Removable formwork — a disastrous variety of volumetric boxes for the construction of various monolithic structures made of concrete, slag concrete, reinforced concrete and other materials in construction. Read about its device in the article.
The scope of boxed collapsible forms
The video is installed by the formwork
Collapsible formwork are auxiliary devices and are subject to dismantling after the end of the formation of monolithic structures. At the same time, formwork forms are simply and quickly mounted, and the principle of repeated use positively affects the cost of work.
In the construction, the scope of such formwork covers the manufacture of different in the complexity of monolithic structures from concrete and its derivatives. Often to such a technology, they resort to the construction of concrete ceilings between the floors of high -rise buildings. The sliding method of wall formwork is used to form large vertical monolithic shapes. In this case, it is possible to obtain traditional and non -standard walls, fences and other fences. A distinctive feature of this method is that, as the concrete is phased, removable formwork elements are gradually raised upward.
With the help of collapsed skin, foundations and less large -scale forms are made, for example, stairs, fireplaces, flower beds, fountains, pools.
How the removable formwork with your own hands is mounted?
Video video shows the installation of formwork with your own hands
Most often, forms for filling are made of wooden boards, plywood and bars. These are the simplest in work, available and cheap materials, however, plywood shields are permissible only for thin partitions or structures with small geometric sizes. In addition, steel or aluminum sheets can be used. They greatly facilitate the work, but for reasons of savings, standardized frames from these materials are usually rented.
Regardless of the selected material in the manufacture of collapsible forms, several technological conditions must be met. The entire structure is performed with large stiffness indicators and is firmly fixed. Separate elements of the form are driven to each other with minimal gaps. The frame over the entire height is obliged to withstand the pressure of liquid concrete without destruction and deformation. The material for work must be chosen taking into account its minimum adhesion to concrete.
Consider the manufacture of the most common wooden formwork shapes. First, shields are shot down from boards and bars with nails or screws, observing the following rules:
The most optimal sizes of the board: thickness — 4-5 cm, width — 20-30 cm;
The height of the shields should correspond to the height of the concrete pouring, the maximum length is up to 3-4 m;
The bars with a section of 4×4 cm are located on the outside of the shape every 1-1.5 m, the hats of nails — from the internal;
Dad is compacted in a slot with a width of up to 5 mm, and more than 5 mm are clogged — the rails are clogged.
Formwork slots can be a source of leakage of cement milk from liquid concrete, which reduces the strength characteristics of the future monolith. To eliminate leaks, as well as for the formation of more even concrete surfaces, it is recommended to extend the inner surface of the box in shape with roofing material or the. Next, finished shields are installed along the boundaries of the future concrete structure, propping up from the outside with wooden spacers. On the inside, the opposite shields are connected by jumpers from wire or timber.
Removable formwork for the foundation — step -by -step instruction
The most popular cast concrete form in private construction is the strip foundation. Having mastered the technology of manufacturing such a collapsible form, you can easily make most other formwork.
First, a trench is prepared with a strong bottom. Then the location of the formwork is planned. At this stage, pegs are driven into a trench around the perimeter of the concrete structure, which are connected by fishing line or rope. Retreating from marking to the wall of the trench to the width of the shield, the bars are firmly driven. The shields are installed close to them and are attached to the bars, and the latter are strengthened by support. The joints of the shields from the outside are connected by the boards. The inner plane of the shields forms the shape of a concrete structure. When performing wide foundations, the opposite sides of the box in the entire length are connected by jumpers.
At the site of technological holes in the foundation, nozzles are installed. They are filled with sand in order to prevent deformation under the weight of concrete. In order for the formwork to be easier to remove in the future, all its elements that will contact with liquid concrete are recommended to be covered with any oily composition.
Dismantling of a collapsible form — a fairly laborious stage. This work is performed after complete hardening of the concrete solution.