Where a claim against one defendant remains and all claims against other defendants are resolved, liability is apportioned by determining the culpability and causal impact of each wrongdoer.
In 2005, a serious roof collapse occurred in a section of the Lane Cove Tunnel. Thiess Pty Ltd and John Holland Pty Ltd (plaintiff) entered into contracts with structural designers, a geotechnical engineer and an independent verifier.
The case was settled against the designers and the independent verifier prior to the hearing. The claim against the geotechnical engineer was determined by the court.
The court awarded $6,983,333.00 in damages against the geotechnical engineer (being one third of the agreed amount of damages) to the plaintiff.
In his judgment, McDougall J found that the designers had departed from the standard imposed upon by their contract with the plaintiff as the support design that was produced for the collapsed area did not reflect the agreed design philosophy. His Honour further found that the geotechnical engineer was in breach of its contractual obligations to the plaintiff by failing to continuously assess the ongoing suitability of the design in light of the changing ground conditions and, where the ground conditions had changed, failing to notify the designers of such changes. No liability was found on the part of the independent verifier.
McDougall J confirmed that there are two elements to be considered when apportioning liability between wrongdoers, as set out in Podrebersek v Australian Iron and Steel Pty Ltd (1985) 59 AJLR 492. First, there needs to be a comparison of the extent of the culpability of each wrongdoer. Second, the relative impact of each wrongdoer's acts in causing the damage must be considered, a concept referred to by his Honour as 'causal potency'.
His Honour determined that the culpability and causal potency of the geotechnical engineer was sufficient enough, in his judgment, to be apportioned liable for one third of the agreed damages, with the designers apportioned two thirds.
In reaching his decision, his Honour considered section 5O of the Civil Liability Act 2000 (NSW) which provides a defence of 'widely accepted competent professional practice'. His Honour considered that the widely accepted peer professional opinion can only be assessed by reference to the specific contractual obligations undertaken by the professional in question. In this case, the expert evidence did not consider the specific the contractual obligations of the geotechnical engineer and as such, did not make out the defence.