Seismic Assessment and Strengthening of the Majestic Centre, Wellington
Mr. Hamish McKenzie
(Principal – Structures, Holmes Consulting, Wellington)
Auckland Presentation: Tuesday 16 October 2018
The Majestic Centre is located in central Wellington, New Zealand. Constructed circa 1991, the building comprises a 25 storey tower above a five storey podium. The tower has a dual lateral load
resisting system; a perimeter reinforced concrete moment frame and two central shear cores. Following the Canterbury Earthquakes, an Initial Seismic Assessment (ISA) of the Majestic Centre was followed by Detailed Seismic Assessment (DSA, 2011) of the structure using both modal response spectrum (MRSA) and non-linear time-history (NLTHA) analysis methods. NLTHA and performance based assessment methodology concluded a seismic assessment rating in the range 35-45%NBS which, whilst above an Earthquake Prone threshold, identified a number of critical structural weaknesses (CSW’s). This was considered inconsistent with the building’s ‘Grade A’ office status and posed a risk to the building occupants and the surrounding Wellington CBD. Design and construction of strengthening works progressed in parallel from 2012 whilst maintaining a fully tenanted building. The project was completed in late 2016. This extremely ambitious and challenging project has served to demonstrate that seismic strengthening of large commercial buildings ‘in-service’ is possible provided owners, designers, contractors, regulators, and tenants are willing to work together. This presentation will provide an overview of the assessment, analysis, design and construction processes from a Structural Engineering perspective.
Biography
Hamish McKenzie has nearly two decades of experience as a consulting engineer, working on projects locally, nationally and internationally. He has a wide range of experience, spanning commercial and public structures of all shapes and sizes. Hamish has taken a leadership role on several complex major developments, including the National Library Refurbishment, Te Rauparaha Arena in Porirua, Government House Refurbishment, and Shed 6 Redevelopment. He has also delivered a number of important seismic assessment projects, including the Civic Square Campus Buildings, Wellington Railway Station and Parliament Campus. Hamish has also been involved with several industry initiatives including NZSEE Initial Seismic Assessment training, and he currently sits on the Engineering NZ Engineering Practice Advisory Committee—a group that advises Engineering NZ on areas where engineering practice guidance is lacking.
