Come see us at Australasian Tunnelling Conference ATS2020+1 Stand 41 where we are launching Spannring in Australia – Spannring is the new way to support reinforcement in tunnels that replaces expensive custom lattice girders! #construction #steel #engineering #manufacturing #concrete #australia #innovation #patented
PRESRTESS ARCH vs CUSTOM LATTICE GIRDERS
Spannring Method allows for prestressed arches of STANDARD reinforcement to be used in the lateral orientation of the tunnel, instead of custom fabricated lattice girders.
Using the patented system, the prestressed arch arch is held in place by Spannring concrete spacers. Longitudinal reinforcement can be tied conventionally and the spacing between outer and inner reinforcement layers can be provided using conventional stirrups or straight lattice girders.
- CUSTOMIZED GANTRY + SUPPORTS
Using a simple customisation to a standard rolling gantry, it is possible to create a temporary support for the preferred contour of the tunnel reinforcement. Surveying tools are required to confirm the correct alignment of the temporary supports to match the profile of the reinforcement.
- SPANNRING SPACERS
The SPANNRING Spacers are fitted by cutting to length the stirrups of them to ensure the correct spacing between the uneven cut tunnel surface and the desired reinforcement profile. They are then tightly fitted between the tunnel surface and the reinforcement and secured with conventional tie wire.
For very short spacing the SPANNRING Mini Spacer can be used.
- TENSIONING TOOL
Once the SPANNRING Spacers and reinforcement are supported together, the tensioning tool and clamps are fitted to create tension between overlapping strips of reinforcement. Once enough tension is created the clamps are locked in which results in the reinforcement arch being fully self supported, and the gantry supports can be lowered to move the gantry towards the next arch location.