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

it seems that forces were burdened by the weaker areasnearby. Therefore, with consideration to issues involvedin crack repair using resin, aramid rods were inserted intothe bricks joints close to where there were cracks and filledwith grout. Accepting the fact that cracks may appear againin case of future earthquakes, the importance of keepingrecords of repairs was stressed (Imazeki 2017, p44).Re-laying of bricks in a brick masonry cultural property,excluding cases for restoration of lost elements, will mosttimes involve correction of major damage to the masonrysuch as 1 recovery of fallen areas or 2 cracks and spalling.Problems in re-laying were discussed at an on-site workshopheld in October 2016 at Chateau Kamiya Old WineryFacility (hosted by Restoration Research Society for CulturalProperty Structures), and the opinions gathered then variedfrom evaluating this process as a way of making efforts toleave intact the original materials, to accepting the procedureof re-laying by considering restoration as a chance to learnbuilding technology to pass onto the future (Kawasaki 2017,p105). According to this article, it seems that there weremore participants agreeing to the former way of thinking,while at the same time, the following comments wereheard: 1 fear of losing traditional building technology, 2difficulties regarding techniques and cost, and 3 questionson whether application of traditional techniques could beconsidered as an act of preservation (Kawasaki 2017, p108).Regarding 2 and 3 , there may be problems involvedregarding brick masons. Mitsubishi Building No. 1 (photo17) was reconstructed during 2007 to 2009 as a partof the redevelopment project of Tokyo’s Marunouchibusiness district. Close to one hundred brick masons wereinvolved and approximately 2.3 million bricks were used inconstruction (Ogawa 2010). The author heard from a brickmason who took part in the restoration of Former TemiyaRailway Facilities Shed No. 3 that for reconstruction ofMitsubishi Building No. 1, brick masons were gathered fromall across the country, from which we learn that there arephoto 17 Mitsubishi Building No. 1not many brick masons today. With fewer chances to buildbrick masonry structures, it can be imagined that in thefuture, rather than re-laying bricks in restoration, there willbe more cases in which the original masonry construction isleft intact.４．Issues Regarding Physical Properties ofBrick Masonry Cultural PropertiesMajor issues concerning physical properties of brickinclude salt damage and material deterioration due todamage caused by freeze-thaw. In the former, as waterevaporates from the brick surface, salts dissolved in watercrystallizes on the surface and damage the brick surfaceand in the latter, water that had entered from the exteriorwall into the porous brick material repeats expansion andcontraction creating cracks on the surface and causingspalling on the outer surface. The main point in preventingboth types of damage lies in suppressing moistureabsorption by the brick walls.In areas exposed to rainfall throughout the year, such asunder the eaves, below wall openings, and where walls meet,they can be coated with permeable chemical agents whichhas been proved effective through material testing (Aikawa2015).What is difficult to control is water absorption from thefoundations. Preventive measures have been consideredfrom early on and in manuals regarding brick masonryconstruction and structures that have actually been built,consideration for vapor barriers has been confirmed fn 7 .In the restoration of Former Temiya Railway Facilities ShedNo. 3, moisture-proofing was installed in the partition walls.First, the buried foundations of brick walls were exposedand holes were made in the joints at 500mm intervals forinserting wire saws. The blade of a wire saw was threadedinto every other hole to make a cut to reach the adjacenthole to be filled with shrinkage-compensating mortar. Then,the rest of the space between the holes was cut in the sameway and injected with mortar (JACAM 2010). This procedureinvolving a moisture-proofing barrier at the brick foundationcan be taken as a method relying on traditional preventivemeasures. This was made possible at this site, as it wasundertaken at the same time as the ground was dug forsoil improvement work, providing necessary conditions forconstruction.Also, a different indirect approach as opposed to the directmethod explained above is being studied for applicationat a tunnel of Usui Pass Railway Facilities, an ImportantCultural Property. At this tunnel, problems have longbeen raised regarding brick deterioration due to salts andfreeze-thaw. Surveys of the damage process revealed that29