Lateral spreading-induced abutment rotation in the 2011 Christchurch earthquake: observations and analysis

• Published in: Géotechnique 2013-12, Vol.63 (15), p.1310-1327
• Main Authors: HASKELL, J. J. M, MADABHUSHI, S. P. G, CUBRINOVSKI, M, WINKLEY, A
• Format: Article
• Language: English
• Subjects: Abutments; Bridges; Bridges (structures); Cities; City centres; Decks; Deformation; Earth sciences; Earth, ocean, space; Earthquake damage; Earthquakes; Earthquakes, seismology; Engineering and environment geology. Geothermics; Engineering geology; Exact sciences and technology; Internal geophysics; Liquefaction; Piles; Prestressed concrete; Rivers; Seismic activity; Seismic phenomena; Spreading; Suburbs
• ISSN: 0016-8505; 1751-7656
• DOI: 10.1680/geot.12.P.174

A series of strong earthquakes near Christchurch, New Zealand, occurred between September 2010 and December 2011, causing widespread liquefaction throughout the city's suburbs. Lateral spreading is developed along the city's Avon River which damages many of the bridges in the east of the city centre. The short- to medium-span bridges exhibited a similar pattern of deformation, involving back-rotation of their abutments and compression of their decks. By explicitly considering the rotational equilibrium of the abutments about their point of contact with the rigid bridge decks, it is shown that relatively small kinematic demands from the laterally spreading backfill soil are needed to initiate pile yielding, and that this mode of deformation should be taken into account in the design of the abutments and abutment piles.