Deficiencies in the design of Christchurch's tallest building led to its failure during the February earthquake and came close to causing a total collapse.
A Royal Commission into the Canterbury earthquakes has resumed and on Tuesday focused on how the Hotel Grand Chancellor withstood the 6.3 quake on 22 February last year.
Some 182 people died when the quake caused buildings in the central city to collapse. While no one died inside the Grand Chancellor, the damage was so bad it is now being demolished.
The inquiry was told the 28-storey hotel slumped by almost one metre when one of its key supporting walls failed.
Structural engineer Adam Thornton told the commission the collapse of the supporting wall, known as a shear wall, led to extra pressure being put on nearby columns.
Mr Thornton said the columns slumped by half a metre, but remarkably managed to hold the east side of the building up and prevented the building's total collapse.
Emergency temporary repairs were carried out on these columns in the immediate aftermath of the February quake to ensure that the high rise did not fall on to surrounding buildings.
Mr Thornton said the building of an internal, or return wall, would have prevented the collapse of the shear wall in the first place.
He said there were a number of possible reasons why the original design did not include a return wall, including pressure from the architect to cut down on the number of interior walls inside the Grand Chancellor.