Completion of the Renovation of the Old University Library

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 took place over two years and four months starting in February 2017, and the project was finished on schedule (see photo). For those visiting the Mita Campus, the composition with the Old University Library in the background has always been the most important scenery, so it is a pleasure to finally be able to reveal its original appearance. Ultimately, this project will conclude once the details of the construction 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 main part of the renovation, the seismic isolation retrofit work, employs an innovative method that installs seismic isolation devices beneath the building's foundation to make it earthquake-resistant without changing the building's shape.

The Old University Library was built in 1912, with the Second Stack Room added in 1927 and the Third Stack Room in 1961. As a result, the building has a unique shape, and each structure is different. Furthermore, the connections between buildings and the utility systems are intricately intertwined. This time, the sections excluding the Third Stack Room were seismically isolated. While disconnecting the Third Stack Room, excavation proceeded to a depth of 6 meters right next to it. Additionally, the work was carried out while maintaining some library functions and keeping the building in use, making the seismic isolation work extremely difficult to ensure it did not affect the surroundings.

Since the work was primarily underground, a considerable amount of time was spent on excavation. While supporting the building, approximately 9,000 cubic meters of soil (equivalent to 1,350 ten-ton trucks) were removed to dig down to 6 meters underground. At the bottom, 1.8-meter-thick concrete called a pressure slab was poured. Simultaneously, 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 to see if the load transfer would cause any abnormal deformation in the building. The transfer, which took two days, was completed successfully as planned, with a displacement (settlement) of only 2 mm (allowable limit: 5 mm). The fact that this was achieved with millimeter-level precision is a testament to the high technical skills 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 quite spacious and large-scale project (photo).

The dry area in front of the building contains bricks from the Meiji era, which were decided to be 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 some areas, such as part of the exterior landscaping, 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. It has become quite clean with the blackening removed, but it may be difficult to tell 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 keep 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 The 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 on the 5th floor of the First Stack Room remain bent and twisted 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 leave 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 condition of the Octagonal Tower was particularly dire. It originally had leaks, and during the Great East Japan Earthquake, bricks had fallen off. The exterior stones 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.

Based on the investigation, 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 construction, 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 scheduled to be set up as an exhibition room introducing the history of Keio University. Until now, it has been in a closed state, but by preparing it as 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. I would like to express my gratitude to Mitsubishi Jisho Design Inc., the Association for Conservation of Cultural Heritage, and Toda Corporation, who were involved in this construction, as well as the Agency for Cultural Affairs, the Tokyo Metropolitan Government, and Minato Ward for their guidance.