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

6.Methods for StructuralReinforcement and Present Issues6-1. IntroductionIn Section 6 and hereafter, cases of structuralreinforcement adopted to partially preserve brick masonrytechniques will be dealt with. Firstly in this section,regarding earlier approaches for reinforcement of brickmasonry structures, the relationship between the buildingelements prioritized for preservation and reinforcementmethods will be focused on, while touching on residingissues. Then in Section 7, several restoration cases that canbe referred to in considering future structural reinforcementof brick masonry structures will be introduced.6-2. Types of structural reinforcementStructural reinforcement for brick masonry structures canbe largely grouped into two: 1) methods for strengtheningbrick walls (interior reinforcement, exterior reinforcement,reinforcement inside walls, and joint reinforcement)and 2) methods that decrease the impact of earthquakeforces (seismic isolation and seismic vibration control).Introduction of each of these reinforcement methods willfollow.? Interior reinforcementStructural reinforcement is installed from inside thebuilding with the aim of preserving the exterior design,considering its appearance as a component of the locallandscape. A general transition of this method can beseen through the following restorations in the order ofphoto 6-1 Inner side of brick wall is strengthened with reinforced concrete（Headquarters of the Imperial Guards）reinforcement with reinforced concrete (1977, Headquartersof the Imperial Guards) (photo 6-1), steel framereinforcement (1981, Doshisha (Former English School,Theological School, and Harris School of Science) / ShoeikanBuilding), steel plate reinforcement (1990, Doshisha Chapel),and“house-in-house”reinforcement (2007, Maizuru NavalArsenal Bullets Warehouse and Rifles Warehouse) (photo6-2).Among these methods, the use of reinforced concrete canbe seen starting in the 1970s when full-fledged structuralreinforcement of nationally designated Important CulturalProperty structures came to be executed. The inner side ofthe brick walls of the Headquarters of the Imperial Guardsstrengthened with reinforced concrete is completely hiddenfrom view.Also, at Doshisha Chapel which was reinforced withsteel plates from inside, the interiors have been lost dueto changes made to increase the wall thickness requiringalterations in installation of window and door fittings.Because the reinforcing wall was consolidated with thebrick wall, if the reinforcing wall should in the futurebecome damaged, it would be difficult to remove only thereinforcement without affecting the brick wall at all. Theabove method also involves the problem of altering the basicstructure of the building from brick masonry to reinforcedconcrete.On the other hand, steel frame reinforcement was adoptedfor the first time in an Important Cultural Property structureat Doshisha Shoeikan Building. Compared to the methodusing reinforced concrete, alteration to the interior wallsis limited to areas where the steel frame is attached to thebrick, enabling preservation of a large portion of the innerwalls. However, steel frame reinforcement tends to beadopted together with other reinforcement methods, suchas insertion of steel rods into walls, meaning that althoughvisible changes may be minute, a large area within the wallsmay be affected by introduction of reinforcement.In recent years, these past experiences have led tothe development of an alternative“house-in-housereinforcement”method of constructing an independentreinforcement structure, creating a separate interior spaceto support the floor of the upper level and such. In thisphoto 6-2 Space where the reinforced concrete structure was introduced（Maizuru Naval Arsenal Bullets Warehouse and Rifles Warehouse（building 3,"Maizuru Chiegura"））photo 6-3 Reinforced concrete buttresses were set on the second floor facingthe courtyard (surface of the buttresses are covered with bricks)（Former NagoyaCourt of Appeals Building）105