Rodolfo B. Sancio

Correlation between ground failure and soil conditions in Adapazari, Turkey

Ground failure in Adapazari, Turkey during the 1999 Kocaeli earthquake (Mw ¼ 7.4) was severe. In four central downtown districts, where more than 1200 buildings collapsed or were heavily damaged, hundreds of structures tilted and penetrated into the ground due in part to liquefaction and ground softening. Based on a multi-institutional subsurface investigation program, soil conditions along four lines in which ground failure was surveyed after the earthquake are classified into four generalized subsurface site categories. This classification is primarily based on the presence or absence of shallow and intermediate depth liquefiable soils. Observations of ground failure are found to correlate well with site categories that are susceptible to liquefaction according to current state-of-the-art methods without strict adherence to the Chinese criteria. Soils that liquefied were found to meet the liquid limit and liquidity index conditions of the Chinese criteria. However, soils that liquefied did not typically meet the clay-size condition for liquefiable soils by the Chinese criteria. q 2002 Published by Elsevier Science Ltd.

Liquefaction-induced ground deformations at Hotel Sapanca during Kocaeli (Izmit),Turkey earthquake

Abstract This paper presents a study of liquefaction-induced ground deformations at the Hotel Sapanca site during the 1999 Kocaeli (Izmit)—Turkey earthquake. The paper discusses: (1) observed ground deformations and displacements after the earthquake, (2) the results of field investigations by means of borings and in situ index tests including standard penetration tests (SPT), static cone penetration tests (CPT) and piezocone (CPTU) tests, (3) analyses of observed ground settlements and lateral deformations by a suite of methods, and (4) comparisons of observed and calculated ground movements.

AN ASSESSMENT OF THE EFFECT OF ROD LENGTH ON SPT ENERGY CALCULATIONS BASED ON MEASURED FIELD DATA

The penetration resistance of a sandy soil, as measured by the Standard Penetration Test (SPT), is extensively used in geotechnical engineering. There are many factors that influence the energy transmitted to the rod string and sampler by the impact of the hammer on the anvil and thus affect the value of the blow count or N-value. This paper presents the results of a series of site investigations performed in northwest Turkey following the 1999 Kocaeli earthquake, where close to 2000 direct measurements of the energy transmitted by the hammer to the sampling system were conducted. It was found that short rod lengths have a small influence on the energy ratio when this is calculated by the force-velocity method. It was also observed that the N-value of the test interval has an influence on the effect that short rods have on the energy ratio calculated by the force-velocity method. Additionally, for this study the calculation of the energy ratio by the procedures outlined in ASTM D4633, which is currently withdrawn, is significantly greater than the energy ratio calculated by the force-velocity method.

Geotechnical Engineering Aspects of the June 1999 Central Mexico Earthquakes

An earthquake of moment magnitude (Mw) 7.0 struck the central region of Mexico on 15 June 1999 between the states of Puebla and Oaxaca. A second event with a moment magnitude 6.3 occurred on June 21, also affecting the central region of Mexico but with minor consequences. Attenuation relationships of peak ground acceleration with hypocentral distance for the June 15th event were compared with strong-motion recordings over a variety of geologic site conditions. Significant site amplification was observed and was correlated with deep soil conditions. The June 15th event caused significant damage of unreinforced masonry structures, such as churches and houses, including more than 500 historical buildings. Puebla City and the towns of Tehuacán and Acatlán de Osorio were the urban areas hardest hit by the earthquake. Although the earthquake was felt in Mexico City, the damage was light and mostly restricted to nonstructural elements. Comparison with observations obtained during the September 1985 earthquake suggest that significant soil nonlinearity, resulting in increased amplification at larger periods, can be observed for soft soil sites.