An experimental program investigating the seismic response of dowel type panel-to-foundation connections was undertaken. Low-rise precast concrete wall buildings represent a significant portion of the New Zealand building stock, but there is limited evidence of the seismic performance of existing connections between panels and other structural elements. This paper aims only to provide an overview of the assessment, analysis, design and construction processes from a Structural Engineering perspective. This extremely ambitious and challenging project, undertaken by Kiwi Property and their consultant and contractor team 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. These issues are covered in further detail as part of this paper.ĭesign and construction of strengthening works progressed in parallel from 2012 whilst maintaining a fully tenanted building. CSW’s identified included L5 transfer beams, shear core foundations, non-ductile shear core walls, tower diaphragms, precast cladding panel connections, podium roof load paths and seismic displacements and tower floor related issues associated with 1980s precast flooring detailing. 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. 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). 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. Following the Canterbury Earthquakes, the building’s owner, Kiwi Property, commissioned seismic assessments of their property portfolio. The tower has a dual lateral load resisting system a perimeter reinforced concrete moment frame and two central shear cores.
Constructed circa 1991, the building comprises a 25 storey tower above a five storey podium. The Majestic Centre is located in central Wellington, New Zealand.
0 kommentar(er)
