Columnar or pile foundations are inseparable from the concept of a grillage. Land owners who are going to build a private house on such a platform need to comprehensively consider the acceptability of this type of foundation. In addition to the price advantage, in contrast to the jellied "pie", it has other advantages and disadvantages.

The grillage is a horizontal part of the foundation that distributes the weight of the object and transfers the load to the platform supports.

A single design is achieved by ensuring the rigidity of critical units.

The advantages of the base in strength, durability, the possibility of using on any capricious soil - quicksand, clay, sandstone. In addition, due to the small volume of preparatory steps and the lack of a large amount of concrete, it is considered the cheapest of all known foundations.

There are also disadvantages - it is impossible to arrange a basement or a cellar under the object, since the covered part - the walls - are absent. Also, a high foundation can be a problem in windy winter weather - snow deposits under the floor do not contribute to heat. In this case, a pick-up is set up - a brick barrier, which leads to an increase in the cost of the project.

If bored piles are used for the foundation, then you cannot do without construction equipment - you need to prepare a site for entry. This will also require a cash investment.

The longevity of the residential building, the possibility of arranging several floors and the bearing capacity of the object as a whole depend on which grillage will be laid on piles or pillars. The grillage is classified into the following types:

By location

• Recessed... Part of the grillage goes into the ground, the width of the base is impressive - from 0.5 m. This type of foundation is typical for objects of several floors, built on soils that are not characterized by stability.
• Not buried... The bottom sole of the grillage lies on the ground. The best option for the required reliable stability. The entire load is distributed not only to the supports, but also to the entire plane of the base.
• Hanging... The height between the house and the ground is 10 centimeters or more. It is made for wooden and steel grillages in order to exclude interaction with soil moisture. The pillars or piles are impressive and take the weight on themselves so that the structures do not sag under the load of the house.

By material

• Reinforced concrete grillage... In terms of reliability, it is not inferior to a monolithic slab. Requires a large preliminary amount of work - setting the formwork, reinforcement. In this case, the piles are located close to each other, since the structure is heavy. As a rule, such a grillage is never hanging.
• Tape... It includes steel channels, wooden beams. Laying takes place by cutting or screwing in anchor bolts.
• Combined... The foundation is a prefabricated structure - steel screw piles, reinforced concrete pillars and a wooden grillage plane. Together, such a design is cheaper than a homogeneous one, which is why it has gained popularity among home-grown builders.

By design

In terms of installation, there are only three types of grillage - monolithic-pouring, monolithic-prefabricated, prefabricated. Depending on their own financial capabilities, efforts, availability of equipment, manual assistance, they choose the most acceptable one.

Piles or poles

Choosing supports for a future residential building is a responsible occupation. Of course, brick or block pillars will be the cheapest. However, they are suitable for small one-story houses without constant load - summer cottages, for example. For objects of several floors, with year-round living, reliability is required - piles. They are of several types:

• Reinforced concrete... Externally, they are round or square cast pillars with a pointed end, for easy entry into the ground. For them, pits are dug into which supports are placed and poured with concrete. Preliminarily, the ends of the piles are waterproofed from soil moisture, since cement and other components crumble due to freezing, accumulation of moisture and other natural disasters.
• Metal screw... Different lengths make it possible to arrange piles to any depth - it should always be below the freezing point. Convenient heads allow you to screw the grillage into the surface reliably and firmly.
• Wooden... Such piles are extremely unreliable due to their tendency to deterioration, decay, mold, and cracking. Or they should be made of rocks inert to dampness - larch, cedar. Accordingly, the price of such supports is high and unacceptable for budget construction.

The best construction option is steel screw or reinforced concrete piles. You can install them manually without involving construction equipment. It is important to choose the right number of supports so that the object remains reliable and stable at all times.

The location of the piles in the grillage

There are several ways to properly position the piles. Each of them ensures a secure position of the grillage under the house. The choice is important depending on the size of the object.

