Case Histories of Foundations on Top of a Rupturing Normal Fault During the Kocaeli 1999 Earthquake

Although the Kocaeli (Turkey) earthquake was triggered by reactivation of the North Anatolian strike-slip Fault, normal faulting also occurred within the pull-apart basin of Gölcük. Its effect on overlying structures is summarized in this paper. The normal rupture caused maximum vertical displacements of up to 2.5m. Several structures were crossed by the rupture. As expected, many of them either collapsed or were severely damaged. Surprisingly, several structures survived the dislocation with no damage, while in some cases the rupture deviated, “avoiding” the structures. The foundations of the involved structures comprised a variety of types, ranging from simple separate footings to box foundation and to piled foundation. The paper provides a comprehensive description of the observed fault-foundation interaction patterns, accompanied by the results of soil exploration and geological trenching. Each structure is analyzed through the use of finite element modelling to reveal the main aspects of Fault Rupture––Soil–Foundation–Structure Interaction (FR–SFSI)

Soil Response During the 1988 Armenia Earthquake

Building damage statistics from the 1988 Armenia earthquake are presented and discussed. These statistics are correlated to the local soil profiles in the two major cities of Leninakan and Kirovakan. The soil amplification effects on building damage during this earthquake are investigated. One-dimensional site response analysis results and valley effects are presented to explain the extent and pattern of damage in the two cities

A Case History on Soil and Topographic Effects in the 7th September 1999 Athens Earthquake

Large concentration of heavy damage to residential and industrial buildings occurred in the small community of Adámes, near the banks of the Kifisos river canyon, during the 7-September- 1999 Earthquake. To explore whether the particular topographic relief and/or the actual soil profile have contributed to the observed concentration and non-uniform distribution of damage within a 300 m zone from the edge of the canyon cliff, wave propagation analyses are conducted in one and two dimensions. Soil layering and stiffnesses are determined from 10 SPT-boreholes and 4 crosshole tests. Ricker wavelets and six realistic accelerograms are used as excitation. The results show that the 2D topography effects are substantial only within 50 meters from the canyon ridge, but these effects materialize only in the presence of the relatively soft soil layers that exist in the profile at a shallow depth. The so-called Topographic Aggravation Factor (defined as the 2-D / 1-D Fourier spectral ratio) varies from 1.5 to 2.0 over a broad frequency band which covers the significant excitation frequencies. At the location of four collapsed buildings, about 250 in from the edge, 2D (topography) effects are negligible, but the specific soil profiles amplify one-dimensionally all six ground base excitations to spectral acceleration levels that correlate well with the observed intensity of damage

Centrifuge testing of a bridge pier on a rocking isolated foundation supported on unconnected piles

Volume conduction models can help in acquiring knowledge about the distribution of the electric field induced by transcranial magnetic stimulation. One aspect of a detailed model is an accurate description of the cortical surface geometry. Since its estimation is difficult, it is important to know how accurate the geometry has to be represented. Previous studies only looked at the differences caused by neglecting the complete boundary between cerebrospinal fluid (CSF) and grey matter (Thielscher et al 2011 NeuroImage 54 234-43, Bijsterbosch et al 2012 Med. Biol. Eng. Comput. 50 671-81), or by resizing the whole brain (Wagner et al 2008 Exp. Brain Res. 186 539-50). However, due to the high conductive properties of the CSF, it can be expected that alterations in sulcus width can already have a significant effect on the distribution of the electric field. To answer this question, the sulcus width of a highly realistic head model, based on T1-, T2- and diffusion-weighted magnetic resonance images, was altered systematically. This study shows that alterations in the sulcus width do not cause large differences in the majority of the electric field values. However, considerable overestimation of sulcus width produces an overestimation of the calculated field strength, also at locations distant from the target location