What is Tunnel Formwork System | Advantages | Process | PPT

Hello everyone, in this article, I am going to explain what is tunnel formwork system? Why we use the tunnel formwork system? What are the advantages of the tunnel formwork system? When tunnel formwork is suitable? Construction procedure of tunnel formwork system, and limitations of tunnel formwork system, etc.

So read the article till the end, and if it was useful so share it with your friends because sharing is caring.

What is tunnel Formwork system?

A tunnel formwork system is a type of formwork system in which an RCC Slab and Wall are cast in a continuous pour of concrete.

The tunnel formwork system consists of 2 half cells (L-shaped) made of steel that are joined together to form a room or cell unit. These several rooms are made a building.

In tunnel form system wall and slab are casted in a single process within a single day.

The formwork system consists of 20 to 30% of total cost of project.  So it is necessary to choose a perfect formwork system for various types of construction projects. Because it affects the total cost of a project.

Time is also a major factor that affects the total cost of the project. And the formwork took 60% time of concrete construction. That’s why choosing the perfect formwork system is necessary for any type of project.

Tunnel formwork is best for repetitive room design construction as well as high rise building construction like the apartment, hostels, hospitals, etc.

The cycle time of the tunnel formwork system lies between 1 to 3 days that is very less compare to other formwork systems. So tunnel formwork took a lead in time-saving of projects which indirectly affect the total project cost.

Also using tunnel form we not need any type of plastering work.

Slab Cycle time:

Slab cycle time is the amount of time that is required between the casting of slabs. Generally, it is referred to as a cycle time of formwork.

Slab cycle time involves the following activities.

  • Wall shuttering
  • Slab shuttering
  • Slab level
  • Leveling
  • Line and plumb
  • Wall reinforcement
  • Slab reinforcement
  • Electrical fitting
  • Casting of slab
  • De shuttering wall
  • De shuttering slab

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Advantages of Tunnel formwork system:

  • Economical
  • Fast and Reliable
  • Safe
  • High quality

1. Economical:

It is economical for large construction of multiple similar modular units, like apartments, hostels, hospitals, etc.

2. Fast and Reliable:

Tunnel formwork required less slab cycle time due to that construction becomes fast and reliable.

3. Safe:

Construction of box type structure is safe against horizontal forces like earthquake and cyclone forces.

4. High Quality:

Tunnel formwork gives high quality of finishing due to that we not need of any type of plastering work.

When tunnel formwork is suitable?

Tunnel formwork is suitable for repetitive cellular construction such as residential blocks, hotels, student accommodation, barracks, and prisons.

  • It is suitable for Rapid construction.
  • It is suitable when we need a Column less structure.
  • It is suitable when we need High-quality construction.
  • It is suitable for High rise building construction.

Construction procedure of Tunnel Formwork System:

The sequences of construction of tunnel formwork system are as follows.

  • Stripping of the formwork from the previous day.
  • Positioning of the formwork for a current day phase with the installation of mechanical, electrical and, plumbing services.
  • Installation of reinforcement in the wall and slabs.
  • Last is concreting.

Tunnel Formwork Vs Aluminium (mivan) Formwork:

ActivityTunnel FormworkAluminium Formwork
Capital CostHigh High
Speed of WorkFastModerate to Fast
Cycle Time for RCC work1 to 3 days 10 to 15 days
NOS of repetition of shuttering materialMore than 500100 to 500
Quality of ConstructionGood quality Good quality with proper care
Plastering RequiredNo need of plastering work requiredPlastering Not required if good precaution taken
Cost of Shutting9000 to 10000/sft area4000 to 5000/sft area
Labour CostAround 150 to 250Around 250 to 350
DurabilityHigh High
Casting SystemRCC MonolithRCC framed
CuringThermal CuringCompound curing

Limitations of Tunnel Formwork System:

  • Tunnel Formwork is not suitable for small projects
  • A high initial investment of formwork and other types of machinery is required in a tunnel form system.
  • Need to design a building suitable for this system.
  • Due to speedy construction, high cash flow management required.
  • A skilled labor force is needed compared to traditional systems.

Conclusion:

It can be concluded that, though initial investment and per day operational cost in tunnel formwork is more, due to more reuses and reduced slab cycle time tunnel formwork works out ultimately economical.

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