• Single location... Each pile will be located under the intersection of the grillage strips. It accounts for the weight of a load-bearing wall or corner. Quite a solid foundation for a one-story building.
• Tape... The piles are placed with equal spacing along the length of the grillage perimeter. Suitable only for small buildings - summer cottages, baths.
• Stripes... The piles are evenly spaced under the grillage with equal spacing along the strip. Suitable for single-storey buildings with a large number of rooms or outbuildings.
• Bushes... The places of the highest house loads are calculated, the marks are projected onto the ground, where pits will be dug for the installation of piles.
• Field or chess... They are used for large-area grillages - the objects are appropriate. Piles are installed staggered or equidistant from each other.

You cannot deviate from the prescription of the project. If it indicates the exact location of the piles under the grillage, then it is necessary to adhere to exactly this distribution of supports.

Having decided on the desired option and purchasing the required number of piles, they begin to work. Ideal weather conditions are early autumn or late spring, when the earth gives off moisture intensively, there is little precipitation, and the temperature does not exceed 15 C.

Tools and materials

Depending on the selected grillage option, you will need the following:

• Excavation tools: shovels, crowbars, picks.
• For reinforced concrete grillage: boards or plywood for formwork, for steel piles - crowbars or long pipes for screwing in.
• For wood: tools for working with wood - saws, pry bars, axes.
• Control and measurement tools: tape measure, plumb line, levels.

In addition to piles, concrete and material for the grillage, they acquire coating waterproofing and / or anti-corrosion agents. For a wooden grillage, impregnating protective compounds are bought.

Site preparation

The soil is freed from vegetation very carefully - this is an important condition for any type of foundation. If there are plantations in the form of shrubs and trees, then after uprooting the soil is shed with chemicals that stop further growth.

Further, the site is leveled and marked out. To do this, use stakes and a rope stretched between them. When the contours are marked, they begin to mark the places for inserting supports - remove 5 cm of soil for piles or dig holes for reinforced concrete pillars.

Installation of supports

Steel screw piles are screwed in by means of a scrap or a long pipe inserted into the head. The pile must be exactly perpendicular to the ground. After screwing in all the units, check the flatness of the ends for compliance with the level, and, if required, cut them to the desired size.

Reinforced concrete pillars are laid in a different way:

• A layer of gravel and sand is poured into the pit - 15 cm each. They will divert the incoming groundwater.
• The ends of the pillars are wrapped several times with roofing material or coated with bitumen mastic each time after the layer has hardened.
• Supports are inserted strictly perpendicular to the ground and poured with concrete. To save the mortar and give the forest strength, the void around the pillar is filled with construction waste - fragments of bricks, stones.

The complexity of the installation of reinforced concrete supports is to fit their ends into one plane. A diamond wheel may be required to cut concrete and reinforcement. Installation of the grillage on steel piles is carried out immediately, on concrete pillars - after the final hardening of the solution.

Installation of concrete grillage

After the reinforced concrete piles have hardened, they put out the formwork from thick moisture-resistant plywood and supports or ready-made shields - there is already support there. If you need to insulate the foundation in advance, then the width of the wooden boxes is calculated with a margin. A sand-crushed stone pillow is poured into the finished boxes, expanded polystyrene plates are laid along the walls, reinforcement is knitted.

After all the procedures, the grillage is poured. To do this, they buy a ready-made solution from a mixer and fill in the area at a time - the inhibition of construction will lead to delamination of the concrete. If you want to save money, then rent a mobile construction mixer and mix the solution yourself. However, even in this case, it is required to do everything in one day. The filling is carried out slowly, expelling the air, piercing the thickness with a rod, until a white "milk" appears on the surface.

Installation of wood and steel grillage

A beam, a section of at least 150 cm, is laid on piles by the method of cutting in half a tree. Holes are drilled in the wood in advance for adhesion to the pile heads. Before laying, it is important to coat them with bitumen so that the interaction of cold metal and warm wood does not create condensation.

Metal channels of the required size are put on piles and screwed to the heads. The cross members are welded. For reliability, in the corners of the future building, the grillage is reinforced with steel reinforced corners. After work, the steel structure is coated with an anti-corrosion agent.

