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

studying the building’s history and inspecting theconnections made between the newer additions in structuresthat have undergone alterations and have had additionsmade has been pointed out. At the same time, it was notedthat regarding seismic performance of buildings that may beaffected by adjacent buildings at the time of an earthquake,this impact needed to be considered in evaluation of seismicperformance. Additionally, after the Friuli Earthquake,studies on typical mechanisms of collapse focusing onchurch structures were expanded to include other buildingtypes, and the different patterns have been organized on achart which can now be used as data for limit analysis. In2007, the results of discussions and research after the FriuliEarthquake were collected in to a guideline for evaluationand mitigation of earthquake risks concerning culturalproperties.The 2009 L'Aquila earthquake which occurred in centralItaly brought damage to the historic center of L'Aquila andsurrounding villages. Among these places, damage to theurban fabric of L'Aquila, the capital of the region and a largecity with numerous historic structures, was particularlysevere (photo 4). The frail walls of stone masonry structures,composed of irregularly shaped stones built with weakmortar widely seen in this area, crumbled and inducedfurther damage. Also, as had been confirmed earlier inthe Umbria Earthquake, damage appeared on structuresreinforced with modern construction techniques. Especiallyin those that had their wood-frame roof and floor structuresreplaced with reinforced concrete slab, there were manycases where it was apparent that these reinforcements hadamplified the damage.Groups of buildings in densely built city blocks were alsoheavily destructed and their recovery became major issues.In order to make the entire group of buildings sufficientlyearthquake-proof, property owners of the damaged buildingswere required to establish an association comprised of morethan one-half of the owners to work on recovery of theblock. Also, research on evaluation of seismic performanceas well as preventive methods for groups of building wasadvanced.Because the number of affected buildings was extremelylarge, it was foreseen that a long time span would benecessary for recovery. Therefore, so as to protect thebuildings from further damage by aftershocks, temporaryreinforcement and monitoring of the condition of damagewere executed. Regarding temporary reinforcement,based on results of damage surveys immediately after theearthquake, highly dangerous structures and elementsthat might collapse were selected and prioritized forreinforcement. Such methods as those employing logsupport, scaffolding pipe attached onto leaning walls, orbands applied around buildings to prevent corners fromopening were adopted. They were chosen not only fromthe point of view of structure, but also by judging from thesurrounding environment, economic efficiency, workability,as well as effects on the cultural property. Such experiencegained through these cases was reflected on variousoutcomes including the handbook for designing temporaryreinforcement which was enforced after the earthquake.Also regarding monitoring, instruments for measuringdisplacement and recording oscillation were placed insidebuildings to take measurements at regular intervals orat times of aftershocks, so that the results could be usedto make comprehensive evaluations of the buildings’conditions. This system is used not only for post-earthquakemonitoring. It can be applied for adjusting parametersof numerical models by comparing performances ofactual buildings and numerical models, or to confirm theeffectiveness of reinforcement by comparing measurementsfrom before and after installation. Also from 2010 to 2012,a group comprised of 18 universities from 12 countries ofEU worked together on a research project called NIKER,photo 3Damage caused by contemporary reinforcement method inUmbria Earthquake（replacement of the roof structure with areinforced concrete slab)photo 4Damage caused by the L'Aquila Earthquake（Santa Maria del Suffragio Church）36Chapter 4 Earthquake-Proofing Measures for Masonry Structures in Italy