B.Zero Tondo™ Steel Arch

Our patented B.Zero Tondo™ Tunnel Support System is a new solution in tunnelling and provides extremely efficient first stage support. It has been developed to respond to the market demands for a cost-efficient and safe alternative to traditional tunnel steel arches.

B.Zero Tondo™ are unique tubular steel-arch ribs, filled with pumped concrete in-situ and offer greater structural efficiency than traditional steel-arch supports.

B.Zero Tondo™ offers a greatly enhanced response to deformations within the tunnel excavation, especially non-homogenous load conditions. Due to the optimal performance of tubular elements B.Zero Tondo™ exhibits lower stress values, compared to traditional “I” section steel arches.

Accordingly, fewer B.Zero Tondo™ arches are needed per km of tunnel than traditional arches, saving time, cost and steel usage.
A final benefit is that the circular profile reduces shotcrete rebound and shadowing, reducing use and waste.