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An earthquake sequence struck the province of L'Aquila (central Italy) leaving 305 dead, about 1,500 injured, and 29,000 homeless. Hundreds of low-intensity events occurred between January and March, 2009. The mainshock took place on April 6, 2009, and its epicenter was located at about 6 km southwest of L'Aquila town; three stronger aftershocks happened on April 7 and 9, 2009. This paper focuses on actual performance of older and more recently constructed building structures during the earthquake sequence. After the main seismological characteristics of the sequence are described, the most significant observed damages are analyzed and associated with theoretical failure modes for both reinforced concrete and unreinforced masonry buildings. Since older masonry structures were more seriously damaged, the effects of the earthquake are described with more emphasis to ordinary masonry and cultural heritage buildings (churches, palaces, and castles). In conclusion, a number of lessons may be learned from the L'Aquila earthquake sequence. Several features are highlighted and some proposals are given to upgrade the current methods of structural analysis, as well as the existing codes. [ABSTRACT FROM AUTHOR]

The work described herein was conducted within the framework of an ongoing research program on the dynamic behavior of the Tower of Matilde, the bell tower of the Cathedral of San Miniato, Pisa, Italy, an interesting case study for its current structural arrangement and the modifications it has undergone over the centuries. This paper (Part I) details the experimental analyses performed in order to obtain an accurate measure of both the motion of the tower’s bells and, consequently, the time function of the dynamic actions transmitted to the tower during their motion. We then demonstrate how it is possible to arrive at an accurate, even though approximate, analytical description of both the bells’ motion and their actions by means of only a few experimental measurements and a simple mechanical model (also called in the following additional mass model). [ABSTRACT FROM AUTHOR]