Completion of Renovation Work on the Old University Library

2019/07/09

At the end of May 2019, the renovation work on the Old University Library was completed. Following a year and a half of design, construction was carried out over a period of two years and four months starting from February 2017, and the project was finished on schedule (see photo). For those visiting the Mita Campus, the view with the old library in the background is the most significant landscape, so it is a pleasure to finally be able to reveal its original appearance. Ultimately, this project will conclude once the details of the work are compiled into a report and submitted to the Agency for Cultural Affairs.

The cost of this renovation was approximately 2.6 billion yen (including design and supervision fees). Of that amount, a total of 1.08 billion yen in subsidies was obtained from the Agency for Cultural Affairs and the Tokyo Metropolitan Government.

This renovation was a major project aimed at resolving seismic resistance issues and repairing deteriorated areas such as the exterior and interior to ensure its preservation for the future.

The seismic isolation retrofit work, which was the main part of the renovation, adopted an innovative construction method that installs seismic isolation devices under the building's foundation to make it earthquake-resistant without changing the building's shape.

The Old University Library was built in 1912 (Meiji 45), with the Second Stack Room added in 1927 (Showa 2) and the Third Stack Room in 1961 (Showa 36). Consequently, the building has a unique shape, each structure is different, and the connections between buildings and facilities are complex. This time, the parts excluding the Third Stack Room were seismically isolated; while disconnecting the Third Stack Room, excavation was carried out to a depth of 6 meters next to it. Furthermore, some library functions were maintained and utilized during the construction, making the seismic isolation work extremely difficult as it had to be done without affecting the surroundings.

Since the work was primarily underground, a considerable amount of time was spent on excavation. To dig down to 6 meters while supporting the building, approximately 9,000 cubic meters of soil (equivalent to 1,350 ten-ton trucks) were removed. At the bottom, 1.8-meter-thick concrete called a pressure slab was poured, and at the same time, the building's foundation was firmly reinforced with concrete and PC steel. The space between that foundation and the pressure slab became the seismic isolation layer, where the seismic isolation devices were installed. The total building weight of 16,000 tons is supported by 54 seismic isolation devices. The load on a single device ranges from 300 to 400 tons.

On January 15 and 16, 2019, work was carried out to transfer the building load to the seismic isolation devices. This was the so-called "transfer operation," performed by jacking down the load-transfer pillars. It was a moment of great tension, watching for any abnormal deformation in the building due to the load transfer. The transfer, which took two days, was completed successfully as planned, with a displacement (settlement) of only 2 mm (allowable value: 5 mm). The fact that it was performed with millimeter-level precision is a testament to the high level of technical skill of the people involved. You cannot tell by looking at the appearance above ground, but when you go underground, you can truly feel that it was a very large-scale and extensive project (photo).

The dry area in front of the building contains bricks from the Meiji era, which were preserved. We struggled with the design regarding the interface with the seismic isolation layer, and the bricks on the back of the dry area are exposed, resulting in a slightly strange shape (photo).

The preservation and repair work was carried out under the supervision of a work supervisor specializing in cultural properties. It was performed by specialized craftsmen for each trade, including brick, sheet metal, stone, slate, sashes, glass, and plaster.

Although there are some areas, such as part of the landscaping, that have changed from before the construction, the exterior appearance of the building was maintained in its original form. Bricks and stones were replaced and preserved, and finally, the entire building was cleaned. While it has become quite clean with the dark stains removed, it may be difficult to notice exactly how it has changed compared to before.

There is a relief of The Pen Mark above the entrance. Originally made of granite, it was destroyed during the war and repaired afterward. Although the bottom left of The Pen Mark was chipped, we intended to leave it as it was if it were in good condition. However, when we gave it a light tap, it simply fell off. We spent six months deciding how to repair that Pen Mark. We enlarged Meiji-era photographs, created drawings, made the shape close to what it was at the time, and restored it using cast stone (photo).

The steel frames in the attic of the 5th floor of the First Stack Room remain twisted and bent due to war damage (photo). We initially considered reinforcing them but ultimately decided to do nothing. This room was originally used as a stack room, but we decided to keep it empty, remove the ceiling, and make it available for viewing as a site that conveys the remains of the war. It is worth a visit as something that tells the history of the hardships the building endured.

In the repair work, there were many problems overall, but the Octagonal Tower was in particularly bad condition. It originally had leaks, and during the Great East Japan Earthquake, bricks had fallen off. The stones on the exterior wall that were repaired after the war were in poor condition and looked as if they might fall at any moment. Being able to perform fundamental repairs this time was also important for the maintenance and management of the building.

Through investigations, the scope of repairs increased significantly from the originally planned preservation work, but fortunately, we were able to proceed with the schedule as planned.

In carrying out this project, past literature, drawings, and photographs were of great use. In particular, the fact that photographs taken during construction in the Meiji era remained was a great reference and was utilized in the work.

University campuses change their appearance with the times, but it is also important that there are landscapes that remain unchanged no matter how many years pass. The Old University Library will be passed down to the next generation as a cultural heritage and will continue to watch over the progress of Keio University.

In the future, the Old University Library is planned to be developed as an exhibition room introducing the history of Keio University. Until now, it has been in a closed state, but by developing it into an exhibition room, it will become an environment that is easy for many people to enter.

Finally, handling an Important Cultural Property was a task that involved considerable mental strain on-site, but I would like to thank Mitsubishi Jisto Design Inc., the Association for Conservation of Cultural Heritage, Toda Corporation, and the Agency for Cultural Affairs, the Tokyo Metropolitan Government, and Minato City for their guidance.