History of the building

Architecture of the International Library of Children's Literature: Preservation and Renovation of an Old Brick Building from the 1900's

The following is an abridged translation of a brochure titled, "Architecture of the International Library of Children's Literature: Preservation and Renovation of an Old Brick Building of the Meiji Era," published by the Kanto Regional Development Bureau, Ministry of Land, Infrastructure and Transport in March 2002.

1. Overview

The International Library of Children's Literature (ILCL), fully opened in 2002, is housed in the renovated building of the former Ueno Library (Branch of the National Diet Library), which had originally been the Imperial Library. The renovation aimed to preserve and reuse the original building while adding new functions. The original building dates from 1906 and was extended in 1929. It has been designated as a metropolitan historic building by the Tokyo Metropolitan Government. In renovating the building, the design was done by Tadao Ando Architect & Associates Co. Ltd. and Nikken Sekkei Co. Ltd., and construction work by Konoike Construction Co. Ltd. under the supervision of the Kanto Regional Development Bureau, Ministry of Land, Infrastructure and Transport.

International Library of Children's Literature (east side)

2. Brick Buildings of the Meiji Era and their Safety

The style of most buildings constructed during the Meiji Era is called "steel framework with brick cladding." In this construction method, the building is held up by bearing walls of red brick masonry and floors supported by steel beams and pillars. The extension constructed during the Showa Era is based on the same construction method as the one common today, using a frame of steel beams and pillars of reinforced concrete. Though the external appearance of the extension looks like the part built in the Meiji Era, the content, in fact, is completely different. The exterior wall of the extension uses cladding which imitates the facing of the Meiji Era and artificial firebricks covered in plaster. The methods for roof framing were also different in the Meiji Era and the Showa Era. The roof framing of the Meiji-era part was built by a method called "queen's truss" using Douglas fir, imported timber, while the roof framing of the Showa-era extension was steel truss.

1.The facing is plastered onto the masonry as if biting into it.
2.Meiji-era roof truss called "Queen's truss"

No matter how historically important and valuable a building is, its safety must be ensured first for people to use it. The investigation conducted prior to the renovation revealed that the Meiji-era building was lacking in structural strength according to the current building code on quake resistance, and that many points were found nonconforming to the current disaster prevention and fire code, which led to the conclusion that large-scale structural reinforcement and renovation were needed to bring the building up to current building standards.

There are contradictions between preserving and ensuring the safety of old buildings in many ways. Reinforcing the structure's framework by adding materials to make it more quake-resistant could greatly affect and change the original building's interior and exterior design which must be preserved. To avoid this undesirable change, it was decided that seismic isolation should be adopted. This method isolates the building from the ground so an earthquake does not hit the building directly and the influence of a quake on the building would be lessened to the minimum of one third to one fifth. By applying this method, the reinforcing work on the building could be minimized.

At the same time the frame structure composed of the red brick walls and wooden roof framing of the Meiji-era part and the reinforced concrete of the Showa-era extension was tested by putting fragments through various testing methods, the result of which proved that those parts had no problem with strength and durability.

It would not have been possible to preserve the original interior design if we had simply done regular renovation work in order to resolve the problems related to disaster prevention. Based on the premise that we must ensure safety, we set up new escape routes, compartments, and smoke control equipment, confirmed safe evacuation through simulations, and obtained the necessary certification from the Ministry in charge. As a result of these efforts, we were able to preserve the appearance of the internal space in its original form. The glass service area and the two concrete cores, which comprise the latest extension of the Heisei Era, provide escape routes as well as connecting ways between the new facilities.

Seismic isolation for retrofitting

Seismic isolation, which isolates a building from the ground to minimize the direct effect of quakes to buildings, has been already applied to many cases in constructing new buildings. However it is still rare for this method to be adopted to retrofit existing buildings. One of the rare cases is the Main Building of the National Museum of Western Art, which is within walking distance of the ILCL. The museum was retrofitted by seismic isolation in 1996-1998. In the case of the museum the seismic isolator was set up beneath the foundation to make the whole building including the basement floors more quake-resistant. In the case of the ILCL, for the sake of safety, the seismic isolator (lead damper and laminated rubber isolator) was installed on the first basement floor to make only the aboveground floors seismically isolated. This is the first case in Japan to adopt seismic isolation in retrofitting a building with brick bearing walls.

Image of the Construction Process of the ILCL

Retrofitting the ILCL was done by the following procedure: 1) remove the first floor; 2) set up straining sills of reinforced concrete so as to sandwich in and tighten up the brick walls until the sills and walls become unified; 3) set up jacks underneath the straining sills to support the all-out weight of the building (approximately ten thousand tons); 4) remove the part of brick walls below the sills and the brick foundation; 5) establish new footing beams of reinforced concrete below; 6) install seismic isolators between the building and the footing beams. When jacking up the building, a computer console was used.

