The first Tsutenkaku Tower was built in 1912. Later, with the cooperation of local volunteers, an attempt was made to make Tsutenkaku, designed by Takenaka Naito in 1956, seismically isolated. In the renovation, it was required to improve the earthquake resistance in preparation for disasters such as the Nankai Trough Earthquake, to maintain the appearance of the building as a registered tangible cultural property, and to ensure the safety and continuity of business during the construction period. Therefore, the seismic retrofitting work was carried out by using the seismic isolation structure of the middle floor of the steel tower building, which can minimize the influence on the appearance of the tower because the repair area is concentrated at the base.

Japan | Osaka

Shinkenchiku March 2016 issue 174P