So, the installation is simple. Considering that in any construction, the creation of the foundation takes the lion's share of the budget, independent work is fully justified. Scrupulous adherence to the recommendations will make the work durable, worthy of any object.

Diy grillage installation video

In the construction business, this term is called a horizontal structure in the form of a flat lattice frame. The elements are supported and rigidly connected, as a rule, with columnar or pile foundations, distributing the load on them from the overlying buildings - internal and external walls, floors.
The grillage device can be carried out in three main ways.

He might be:

• fully or partially buried in the ground foundation;
• lying freely on the earth's surface;
• towering above the foundation to the height planned by the project.

Structurally, it is possible to perform both monolithic (only for reinforced concrete) and prefabricated (beams and girders made of precast concrete, metal or wood).

In contact with

What is a grillage in construction

The use of such grillage structures has proven itself well in individual construction. Various types of grillages are suitable for most common low-rise basement buildings - brick, wood, frame. Pile-grillage foundations have long been used in areas with the danger of floods, mudflows (they allow water streams to pass freely under the house without causing significant damage).

Used in permafrost conditions(do not allow the foundation under the house to thaw and lose its bearing capacity). Currently, they are widely used for individual construction, as they are characterized by small volumes of earth and concrete work, their reduced labor intensity and cost.

Important! It is inappropriate to use structures of this type of foundations for multi-storey residential construction outside the permafrost zone.

The disadvantages are:

• the impossibility of arranging basements or basements;
• additional costs for insulation of the first floor overlap.

Views

Reinforced concrete

Has three types:

• Monolithic. It is made at the construction site from monolithic reinforced concrete, rests on bored reinforced concrete piles or posts, with which it is rigidly connected with the help of reinforcing cages;
• Made. Manufactured in a factory way from precast concrete products, which are connected with each other using special locks, dowels and embedded parts, requires constant geodetic control when breaking down axes and installing;
• Prefabricated monolithic. Part of the structure can be manufactured directly at the construction site, and the rest can be factory-made.

Metal

It is made in the form of a welded frame made of rolled metal profiles. You can make a grillage from a channel, angle, I-beam. The structure rests on piles(driven, screw or bored), posts (reinforced concrete, rubble concrete, brick).

Wood

Power load-bearing wooden structures are made of beams, composite or glued logs. It rests on vertical supports in the same way for a metal grillage. In some cases, driven piles from logs are used, which are protected with deep impregnation antiseptics before use. These antiseptics include, for example, creosote, which is used to protect railway sleepers.

Which grillage is suitable for different types of buildings

Monolithic

For light one-story buildings, a monolithic reinforced concrete pad can be used on shallow piles (above the soil freezing depth).

Important! This method is applicable for light one-story buildings.

The horizontal frame is raised above the ground to a height of at least 400 mm. This ensures the equalization of temperatures under the house and the environment, which allows in the winter period to significantly reduce the unevenness of the influence of the forces of frost heaving of the soil (when freezing the soil increases in volume) on the piles and to prevent them from distortions, distortions and destruction.

Grillage with a base below the depth of soil freezing

For ordinary one-two-story individual houses or country cottages, you need to use foundations on piles or brick posts, buried below freezing soil... In the middle lane, this value is 1.5 - 2.5 m. More exact value can be found in the nearest construction organization.

Sometimes a part of the foundation can be made not as a flat frame lattice, but as a concrete pad in the form of a solid monolithic slab. This system can be based on a pile field, arranged with a certain pitch and distance between the piles.

The slab should also be buried, lying on the ground or raised. The above-ground elements of the house are then erected on it. It is better if the horizontal and vertical elements of the foundation are rigidly connected to each other by reinforcement.

For the construction of industrial facilities - a variety of large-span structures, such as workshops, warehouses, hangars, prefabricated foundations are arranged, the main load-bearing elements of which are concrete, so-called, glasses.

They are installed in pits previously dug to a predetermined depth on a group of driven piles (the so-called bush) and serve as supports for prefabricated vertical reinforced concrete columns and horizontal structures, on which reinforced concrete enclosing panels or brick walls are later mounted. In housing construction, this method is practically not used.

