Kelvin Street, InvercargillAn Invercargill building with a high profile long term bank tenant was evaluated as having a ‘less than acceptable’ earthquake %NBS rating. The building owner required a strengthening scheme to lift the building to above 67%NBS capacity while keeping the bank with full customer access / functionality during the strengthening retrofit construction.
Two building elements were involved (a later addition conference room plus staff facilities and the original 2 storey construction). This involved careful analysis of the existing tilt slab and reinforced concrete structures using a ‘push over analysis’ technique to determine the displacement performance / capacity of the existing structural elements and to provide a strengthening scheme that would add to the existing structure capacity rather than adding an entirely new lateral load resisting system that would require greater intervention and intrusion into the structure with subsequent loss of amenity and/or bank operation. This design analysis approach minimised the overall project cost while providing a high level of assurance of the building performance under earthquake conditions.
The project was completed significantly less than original budgeted costs and without any closure or disruption to the bank operation – a win win for both the building owner and tenant.