Liquefaction consideration on building foundation design (with emphasis on 1990 Philippine Luzon earthquake and the 1995 Hyogo-ken Nanbu earthquake) : J. E. Tigas, Individual Studies by Participants at the International Institute of Seismology and Earthquake Engineering, 31, 1995, pp 277–292

Abstract

On July 16, 1990, the Philippines was again strucked by a strong earthquake with a magnitude of 7.8 on the Richter scale. Several geologic features were produced as a result of this earthquake. These include fault-related ground ruptures and secondary ground failures, such as liquefaction, lateral spreading and landslides. The intense ground shaking triggered by the earthquake caused water saturated unconsolidated sediments to loose coherence and assume the property of a liquid. When water pressure exceeds that of the confining pressure, water and sediments are expelled forcibly towards the surface in the form of water and sand fountaining forming conical sand features. The process is commonly known as liquefaction. The subsequent loss in volume and underlying support results in subsidence and tilting of buildings which happen to be built on top of the liquefying layer. Dagupan City suffered much with this phenomena. This paper aims to present the study of foundation design (especially the 1995 Hyogo-ken Nanbu Earthquake ) for further application to the area of Dagupan City, Philippines considering the effect of liquefaction during the 1990 Philippine Luzon Earthquake. Inspection and evaluation was made on the foundation design of the area vulnerable to liquefaction to found out the effectiveness of the methods used. This paper will therefore discussed the evaluation of liquefaction potential and the necessary soil improvement method for foundation use. And then foundation design will be presented.