TWO INVESTIGATIONS will be held into the cause of the collapse at Nicoll Highway.
One, for the Land Transport Authority, is already under way and is expected to report in two to four months. Its conclusions are not expected to be made public.
The second, for the government, will not start until June. Its results will be publicly available.
Both investigations will seek to establish whether negligence was to blame for the collapse, and whether any party will be criminally liable.
Issues on the agenda include:
adequacy of temporary works design;
quality of materials and workmanship;
adequacy of supervision of the five or six tiers of subcontractors by the main contractor;
whether the LTA's supervisory regime was adequate;
accuracy and adequacy of instrumentation;
adequacy of the design against base heave;
whether struts had been removed to allow machine access and then replaced incorrectly;
whether jacks used to pre-compress the struts had been installed correctly, and whether they were working properly; and ladequacy of the connection between the base slab, diaphragm walls and heave piles.