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

dedicated to anti-seismic protection of cultural properties.Interdisciplinary research and development concerningsuch topics as methods to analyze the seismic performanceof cultural property buildings to fully utilize their inherentproperties or reinforcement materials and technology whichwould increase structural performance through minimumintervention. Many structural experiments and on-sitesurveys have been executed. The outcome of this project isavailable to the public on their website (http://www.niker.eu).In 2012, there was an earthquake in the region of Emilia-Romagna in northern Italy and historic structures of theWorld Heritage sites of“Ferrara, City of the Renaissance,and its Po Delta”and“Mantua and Sabbioneta”were struck.Among all, damage to the Estense Castle in Ferrara wassevere and the small tower at the top of the turret roofbecame partially collapsed. After the earthquake, the turretwas restored and a steel bracing system was introducedinto the upper interiors, although the numerous cracks thatappeared on the fresco painting inside remain to be restored,having only been temporarily treated (photo 5).This earthquake can also be noted that it occurred inthe plains with mainly brick masonry construction. Pastearthquakes that brought severe damage to structures hadbeen observed in mountainous areas with mostly stonemasonry buildings.3．Present Anti-Seismic Measures3.１. Codes and PrinciplesRepresentative codes and principles regarding seismicprotection of cultural property structures in Italy are theCode for Protection of Cultural Landscapes (Codice deibeni culturali e del paesaggio), Guidelines for Evaluationand Reduction of Seismic Risks in Cultural PropertyStructures (Linee Guida per la valutazione e riduzionedel rischio sismico del patrimonio culturale to be calledphoto 5Damage caused by the Ferrara Earthquake（Emergency treatment for cracks inside the Estense Castle）“Cultural Property Guidelines”from hereon), and Standardsfor Construction Techniques (Norme Tecniche per leCostruzioni).Firstly, in article 29 clause 4 of the Code for Protectionof Cultural Landscapes, it is stated that in restoringcultural property structures in areas prone to earthquakes,consideration for improving seismic resistance (seismicreinforcement) is necessary. The Cultural Property Guidelinesexplain the principles and actual steps to take in settinggoals, structural surveys, numerical analysis, reinforcementplanning, and reinforcement methods, all to be executed withregard to both aspects of protection of cultural propertiesand assuring safety in times of earthquakes. Standards forConstruction Techniques is complemented by notifications(Circolare) and chapter 8, in each of the documents ofstandards and notifications, is dedicated to extant structuresin which anti-seismic measures are dealt with including focalpoints in treating cultural property buildings.In Japan, structures designated as cultural propertiesunder the Law for Protection of Cultural Properties areexempt from observing the building codes applied onbuildings in general, while principles for cultural propertiesare provided for seismic performance. On the other hand, inthe case of Italy, as has been mentioned, cultural propertiesare considered as a group within extant structures to whichstandards for architectural construction are applicable anddetails are given in other documents including the CulturalProperty Guidelines.3.2. Goals for Seismic ProtectionIn Italy, there are three options in the steps to takefor seismic reinforcement on extant structures, as hasbeen partially mentioned. There is reinforcement 1) tomeet seismic standards (Intervento di Adeguament),2) that does not meet seismic standards but increasesseismic performance, no matter how little (Intervento diMiglioramento), and 3) for partially increasing seismicresistance (Intervento Locale). Regarding seismic protectionof cultural property structures, it is reinforcement toincrease seismic performance rather than to meet standardsthat is aimed at and thus, it seems that there are no examplesof the former form of reinforcement being undertaken today.However, in treatments for increasing seismic performance,it is required to make a quantitative evaluation of thebuilding’s seismic performance before and after installationof reinforcement to confirm the effectiveness of the work.It is for the following economical, physical, culturalproperty-related, and structural reasons that reinforcementto fully meet the standards tends to not be selected. First ofall, if such reinforcement were to be undertaken, the scale of37