ブックタイトル「煉瓦造建造物の保存と修復」英語版

概要

「煉瓦造建造物の保存と修復」英語版

which may in turn damage the wall surface.Doshisha University Yushukan, an Important CulturalProperty, is the university’s first library constructed in 1887(Meiji 20). The building experienced a fire in 1928 (Showa3) and was burnt down with only the walls remaining. Thiswas a pioneering example of restoration employing concretereinforcement headed by Goichi Takeda (Nishizawa andKaneta 1989-2, p75).Later in time, the method of creating a reinforced concretewall on the inside was adopted in the restoration of theImperial Guard Division Headquarters an Important CulturalProperty (photo 1). The building constructed in 1910 (Meiji43) was renovated in 1978 and became the Crafts Galleryof the National Museum of Modern Art, Tokyo. Through thisrestoration, reinforced concrete walls were installed on theinside integrating the brick wall with the reinforcing elementfor providing security against fire and crime, as well as toenlarge exhibition spaces by removing the interior walls. Amat foundation system to prevent uneven settling was alsointroduced. Regarding this restoration, there is an interestingtestimony.“That building was scheduled for demolition. ProfessorTaniguchi with people from The Japan Institute of Architectsand Architectural Institute of Japan went directly to Mr.Eisaku Sato (Prime Minister) and overturned the decision forthe building to be taken down following Cabinet approval.Because there were no precedents, it was important tocarefully choose how to present our intentions on theissue. At the same time, it was a work of Chin Tamurarepresenting a typical government building style. We had tohave him understand that preserving this structure wouldbe considered as an achievement on his part in the future aswell. This was the most difficult thing to do.Technical problems followed after this stage, when itbecame clear that there was severe uneven settling, of 25cmwithin a distance of 23.6m. All exterior walls were to bepreserved. Preservation of the two stories of the centralportion of the building (entrance hall) was a requisite as adesignated Important Cultural Property, but the rest couldbe renovated freely. After these conditions were madeclear, it was decided that the entrance hall would be totallypreserved while all interior finishes were to be removed. Thiswas because all brick walls were cracked due to the GreatKanto Earthquake in 1923 and had all become separated.In some corners, walls had moved to form gaps as large as10cm”(Round-table talk (1989), p34).The installation of reinforced concrete walls was requireddue to technical reasons, for preventing settling andcracking of brick walls and for adaptive use of the structureas a museum, and therefore, certain areas of the buildingseem to have been selectively preserved for conveying theideology of the architect.Later in 1986, in the restoration of Harris Science Hallat Doshisha University, an Important Cultural Property, thestructure was also strengthened using reinforced concretewalls, with styrene layers installed in the foundation toprevent sinking due to an increase in weight. However, afterthis project, reinforcement with reinforced concrete hasnot been actively adopted in restoration of brick masonryImportant Cultural Properties.Some reasons raised for this were that because a newstructure was constructed within the brick masonrybuilding, the interior had to be given up (Yatani 1998, p118)or that this method could be applied to only limited areasin Important Cultural Property buildings from the point ofview of reversibility as well as protection of the brick walls(Hasegawa 2012, p69). Also, efflorescence due to the useof concrete may cause damage to the reinforced brick wall(Matsuo et al. 2005, p23) fn 2 . Because reinforcement withreinforced concrete was a method employed in the earlyeras of masonry restoration, as various ways of masonryreinforcement came to be devised including the use ofsteel frame, many disadvantages of this technique becameapparent.photo 1 Imperial Guard Division Headquarters（currently Crafts Galleryof the National Museum of Modern Art, Tokyo）３.２. Steel Frame ReinforcementThis is a method of installing a steel frame separate fromthe building on the inside to support the exterior walls. Thiswas derived through an attempt to seek new reinforcementmethods to take the place of what had then become aconventional method of using reinforced concrete, andis adopted in numerous cultural properties today. As thismethod was being developed, the brick masonry structurewas analyzed to fully understand its system, starting atthe point of construction and reviewing the conditions ofdamage after the Great Kanto Earthquake, to seek whatimprovements could be made for higher seismic resistance.23