it is necessary to reinforce the supports, especially if the pile-grillage foundation is being built on heaving or soft soils. In SNiPs, it is indicated that frames with a round, square or triangular section can be used for columnar structures. It is necessary to make the frame 15-20 cm longer than the depth of the pile. These reinforcing ends will be connected to the frame of the monolithic grillage.
3. Filling in progress concrete mortar. Here, the M400 brand is used with the recipe - one volume of M400 cement, two volumes of fine sand, three volumes of crushed stone (fine or medium fraction).
4. Mandatory bayonet concrete mass to remove air from it.

If the soils at the construction site are weak, it is recommended to strengthen the walls of the wells. For example, twist the roofing material into a tube and lower it inside. Instead of roofing felt, any pipe is suitable here: metal, plastic or asbestos. The main thing is to withstand the diameter of the pile foundation.

If a monolithic grillage is installed on weight, then the pillars are poured with an exit above the ground level. For them, you will have to build the formwork of the basement, for which you can use all the same pipes. So, the pile foundation is ready.

The construction of the grillage

Since the grillage is a strip foundation, of a shallow type, it must be built according to the appropriate technology.

1. The trench is backfilled sand or gravel with a thickness of 20-30 cm. The laid layer is rammed.
2. Formwork is being installed from any flat material. By the way, it is not difficult to assemble the formwork for the strip foundation with your own hands.
3. Fits inside reinforcing frame made of reinforcement. It should be located in the body of the foundation structure, so it is recommended to place supports under it.
4. The ends are connected reinforcement of pillars with a frame in the grillage. This is done either by electric welding or with the help of a knitting wire.
5. Concrete is being poured, made according to the same recipe as the solution for piles.
6. Necessarily flooded in the formwork, the material is subjected to vibration.
7. Top design closed with burlap or polymer film. If it is hot outside, then you will have to pour water on the pile foundation with a grillage two or three times a day. The reason is the rapid drying of the mixture, which will lead to cracking.
8. In a week you can remove the formwork, load the foundation after 28 days (raise the walls, install the ceiling).

Many violate the requirements of SNiP, not withstanding the drying time of the concrete structure, believing that, for example, the foundation for a house made of aerated concrete will withstand a small load coming from an aerated concrete structure. And this is a big mistake. No one knows in what time range chemical processes take place inside the concrete mass.

How quickly concrete gains brand strength. After all, this indicator depends on many factors, which cannot be taken into account at the construction site. Therefore, the time range is set to 28 days. This one is not so simple step-by-step instruction do-it-yourself construction of a pile-grillage foundation.

Combined variant

This is the technology of erecting a grillage with a slab. That is, there is no pile foundation in it. Usually this option is used in the construction of private houses, if the developer decides to build a house with a basement or basement on weak unstable soils.

That is, a monolithic slab with a grillage is being built in place of the house. The complexity of the construction of this structure lies in the fact that it is necessary to pour concrete so that the slab and the grillage are one. Therefore, a single reinforced frame is created.

To do this, you will have to lay a metal grate in the slab, and attach vertical pieces of reinforcement to it in two or three rows at the location of the tape, which will be connected to each other in a frame cage. The distance from the edge of the grillage to the edge of the slab is determined by the installation of vertical reinforcing bars.

But there is another difficulty - the installation of formwork for the grillage. There is nothing to attach it to, especially for internal shields. After all, the edge of the grillage is located far from the bearing support. Therefore, each element monolithic slab with grillage is poured separately. This technology is defined by SNiPs.

• First the floor (slab). By the way, you can carry out its thermal insulation by falling asleep on top of the expanded clay pillow. The poured concrete must gain at least 70% of the branded strength, which takes 20-21 days.
• Then mounted formwork for grillage, and concrete mortar is poured.

This type of foundation means high material costs, difficulty in manufacturing, and requirements for accurate calculations. This is especially true of the distance from the edge of the grillage to the edge of the slab. The smaller the distance, the greater the load on the edges of the slab foundation, which can cause it to collapse.

Even if it is laid under aerated concrete. But there are also advantages. For example, there is no need to dig a pit below the level of soil freezing.

