MBIE Issues Warning on Loop Bar Detail

This is the first time a warning has been issued under the Building Act 2004 to Building Consent Authorities. It means that building consent is unlikely to be issued for any new building with a loop bar detail. See the full alert here.

MBIE proposed banning the loop bar detail in late 2017, and a move Engineering New Zealand supported. The independent expert inquiry into Wellington’s Statistics House after the Kāikoura earthquake found the performance of the loop bar hanger contributed to the precast floor collapses in the building. 

There are, of course, other design elements which can contribute to poor performance in a building. The latest version of the Concrete Structures Standard includes enhanced provisions for the design of precast floors. This is addressed in Amendment 16 to B1/VM1, which took effect on 3 April 2018. 

These issues have been discussed extensively by officials, Engineering New Zealand and our affiliated technical groups. Our shared view is that any system that has not performed adequately must be addressed holistically. MBIE is currently developing additional guidance to assist engineering practitioners in the seismic assessment of precast concrete floor systems.