By the EERI Reconnaissance Team.
March 16, 2011. Earthquake Engineering Research Institute.
Today I spent the day entirely outside the Christchurch Business District (CBD).
Nathan and I were following up on a contact given us by one of the volunteer engineers doing building assessments. The purpose of today was to look at damage to industrial facilities and how they fared during the recent event. We spent most of the day in and industrial area to the east of the CBD which is about 2 – 3 km from the epicenter of the M 6.3 event according to the Kiwis we met. Using our first contact we found a tilt-up building with steel roof beams. The building unfortunately did not perform well, is currently stabilized by shoring, and is scheduled for demolition/deconstruction. A very similar building 25m to the east experienced damage but will be saved and is in fact currently operating. Based on reconnaissance of approximately 8 buildings in this area some preliminary findings include:
-Pre-engineered metal buildings have performed very well. The steel frames with one minor exception showed no signs of permanent damage.
-When using precast panels for lateral resistance in the non-frame direction of metal buildings, the frame to panel connection is a critical detail. Lack of appropriate connection regularly resulted in panel loss or severe damage.
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| Figure 1. |
-Tilt-up buildings require special detailing to ensure a ductile connection at the roof diaphragm. Inadequate detailing of this connection resulted in poor performance and damage.
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| Figure 2. |
As a final thought for this post, we were very grateful for the kindness of the many building owners/occupants who allowed us to walk through their building and who were willing to share their stories with us. We really saw the sad side of things as one building owner is moving all his production to other facilities while his building is rebuilt. Another owner can no longer use the site they are currently on due to significant liquefaction induced settlement and heaving. Their structure is repairable, but the soil conditions can no longer support the required levelness tolerances for the machinery without complete replacement of the slab. Because of this uncertainty, over 200 employees were laid off. It is a sobering reminder of the hidden costs of those who survive natural hazards of this magnitude.
Learning from Earthquakes: First person reports
