Ruth Gardner's Blog 14/08/2011: Building Braced
Articles, UC QuakeStudies
An entry from Ruth Gardner's blog for 14 August 2011 entitled, "Building Braced".
An entry from Ruth Gardner's blog for 14 August 2011 entitled, "Building Braced".
The old Christchurch Railway Station Clock Tower was damaged during the 7.1 magnitude quake on 4 September 2010 and was braced by the wooden sleeve until repaired. However, although the sleeve did its job during the 6.3 magnitude quake on 22 February 2011, the lower part of the tower started to break away.
This paper presents preliminary field observations on the performance of selected steel structures in Christchurch during the earthquake series of 2010 to 2011. This comprises 6 damaging earthquakes, on 4 September and 26 December 2010, February 22, June 6 and two on June 13, 2011. Most notable of these was the 4 September event, at Ms7.1 and MM7 (MM as observed in the Christchurch CBD) and most intense was the 22 February event at Ms6.3 and MM9-10 within the CBD. Focus is on performance of concentrically braced frames, eccentrically braced frames, moment resisting frames and industrial storage racks. With a few notable exceptions, steel structures performed well during this earthquake series, to the extent that inelastic deformations were less than what would have been expected given the severity of the recorded strong motions. Some hypotheses are formulated to explain this satisfactory performance. http://db.nzsee.org.nz/SpecialIssue/44%284%290297.pdf
The damaged clock tower on Victoria Street, wrapped and braced to prevent further damage. The photographer comments, "Diamond Jubilee Clock Tower in Christchurch. Its legs wrapped up for protection. Volcanic stone and limestone clock tower with ornate wrought iron work with coloured glass around part of the tower and four clock faces. Clock Tower built in this location to commemorate the Diamond Jubilee of Queen Victoria. Has two white marble plaques and one bronze plaque set on stone work above arches".