Monday, 26 May 2014

Contract 917A & 918A

Macdow has closed Fourth Avenue earlier this month to facilitate the movement of construction machinery between the previously-segregated sites. We thank one of our readers, Marcus Tan for writing in to us to inform us of the closure. This is an example of how informative contributions of site & tunneling updates can be, and are warmly welcomed. We encourage more to contact us via the feedback portal on the right sidebar.

Currently, the lane has been planned to remain closed until the completion of works in January 2016, however the project team has assured me that they will try to expedite works and push for an earlier reinstatement, possibly by the end of next year.

Signage showing the closure of Fourth Avenue
Access to Fourth Avenue via Third Avenue 
Construction materials line up the closed road

S602 is progressing well downstream. It is now at the intersection of Anamalai Avenue, passing its 800th ring. Following the similar schedule driven by its sister machine S603, we estimate the breakthrough of the final BP tunnel in 3-4 weeks.

Cutter location at the cone marked with the red stick


Heading north to the Tan Kah Kee site. The scene has changed quite a bit since the last update. 2 gantry cranes have been decommissioned over the CCT and the launch shaft to Sixth Avenue this month. The remaining GC standing at the site is over the launch shaft to BTN, which will only be dismantled following the completion of tunnelling works.

Legs of the dismantled Gantry Crane
Main span of the crane
Overview of backfilling progress
SK is in the midst of felling trees along the canal, to prepare foundation works for the future permanent Pedestrian Overhead Bridge that will be integrated with the station entrance. The bridge will be barrier free and will feature a green honeycomb design as part of the overall station's aesthetics. The bridge will be pretty dramatic in size and looks, with the choice of green to help blend in as the opposite landing of the bridge leads right into the Watten park.

Branches have been chopped, the felling process will be proceeded with the help of ropes
The span of the existing, temporary bridge in the background along Bukit Timah
Render of the upcoming POB at TKK on Bukit Timah side
Dunearn Road side
Future bridge landing at Dunearn Road
Integration with Watten Park

Renders by Ong&Ong, Architectural consultant for C918

For the final tunnel to Botanic Gardens, S605 has been obstructed by many aggregates, together with porous rock that hinders the progress the slurry machine. The entire shield of the TBM is currently right below the Inner Bound tunnel of the operational Circle Line. Extreme caution is being exercised by LTA with the surrounding 3 rail tunnels to minimize movements. The machine has only been able to achieve 3 hours of mining and 2 sets of ring building within the past week.

The center bearing of the cutterhead has come loose, and 3 attempts have been made this week to yield the bearing back to the cutter via heating - however all resulted in it cracking under 1 hour of pressure from the TBM. A fourth attempt will be made tomorrow night and should it still fail, the contractor will bring in a new bearing, costing around $20,000 - an unwanted expense that they're trying to avoid with only 9 rings left to cast.

We will be providing daily updates of the machine at the top right corner of the page.

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