EQ STRUC was engaged due to the need for careful consideration of the heritage characteristics of the building in the earthquake retrofit design. The building is a single storey 1924 unreinforced masonry church with a Historic Place Category 2 rating. The church featured two leaf thick masonry cavity walls with regularly spaced masonry buttresses around the building perimeter, supporting the timber truss roof system.
We utilised innovative retrofit methods such as near surface mounted (NSM) carbon fibre reinforced polymer (CFRP) strips embedded into masonry to improve the earthquake performance of the walls. In addition, new reinforced concrete columns were hidden inside the original rubble filled masonry buttresses and new timber trusses were constructed to replicate existing trusses. The project was completed in 2015 achieving a new earthquake rating of 67%NBS. The solution did not alter the external and internal appearance of the building, which was a key project objective.
Key Project Achievements:
67%NBS was achieved with a limited project budget and strict heritage requirements;
The strengthening design was award the “Earthquake Strengthening Award – Best Project Under $1m” by New Zealand Society for Earthquake Engineering.