WSP’s design consists of Approved for Construction drawings for the vertical structural elements of the building.
“The investigation has focused on the final as-constructed/as-built structure,” says Guy Templeton, President and Chief Executive Officer of WSP in Australia and New Zealand. “The report concludes that the specific localised areas of damage did not meet code as constructed. We confirm that our Approved for Construction Design meets National Construction Code, including the areas of damage, which were not built as originally designed by WSP.”
The final report notes several factors which are considered to have contributed to the causes of damage including:
- The as-constructed hob/panel assembly;
- Changes made after the original WSP Approved for Construction design, exacerbated by construction and material issues.
“We did not under-design the hob/panel assembly,” says Mr Templeton. Put simply, it was not built as originally designed and changes made by others during construction have resulted in ‘under-design’ as the report states, or in other words, under-strength. The report recognises problems in construction and material deficiencies.”
WSP remains committed to helping people get back into their homes safely, and as soon as possible, into a fully restored building.
“We sincerely appreciate how difficult this situation has been for the residents and we are doing everything in our power to minimise ongoing impact,” says Mr Templeton.
“WSP has completed its design of remedial works and will continue to support the Design & Construct Contractor (builder) and other stakeholders during implementation as required.”
An hour after the issue was reported on Christmas Eve, WSP mobilised a team of experts from around the country, New Zealand and the United Kingdom to ensure public safety was maintained, identify the root causes and support the builder in rectifying the problems.
Mr Templeton explains, “Our people have been working extremely hard to scrutinise the problems and provide the support necessary to develop effective remedial works. They have collaborated closely with the government’s appointed engineers – Professors Hoffman, Carter, and Foster; the builder’s engineers – Rincovitch Partners; and the residents’ appointed engineers – Cardno.
“We take our obligations very seriously. We have been there every step of the way, throughout the process, and we will see this through to the very end. Our people are actively engaged in the overall solution and providing input.”
Advocating for industry changes
“We agree in principle with recommendations for industry reform and welcome an opportunity to make a contribution,” says Mr Templeton. “For example, introducing mandatory structural inspections in high-rise buildings at hold points during the construction process. This will facilitate verification of construction in accordance with engineer Approved for Construction design. It will introduce additional checks and balances which provide a high level of assurance that Approved for Construction design is what is constructed. New South Wales is in a position to lead the way in national reform.”
There is a high degree of complexity surrounding any large-scale construction project due to the numerous parties involved in the project and their contractual roles.
For Opal Tower, developer Ecove entered into a Design and Construct contract with Icon Co (builder) who in turn engaged WSP (structural engineers), Wood & Grieve Engineers (hydraulic consultants), Traino Group (concreting contractor), McKenzie Consulting Group (building certifier), Evolution Precast Solution (precast concrete walls supplier), and APS (floor slab engineers), among others. Sterling Project Solutions acted as the Superintendent of Works (Project Manager) for Ecove.
Phase 1 and phase 2 of the remediation works which included propping safety measures and repairs to the isolated areas are now complete. In consultation with relevant stakeholders, WSP has completed the Approved for Construction design for the final phase that focuses on wall strengthening and augmentation works. This will act as a load transfer mechanism between the existing pre-cast wall and the insitu concrete columns. The design is currently with the qualified independent structural engineers – Cardno.
“Once all remediation is complete, Opal Tower will be restored to a high structural standard,” says Mr Templeton. “The numerous assessments undertaken to date indicate that no stone has been left unturned in investigating, analysing and rectifying the issues.
“Our aim is to restore the confidence of the residents and the general public in this building.”
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