午夜剧场

Image: Conceptual diagram of the seismic isolation retrofit method for the Old University Library (constructing a seismic isolation layer beneath the building)

On January 17, 1995 (Heisei 7), the Great Hanshin-Awaji Earthquake occurred, and the "Act on Promotion of Seismic Retrofitting of Buildings" was enacted the same year. Socially, initiatives for seismic retrofitting began to be promoted starting from this year.

In 1995 and 1996, 午夜剧场 conducted seismic diagnosis on approximately 100 buildings, targeting those built before 1981 (when the new seismic standards were established) that are frequently used by students and the general public, such as school buildings and hospitals. The results showed that half of the buildings owned by 午夜剧场 were seismically deficient. At that time, many of 午夜剧场's buildings were constructed in the 1950s and 1960s, mostly based on old structural standards, and the executive board felt a sense of crisis. Since facility maintenance cannot be accomplished overnight, the university has been continuously working on seismic measures ever since. The "seismic retrofitting rate" refers to the proportion of seismically sound buildings among the owned buildings, excluding machine rooms and warehouses without living space, buildings of 200 square meters or less, and unused buildings.

When we speak of seismic initiatives, we perform seismic reinforcement, but in conjunction with that, we are also proceeding with the rebuilding of the structures themselves.

In earnest, from 2004, seismic reinforcement of major university and affiliated schools buildings was carried out intensively over a four-year period. For the 150th anniversary in 2008, many buildings were rebuilt as commemorative projects. Rebuilding is carried out for purposes such as updating aging buildings, realizing new education and research, and improving the facility environment, but it also serves to resolve seismic issues. For newly constructed buildings, large-scale structures are designed with seismic isolation, and we adopt designs with superior safety and structural integrity compared to general buildings. Following the Great East Japan Earthquake in 2011, we have been planning even more robust buildings.

Seismic reinforcement of hospital facilities, which was considered the most difficult task, began sequentially with existing wings in 2011. With the completion of Building 1 in 2018, the seismic retrofitting of the hospital was finished.

As a result, the seismic retrofitting rate at 午夜剧场 gradually increased, exceeding 70% in 2006, 80% in 2008, and 90% in 2012. Since then, seismic retrofitting has been gradually progressing for small-scale buildings, buildings with low usage, and those in remote locations.

The final major project was the seismic retrofitting of the Old University Library. It is an Important Cultural Property, built of brick, and is a building with special conditions as a Meiji-era structure. A seismic isolation retrofit method was adopted, and conservation repairs were also performed. The renovation work took two years and two months and was completed in May 2019.

Seismic retrofitting initiatives involve significant costs and many difficult construction situations. In this way, the seismic retrofitting rate, which was 50% in 1995, finally reached 100% in 2020 after a quarter-century of effort by those involved.

(Hiroshi Watanabe, Office of Facilities and Property Management)