The report pinpoints three failings as particularly signifi cant.
Back analysis of ground movement data was 'abused' to give acceptable results, enabling construction to continue.
It says: 'The two critical back analyses were geotechnically flawed. There were repeated breaches of the instrumentation review levels. All the experts agreed that on the basis of the second back analysis work should not have been allowed to proceed in that area.' There was a 'failure to institute a regular, close and effective monitoring regime'.
'The catastrophic collapse was the finale to mounting incidences and warnings in the C824 project of excessive wall deflections, surging inclinometer readings, waler beam buckling, stiffener plates buckling, ground settlement, trespass of water and soils into the excavation through cracks in the diaphragm walls, failure of concrete corbels, failing waler beams, falling support brackets, plunging strain gauge readings, and the 'thung' sounds of distress over six hours on 20 April 2004 from the heart of the strutting system, ' the report said.
Project managers failed to identify and eliminate hazards and risks.
'A critical safety failure was that no stop work order was issued in the face of unsafe acts, unsafe conditions and unsafe attitudes. A stop work order is an essential and crucial element that must exist as a viable safety measure in the construction process. A stop work order must be an exercisable and realistic option.' Further criticisms include:
l Lack of competent staff carrying out specialised work.
l Incapacity of project managers and supervisors to identify adverse trends during construction and take corrective action.
l Poor chain of command and communication between LTA, Nishimatsu-Lum Chang joint venture and subcontractors.
l Lack of clarity in the reporting structure for decision-making.
l The overall competency of the builder was insufficient.
Responsibility for making sure the project was managed safely and efficiently fell to Nishimatsu, the COI states. 'Human failings were the result of deep-rooted organisational failings, ' it says.