Dizhur, Dmytro1; Giaretton, Marta2; Crowe, Kevin3; Cleaver, Timothy4 nand Ingham, Jason5
1 Lecturer, Dept. of Civil & Environmental Eng., University of Auckland, Private Bag 92019, Auckland 1023, New Zealand, ddiz001@aucklanduni.ac.nz
2 Research Fellow, Dept. of Civil & Environmental Eng., University of Auckland, Private Bag 92019, Auckland 1023, New Zealand, mgia506@aucklanduni.ac.nz
3 Graduated Engineer, Dept. of Civil & Environmental Eng., University of Auckland, Private Bag 92019, Auckland 1023, New Zealand, kcro486@aucklanduni.ac.nz
4 Graduated Engineer, Dept. of Civil & Environmental Eng., University of Auckland, Private Bag 92019, Auckland 1023, New Zealand, tcle063@aucklanduni.ac.nz
5 Professor, Dept. of Civil & Environmental Eng., University of Auckland, Private Bag 92019, Auckland 1023, New Zealand, j.ingham@auckland.ac.nz
ABSTRACT
Out-of-plane failures induced by earthquake loads are one of the most critical deficiencies of clay brick unreinforced masonry (URM) buildings. Despite a number of seismic improvement techniques having been previously investigated and applied, there is a significant lack of experimentally validated solutions that consider the viability of these interventions in terms of overall associated cost and practicality, and impact on the building tenants, aesthetics and heritage building fabric. The main objectives of the research presented herein were to develop and validate seismic securing techniques for URM walls that satisfied the above conditions, in consultation with industry representatives. Shake-table testing of three full-scale double-leaf solid clay brick URM walls was undertaken. Wall specimens were H3300 × W1200 × T220 mm and closely simulated in-situ conditions. The vertical timber framing that is typically a nonstructural support of the inner wall lining was used as part of the retrofit solution and was fixed to the wall with steel brackets and mechanical screw-ties in order to form a strong-back. Posttensioning was also investigated as a second form of retrofit intervention. Wall and retrofit construction details, test set-up, observed crack-patterns, peak ground acceleration (PGA), wall acceleration and displacement profiles at failure, and quantification of the improvement in seismic capacity associated with use of the proposed retrofit techniques are presented herein.
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