Combined NZGS CSG NZSEE Meeting
6.00pm – 7.30pm, Wednesday 17 November 2010
Lecture Theatre E1, College of Engineering, University of Canterbury
This Canterbury Technical Clearinghouse meeting summary was prepared by Bruce Deam on behalf of the NZSEE. This version (0.1 - 6 Dec) is waiting for corrections from the contributors. Click on contributor's names to send them an email message.
John Snook (John Snook Consulting and Canterbury Structural Group chair) outlined the agenda for the meeting and conveyed the following matters arising from the previous joint meeting: Helen Rutter (Aqualinc Research Ltd) reported that there were some unusual surface water appearances. Dave Brunsdon (Engineering Advisory Group) indicated that the phase 1 guidance document had been introduced to insurers, was currently with the Department of Building and Housing, was to be presented to territorial authorities and released within two to three weeks.
Helen Grant (Environment Canterbury Hazard Analyst) outlined her role providing science liaison with the Canterbury Group Recovery Office, which involves many interacting organisations working together in a process that is still not well defined. There is still uncertainty over who has oversight over investigations/research within the Recovery structure; the Recovery Commission is a logical choice.A Recovery Group workshop on 17 November discussed issues around phasing the land remediation and housing, accounting for social and economic aspects as well as technical ones.The Natural Hazards Research Platform is looking at performance standards for rebuilding infrastructure to accommodate the anticipated similar of greater (Alpine fault) shaking over the next 50 years. Seismic hazards need reassessing.Environment Canterbury and territorial authorities are working with the Engineering Advisory Group to develop the building guidelines chapter on flood risk and the consequential revisions to floor level requirements. New surveys are required to make the decisions. She has a spreadsheet tracking geotechnical investigations (see geospatial and geotechnical information)GNS Science are compiling a liquefaction map from a number of different sources, including T&T, UoC, Lincoln university, consultants and their own mapping of rural areas from satellite imagery and aerial photos. The map should be able to be distributed to the forum by Christmas.
Warren Lewis (Lewis and Barrow) introduced hmself as a structural engineer who has been commissioned to conduct field investigations and report the scope of works to repair for insurance purposes. He presented a list of questions (a wish list), noting that it is more important to incrementally improve information and infrastructure rather than have step changes. He expressed frustration at the news media providing more information than through 'official channels'. He outlined his written questions as:There was reliquification on Sun 14, so when were contractors likely to be able to start?Are satellite photos available? (This was answered later by Helen Grant, who indicated that they were for recovery purposes only and they were not able to be onsold.)When would the zone information be available? (It was published a fortnight later.)Are the approval processes being sped up?Younger staff needed more information about older types of construction.Can information that changes by the day be emailed rather than posted on web pages?
Warren then outlined how he was curious about how piled houses had performed, finding that two of his designs with raking piles were undamaged in spite of lateral spreading around the houses. In response, Geoff Banks indicated that he had observed 'fence post' piles snapping and highlighted the need for more information sharing. Others had observed piles which had set in gravel above recently liquefied layers and related how piles driven through a liquefied layer could be left overnight to improve their driving resistance when retested in the morning.
Warren also outlined how, in the past, he had remediated slabs with slump in the centre by drilling a hole into the centre, attaching a standpipe and pouring in shrink-compensating flexible grout until the slab was level again.
There was a general discussion on insurance. This covered residentaial insurance (which required compliance with the code the day before the eathquake) and commercial insurance (replacing like with like) that would fund assessments so clients could begin reinstatement. Someone observed that there could be other costs (e.g. for disabled access) on top of structural costs and another that remediation needs to avoid involuntary alterations to the building, either the elements or the building as a whole.
Bruce Deam outlined a list of proposed restoration techniques for commercial and industrial structures that needed confirmation that they were important and further development to provide guidance. The techniaues was discussed and extended, with the expectation that those with a direct interest in specific techniques would contribute to the guidance. (The link above is to the current list. The suggestions presented to the meeting only included crack repair techniques, crack width thresholds, floor diaphragm repairs, restoring serviceability stiffness and cover plates over seismic joints.)
The participants agreed to have a further meeting on 1 December with an insurance industry representative in attendance.
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