Seismic response and aftershock fragility curves for Non-ductile Mid-rise buildings comprised of reinforced concrete frame with masonry infill. (November 2022)

• Record Type: Journal Article
• Authors: Fikri, Rijalul; Ingham, Jason
• Is Part Of: Structures. Volume 45(2022)
• Page Start: 1688
• Page End: 1700
• Publication Date: 2022-11
• Subjects: Aftershock Fragility Curves -- Masonry Infill -- Canterbury Earthquakes -- Collapse Fragility; Structural engineering -- Periodicals; 624.1
• DOI: 10.1016/j.istruc.2022.09.108
• Languages: English
• ISSNs: 2352-0124

Abstract

Abstract: The 2010/2011 Canterbury, New Zealand earthquake sequences showed that aftershock earthquakes can be more destructive to existing buildings than the mainshock earthquake, particularly for buildings that were designed prior to the adoption of ductility requirements. Following the Canterbury earthquakes it was observed by post-earthquake reconnaissance teams that the level of damage for a number of non-ductile masonry infill buildings had increased from minor damage in the mainshock to moderate and major damage in the aftershocks. The majority of these non-ductile masonry infill buildings were constructed before the establishment of the New Zealand Standard (NZS) 4203 in 1976, and it was found that these buildings were constructed using low grade undeformed (smooth) longitudinal reinforcement and incorporated seismic detailing that was assessed as inadequate when compared to current design practice. The reported study was conducted to investigate the behaviour of non-ductile mid-rise masonry infill buildings when subjected to a combined mainshock-aftershock earthquake sequence, with the associated development of fragility curves that can be used to forecast the potential for building damage and collapse. Incremental Dynamic Analysis (IDA) was undertaken to seismically assess these non-ductile mid-rise masonry infill buildings, and a set of aftershock fragility curves was generated for different damage states following mainshock shaking. It was established that as the Inter-storey Drift Ratio (IDR) of a mainshock-damaged building increased, further damage that derived from aftershock shaking occurred at a smaller spectral acceleration intensity, illustrating that these mainshock-damaged buildings were highly vulnerable when subjected to a smaller intensity of aftershock earthquakes.