A laminated rubber isolator (left) is a multilayered rubber bearing reinforced with steel plates. It supports the load of the building and has a horizontal elasticity function. The lead damper (right) absorbs the earthquake energy.

1.After the straining sill was completed, while computer-controlled jacks were supporting the building, the original brick foundation was dismantled and removed.
2.Completed seismic isolation layer. The lead damper and laminated rubber isolator can be seen at the back.

3. Preservation and renovation of the interior

The original appearance remains in the Museum (the former Reading Room), Gallery of Children's Literature (the former Special Reading Room), Meet the World (the former VIP Room), the Grand Staircase and the adjacent corridor with decorative plasterwork. Preservation of the interior as well as the exterior of the building was a significant challenge to the restorers. The walls and ceilings of these rooms have been preserved and renovated exactly as they were.

The parquet of Meet the World was restored, while a new layer of flooring has been added above the old floors of other rooms to contain the air conditioning system and wiring. In the Museum and Meet the World, you can see the old floors through glass inserted between the new floor and the walls.

The Meiji-era wooden roof truss and roofboard of the building except for the roof of the stacks have been conserved although these parts cannot be seen from outside.

1.Parquet of Meet the World
2.Old floor through the glass
3.Ceiling with a restored chandelier of the Museum (former General Reading Room)

1) Preservation of decorative plaster walls and ceilings and the technique

The beautiful plaster moldings on the walls and ceilings of the building date from its foundation. However, after continual renovation over 100 years, the layers of paint which had been put over the plaster had peeled off in places. Therefore, before doing new plasterwork, every bit of the paint had to be removed by hand using chisels and a mechanical hand-grinding tool called "leutor" (trade name).

2) Restoration of lighting fixtures

When we started the reconstruction, the chandelier of the Grand Staircase was the only lighting fixture that was left from the original building. While the lights installed at the Showa-era extension of the building were still being used in Gallery of Children's Literature (the former Special Reading Room), the chandeliers of Museum (the former Reading Room) and Meet the World (the former VIP Room) had been lost. After investigating other examples of the same period, photographs and the remaining chandelier of the Grand Staircase, the lights have been restored and placed in the respective rooms.

3) Grand Staircase

The three-story stairwell faces you right after you step into the building. Wood paneling under stairs gives a finished appearance. As the cast-iron staircase handrails are too low to meet modern standards, glass panels have been added in parallel with the restoration of the original iron rails. The Grand Staircase and the corridor to the 2nd floor and the 3rd floor are separated by thick wooden doors made of zelkova, above which there is a glassed-over arch. All the original wooden fittings were repaired and adjusted.

Grand staircase (2nd floor). Wood paneling is attached to the underside of the stairs. In front of the original cast-iron staircase rails, glass panels were added.

4) Preservation of fittings

1.We chose not to repair the glazed bricks whose surface has peeled off.
2.The wooden window sashes facing onto the 3rd-floor lounge have been preserved in their original state.
3.Repaired wooden window sashes of the 2nd floor

4. Preservation of façade

The façade, designated as a metropolitan historic building, is an important component of the cityscape. In renovating the building, we paid great deal of attention to keeping the flavor of the Meiji-era building.

1.Decorative panels between upper and lower windows are made of cast-copper.
2.Decorations under the eaves are made from copper plates. They are formed in one piece with the eaves.
3.The original iron lightning rods were restored using aluminum.

5. Heisei-era concept

The purpose of the Heisei-era enlargement has been to provide a space where children and researchers feel comfortable and secure, as well as up-to-date functions to meet the demands of the information society. The added facilities have been kept to a necessary minimum: stairs, elevators, cafeteria, and technical units for information system, air-conditioning and disaster prevention.

As the technical units are underground, the only Heisei enlargement parts that people can see are the two glass boxes and the two vertical concrete structures (core).The glass box that cuts across the building on the first floor contains the entrance and cafeteria, and another box going through the third floor connects the rooms and the concrete core housing the stairs and elevators.

There are no pillars in the Heisei-era part. The omission of pillars has the visual effect of highlighting the bricks and stones of the original building, and at the same time it gives a completely new appearance to the building as a whole, perfectly melding the classic style and modern style.

View from the garden on the west side. Two glass boxes are passing through the two concrete shafts.

Copyright (C)2002 Kanto Regional Development Bureau, Ministry of Land, Infrastructure and Transport
Copyright (C)2006 National Diet Library [translation]

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