Installation of screw piles is especially in demand where the territory for the construction of a house is characterized by problematic soils and difficult terrain, as well as in the case of direct proximity to underground utilities. A screw base will be an excellent solution if you plan to add an extension to an existing structure. Installation of pile-screw foundations is popular in suburban housing construction. Let's try to figure out why the use of technology has become so widespread.
Mounting Methods
Screw piles can be installed in two ways.:
- By hand.
- Mechanized.
The choice is determined by several important factors that must be taken into account, otherwise the base of the house may not be mounted correctly:
- soil characteristics (density, rockiness);
- nearby groundwater;
- remoteness of communication highways;
- density and age of the nearest buildings;
- personal preferences of developers.
Next, we will examine in more detail the manual and mechanized installation of screw elements separately and we will analyze their features, advantages and disadvantages.
Manual installation
Do-it-yourself installation of screw piles is most often carried out if it is impossible to arrange an access for equipment directly to the construction. It is also impractical to catch up on equipment for the implementation of a small amount of work (up to 10 piles of small diameter), thereby increasing unnecessary expenses. Naturally, it is impossible to tighten screw piles with the help of technology where it is necessary to observe the regime of "silence" in the conservation area.
The main advantages of the method in which a screw foundation is installed with your own hands without special equipment can be attributed to its cheapness, because you do not have to rent equipment and accessories. In this case, the base of the house is mounted with the involvement of three people, preferably physically strong. Of the fixtures, it is necessary to stock up with a shovel, sledgehammer and level for 3 planes, as well as lever wrenches that can be replaced with pipes (a fixture that ensures the rods are wrapped).
Disadvantages
If we talk about the disadvantages of manual screwing, they are as follows:
- possible critical deviation of the supports from the vertical with an error of 5 cm or more;
- the likelihood that the tightening of the screw piles will not be fully completed due to a lack of human resources and the depth will not reach the required level;
- the base of the house is mounted on a limited space;
- the diameter of piles exceeds 108 mm or, in a very rare case, 133 mm.
If all these points are not relevant for you, you can safely install a screw foundation with your own hands without additional devices.
Mechanical installation
Those who can not or do not want for any reason to manually install supports for future house construction will be forced to use equipment for twisting screw piles. Here you will need a special machine - a drilling rig with a torque of 2000 - 4000 N (Newtons). The use of such a technique ensures the wrapping of support elements even in very dense soils (stones and boulders do not count).
The mechanical device guarantees optimal deepening of the supports and their quick installation. Also here you can not worry about deviation from the vertical axis. The installation for twisting screw piles justifies itself where large-diameter elements will be used or an impressive amount of them is needed. With the help of the unit, the base for the house can be mounted in a limited space, where the device for manual procedures is not suitable due to the bulkiness of the rods and insufficient scroll angle. Also here, the depth will be guaranteed to be maintained in the given parameters.
We draw your attention to the fact that, if necessary, a grillage can be installed on screw piles, it does not matter how they were mounted.
Step-by-step installation instructions
The technology of installing screw piles provides for preparatory work, during which soil analysis is performed on the ground. Based on the results, the size of the conical supports is selected and their number is calculated. They also mark the site with a milestone marking the places where the dive is planned. The screw rods themselves must be treated with an anti-corrosion agent or primer and the level of immersion noted.
Remember that the construction of the foundation, namely the turning of piles, it is customary to start with a corner milestone, located at the highest point of the relief. Then proceed to the installation of corner rods, and then place the remaining supports according to a given step.
Manual installation
At the place of marking with a special drill (drill), holes of the required diameter are drilled. This process is not necessary to carry out a drill, and the holes can be done with a conventional shovel. Piles are placed in the holes, the verticality of their installation is measured and twisting to the required level is carried out.
To twist the piles, it will be necessary to use a metal rod or scrap, which is inserted into the technological holes of the bearing element, and already reinforced pipes of the corresponding diameter are put on them - this design will be rotated. Manual twist is carried out clockwise until the required pile deepening. Usually the rotation is carried out by two, and another person controls the verticality of the rod with the help of a level.
When all the elements are installed, they must be aligned in height, trimming at the level of the mark determined by the optical range finder or stretched wire. The foundation of the house must be reliable, so the piles are reinforced by pouring concrete mortar, after hardening of which, it is necessary to weld the headband. The seams left by the welding machine are treated with an anti-corrosion compound.
Self-assembly of screw piles does not take much time, and it takes less than half an hour to install each individual element. Please note that the supports are buried by at least one and a half meters - this is the average mark of soil freezing. If this rule is not followed, piles will be mobile during freezing and thawing of the soil.
Mechanical installation
For this kind of installation, you will need a machine with hydraulic rotators for large-sized piles located on an excavator or a truck. Medium and small diameter bearings are best installed with a screwdriver - this is a special compact device.
Immersion of the screw support is carried out by hydraulic motors operating in different power modes. Both types of devices quickly put the piles in place, while the depth is checked very carefully, and special centralizers or on-board computers monitor the angle of inclination and ensure the perpendicular entry of the pile.
Piles are placed on special seats on the equipment and ensure their fixation. The mechanical device exposes the support at the intended point and deepens it to the desired level. Next, the holders are removed from the screw cone and spend its final processing:
- poured with concrete;
- weld the headband;
- process the seams.
It depends on each stage what the finished foundation of the house will be, so it is strongly recommended not to neglect the instructions during the construction of the foundation.
Support Quality Control
A step-by-step instruction for any method of mounting screw piles ends with a no less important recommendation than the main working points. We are talking about tests for resistance to pressing and pulling effects, which will help to build a quality screw foundation with your own hands..
The process itself is carried out in a few days (from two to ten days, depending on the nature of the soil), for which the supports are alternately subjected to design loads in both directions. Couplings, winches or hydraulic jacks are usually used as cargo. If a grillage is installed on screw piles, the base of the house is being finalized in accordance with technological rules. The construction of the grillage is a very crucial moment, so you need to approach it no less seriously than the installation of bearing rods.