Seismic Performance of Precast Hollow-Core Floors: Part 2--Assessment of Existing Buildings.

Past research has indicated that precast concrete hollow-core floors in buildings are susceptible to non-ductile failure modes when subjected to earthquake deformations. While this research has led to the development of more robust connection details suitable for hollow-core floors in new buildings, the existing building stock with hollow-core floors in New Zealand is still at risk and needs to be assessed. Damage to buildings containing hollow-core floors in Wellington, New Zealand, during the 2016 Kaikoura Earthquake prompted the need to better understand the behavior of hollow-core floors and enable those with limited drift capacity to be retrofitted or replaced. Based on tests described in a companion paper, models are developed for three potential failure modes: loss of seating (LoS), positive moment failure (PMF), and negative moment failure (NMF). Implementation of these models in the New Zealand Seismic Assessment Guidelines is discussed. Applying the Guidelines to a database of 112 existing buildings with hollow-core floor units in Wellington indicates that the most likely mode of failure is loss of seating. [ABSTRACT FROM AUTHOR]