Grillage making

Elements in this version are usually mounted on vertical elements with an upper mark corresponding to the lower mark (at the bottom of the horizontal part), they are made in the form:

Manufacturing of a tape grillage

By location type:

• buried... A pit is torn off along the marked axes to the required depth, the width of which must correspond to the width of the beams that make up the horizontal frame. If the rack is partially recessed, then inventory or self-made formwork is installed at the required height;
• lying on the ground. In this case, after the horizontal leveling of the site, the formwork is installed at the required height directly on the ground, while the width of the foundation grillage will correspond to the distance between the sides of the formwork;
• high pillow. Its construction begins with calculating the height of the formwork, which is determined as the sum of the values ​​of the height of the excess (at least 400 mm and the calculated height of the beam). After installing the formwork into it, up to the mark of the upper part (heads) of the supports, sand is poured in layers, compacted and leveled, then the reinforcing cage is started and concreting is carried out. After the concrete has set (4 weeks), the formwork is disassembled, sand is removed from under the finished structure, leaving the necessary space between the ground and the bottom of the beam

Important! when tying the frame, you need to use only knitting wire, since when using welding, high-temperature exposure will sharply reduce the ability of the rods to withstand tensile stresses.

To protect the reinforcement, a protective layer of concrete with a thickness of at least 25 mm is always created around the perimeter of the cross-section of the rack.

To create such a layer from the bottom of the beam, small fragments of brick or concrete must be placed under the lower rods of the frame. Concreting is carried out with concrete of class not lower than B25 - B30.

You can use both imported mixing concrete, and prepared yourself using a concrete mixer. Concreting should be carried out continuously until the completion of the work.

Important! A break in concreting for more than 4 hours will lead to the fact that unintended seams and cracks appear in the grillage, which can then lead to the collapse of the walls erected on them.

To prevent the formation of looseness, air bubbles, cavities and cavities, which reduce the strength of the structure, during operation a flexible shaft submersible vibrator should be used... It is not recommended to apply loads to the foundation structures earlier than 28 days after their manufacture.

Manufacturing of a metal grillage

Rolled metal is used as horizontal load-bearing elements of such a structure. Since the height of the grillage is unlikely to be less than 250 - 300 mm, lifting mechanisms will be required for the installation of individual parts. The span must correspond to the distance between the axes of the supports, on which the ends of the elements used must converge and be joined together by welding, both in the longitudinal and transverse directions. The use of split beams of two or more parts, if they do not rest on vertical supports in the joint zones, is not allowed.

At the points of contact between the metal frame and the supports, it is necessary to arrange a waterproofing protective layer of roofing felt or other roll material.

After installation, metal elements must be treated with anti-corrosion compounds and protected from weathering with resistant enamels.

There should be no places in the structure where rainfall or condensation in the form of dew can fall, accumulate and stagnate. Otherwise, even waterproofing will not help.

Important! Inspection of the metal structure should be carried out at least once every 2 ... 3 years and its anti-corrosion protection should be renewed.

Making a wooden grillage

Wooden structure beams are made from logs, beams, glued beams, certified for outdoor use. Like metal beams, wooden beams are stacked on prefabricated supports, which can be of any type. The elements that make up a wooden grillage, like a wooden one, are interconnected with the help of various incisions, cuttings, metal driving brackets, screws, threaded dowels.

Important! To prevent the appearance of mold, rot, damage by wood-eating insects, the elements must be treated with antiseptics before use, and to protect against fires with fire retardants - substances that do not allow the wood to maintain combustion.

Before the installation of wooden structures on the tops of the supports reliable waterproofing must be arranged preventing the filtration of water from wet soil to the overlying elements.

The wooden structure can be used for the construction of solid timber or timber frame one-story houses.

With proper strengthening of the foundation, the wooden structure can be used in the Far East and North, where the ground freezes by more than 50 centimeters during the winter.

However, additional insulation will be required.

