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

wall, holes were made from the heights of the ceiling andfloor of the upper story to be inserted with pre-stressed steelbars. However, there was a difference in the constructionmethod which unlike at the Main Hall at Seisen University,grout was poured into the holes for strengthening themortar joints (Park & Kinoshita 2000, p55).３.８. Reinforcing Mortar Joints with Aramid RodThis is a method in which aramid rods are insertedinto extant brick joints to bear tensile strength, so thatthe tendency of the brick wall to bend outwards can bedecreased. In Important Cultural Properties, it was used atFormer Shimonoseki British Consulate and Chateau KamiyaOld Winery Facility / Office Building (Nishikawa et al.2013, p72). At Chateau Kamiya Old Winery Facility / OfficeBuilding, aramid rod reinforcement was inserted by carvinginto the joints in the areas above wall openings, where wallswere under the stress of bending outwards, and in wallswhere cracks had formed.Reinforcement of mortar joints is a patented techniquethat can minimize damage to brick wall elements throughapplication (Hasegawa 2012, p71). Also, because thismethod involves insertion of reinforcement into the brickjoints, the reinforcing elements are not visible, and thereforeeffective for conveying the original appearance. Additionally,reinforcement members are rustproof and rot-resistant,making this method highly durable (Tominaga 2016, p66).３.９. Seismic Base IsolationThis is a method of installing a seismic base isolationsystem by creating an underground pit while supporting thestructure above. This had been adopted in the post-HanshinAwaji Earthquake (1995) recovery project of Building onLot No.15 in the Former Foreign Concession in Kobe, anImportant Cultural Property, which was totally destructed bythe earthquake as well as at Tokyo Station Marunouchi MainBuilding (photo 16), an Important Cultural Property.photo 16 Tokyo Station Marunouchi Main BuildingKeio University Library, an Important Cultural Property,is presently undergoing restoration (as of May 2017)employing the base isolation system. Reinforcementbeams are being placed around the foundations of thebase isolation layer, so as to minimize impact on the extantfoundation structure. Former Nagasaki British Embassy, anImportant Cultural Property, is also being planned to adoptthis seismic base isolation method in the main buildingtogether with the subsidiary structures.A merit of base isolation is that the degree ofreinforcement on the building to be supported can bemade lighter, which would have less impact on the exteriorand interior designs. However, because this requiresconstruction of an underground pit, the foundations wouldneed to be reinforced. Also, when underground remainssuch as foundations of an earlier structure or burieddrainage systems are discovered, they must be removed forpit construction and thus, preservation of these artifacts willneed to be considered. Additionally, because the structuralfeatures of the building will be totally altered throughadoption of this system, the originally aimed structuraldesign may be lost, which raises another question inpreservation (Hasegawa 2012, p72).３.10. Crack Repair and Relaying of BricksRepairs are made on cracks, walls swelling outwards, orwalls slipping at brick joints, in other words not on the entirestructure as with reinforcement, but on limited damagedareas according to each of the conditions.Therefore, it is difficult to categorize repair methods aswith reinforcement methods and thus, Chateau KamiyaOld Winery Facility, an Important Cultural Property, willbe dealt with as an exemplary restoration case, referringto discussions from a workshop held at the completedrestoration project site.Chateau Kamiya Old Winery Facility was damaged bythe Great East Japan Earthquake of 2011 and restored forrecovery from the disaster. The Japanese Association forConservation of Architectural Monuments (JACAM) thatdesigned and managed the restoration project has reviewedpast repairs that had been undertaken on the damagedbuildings (JACAM 2016, Imazeki 2017, p35).In repairing cracks in brick masonry, there are timeswhen resin is injected for repairs, relying on its fluidity andadhesive property. Chateau Kamiya Old Winery Facility /Office Building was previously repaired using this method,and observations of the damaged structure revealed thatnew cracks had appeared in places close to the cracksrepaired earlier. They are areas where cracks tend to formand because the areas repaired were strongly adhered,28Chapter 3Restoration of Brick Masonry Cultural Property Structures