Innovative Construction Technique: Tunnel Form

Building construction of 10.25 lakh sq. ft to erect 14-storeyed 15 skyscrapers, totalling 1,200 flats, on 45 acres of land would normally take minimum five years under conventional construction methods and that too if all the 15 towers are built together. However, the ultra-modern and innovative French, German and Chinese material handling and construction techniques would take hardly one-third of this time.

The French construction technique called Tunnel Form (TF), eliminates building material-handling by one-third since the construction is not only fully mechanised but most of the site activities like foundation, columns, beams, slabs, infill walls, lintels, chhajaas, door-frames and internal/external plastering are clubbed together into only one single synchronised construction action.

Interestingly, this technique is called Tunnel Form because it works on the principle of tunnel construction. The TF technique is a properly industrialised system and patented by a French innovator company, namely Outinord, by exploiting the theory and concept of tunnel construction to building construction. Besides, the TF technique is so called because a tunnel is formed out of the inside walls and the slabs together for monolithic casting of load-bearing walls and slabs in one continuous concrete pour. After casting of the unit of form work, a part of the tunnel is pulled out by wheels mounted on jacks/hydraulic system. As such TFs are necessarily required to be very rigid and sturdy. The TF work is a high performance tool enabling Striking, Erection and Concreting on the same day as compared to three different actions, compulsorily separate and extended up to many weeks! Whereas in TF the speed is achieved on account of: 

• Mechanization in form work.

• Handling of large room-size form work by fully electronic tower crane up to any height.

• Minimum number of components to be handled.

• Placement of form work is very rapid as the kickers forming the base of each wall are cast simultaneously as the slab.

• Works of columns, beams, slabs, walls, lintels, chhajaas, door frames and internal/external plastering is done in a single action.

• It creates a simple focus for operation, concentration and production resources.

And the most consolidating and also aesthetic aspect of TF technique is that the entire construction doesn't have a single joint. Moreover, its plaster is all weather-proof and doesn't chip out the way convention plaster does, more so in the moist weather.

The strength of a building built under TF technique is as such that the building won't collapse for a minimum of a century!.