Conclusion

The device of a pile foundation with a grillage, regardless of whether bored piles or screw piles are used, is based on an accurate calculation of structural elements in terms of their size, location and depth.

Warming of the pile-grillage foundation for aerated concrete, its finishing and other construction operations is the second. The main thing is the construction of the structure itself exactly according to SNiP.

They are a radical method for solving the problem of weakly bearing or flooded soils.

They rest on deep solid layers, freely passing through problematic surface layers, which makes it possible to build on peat bogs, quicksand and other soils unsuitable for creating traditional foundations.

Given the prevalence of such sites in Russia, especially in the northern regions, we can safely say that pile foundations are no less important than strip foundations.

Often they are used even on relatively stable soils, considering the possibility of raising the water table and flooding in the spring. The most common type of pile foundations, which will be discussed in this article, is a pile-grillage foundation.

Consider its capabilities and design features.

A pile-grillage foundation is a supporting structure consisting of a system of vertical supports (piles) that come into rigid contact with dense layers of soil (clay, coarse-grained or rocky), and an external strapping belt that carries the walls of the house and transfers the load to the piles.

All issues and methods of construction of pile-grillage foundations are regulated by SNiP 2.02.03-85. Exist different variants structures that use certain types of piles, sizes and material of the grillage.

Combinations of these elements make it possible to obtain the most suitable foundation design, which has the optimal set of parameters for given conditions.

NOTE!

The pile-grillage foundation is very similar to the pile-tape type, which causes a lot of controversy and inconsistencies. Some experts combine them into a single group, others fundamentally divide them according to the way the tape is supported. They did not reach a common opinion, which must be taken into account when studying the special literature.

With monolithic grillage

A pile foundation with a monolithic grillage is a system of piles immersed in the ground to the required depth.

A monolithic reinforced concrete grillage is installed on the upper part, which has a common reinforcing cage with the piles and is most rigidly connected to them.

Outwardly, the grillage looks like a kind of traditional tape, but the difference between them is that the tape transfers the load to the soil surface, and the grillage distributes it along the system of vertical supports and, through them, onto dense soil layers.

At the same time, in most cases, the dimensions and general parameters of the tape and the grillage differ little and have almost equal capabilities. The pile-grillage foundation of this type is the most rigid structure that can withstand all external loads.

In particular, such a foundation has proven itself well on problematic soils located on a slope. Such a design is the only one capable of performing its functions in such conditions.

Device

The pile-grillage foundation consists of vertical supports installed in rows, bushes or in the form of a pile field. The order of the piles is determined by the material and dimensions of the building, its configuration and the concentration of massive elements that need a strong and reliable supporting structure.

Also, the depth of immersion of piles, often their type and material, depends on the design parameters of the future construction. The loaded piles are cut to the same height to form a horizontal area.

If reinforced concrete piles are used, only the concrete parts are to be trimmed, and the reinforcement is left for welding with the grillage armored belt.

If a metal or wooden grillage is planned, the reinforcement is also cut, and special structural elements are installed on the tops of the piles - heads, which are a kind of cap with a landing platform for mounting the strapping beams.

When should it be built?

The pile-grillage foundation is mainly made of reinforced concrete. This puts forward quite specific requirements for the conditions of construction in terms of air temperature - it should not fall below +5 °.

This ensures the normal process of concrete hardening and allows you to get a solid casting with the desired qualities. Therefore, the optimal time for construction is the warm season, ideally from the end of April to the end of October (in some regions this range is already limited to three summer months).

No less important are the weather conditions that can completely spoil the conditions for work - prolonged rains can turn the construction site into a continuous swamp, which excludes any possibility of construction.

These features must be taken into account when planning and determining the timing of work.

Pros and cons

The advantages of a pile-grillage foundation are:

• The ability to build on problematic, watered or weakly bearing soils.
• High bearing capacity, strength.
• Relative simplicity of design, the possibility of independent work.
• Multivariance, allowing you to change certain elements if necessary.
• Small earthworks.
• The ability to firmly install on slopes, quicksands, folds.
• Resistance to external influences, tolerance of frost heaving or soil movements.
• Economical, low consumption of materials. Some types of piles can be made directly on the site, which reduces the volume of transportation and the use of special equipment.

