Success at Brightwater conveyance tunnel in Seattle, WAThe JV JCT (Jay Dee Contractors/Frank Coluccio Construction/Taisei Corporation) has announced that their EPB TBM is stopped just short of the Ballinger Way retrieval shaft, and is poised for breakthrough.The JV completed the 6.4 km-long tunnel in a single upgrade drive from Point Well portal structure to Ballinger Way retrieval shaft, traversing glacially deposited outwash and tills at 5 bar pressure. Best shift was 26 rings; best month was 392 rings, or 624 m advance.Another JV of Jay Dee Contractors/Frank Coluccio Construction has been awarded the construction of Reaches 3C & 3D comprising 3.18 km drives through the troubled Brightwater Central BT3 tunnel section, for which the TBM is being modified to tackle anticipated 7.3 bar pressure. For five-year project history visit tunnelbuilder archive us/94. 23/10.