Abstract:
Based on observed behaviour in previous earthquakes and subsequent extensive research, it is now well understood that hollow-core floors can be highly vulnerable to earthquake damage. This is particularly the case for older floors with poorly configured support details. Between the ‘Purple Book’ and the Appendix C5E of the ‘Yellow Chapter’ the industry is equipped with well-considered assessment tools for hollow-core floors. Very little guidance, however, is provided for the often-required seismic retrofitting of these floors. While Chapter eight in the PCFOG report provides a useful overview of potential retrofit techniques, some of the information has become outdated. In this paper:
• A load combination for the gravity design of precast floor retrofits is proposed,
• High level commentary on the appropriateness of the retrofit methods in the PCFOG document is provided
• Newly developed hollow-core floor retrofits are discussed, and
• The validation of these new retrofits and other observations from a recently conducted super-assembly experiment are described.