Client: Housing Development Board
Engineer: RSP
Main Contractor: Shimizu Corporation
Foundation Sub-Contractor: BSS:L&M JV

Diaphragm Wall: 13,950m2, 0.6m-1.0m thick, 30m deep
Barrettes: 3,700m2, 0.8m-1.2m thick, 30m deep, 52 Nr
Bored Piles: 98@600mmØ, 39@700mmØ, 100@800mmØ, 157@1000mmØ, 122@1200mmØ, 70@1500mmØ, 78@1800mmØ
Prefound Columns: 376 Nr

Shimizu Corporation were awarded the design and build package for the new headquarters for the Housing Development Board of Singapore. Shimizu entrusted the foundations and retaining wall package to a joint venture of BSS and L&M Foundations. The diaphragm wall ran parallel to the existing MRT station and tunnels along one elevation.. Restrictions in this area are very onerous, no chiselling is permitted and the Hydrofraise had to be used for vibration free excavation. Panel lengths were resticted to 3m and debonding was required to the outer side of the diaphragm wall to ensure the effective stress on the MTR structures was not changed by more than 15kpa. Additionally, the diaphragm wall in this area had to cut through the old (but de-stressed) ground anchors used on the station temporary works.


Top down construction

Note the raking struts