Christchurch's Hotel Grand Chancellor was not
strong enough to withstand the February 22 earthquake because of design
changes during construction, the Canterbury Earthquakes Royal Commission
of Inquiry has been told.
No one was killed or seriously injured
in the hotel following the quake that claimed 182 lives last year. But
the building - at 26 storeys the tallest in the city - partially
collapsed and took on a noticeable lean.
Mark Zarifeh, the lawyer
for the commission, told the hearing on Tuesday engineering assessments
following the September 2010 earthquake did not reveal any significant
structural damage.
But when the 6.3-magnitude quake hit five
months later a reinforced concrete shear wall in the southeast corner
ruptured - dropping the corner by about 0.8 metres and sending the top
of the building about 1.3m sideways.
The shear wall carried about
one-eighth of the building's mass - a disproportionate amount - but the
rest of the building was strong enough to hold itself up.
The
hotel was built between 1985 and 1988 and Mr Zarifeh said construction
was reasonably well advanced on its western half before legal action
effectively prevented building any structure within the Tattersalls Lane
right-of-way, at the eastern end.
That meant a structural redesign and the resulting cantilever added to the structural irregularity of the building, he said.
That
also meant unusual forces were placed on the shear wall, which was too
slender and did not contain enough steel reinforcing for the load.
Mr
Zarifeh said the commission would hear evidence that would indicate
that the building did not comply with the standards that were in force
at the time because of the wall.
The Christchurch City Council
relied on a designer certificate signed by a principal of the structural
engineering firm that designed the building when it approved the plan,
he said.
NZN