There are also noticeable downsides.:

• There is no possibility of creating a basement or a full-fledged basement.
• There is a need for a thorough survey of the site with the drilling of test wells or piling.
• Must be strictly adhered to technological requirements and monitor the quality of materials.

When creating a monolithic grillage, a rather long concrete curing time of 28 days will be required. If the piles are also cast directly on the site, it becomes necessary to organize the simultaneous pouring of the entire base to save time.

Kinds

There are different design options for pile-grillage foundations, which differ in the corresponding features:

• Grill material. There are wooden, metal and reinforced concrete structures. The choice is usually determined by the weight and size of the building, the characteristics of the climate and other external factors.
• Structure height. There are species submerged in the ground and those located on the day surface. From the point of view of durability and safety of materials, external structures that do not have contact with ground moisture are preferable. Submerged in the ground - only reinforced concrete options, wood and metal in such conditions do not serve for a long time.

Practice shows that immersion of a concrete tape into the ground is impractical. At the same time, an open grillage forms an air cold gap under the floor of the first floor, which makes it difficult to supply communications and requires the installation of special waterproofed trenches.

This increases labor costs and increases material consumption..

Types of piles

Exist different designs piles:

• Piles-racks. Vertical supports in close contact with solid soil layers. Provide maximum stability and load-bearing capacity.
• Hanging piles. They are held due to the friction force between the side walls and the soil, as well as due to the compacted soil cushion under the tip. There are no supports on solid layers. Strength is ensured by the contact area - the longer the pile, the more securely it is installed. Able to suddenly precipitate due to underground changes in hydrogeology.

By type of immersion, there are:

• driven. They sink into the ground with the help of special mechanisms. They have maximum bearing capacity and stability, but create a considerable danger when immersed for all buildings located nearby.
• Casting. These piles are reinforced concrete castings made directly on the site. Reinforcement is installed in the drilled well and concrete is poured, obtaining a strong vertical rod. Convenient for self-production.
• screw. A specific type of piles immersed in the ground by screwing (like a screw). Allow self-installation, do not require preliminary preparation or excavation.

The material for piles can serve:

• Wood. A traditional material, but today wooden piles have practically disappeared from the scene, giving way to more durable and comfortable types.
• Metal. Apart from screw piles, no special structures are produced. Massive pieces of channel, rail, I-beam, etc. are used. The disadvantage of metal piles is electrochemical corrosion, from which it is almost impossible to protect them.
• Reinforced concrete. Driven and stuffed piles are made from it, obtaining strong and load-resistant supports. It is the most common material, resistant to all loads and almost 3 times more durable than metal piles.

The choice of the type of piles is determined by the technical requirements and construction conditions. Most often driven or bored reinforced concrete rods are used.

How to calculate the freezing depth

The depth of immersion of piles entirely depends on the level of occurrence of dense layers of soil. It is not determined by calculation methods.

Either test drilling or a reference hole is required to demonstrate the true position of the ground layers.

According to the results trial work the depth of occurrence is displayed, which is used in the calculations.

Calculation of the grillage

The calculation of the grillage is a responsible and extremely complex engineering task. All that an unprepared person can do on their own is to calculate the amount of materials needed to create a particular design.

For a full calculation, you need to contact a specialized organization. At a minimum, you can use an online calculator (preferably several) to get certain data.

To independently calculate the amount of materials, it is required to determine the total length of the grillage. If a wooden or metal belt is planned, this length will be the right amount material. FROM concrete structures somewhat more complicated:

Calculation example: let's say there is a house 6: 8 with two internal load-bearing walls 6 and 4 m.

Then the total length of the grillage:

(6 + 8) 2 + 6 + 4 = 38 m.

Then we calculate the volume. To do this, you need to calculate the cross-sectional area.

If the tape is 40 cm high and 30 cm long, the cross-sectional area will be:

0.4 0.3 \u003d 0.12 m 2.

The volume of concrete required for casting:

0.12 38 = 4.56 m3.

NOTE!

When performing calculations, it is necessary to use the same units of measurement, otherwise the obtained values ​​will be incorrect.

