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

5-5. Preservation of the present state: preservation of a wall with penetrating cracks【Case 1：Former NomuraSugar Store Brick Storehouse】Name：Former Nomura Sugar StoreBrick StorehouseConstruction year：Mid Meiji eraStructure：Brick masonry, tile roofingBuilding area 28m2Location：1-12-5 Chuo, Tsuchiura City,IbarakiProprietor：Tsuchiura CityDesignation/Registration（date）：Registered Tangible CulturalProperty（2016.08.01）Restoration period：2011 ? 2012? Overview? Restoration planningWhen this brick masonry storehouse was hit by the Great East Japan Earthquake, largepenetrating cracks appeared on the brick walls and severe wall slippage was observed(photo 5-18). As cracks were enlarged each time an aftershock occurred, the municipalgovernment judged that the building could not be repaired and it was once slated fordemolition. However, a reinforcement program proposed by voluntary members of theJapan Architectural Institute fn 32 changed its fate and the building was preserved in a conditionclose to that as damaged by the disaster, without reconstructing the walls (photo 5-19) fn 33 . Asa background for this change, of course, there was a citizens’petition for preservation of thebuilding that had housed a coffee shop before the earthquake. It was people’s attachment thatled to preservation of the structure fn 34 .? Restoration MethodSo as to preserve the wall with enlarging cracks, stainless steel pins were inserted frominside the walls, a new foundation was constructed, and a steel frame was also installed inthe roof structure for support from inside. The gaps made by cracks were filled with brickscollected from nearby collapsed brick structures. Stainless steel pins were inserted in thevertical direction in every other brick course and in the horizontal direction from the upperend of each header brick (figure 5-7).In walls that had been severely destructed by penetrating cracks, reinforcement with stainless steel pin insertion wasadopted. In this method, reconstruction or replacement of damaged areas was avoided and the original masonry techniquescould be saved. Also, by reinforcing the wall while keeping intact the slippage in brickwork caused by the earthquake, itssignificance as a disaster-affected structure was maintained.It needs to be noted that follow-up inspection of the aging of stainless steel pins used in reinforcement as well as of theprogress of crack damage on the walls is necessary.photo 5-18 Condition of inner side of the wall after the earthquakce（black lines indicatepenetrating cracks）photo provided by : Prof. Masaki Fujikawa of University of Tsukubaphoto 5-19color）Outside of the wall after restoration（slipped area in redCracks in brick wall due to the earthquake.Black areas are cracks.Cracks are filled with bricks. Red colored areasare filled bricks.Brick wall is reinforced with stainless steelpins. Green circles are inserted pins.photo 5-7Flow chart of repair / reinforcement of cracked brick wall surface101