ASLAN 100 Glassfiber Rebar and the Softeye Technique
August 2007
Aslan 100 - GFRP - Glassfiber reinforcing bars are used in the construction of special projects, such as bridge building, the construction of tunnels and docks/quays. The fact that ASLAN 100 is rust free is a great advantage on the reinforcing steel bar which is used under normal construction circumstances.
One way of making optimal use of ASLAN 100 is in tunnel building. The GFRP was found to be a great time-saver when it is being used in the construction in England of the Docklands Light Railway and also in Dubai in the construction of the Dubai Metro.
The Dubai Metro is 52 kms long. The contract is in the hands of Dubai Rapid Link, a consortium headed by Mitsubishi Corporation. The project comprises 29 stations, 4 of which are underground. These underground stations are built with diaphragm walls (slurry walls). Tunnelling is done using a Tunnel Boring Machine (TBM) with a daimeter of 9.56 mts. Breaking through the steel reinforced slurrywalls with the TBM has always been a challenge for tunnelling contractors and engineers. The TBM needs to stop and the concrete and steel reinforcement in the slurrywall need to be manually cut and removed. This causes weakness in the waterproofing and safety protection taken.
Using the Softeye technique resolves this problem. The ASLAN 100 GFRP replaces the steel reinforcement to provide a soft type rebar when constructing the slurrywalls. Softeye is the section of the wall reinforced by ASLAN 100 through which the Tunnel Boring Machine (TBM) will enter/exit. It gives substantial time saving, reduces problems of water permeability and improves safety conditions. The cutting operation of the TBM is simplified due to low transveral resistance of the glassfiber materials compared to steel.
So far, the ALSAN 100 has been used in the construction of the Dubai Metro in Union Square (4 softeyes), in Al Rigga (2 softeyes), in Port Said (2 softeyes) and Burjuman (1 softeye)
In the construction of the Docklands Light Railway in England, the exit of the TBM through a softeye was well photographed and filmed. The machine broke through a tunnel under the River Thames to appear at the Woolwich Arsenal Station on 23rd July 2007. The ASLAN 100 GFRP could be seen nicely broken, thus avoiding the violent rapture associated with the breakage of hard reinforcement steel and the resulting danger in safety conditions.
This write up is prepared courtesy of Bert Kriekemans of Fortius BK International, agents for Hughes Brothers of Nebraska USA, producers of ASLAN 100 glassfiber reinforcement.
The product is available from stock at JM Vassallo Vibro Steel Ltd of Mdina Road, Zebbug, Malta - Europe.
For more information kindly visit the ASLAN 100 page.