Construction technology

Procedure:

• Training. The area of ​​​​the site is freed from foreign objects and plants, a thorough marking is carried out. Pegs mark the points of installation of piles.
• Well preparation. At the marked points, drilling is performed to a predetermined depth. Sleeves made of plastic pipes or rolled roofing material are immediately laid inside the wells. A reinforcing cage is assembled and lowered into each well.
• Pouring concrete. The cavities of the wells are filled with concrete, bayoneted, removing air bubbles. The poured concrete is cured for 20 days before gaining structural strength.
• Formwork assembly. While the wells are freezing, the formwork is carefully assembled for pouring the grillage. Usually use edged board with a thickness of 25-40 mm. The shields are assembled and installed in the desired position, controlling the coincidence along the axes and horizontally. The inner part is covered with polyethylene or roofing felt.
• Reinforcing belt. The frame is assembled and installed inside the formwork. The rebar protruding from the wells is welded to the grillage rods, forming a single belt.
• Filling the grillage. After the wells have hardened, the grillage is poured. Concrete grades M200 and higher are used. Filling is performed at one time, without long breaks. After that, the solution is bayoneted, covered with polyethylene or burlap and incubated for 28 days until completely solidified.

Formwork can be removed 10 days after pouring. At the end of the exposure period, proceed to further work.

The main mistakes during construction

Typical mistakes that are often encountered in the construction of pile-grillage foundations are:

• Weak connection of piles and grillage, which reduces the stability and strength of the structure.
• No air gap between the high grillage and the ground.
• Increased spans between piles, causing deflection of grillage beams and cracks between the foundation and walls.

All these errors are the result of a lack of experience among the builders or an incorrect calculation of the pile field, which allowed too large distances between the supports. All these shortcomings need to be eliminated by strengthening the connections, installing additional supports and creating a high-quality false base.

The work is quite complex and responsible, but absolutely necessary, otherwise the life of the house will be significantly reduced.

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The pile-grillage foundation is a fairly strong and durable structure, which is ideal for the construction of residential buildings both on ordinary and unstable soil. By creating monolithic structure, this technology combines all the advantages of a pile, columnar, and strip foundation. In addition, it is not difficult to build a pile-grillage foundation with your own hands. What is needed for this, and what subtleties of installation you need to know, we will try to figure it out.

What is a pile-grillage foundation

The technology for building a pile-grillage foundation was invented in Finland, where there have always been problems with the soil, and houses are made of wood (that is, they are quite light).

Important! Such a foundation is more suitable for the construction of low-rise light houses (for example,). For a brick structure, it will also fit, the main thing is to make the correct calculations for the distribution of the load on the base.

The pile-grillage foundation combines all the advantages of its progenitors: the load is evenly distributed over the grillage, and the piles securely fix the foundation, protecting it from destruction in heaving soils or groundwater passing close to the surface.

Foundation device

1. Piles are the basis of the entire structure. They sink to a depth below the level of soil freezing (individually for each region), and take on the entire main load.
2. The edges of the piles above ground level are tied with grillage tape. Outwardly, it is no different from the classic strip foundation: the reinforced concrete is located under all the load-bearing walls, and takes on the main load. End up coming out monolithic foundation, which securely fixes the structure.

Interesting to know! Comparing the grillage type of foundation with its progenitors, it definitely wins. requires more financial costs and does not have such stability, but loses in terms of load distribution on the base.

For installation, drawings and diagrams made by a professional are required, and for accuracy on the ground, markings are first made.

To resist the movement of the soil, it is necessary to make a shallow foundation. For it, piles of asbestos pipes are used, inside which reinforcement is laid and concrete is poured. Below we will take a detailed look at the step-by-step instructions for this example.

Pros and cons of a pile-grillage foundation

Any design has its pros and cons, pile-grillage foundation is no exception. Let's talk about them in more detail.

The strengths of this foundation include:

• For installation, you do not need to involve builders and special equipment, you can do it yourself.
• It will take a little time to lay the foundation under it.
• Low financial costs.
• This is a universal foundation for different types of soil. It can also be done on terrain with difficult terrain.
• The foundation is highly reliable, does not collapse during seasonal movement and heaving of the soil.

