Bukit Sari Residence

Bored pile foundations for the Bukit Sari residence on a hillside in Semarang. 39 drilled piles in total, with drilling completed in eight working days in September 2021.

Piles of Ø 800 mm (main bars 14D19, spiral D10-150) and Ø 1,000 mm (20D19, spiral D10-125), with effective lengths of about 12–15 metres, K-300 concrete, tied together by pile caps at the pile heads.

The challenge was the ground: silty clay mixed with boulders along the full depth of the holes, on a sloping site that had been excavated first. Before production began, a trial bore confirmed the method and equipment; after that, every pile was logged in its own piling record.