Record of Lateral Pressure Taken During Earthquake

Abstract

ABSTRACT This report describes a measured record of earth pressure and water pressure which acted upon the perimeter basement walls of a building during an earthquake. The record was obtained, when the “Off Miyagi Prefectuce Earthquake” (magnitude 7.4) occurred on 12th June, 1978, at the alluvial formation area in Yokohama City about 380 km away from the epicenter. The number of record-taking points were 7 points for earth pressure and 3 for water pressure ; 10 points in total in the perpendicular directions. The record was taken by detecting the earthquake with an acceleration transducer and by continuously measuring and recording, from the instant when the starter was triggered, with a dynamic strain meters. From this record, the properties of earth and water pressure were found to be as follows: 1) Maximum amplitudes of the earth and water pressure ∆ pE during the earthquake with respect to those p at normal times were within the range of 2.74 to 6.37kN/m2, the ratios between them, ∆ pE/p, were 0. 011 to 0. 374, and both the value and the ratio tended to become larger when getting closer to the ground surface, 2) a long-period component of about 10 sec was observed in the individual records, 3) water pressure and earth pressure indicated properties which noticeably resembled each other.