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

approach, there may be cases where a large area of the wallis reinforced as in steel frame reinforcement, but effects onthe structure’s surface is little. However, it needs to be notedthat because large changes are made to the interior space,the design of the reinforcing element needs to be handledwith sufficient consideration to the historic structure.? External reinforcementMethods for installing structural reinforcement fromoutside the building in order to preserve interior finishescan be grouped largely into those with reinforced concretebuttresses (1989, Former Nagoya Court of Appeals Building)(photo 6-3) and steel frame buttresses (1995, FormerYamagata Prefecture Assembly Hall).Although both methods are generally adopted placingpriority on preservation of the interiors, considerationis necessary regarding the exterior appearance, asreinforcement members are visible on the outer walls. AtFormer Nagoya Court of Appeals Building where buttressreinforcement was introduced for the first time in restorationof an Important Cultural Property structure, buttresses wereplaced in a location hardly visible from around the buildingand the surfaces of buttresses were finished with tiles tomatch the surrounding brick walls. Also, as with the earlierexample, reinforcement was also placed inside walls.? Reinforcement within wallsThis is a method of placing reinforcement within walls topreserve the building’s interior as well as exterior. Variousconstruction methods of inserting stainless steel pins (1990,Former Kanazawa Military Armory (Ishikawa prefecturalMuseum of History)) (photo 6-4), steel bars (1995, FormerYamagata Prefecture Assembly Hall), or steel bars forprestressed concrete (2001, Seishido) have been devised inphoto 6-4 inserting stainless steel pinsphoto provided by : Prof. Masaki Fujikawa of University of Tsukubaphoto 6-5 wall in which fiber materials are buried（fiber materials are buried inthe joint courses with blue circular marks）（Chateau Kamiya Old Winery Facility）this order.All methods require drilling of holes into the walls andfor inserting stainless steel pins, an adhesive such as epoxyresin is used. For inserting steel bars, epoxy resin or cementslurry is employed as well. On the other hand, reinforcementwith steel bars for prestressed concrete, which involvestightening of the wall on the top and bottom with no needfor injecting with mortar and such materials, makes futurereplacement of weakened steel bars possible. Regardingdrilling techniques, it is more difficult to remove the crushedbrick particles from the holes as they become deeper,therefore requiring for their removal additional holes on thewall surface branching out from the drilled holes. Also, tocool down the heat produced by machine drilling, there aretwo methods: 1) the wet drilling technique of pouring waterinto the holes to cool the machine and 2) the dry drillingtechnique of sending specialized air into the machine forthis purpose. With the former method, there is fear of waterseeping out from the inner walls resulting in soiling of theinterior finishes, while with the latter dry drilling method,there may be chances of powdered brick leaking into theinteriors, which can be prevented by sealing the gaps in walls.? Reinforcement of brick jointsThis is a method of removing a part of the pointing forinstalling reinforcement within the joints.Aramid fiber is most commonly used for reinforcement(2014, Former Shimonoseki British Consulate) (photo 6-5).For increasing the shear strength of joints and out-of-planeflexural capacity of the brick wall, a portion the pointing ofsurface joints is removed and inserted with aramid fiber andreplacement pointing material.With this method, damage to bricks can be avoided andareas of joints to be altered can be limited. However, asthis method is irreversible, extreme care is necessary formaintaining the color and design of pointing.? Seismic isolation and seismic vibration controlThis is a method of installing seismic isolation or seismicvibration control systems underneath the building foundationto decrease seismic forces that may affect structures.In brick masonry structures, Building on Lot No.15 inthe Former Foreign Concession in Kobe (photo 2-17)totally destructed by the 1995 Hanshin Awaji Earthquakewas restored through reconstruction employing seismicisolation in 1998. This was later adopted in large-scalebrick masonry structures such as at Osaka City CentralPublic Hall in 2002 and at Tokyo Station, MarunouchiMain Building in 2012. Because it requires digging of abasement level for introduction of seismic isolation facilitieswithout dismantling the building, alterations to the originalfoundation structure including the brick substructurecannot be avoided.106Chapter 6A Collection of Case Studies of Preservation and Restoration of Brick Masonry Structures