The new formwork systems are reusable with little waste generated compared to traditional formwork.
The assembled units are intended for use throughout the duration of a project without dismantling. Increased speed and time efficiency on-site. The repetitive nature of the work, combined with the engineered nature of the formwork, allows site teams to finely tune their operations, which in turn leads to minimal concrete wastage
In order to achieve a good release performance, easy application and cleaning of the formwork, without any defects, it is important to use the right release agent technology and formwork typ. Moreover the application of resource friendly technologies with a high degree of sustainability is becoming more and more important every year in modern and esthetic visually of concrete constructions
In general the formworks systems based on the materials, presented in figure :
The construction of formwork takes time and involves expenditure up to 20 to 25% of the cost of the structure or even more. Design of these temporary structures are made to economic expenditure. The operation of removing the formwork is known as stripping. Stripped formwork can be reused. Reusable forms are known as panel forms and non-usable are called stationary forms. Timber is the most common material used for formwork
Modular means the scale and size that today in concrete metal formwork, modular is used to make products that have a wide variety and applications in concrete formwork. Modular formwork is a system of high-use concrete structures that due to the ability Installation in different models has a very wide application.
Due to its flexibility, the concrete formwork can be easily expanded in all directions and has various uses in the execution of all concrete structures such as foundations, columns, walls, beams, slabs and و and consists of modular forms, modular corners, backing. (Pipes, solders, etc.), fittings (wedges, clamps, bolts, washers and nuts) and support plugs (two-arm jacks, telescopic jacks, etc.).
The disadvantage with timber formwork is that it will warp, swell and shrink. Application of water impermeable cost to the surface of wood mitigates these defects. On the process of the development technology in civil engineering works are developed the different types of concrete formwork
Each of the system must to fulfill the requirements for formwork:
- Easy removal
- Economy
- Strength
- Rigidity
- Less leakage
- Smooth surface
- Light weight
- Quality
- Supports
The main concrete elements for different positions and forms are constructed on the formwork system, which will be
- Flat slabs
- Columns formwork
- Ribbed and waffle slabs
- Beams and slabs
- Post-tensioned slabs
- Tunnel form
- Table form
Improvement of methods of formwork installation:
– rational choice of formwork, including enlargement of shuttering panels into reusable cards with no need to demount them and application of shaft formwork, which shorten the duration of shuttering works
– application of coatings eliminating adhesion and the need to lubricate formwork
– reduction of the distance of formwork movement by a crane
The main causes of formwork failure are:
Improper stripping and shore removal
inadequate bracing
vibration
Unstable soil under mudsills
Inadequate control of concrete placement
Lack of attention to formwork details.
Improvement of methods of formwork installation:
– rational choice of formwork, including enlargement of shuttering panels into reusable cards with no need to demount them and application of shaft formwork, which shorten the duration of shuttering works
– application of coatings eliminating adhesion and the need to lubricate formwork
– reduction of the distance of formwork movement by a crane
