What is Tunnel Formwork or Box House Formwork?

Tunnel or box formwork system is one of the most important and suitable formwork methods for mass builders in the construction industry. It is an integrated earthquake-resistant structure for integrating shear walls and ceiling joists (slabs). In recent years, as the government has prioritized mass housing construction for Iranian youth and families, the necessity of mass housing construction with tunnel and box system formwork has increased. Due to low cost, high speed, and avoidance of traditional systems, we are proud to meet our customers’ demands in the field of concrete parts formwork manufacturing with our capabilities in software design of new tunnel systems and the ability to produce molds with the best quality.

Components of the Tunnel Formwork System:

• Pin and Wedge
• Double-screw Jack
• Machined Wheels and Shafts
• 1200 kg Body Vibrator
• Mold Corner Tips
• Mold Keys for separating the mold from the dried concrete piece

Advantages of Tunnel Formwork from the Perspective of Construction Industry Professionals:

• Reduced time in mold assembly and disassembly, which leads to lower long-term project costs regarding labor, and automation of concrete pouring time.
• Flawless concrete output product.
• By utilizing tunnel system molds, due to the uniformity and repetitive nature of production stages, skilled individuals are not required in this field.
• Elimination of internal finishing.
• Elimination of wood components, wire, and nails used in traditional formwork.
• Very high structural resistance due to the integrated structure (side walls and ceiling).
• Use of ready-made and pre-woven meshes, which eliminates separate and high rebar costs.

What does the quality of concrete formwork depend on?

1. Concrete formwork resistance with a probable coefficient of 2
2. Rigidity of concrete formwork (smooth surface – elimination of weld lines)
3. Impact resistance of concrete formwork (designer and manufacturer must consider suitable places for impact and hammering of the formwork)
4. Durability of concrete formwork (at least 60 full months of product warranty guaranteed to the buyer)
5. Weight of concrete formwork (avoid high formwork weight by using rectangular sections and profiles).

Concrete Formwork Resistance

The resistance and strength of the materials forming the concrete formwork must be such that they can withstand any external force and pressure. This factor also ensures the safety of the formwork.

Concrete Formwork Rigidity

Given that concrete is a very heavy material, the rigidity of the concrete formwork must be such that it does not bend under the applied load. Even if such a displacement occurs in the structure, it should be very small and predictable. Because if this deformation and displacement are extensive, it will significantly affect the concrete’s deviation surface. Therefore, to determine the amount and location of these deviations, the rigidity of the formwork’s constituent material must be constant.

Concrete Formwork Impact Resistance

The construction of these molds must be such that they are not only resistant to impact and damage but also no piece of the mold separates or breaks off. To ensure this feature, the shedding behavior of the mold’s constituent materials must be examined and determined. Of course, it should be noted that when manufacturing these molds and to increase safety, the selection of ductile materials is more important than brittle materials.

Concrete Formwork Durability

The durability of concrete formwork is one of the most important features of a good mold. This is because it is both economical and guarantees its quality, allowing the mold to be reused. Given that concrete molds are usually made outdoors, and during production intervals and the connection of other components, this structure is exposed to environmental conditions and air, it is expected that this structure and its internal panels are made of materials that are resistant to environmental factors such as wind, rain, humidity, direct sunlight, corrosion, weathering, etc., and decompose less.

Concrete Formwork Weight

Usually, the assembly of concrete formwork parts and components is done manually. Naturally, if the weight of these parts and components is heavy and human forces cannot move and connect them, a crane will be needed. Therefore, if you want the cost of this project to be more economical, produce the formwork parts and components in such a way that they have a suitable weight so that workers can move them manually.