Features of grillage structures

The erection of grillage foundations (perhaps, with the exception of a wooden one for the simplest country house) seems to be a difficult task that requires special knowledge and experience in performing such work to solve it. A contractor who does not have certain skills, does not fully understand what a foundation grillage is, may not be able to cope with this work, which will entail a complete or partial alteration.

Useful video

It should always be borne in mind that to calculate the bearing capacity of the foundation soils, the choice of the type of foundation, it may be necessary to conduct engineering and geological surveys. And to collect the loads acting on the foundation, determine the cross-sections of the bearing elements, calculate the consumption of cement, sand, crushed stone, the number of reinforcing bars, certain sections, you will definitely need the help of specialists.

A grillage is a frame that is mounted on piles. It is necessary to support and evenly distribute the weight of the building under construction. Competent binding of screw piles is just as important as the pile foundation itself. There are several types of grillage and a method of strapping the pile-screw foundation

1. Foundation on screw piles

For the first time, screw piles, like many modern technologies, began to be used by military structures. Strength, affordable cost and quick installation of structures without the use of earthworks were excellent for the construction of structures on the battlefield.

Undoubtedly, like all developments related to the defense industry, they gradually began to enter other sectors of the national economy. Today, pile-screw foundations are being successfully mastered by builders for the most peaceful purposes - housing construction.

The pile-screw foundation is an economical and convenient choice for the construction of private houses. Screw piles are steel pipes with a tip and blades at one end and a hole at the other. With the sharp end, the pile is screwed into the ground manually or with a drilling mechanism to a depth of one and a half meters. At the other end, a base (head) is mounted with a vertical surface for the harness. Another common name for the binding of screw piles is the grillage.

Piles are usually installed around the perimeter and under highly stressed parts of the building. The number of piles, screw-in depth and location are calculated based on the scale of the entire structure.

2. Types of screw pile grillage

The main classification of screw pile strapping is carried out according to the type of material used. Each of them has its own advantages and disadvantages. Grillages are:

• Wooden
• Metallic
• Concrete

In the wooden grillage, the role of the strapping is performed by the beams laid on the pile heads.

The metal grillage is made of metal beams welded to the heads of screw piles.

The concrete grillage is carried out during the construction of the heaviest structures, and the role of the house is supported by concrete beams connected to the piles.

Let us consider in more detail each method of installing a grillage on screw piles.

3. Wooden high grillage. Preparing for installation

Wooden grillage is usually used in low-rise construction. It is well suited for country houses and one-storey cottages with an attic. Most often it is used in the construction of frame structures. The first crown of the bar laid on the heads acts as the foundation strapping. Since wood is adversely affected by moisture inevitably adjacent to the soil, the timber must be treated with special compounds that prevent decay and give the wood hydrophobic properties. After that, the beams are installed on the pile heads.

Before installing the beams themselves, after screwing in the piles, it is necessary to perform several more operations to prepare the installation of the grillage.

1. Align the height of the piles (you can simply cut off the excess)
2. Install the heads (metal plates that have holes for fixing the bars)
3. Priming and applying an anti-corrosion layer to the piles (if this was not done before installation)
4. Make a waterproofing gasket from roofing material, bikrost and similar materials between the heads and the beam

Wooden beams must also be prepared for the construction of the foundation. First of all, they must be dry. It is best to use the timber after chamber drying. If it is too expensive, the tree must be kept for up to 3-4 months in well-ventilated stacks to dry. Then they are impregnated with a special antiseptic and also a substance that reduces the flammability of the tree - a fire retardant. If glued laminated timber is used, then usually all these procedures have already been performed with it.

4. Installation of a wooden frame

The process of installing a wooden grillage takes place in several stages:

1. Perimeter beams are laid on the piles. For greater strength, they are connected with grooves. This increases the strength of the connection.
2. Then the bars are laid on the inside.
3. Further, all the heads are screwed to the bars. Holes must be pre-drilled in the wood. You can chamfer the wood if you want the nuts to stick out of it.
4. For strength, you can additionally install corners or channels along the edges.

