The seismic isolation retrofit of the main building of the National Museum of Western Art required excavating the foundation ground under the existent building and installing isolation devices beneath the existing footings. Before the installation of isolation devices, it was necessary to construct piles beneath the existing footings in order to support the weight of the building temporarily during excavation process. The piles were made of steel pipe segments, and were driven by oil jacks utilizing the weight of the building for reaction force. During the retrofitting process, the subsidence of the building supported by the piles were monitored and controlled to avoid causing damage to the superstructure.
