Performance-Based Issues from the 22 February 2011 Christchurch Earthquake

At 12:51 pm local time on 22 February 2011, a Mw 6.2 aftershock of the September 4, 2010, Darfield Earthquake shook the city of Christchurch, New Zealand. The aftershock occurred on an unmapped fault less than 8 km from the city center resulting in the collapse of two reinforced concrete office buildings and one concrete parking garage, and severe damage to numerous others. The region has continued to suffer from aftershocks and further damage to building structures throughout the year following the February earthquake. This paper summarizes the observed damage to buildings in the Central Business District (CBD), with a specific focus on identifying future research to support the development of performance-based design procedures. © Springer Science+Business Media Dordrecht 2014

Secondary structures and attachments under seismic actions: modeling and analysis

The chapter deals with the methodologies focused on the seismic analyses of the so-called secondary (sometimes attachments) elements that are part of a construction whose seismic resistance is delegated to a primary resistant structure. Although secondary elements can be decontextualized from the primary resistant structures, they will be subjected to seismic action as well and, having their own structures, need to be modeled and analyzed by means of methods included in the general methodologies proper of seismic branch. Among the methodologies usually adopted for secondary element analyses, the Floor Response Spectra (FRS)-based analyses become popular due to their recognized simplicity. FRSs provide acceleration (consequently velocity and displacement) to which the secondary element (with a given period and damping) will be subjected to when attached (from which the alternative name attachments derives) to a given part of the structures such as a building floor (from which the name Floor Response Spectra derives). Given that FRS generation could require onerous numerical analyses, simplified expressions are proposed in literature and discussed in the following together with the general methodologies tailored to secondary element modeling and seismic analyses