Seismic Retrofitting Concrete Structures with Post-installed Connections in New Zealand

Abstract

Seismic Retrofitting of concrete structures in New Zealand is of utmost importance, as highlighted by the most recent catastrophic Canterbury earthquakes in 2010 and 2011. With more than 2,800 earthquake-prone buildings in the national earthquake-prone register of New Zealand, ensuring the structural safety of the buildings is urgent and crucial.

This paper focuses on the suitability of post-installed anchors and rebars for seismic retrofitting. While effective solutions for post-installed anchor applications through NZS3101 are available, a significant gap exists in the standard’s lack of comprehensive coverage for post-installed rebar applications.

Drawing from anchoring theories such as EN1992-4, rebar theories such as EN1992-1, and EOTA TR069, and other design theories such as the Critical Shear Crack and EOTA TR066, we examine their applicability to seismic retrofitting and their applicability to New Zealand construction.

In conclusion, this paper advocates for the inclusion of post-installed rebar applications within NZS3101 - aligning with some international practices – and for more guidance on techniques for seismic rehabilitation of existing buildings in the country. By exploring advanced anchoring theories and forthcoming guidance documents, it envisions a future where New Zealand's structures are fortified to withstand seismic forces, ensuring their longevity and safety.