There are several ways to connect the timber at the corners. The two main ones are "in a half-tree" and "in a paw".

The grillage beam can only be laid along the perimeter of the future building, or it can have a more complex shape with transverse beams if the building has large dimensions and many points with increased load on the foundation

After laying the timber, it is necessary to carefully check the horizontal plane. In those places where the timber protrudes slightly from the plane, it can be suspended, and in places where the depressions are formed, it is necessary to make flat pads, for example, from plywood.

5. Metal high grillage

Metal straps are used for more massive structures, including brick buildings or heavy metal structures, such as hangars. Here, a channel or I-beam is laid on the piles, shelves down. The connections are made according to the bearing wall scheme. The connections must be welded and additionally bolted. Due to this, the structure gains greater strength and can withstand the load of the metal. Also, additional reinforcement of the seam does not allow cracks and subsequent ruptures to form on the foundation. For brickwork, the step of the pile row should be no more than 1-1.5 m, since the mass of brick structures will bend the channel at a step of 3m.

The size of the channel can be different. The largest dimension is used to reinforce the loaded axles.

It is necessary not only to weld the metal grillage, but also to additionally tighten it with bolts. This requirement is due to different types of loads - not only lateral, but also vertical. This protects the metal beams from cracks and breaks.

6. Concrete grillage

If the building, which is installed on screw piles, has a lot of weight - this may apply to houses made of logs, foam blocks or frame frames with a heavy roof - it is recommended to install a concrete grillage under them.

Its device requires

• Metal fittings
• Knitting wire
• Concrete
• Plank formwork

After installing the piles on them, reinforcement with a diameter of 12-18 mm with a distance between the rods of 15-35 cm is knitted on them along the perimeter of the foundation. In the upper part of the piles, holes are drilled into which longitudinal bars are inserted.

Then a formwork is mounted around the piles, similar to the one used for pouring the strip foundation. Concrete is poured into the formwork. When pouring concrete, the inside of the pile is also poured.

Thus, a prefabricated foundation structure is created from the actual piles and concrete strapping.

Such a grillage is considered the most powerful and is not inferior to strip concrete foundations of the same parameters, and its installation on piles is much easier.

Usually piles protrude a considerable distance from the ground - up to a meter if the surface is flat. Thus, the pile tie is most often also located at some distance from the ground. This is especially true for wooden and metal grillages. Concrete grillages, on the other hand, are poured close to the ground. This distributes the load more evenly not only along the pile heads, but also on the ground.

7. Pile bush

Sometimes the supports for buildings must be very powerful. Of course, in such cases, bulk concrete pillars are usually installed, but it is possible to use screw piles if they are twisted at a close distance to each other. In this case, the upper parts of adjacent piles are connected to each other. This connection is called a pile bush.

It turns out that several piles work at once to perceive the load in some particularly loaded node.

This method is especially often used in industry, where the construction of conventional concrete foundations is difficult - in swampy places, on slopes, etc.

Pile bushes are strapped using the methods described above, given that the piles are assembled in groups.

8. Conclusion

The installation of the grillage on screw piles determines the final bearing capacity of the foundation. The binding of screw piles must be carried out especially carefully, since the piles are reliable supports, but with a relatively small base area for the foundation. This increases the role of the strapping.

The firm "K-DOM" specializes in the construction of foundations on screw piles for various types of structures - houses for permanent residence, garden houses, hangars, bridge supports. We use all types of screw pile grillages - depending on the type of buildings, soil and terrain conditions.

High foundation grillage made of screw piles

A high grillage is a distribution beam that unites the pile heads and redistributes the load on them from the structures located above, while its base is located above the ground surface. The main regularity in its construction is that the larger the span between the piles, the larger the cross-section of the beam must be used.

This type includes: timber, logs, high-quality beams (channel, I-beam, corner).

Tying the pile-screw foundation with a bar or log

Strapping bar (Fig. 1) - the very type used in the construction of wooden, frame structures. The section of the timber is used: 150x150 mm with a maximum pitch between piles of 2500-2700 mm, 200x200 mm - with a pitch of 3000 mm. Attached to the head with a hairpin.

