Types of wall formwork and their specifications. Materials needed for wall formwork construction. Basic rules on calculating and building wall framework.
Construction process cannot function without additional support tools, as well as consumables. This also applies to wall formwork, without which it is difficult to imagine any concrete wall structure. Housing construction keeps developing therefore the house formwork in the form of formwork systems has also become very popular. They come in different types of design: plastic formwork, steel formwork, polystyrene formwork, sliding formwork etc.
Permanent formwork constructions
Unlike removable formwork, permanent structure is filled with concrete and remains a part of the building. The need to experience high pressure of concrete solution conditions use of prefabricated cladding panels, insulation and other materials as materials for the construction. They not only provide strength and reliability of the design, but do not allow the penetration of moisture and cold inside the concrete monolith.
As a result of pouring wall formwork with concrete solution, obtained structure does not require additional insulation. Such designs are lighter than those made of brickwork, thereby reducing the load on the retaining and load bearing elements.
Polystyrene foam blocks do not require ligation and are arranged in rows above each other. Herewith, each block is attached with the adjacent ones with special locks placed on them. Reinforcement bars are installed into the voids inside the blocks.
Peculiarities of retaining wall formwork
One sided formwork is used for building retaining walls, columns and foundations. Its design features consist in availability of a modular frame system (buttress): when one-sided concreting is done pressure of concrete is transmitted to the base through the retaining frame. Buttress element facilitates transportation, installation and operation of one-sided formwork, allows accomplishment of work in the shortest time and with less effort.
The supporting frame (buttress) can be used with any wall formwork system type – girder, steel, aluminum or combined. Buttresses themselves are made of steel and can be either painted or hot-dip galvanized, since they meet strict requirements for durability, corrosion resistance and lifetime.
Single-sided formwork is easy to install: all the elements are compiled quickly, without additional details. All necessary fasteners are preinstalled on each buttress.
Calculation of the formwork
Calculation of the formwork walls is carried out on the basis of design data. Demand for the material used for manufacture of panels and amount of fasteners will depend on the square of structures built.
You can make formwork independently using various materials. Most applied for this purpose are:
Wood (cutting board),
Plywood, OSB and other sheet materials. The use of laminated materials of this class is most appropriate if you are planning an improvised removable formwork for concrete walls.
Metal (mostly pipe racks, to which the formwork panels are attached; additional structural reinforcement elements).
Expanded polystyrene is used for the manufacture of permanent formwork, which serves as insulation.
General rules for installation of the formwork
Formwork assembly can be carried out in several ways:
- Installation of the previously prepared panels is the most convenient way to make concrete wall formwork, which also reduces the time of construction, because the boards are prepared back during excavation.
- Installation of the elements on site is used less frequently. Basically, it refers to the prefabricated polystyrene foam blocks.
When installing wall formwork you should comply with the following ground rules.
- The formwork should be leveled vertically and horizontally, its top horizontal row should be leveled especially carefully. Correctness is checked with plummet or a building level.
- All the elements must be securely fastened.
- When assembling the panels of sheet material or wood, mounting the elements to the transverse studs should be done from the plane side, it will make the design more robust and facilitate the installation.
- In order to prevent deformation and fracture wall formwork installation must be carried out with the use of sloping supporting piles. To simplify the dismantling and preserve the wall surface formwork must be processed with special grease.