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

Earthquake-Proofing Measures for Masonry Structures in ItalyEisuke NishikawaICCROM, Sites Unit, Project Manager1. IntroductionAn earthquake that occurred in central Italy in August2016 completely destroyed the city center of Amatrice.This brought damage not only to historic structures, butalso had severe effects on humans as well as the economy.Aftershocks continued and in October, in the same region,there was again a series of large earthquakes that made thebuildings affected earlier collapse, enlarging the disaster.Presently in Italy, recovery measures are being undertakenthrough damage analysis and studies on preventivemeasures.In the past, Italy has repeatedly suffered from numerouslarge earthquakes caused by clashing of the African andEurasian tectonic plates, resulting in severe damageparticularly along the Apennines constituting the backboneof the Italian peninsula and the east coast of the islandof Sicily. For example, Rome’s representative artifact ofthe Colosseum constructed in the first century A.D., wasdamaged by earthquakes in the 3rd, 5th, and 9th centuries;in the 14th century a large part of the south wall of theouter ring seems to have collapsed after an earthquake.In the 18th century, further damage was induced by anearthquake and in the 19th century, buttresses were placedon two areas of the outer ring for reinforcement completingthe appearance we see today. Also, the town of Noto in Sicilybecame a ruin following a large earthquake occurring on theisland’s east coast and the town was relocated and rebuiltwhich is today known as“Val di Noto and the Baroque”inscribed on the World Heritage List. There are numerousexamples of historic buildings and ruins with traces ofrecovery and reinforcement after earthquake damage to beseen all around the country.In the modern era, there have been in 1883 the IschiaEarthquake and in 1908 the Messina Earthquake whichbrought severe damage, and academicians from Japanhad then visited the affected areas for research. After theIschia Earthquake, an anti-seismic reinforcement methodof covering masonry structures with latticed iron bars onthe inner and outer surfaces was developed and after theMessina Earthquake, a structural calculation method withquantified earthquake force was proposed. These disastersbrought chances for modern earthquake-proofing measuresfor masonry structures to be advanced. At that time inJapan, as construction of masonry structures applyingtechnology introduced from the West reached its peak, thecountry was hit by the Nobi Earthquake in 1882 and theGreat Kanto Earthquake in 1923, which shed light on theproblem of earthquake resistance. Preventive measures werejust beginning to be studied.Thus, Japan and Italy share a historical background onearthquakes, regarding building damage and methods forrecovery and improving seismic resistance. At the sametime, both countries are presently facing the issue of antiseismicprotection of cultural property structures. Inthis paper, present movements in measures for seismicprotection in Italy will be described following the progressafter particularly the Friuli Earthquake which initiated thedevelopment of seismic countermeasures in recent years.2. Recent Earthquake Damage and AdvancementsThe Friuli Earthquake of 1976 which occurred in theFriuli region close to the national borders of Slovenia andAustria brought severe damage to masonry structures ofthe area including cultural property structures (photo1). In Italy, until this earthquake, full-fledged anti-seismicdesign of masonry structures had rarely been undertaken.For this reason, during the process of recovery after thisearthquake, principles for anti-seismic reinforcement ofphoto 1 Damage caused by the Irpinia Earthquake（Avellino Cathedral）34Chapter 4 Earthquake-Proofing Measures for Masonry Structures in Italy