The foundation on screw piles
Dec 20, 2019
For the construction of the building must be approached thoughtfully, carefully calculate all the stages of construction. First and foremost, you must determine the type of foundation. But what if your site you are facing the so-called "difficult" soils, which include:
- Areas with groundwater;
- Areas exposed to the forces of frost heave;
- Flooded areas.
In this case, one of the fastest and most reliable way to solve the problem is to use a screw-pile foundation.
You can highlight the main advantages of the screw pile-foundation:
- Installation is carried out within one to two days;
- Not required alignment relief area;
- There are no large-scale earthworks;
- Screwing piles is carried out in all weather conditions.
The main disadvantage of the screw-pile foundation are:
- The impossibility of mounting on rocky terrain and in areas with hard limestone layers or rocky soil;
- Piles can not be installed closer than 0.5 meters to an already built home, and installation in this case is difficult because of the use of special instruments;
- It should also be noted that the choice of screw-pile foundation is considerably complicated to build a house with a basement. BUT price such a foundation becomes unreasonably high.
Based on the experience of participants Forumhouse.ru we will tell you:
- Constructive features pile-screw foundation;
- The fact that you need to know to calculate the required number of piles;
- On the secrets of mounting screw-pile foundation;
- On the basic errors when fitting the piles.
Design features a screw-pile foundation
The foundation on screw piles - a group of piles screwed into the ground and is a single field. With the construction of the houses are most commonly used piles with a diameter of 108mm barrel length of 2.5 meters and a diameter of 300mm blade. After the pile is screwed into the ground, it remains on the surface of about 50 cm from its trunk. Then, on the trunk of the pile is welded headroom. As standard, the headroom has 250h250mm sizes.
Headroom necessary for mounting on him strapping beams, channels or raft foundation on which the structure is then mounted.
Pile - a metal tube with a pointed end and a blade attached to the special configuration of its lower part. Due blade pile screwed into soil, compacting it until it reaches the desired depth and are rested in a sturdy base. Because of this pile can carry the design load immediately after installation.
Piles vary in length, diameter, and its purpose, namely:
- Screw pile Ø76 mm - used in the construction of fences,
- gazebos and light additions;
- Screw pile Ø89 mm - suitable for building huts,
- and piers;
- Screw pile Ø108 mm - universal version for the construction of frame and log houses;
- Spiral pile of Ø133 mm and above - used for the construction of houses of logs, concrete blocks and industrial facilities.
When choosing a pile in the first place should pay attention to the following characteristics:
- the wall thickness of the metal stem. In qualitative pile thickness is from 4 to 4.5 mm;
- a metal blade thickness. It should be at least 5 mm;
- The quality of the weld. Unacceptable and undercooked shell portions;
- sheeting piles. If the paint layer is thin or poor quality, then simply wipe on the ground at a twisting piles.
It should also be noted that there are piles with a molded tip. Feature piles such that the piles of the blade tip and forms a single piece made in a foundry, which is then welded to the pile shaft.
This pile is considered more reliable than conventional welded, since it has a large blade thickness, and has only one weld. A can also be screwed into the ground, which has the roots of trees or across small rocks.
How to calculate the required number of piles?
You can often hear the assertion that the piles must be screwed into the ground with a certain step. And so calculate the required number of piles is quite simple - it is only necessary to know the length, width and weight of the structure. But as practice shows - it is fundamentally wrong! So how do you figure out how much you need for your piles foundation?
According to FORUMHOUSE users for the proper paymentand pile field is first necessary to investigate the bearing capacity of soil under the blade of the pile. To this end, in a portion within the control points is performed a trial pile screwing. And on the basis of the received data, calculates the required length of the piles and the number of a specific project houses.
For calculation pile the foundation can use the table, which can be used to determine the carrying capacity of screw piles depending on soil.
The minimum depth for screwing piling Moscow and Moscow region is 1.5 meters, which ensures the installation of the pile foundation below the depth of soil freezing. Correctly set screw pile Ø108 mm is capable of carrying a load of 5 tons.
Features mounting screw-pile foundation
Screwing screw piles can be done either by mechanical means - with the help of machines equipped Hydrodrills and manual method - by a few people.
It should be noted that the mechanical method of mounting piles easier to control the force needed screwing. Also, this method makes it possible to more accurately center the trunk piles. Thereby achieving a higher mounting accuracy. The maximum deviation of the barrel screwed pile of the vertical axis should not exceed 2 degrees.
Once the pile is screwed to the desired depth, made cutting its top. To edge all the piles was put on the same level, you must use a laser level.
Then, the pile shaft is filled concrete mortar. Contrary to popular belief - this is not done to enhance the pile and to expel oxygen from the pile and thus prevent corrosion of metal inside the barrel. In addition, if the pile is not open to concrete, then with the arrival of winter, it can be filled with water and it will break.
What else should pay attention to the installation of piles?
- To determine that the pile is screwed until it stops, or as they say assemblers, "gave denial" can be on a strong deformation of the metal of the barrel lugs;
- Members forumhouse.rurekomenduyut by pouring concrete into the barrel pile Nedolya about 20 cm from the upper level of the pile, and fill in the remainder of the dry cement-sand mixture. This is done in order to draw out the moisture from the remnants of the barrel;
- After welding the end walls, carried horizontal strapping of piles with each other. Most often used for this purpose beams or metal profiles. If the piles protrude above the surface of the earth more than 1 meter, in order to stiffen the entire structure to the trunk piles made Weld angle additional profiles - struts.
Possible errors when installing screw-pile foundation:
- When installing a screw-pile foundation is not allowed exhibiting a uniform level of piles by twisting them. This will lead to the fact that the compacted soil is mellow, and when installing home pile prosyadet exactly the distance which was loosening due to its twisting;
- It is also one of the most common mistakes is that the pile is screwed into pre-dug hole. Depth the so-called "pit" should not exceed 30 cm.
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