Assessment and Retrofits of Transverse Rebar
Principal Researcher: Stefano Pampanin
Staff involved: Athol Carr, Des Bull
Students involved: Alistair Boys
This project is required through recognition of the need to assess poorly transversely reinforced columns (1960s and later, up until 1995 provisions of NZS 3101 – though apparently designers have persisted with 1982 provisions up until recently).
Commercial pressures, particularly in the Auckland commercial building market, require new floors added to existing structures (as an example) and the designers are being asked to confirm that no retrofitting of columns is needed (typically FRP wrapping). In order to do this, the performance of the column, elastic and plastic rotation capacity AND the performance of the laps at the base of the columns (failures of the cover concrete at the laps, led to loss of the internal shear mechanism (truss) and failure of the columns; e.g. Indian Hills Medical Centre, Northridge Earthquake 1994).
Alistair Boys has been preparing a literature review for his study on cyclic (mono and bi-directional) behaviour of existing columns-to-foundation connection typical of the 1950-1970 period.