Compared to classic strip foundation, savings in the construction of pile-grillage on average is 45-50%

Design flaws:

• The basement and basement are excluded if a pile-grillage foundation is selected.
• The floors of the first floor require additional insulation.
• The final mass of the building under such a foundation is limited.

Scope of pile-grillage foundation

The pile-grillage foundation in construction is usually used in the construction of light, one- or two-story buildings, in conditions of "unstable" soil (heaving, swampy, clayey). Often it is used in.

Such a solution will also help during the installation of buildings on a site with a non-standard relief: for example, construction on a hillock.

Subject to all requirements during installation, the grillage type of foundation will last for more than one decade.

Foundation devices with grillage: 1 - roofing material, 2, 8 - bottom trim, 3 - anchor bolt, 4 - anchor immersion depth 100 mm, 5, 9 - grillage, 6, 10 - pillar, 7 - log

Calculation of the pile-grillage foundation

The calculation of a pile foundation with a grillage implies the calculation of the depth of immersion of piles. It is recommended to entrust it to a professional. An error can lead to premature destruction of the entire structure.

In general, for this it is necessary to conduct a whole analysis: to study the features of the soil, take into account the wind and snow load, the climatic features of the region and the mass of all building materials.

Correct calculations of the foundation are the key to high-quality and successful construction of a house.

Consider the algorithm of actions

1. First, we calculate the total mass of all building materials that will be used.
2. Next, we calculate the snow load, after which the total load on the foundation is calculated.
3. The final step is to calculate the total load on the foundation.
4. The result of the previous calculations is multiplied by a factor.

Since the earth tends to move, be washed away by groundwater, swell when freezing, it is advisable to conduct a qualitative assessment of the soil. This study plays an important role in the construction of any type of foundation.

Do-it-yourself pile-grillage foundation

The construction of such a foundation does not require special skills and experience, so those who want to build a house can cope with this task on their own. Consider a step-by-step instruction for installing a pile-grillage foundation with your own hands.

Cleaning and marking the territory

Site preparation is one of milestones construction, the quality of which will determine the comfort of further work. The first thing to do is to remove all excess debris and plants.

Important! Trees and bushes must be uprooted, otherwise they will sprout again and cause problems during the operation of the dwelling.

If it is provided on the territory, it is necessary to carefully remove all weeds. If planned or beds, the top layer of soil (4-5 cm) is removed.

Also at this stage, the marking of the site is carried out. It is necessary for more accurate execution installation work(smooth pouring of the grillage and installation of piles in a predetermined place).

To make the correct markup, the drawing from the drawing must literally be transferred to the ground. It is important that all dimensions exactly match the parameters indicated in the drawings.

For work you will need the following materials:

• level;
• a hammer;
• roulette;
• rope (fishing line);
• pegs.

Places for piles are marked separately. They are distributed over the area in a certain order so that each support has a certain level of load (from 800 to 1600 kg).

Important! Supports are installed at each corner of the future structure, as well as in places where bearing walls or partitions.

Drilling a well for piles

Sometimes the grillage is made at a certain distance from the ground, then there is no need to dig trenches, but this somewhat complicates the process of pouring the grillage.

Holes for piles are drilled with a garden or hand drill. It is also possible to resort to the services of crane drilling machines, but it should be taken into account that this will lead to an increase in the estimated cost of construction by about 10%.

The depth of each hole is made 50 cm more than the level of soil freezing. The diameter of each hole should be slightly larger than 1/3 of the width of the foundation tape. The first 30 cm must be covered with sand and carefully rammed. This will help protect metal parts from soil moisture.

Important! The distance between piles should not exceed 3000 mm. The smaller the diameter of the post, the smaller the minimum allowed distance between piles becomes.

Installation of piles for the foundation

Now we form a "pile field", that is, we install the piles in their places. For the construction of simple buildings, they can be evenly distributed around the perimeter in rows.

Sometimes piles are installed in a checkerboard pattern. This order of placement of supports is often used for the installation of fences.

