The normal‐faulting earthquake of 6 April 2009 in the Abruzzo Region of central Italy caused heavy losses of life and substantial damage to centuries‐old buildings of significant cultural importance and to modern reinforced‐concrete‐framed buildings with hollow masonry infill walls. Although structural deficiencies were significant and widespread, the study of the characteristics of strong motion data from the heavily affected area indicated that the short duration of strong shaking may have spared many more damaged buildings from collapsing. It is recognized that, with this caveat of short‐duration shaking, the infill walls may have played a very important role in preventing further deterioration or collapse of many buildings. It is concluded that better new or retrofit construction practices that include reinforced‐concrete shear walls may prove helpful in reducing risks in such seismic areas of Italy, other Mediterranean countries, and even in United States, where there are large inventories of deficient structures.
The 2002 Molise, Italy, earthquake struck a relatively limited geographical area where the communities are mainly agrarian. While most buildings in the region are masonry, there are significant differences in the type of masonry construction, as material characteristics and construction practices had changed over the centuries. This paper focuses on the masonry buildings that predominate in domestic construction. The most significant features that contributed to the damage pattern appear to be (1) construction criteria, techniques, and details that were inadequate for seismically active areas, particularly in buildings constructed or substantially modified over the past 100 years, and (2) site effects resulting from differences in amplification and frequency of the vibrations that locally increased the destructiveness of the earthquake. The observed damage did not correlate to the vulnerability that would be assigned to the structures under the European Macroseismic Scale.
About 10% of the almost 20,000 buildings damaged by the 2002 Molise, Italy, seismic sequence were reinforced concrete (RC). The most frequent type of damage affected the infill masonry walls, but in some cases cracks in concrete columns were observed. Heavy damage to both infills and structural elements was restricted to a few cases in the meizoseismal area. Almost all the affected municipalities were only classified as seismic in May 2003, following this earthquake. Consequently, construction generally used vertical‐load‐bearing moment‐resisting frames with no explicit design for seismic lateral forces. In particular, the reinforced concrete buildings typically consist of cast‐in‐place unidirectional RC slabs lightened with hollow clay tiles, supported by RC beams and columns. Usually no shear walls are present, except in some cases for the elevator shaft. This paper covers: a) an overview and statistical analysis of damage to RC buildings, and b) a detailed analysis of two damaged buildings.