Metal, unlike concrete, does not absorb moisture (although sometimes condensation can form on it), therefore, the issue of arranging waterproofing for the pile-screw foundation is not of such fundamental importance. Nevertheless, it is still recommended to install a waterproofing pad between the support platform (head) and the wooden structure.

Log (see fig. 2). The first crown of the log structure can be laid directly on the head. The main advantage of a log is the preservation of the integrity of the wood, which increases the resistance of the material to deflection. A rounded log gives a greater deflection in relation to a solid one. This is due to the violation of the integrity of the solid layers of wood.

In the case of concrete foundation structures, to increase the service life of the strapping, it is advisable to make the first crown of the structure from oak or larch. When building a foundation from screw piles, these measures can be abandoned, but only if the grillage height is at least 500 millimeters from the ground level.

Tying a pile foundation with a bar or log is the most economical, and at the same time, the fastest-performing type of connection. It requires the piles to be at the same level to avoid deformation of the piping. If the levels do not correspond to each other, then the alignment is carried out by the method of partial sawing of a bar (log).

Docking a bar (log) is the next stage in the strapping device (Fig. 3). To connect in proportion to each of the bars, cuts are made from above and below, the bar (log) is folded at a right angle. Joints should be treated with special solutions that protect against moisture, laid with jute.

As for the use of antiseptics for treating timber or logs when installing a grillage, this procedure is mandatory only for concrete foundations. In the case of the strapping of the pile-screw foundation, it is advisory in nature, of course, also provided that the height of the grillage is at least 500 mm from the ground level.

Tying the pile-screw foundation with a channel or I-beam

The constructive solution of the metal grillage is determined depending on the loads on the foundation SNiP II-23-81 * "Steel structures", SP 53-102-2004 "General rules for the design of steel structures".

Strapping with a metal channel or I-beam can be carried out both with the involvement of construction equipment, and manually (depending on the size of the channel or I-beam).

Channel (see fig. 4 - 7). Depending on the structure, it can be laid flat or on the edge. The edge version works better for deflection, but there is a torsional moment, therefore a twin channel is recommended.

A channel, laid flat (with shelves down), with a pile pitch of more than 2000 mm, already gives a deflection under its own weight (according to calculations), therefore, using this technology, it is advisable to design a distance between the piles of no more than 2000 mm.

I-beam (see fig. 8). It is advisable to use this type of grillage when reconstructing a foundation.

The connection of all elements to each other in both cases is done by welding.

Since long products (channel, I-beam) have a sufficient thickness (5 and more millimeters), and the operating conditions of a high grillage assume exposure only to atmospheric corrosion, such structures, even in the absence of additional anti-corrosion protection, will operate for the entire period provided for by regulatory documents (GOST 27751-2014 "Interstate standard. Reliability of building structures and foundations. Basic provisions"). Despite this, after the structure is welded, it (at least for aesthetic reasons) should be treated with an anti-corrosion compound.

Low foundation grillage made of screw piles

A low grillage (shallow foundation or reinforced concrete tape (Fig. 9) is a distribution beam that unites the heads of the piles and redistributes the load on them from the structures located above, and its base is located on the surface of the ground or below. In contrast to the suspended one, it distributes the load not only on the heads, but also on the ground (base) under it.

When using this type of grillage, it is necessary to comply with the requirements that are relevant for concrete foundations, for example, in terms of waterproofing and the use of antiseptics (in the case of the construction of a frame-panel or wooden structure), and also take care of observing the rules for arranging the basement (for more details, see the section "Finishing the basement ").

The height of reinforced concrete grillage is determined by calculation in accordance with SNiP 52-01-2003 “Concrete and reinforced concrete structures. Basic Provisions ". Reinforcement is made with flat meshes, as a rule, from A-III (A400) reinforcement. For the grillage, concrete with a strength grade B15 or B20 is used. When calculating, as well as when calculating a pile field, it is necessary to take into account the uneven distribution of loads over the foundation.