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

masonry structures were proposed, with the introduction ofmethods including injection, pinning, and jacketing, whichwere applied onto cultural property structures. Such actionscan be understood to have been necessary for consideringseismic protection for quick recovery, but at the same time,it needs to be noted that the effectiveness of some of themethods proposed had not been proved through theorynor experiment. Also proper reinforcement methods forcultural property structures, with regard to reversibility ofreinforcement and preservation of original materials, werenot sufficiently studied.However, in the immediate years following the Friulidisaster, in 1980, the Irpinia Earthquake hit southern Italyand a large region spanning over the states of Campania andBasilicata was heavily struck. As in the Friuli Earthquake,a great number of cultural property structures wasdamaged and without further studies, the reinforcementmethods mentioned above were applied. In later years,they came to be adopted as general methods throughoutItaly and eventually made its way into being written intothe Standards for Construction Techniques. In the recoveryof cultural properties following the Irpinia Earthquake, inaddition to the above methods, reinforcement by introducinga reinforced concrete slab onto masonry vault ceilingsand wood-frame floor structures (photo 2) or by replacinga wood-frame roof structure with steel frame appeared,which included approaches with large influences on thestructures’significance as cultural properties. In somecases of recovered buildings, which the author has visitedthe sites of, the passing of time of 30 years had resulted indeterioration of the reinforcement members due to metalcorrosion, which suggests possibilities of problems indurability or maintenance appearing after installation.With such underlying issues now apparent, anti-seismicmeasures appropriate for cultural properties continuedto be avidly sought after following these earthquakes.Earlier in 1975, the Ministry for Cultural Environment(present Ministero dei Beni e delle Attivita Culturali e delTurismo) was established, which enabled a large budget tobe made available for the recovery of cultural propertiesafter the Irpinia Earthquake. In 1984, an interdisciplinaryspecialist commission established by the above ministryand People’s Protection Bureau (Protezione Civile) helddiscussions on ensuring safety of cultural properties attimes of earthquakes, which led to a recommendation in1986 to the enforcement of a guideline in 1989. Throughthese procedures, much information was gained throughresearch on reversible reinforcement methods with regardto preservation of extant materials and structure as wellas methods for quantitative evaluation of earthquakeperformance before and after introduction of reinforcement.These efforts eventually led to the introduction ofreinforcement that may not necessarily fully meet theseismic standards, but is intended to increase seismicperformance from the present state; in other words, theapplication of“Intervento di Miglioramento”instead of“Intervento di Adeguamento”came to be accepted. Thisway of thinking was adopted in the 1986 revision of theStandards for Construction Techniques as one of thepreventive measures for extant structures. In the 1996revision, it was expanded to describe the application of thisprinciple on cultural property structures.In 1997, the Umbria-Marche Earthquake which hit centralItaly brought damage to cultural property structures.Particularly at Basilica of Saint Francis of Assisi, severedamage was seen in the structure including collapse ofthe vaulted ceiling. After the earthquake, pieces of thefresco painting from the fallen ceiling and stone materialwere gathered for reuse in the reconstruction as much aspossible. The upper surface of the ceiling was fortified witharamid fiber and the ceiling itself was suspended from theroof structure by steel rods with springs attached. In 2000,the recovered structure was inscribed on the World HeritageList as“Assisi, the Basilica of San Francesco and OtherFranciscan Sites.”In this earthquake, damage was seen in structures thathad been reinforced with methods established after theFriuli Earthquake (photo 3), which clarified that thesereinforcement methods using reinforced concrete were notsufficiently effective and that there were possibilities offurther damage being caused by earlier interventions. Therewas now increased awareness in the necessity of correctlyunderstanding the structural characteristics of a buildingprior to reinforcement as well dangers of reinforcement thatmay greatly alter the extant structural characteristics.photo 2 Reinforcement after the Irpinia Earthquake（replacement ofthe floor structure with a reinforced concrete slab)Also, after the earthquake, the importance of sufficiently35