Assessment of URM Framed Buildings
Principal Researcher: Associate
Professor Jason Ingham
Students involved: Alistair
Russell, Charlotte Knox
Unreinforced masonry buildings can still be found around New Zealand and are often of historical or religious importance. In the 1930s, Auckland was the capital city of New Zealand. It was enjoying a strong economy and a rapidly expanding population. This lead to a building boom, remnants of which are still evident today with many existing pre-1930 buildings still standing. A cluster of these unreinforced masonry buildings are found in the Auckland city central area, some in excellent condition and some ready for demolition. Although these buildings are no longer the most prevalent structural type, they are of significant value to the historical identity of the city.
This project incorporates studies investigating the behaviour of the walls and diaphragms of unreinforced masonry buildings, the material characteristics of the masonry and various retrofit solutions. Most commonly the frame encompasses the front face of the building, as can be seen in the photos below, and is made up of piers and spandrels. To date no research has been conducted on the seismic assessment and retrofit of these frames.
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Masonry framed building in downtown Auckland. |
Masonry framed row-type buildings. |
It is anticipated that the piers which make up the vertical masonry columns of the frame will rock under seismic load. The underlying question behind this research is whether rocking of the piers in unreinforced masonry frames can be relied on as a viable option for the dissipation of seismic energy applied to the frame. If rocking is found to be a viable seismic energy dissipation solution then required retrofit may be minimal and the cost incurred to the building owner will be reduced.
The main aims of this aspect ofr research are:
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Seismic assessment of multi-storey unreinforced masonry frames using fundamental mechanics, finite element modelling and hand calculations. Part two of the research is to confirm that the analysis methods that are currently being used in New Zealand consultancies are accurate for unreinforced masonry frames when subjected to New Zealand earthquake conditions. When there is confidence in the assessment results, the aim is to produce a hand calculation methodology capable of determining the structural seismic performance of any unreinforced masonry frame.
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Development of practical retrofit solutions that can be applied to a range of buildings in New Zealand. It is important that the retrofit solutions that this research produces are economically viable to the client and that will also not detract from the heritage detailing of the building.