At the design stage of the pile field, the following details should be kept in mind:

1. The choice of piles depends on the type of soil;
2. How close to the surface does groundwater flow;
3. The diameter and length of the piles depends on the final mass of the structure (the larger the house, the more powerful, and therefore larger, the piles should be). It also depends on the type of grillage.
4. Be sure to calculate the bearing capacity of the supports.

We proceed directly to the installation of piles. For them, formwork, reinforcement is made, and after that the holes are poured concrete mix. It is recommended to start pouring concrete only after all earthworks have already been done.

You can use screw piles, for the installation of which it is not necessary to carry out excavation. Installation of piles in the ground takes place in several stages:

1. In a pre-marked place for piles, we make a hole with a depth of 10-15 cm.
2. We put the screw of the pile into it and begin to screw it in. This will require 3-4 people.
3. In the course of screwing, be sure to check the evenness of the entry of the support into the ground using the building level.

When buying ready-made concrete supports, you will have to involve special equipment, such piles are driven into the ground.

For each support, it is imperative to make a “heel” on which it will stand securely. To do this, sand is poured into the well, the pile itself is placed in the well and poured with concrete (about 40 cm). Then the support is raised (by 30 cm) so that the concrete spreads under it and creates a support pad.

Foundation formwork

Before starting the installation of the formwork, it is necessary to make a pillow at the bottom of the trench. To do this, 10-15 cm of sand is laid on the bottom, it is poured with water and carefully compacted. Crushed stone is poured on top of the sand.

Formwork can be bought at the store or made independently from ordinary boards, chipboard panels. So that the formwork material can be reused, it must be wrapped with plastic wrap.

1. Initially, along the perimeter of the future grillage, every meter we drive in stakes, to which we mount the formwork panels so that the stakes are on the outside.
2. To prevent the shields from dispersing, an additional support is nailed to the upper and lower parts. Special attention should be given to the formwork elements at the lower corners.

Important! The height of the formwork should be 10-15 cm more than the expected height of the grillage.

Reinforcement of piles and grillage

Reinforcement is a mandatory stage in the construction of the foundation, which helps to strengthen the entire structure as a whole. To do this, after preparing the formwork, a three-dimensional mesh is assembled from metal rods inside it.

The bars are laid in several directions, and at the intersections they are tied with strong steel wire.

Piles are also necessarily reinforced. To do this, take three rods and connect them in the form of a triangle, after which they are placed in place.

The rods should protrude 20 cm above the pile. Sometimes, for additional reinforcement of the rod structure, a circle is assembled completely.

Pouring solution

When pouring concrete, you need to consider some subtleties:

• The density of the finished solution should be medium.
• Before pouring concrete, all reinforcing bars must be connected.

Procedure

1. First of all, all supporting piles are poured. They are left for 1-2 days so that the structure dries out a little and becomes more durable.
2. After that, the tape itself is poured. To do this, it is recommended to use several concrete mixers and pour the mixture simultaneously at several points.
3. Let the foundation dry for a week. If necessary, the surface of the grillage is leveled.

Important! In rainy or cloudy weather, pouring concrete is prohibited, this will lead to a decrease in the strength of the entire structure.

Waterproofing insulation

Thermal and waterproofing of the foundation helps protect the foundation itself from moisture and dampness, as well as the foundation materials of the house.

Metal and asbestos piles also need to be covered with waterproofing, as over time, due to corrosion, their strength decreases. For this, you can use the same material as for waterproofing the foundation tape.

Subtleties of waterproofing:

To protect the piles, the roofing material is rolled up and put into the well in this form. In a trench for tapes, the walls and bottom are completely covered with this material. For reliability, roofing material can be covered with hot resin from above.

The pile-grillage foundation provides for the insulation of the side walls of the foundation, which act as a basement. For this, they are used: polystyrene foam or polystyrene foam, bitumen, etc.

To protect the base from moisture and mold, it is also important to take care of the ventilation holes (air vents). They are made using small pieces of plastic pipe.

It is laid at a certain level of the tape during pouring of concrete, the contour of the pipe is sprinkled with sand so that it can be easily removed. When the foundation is completely dry, the pipe is removed.

Now you know how to make a pile-grillage foundation with your own hands, using the knowledge gained from studying this article.