Pounding Damage to Buildings and Bridges in the 22 February 2011 Christchurch Earthquake

Abstract

This paper addresses the damage to buildings and bridges resulting from relative movements between adjacent structures observed by the authors from building inspections and in-the-field investigations in Christchurch and surroundings carried out two weeks after the devastating earthquake of 22 February 2011. Relative structural response is often initiated by the different dynamic characteristic of the participating structures. Pounding induced damage might occur when the closing relative response is larger than the gap between adjacent structures. In the Central Business District (CBD) of Christchurch City many adjacent buildings have inadequate gaps between them or in many cases even no gap. Consequently, a large number of buildings, already weakened by the previous main shock of 4 September 2010 and its several thousand aftershocks, suffered further damage due to the strong February aftershock. The reoccurrence of excessive soil liquefaction caused particularly heavy damage to bridge sites along Avon River as the spatially varying ground movements induced large relative movement of the ground surface.