Seismic failure of an old pier during the 2014 2 Mw8.2, Pisagua, Chile earthquake

The seismic failure of an old quay wall, built in 1932, located in the Port of Iquique during the Mw8.2, 1 April, 2014, Pisagua, Chile earthquake is studied. A geotechnical exploration, including boreholes, cone penetration test (CPT) soundings, and surface-based geophysical techniques were performed to characterize the materials forming the pier. The data and field observations were analyzed and used to develop a geotechnical finite element (FE) model of two cross-sections, to define the most likely mechanism to explain the failure. The FE results are compared against the deformations measured in a number of cross-sections of the pier, suggesting that the failure can be explained by a combined effect of the dynamic increase in lateral earth pressures and the base rotation of the confining walls due to the lack of proper compaction of the rockfill prism below the confining walls.