Completion of Renovation Work on 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 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 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 this construction work are compiled into a report and submitted to the Agency for Cultural Affairs.

The cost of this renovation work 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 work 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 under 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, each section has a different structure, and the connections between buildings and utilities are complex. 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. Furthermore, the construction had to be carried out while maintaining some library functions and keeping the building in use, making the seismic isolation work extremely difficult to ensure no impact on 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, 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 performed to transfer the building load to the seismic isolation devices. This was the so-called "transfer operation," performed by jacking down the load transfer columns. It was a moment of great tension, watching to see if the load transfer would cause any abnormal deformation in the building. The load transfer, which took two days, was completed successfully as planned, and the displacement (settlement) was only 2 mm (with an allowable value of 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 handling cultural properties. It was performed by specialized craftsmen for each trade, including brick, sheet metal, stone, slate, sashes, glass, and plaster.

Although some parts, such as the landscaping in the outer areas, 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, removing significant darkening and making it clean; however, 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. It was originally made of granite, but it was destroyed in the war and repaired after the war. Although the bottom left of The Pen Mark was chipped, we intended to leave it as it was if it was in good condition, but when we gave it a light tap, it just fell right 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 frame in the attic on the 5th floor of the First Stack Room remains bent and twisted due to war damage (photo). We initially considered reinforcing it, but in the end, we decided to do nothing. This room was originally used as a stack room, but we decided to keep it empty, removed the ceiling, and made it available for viewing as a site that conveys the remains of the war. As something that tells the history of the hardships the building endured, it is well worth a look.

In the repair work, there were many problems overall, but the condition of the Octagonal Tower was particularly terrible. 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.

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 is a landscape that remains 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, but I would like to thank Mitsubishi Jisho Design Inc., the Association for Conservation of Cultural Heritage, Toda Corporation, and the Agency for Cultural Affairs, the Tokyo Metropolitan Government, and Minato Ward for their guidance.