Planning of the foundation a three-story building constructed on potential liquefaction area in Air Tawar Estuary of Padang City

Departement of Civil Engineering, Faculty of Engineering, Andalas University, West Sumatera, Indonesia

^* Corresponding author: rina@eng.unand.ac.id

Abstract

The earthquake has become one of the most lethal problems in Indonesia, especially across the ring of the fire zone. On September 30th, 2009, an earthquake with a magnitude of 7.6 SR occurred, triggering tsunami and liquefaction. The liquefaction potential and tsunami forces need to be mitigated when an earthquake happens to reduce the risk. This study designs the building foundation that can endure the loads from an earthquake, tsunami, and liquefaction in the Air Tawar estuary of Padang City. The soil profile and liquefaction potential can be identified with CPT (Cone Penetration Test) data. After identifying the liquefaction potential, the upper structure was designed to consider the earthquake load and tsunami waves according to FEMA P-464 (2012). Afterward, design the foundation dimensions based on the ultimate load from the upper structure, wherein the amount of the settlement should be smaller than the tolerable soil settlement. The method used in the paper is taking the CPT data in the Air Tawar Estuary. After analyzing the liquefaction potential, making an upper structure design with ETABS 2016, recapitulate the maximum joint reaction to design the foundation that can withstand the ultimate load, and calculate the amount of soil settlement. Thus the design of the upper structure and lower structure take into account liquefaction. The amount of soil settlement obtained in the building design is still within the tolerance range of 9.79 mm, where the maximum limit of reduction is 32m.