pushover analysis

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    • Analysis of the seismic vulnerability of the “Quinto Orazio Flacco” school in Bari (Italy)

    Alessandra Fiore, Pietro Monaco

    Due to the high level of uncertainty characterizing existing buildings, the evaluation of the seismic behaviour of these structures must be preceded by an accurate reconstruction of their history. At this aim the present paper focuses firstly on the historical analysis and successively on the investigation of the seismic vulnerability of the “Quinto Orazio Flacco” school, built in Bari in 1933. The three-storey main masonry building has a M-shaped plan with maximum dimensions equal to 57.8 m and 82.4 m respectively in the transversal and longitudinal directions. In 1963 a new reinforced concrete building separated from the preexistent masonry one was realized along its free perimeter. By the analysis of the capacity curves obtained by suitable pushover procedures performed separately for each building, it emerges that masonry and reinforced-concrete buildings are vulnerable to earthquake-induced structural pounding in the longitudinal direction. In order to investigate this structural aspect, in this paper time history analyses are carried out, using detailed finite element three-dimensional models of the two buildings and a numerical procedure suitable elaborated by Matlab software.

    For this paper is available an extended abstract after the text in Italian

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    • Out-of-Plane Seismic Response of Masonry Façades Some Comparisons Among Full Dynamic and Pushover Analysis

    Siro Casolo, Giuseppina Uva

    Within the framework of the seismic risk assessment of monumental masonry buildings, we focus on the analysis of out–of–plane mechanisms which actually represent the most recurrent collapse mode for the façade of churches or basilicas. A full non-linear dynamic analysis is performed by adopting a rigid body and spring model (RBSM), where damage is entirely ascribed to the out-of-plane flexural behaviour. A phenomenological description of the cyclic response of the masonry material is provided in the definition of the constitutive prescriptions, including plastic energy dissipation and mechanical damage. Then, a comparison is made with a non-linear static pushover analysis, which is performed by means of the same RBSM under quasi-static loading, incrementally applied. The generalized force–displacement curve and the ultimate limit displacement capacity are evaluated, comparing them with the seismic displacement demand. As a case study, the church of Rosario in Guastalla was chosen, that was damaged by the Emilia Romagna Earthquake in 1987. A number of analyses have been performed, by adopting artificially generated accelerograms with different destroying potential, in order to investigate the correlation between the damage indicators obtained with the two procedures. The two methodologies showed a good agreement in the evaluation of the seismic response for low-medium seismic demands, even if NSPs tends to overestimate the damage, especially for high seismic levels.

    For this paper is available an extended abstract after the text in Italian

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    • Seismic response of “simple” masonry buildings

    Mariateresa Guadagnuolo, Giuseppe Faella

    The paper is aimed at evaluating the seismic response of simple masonry buildings complying with the rules provided by the new Italian national seismic code. Only a few of examined buildings fulfil the Eurocode 8 requirements. The buildings have two or three stories and differ in plan and wall geometry. Initially, the requirements for simple masonry buildings provided by Italian seismic code and Eurocode 8 are coMPared. Subsequently, results from nonlinear static analyses and modal response spectrum analyses are presented. Influence of accelera- tion at site and masonry strength is also assessed. Indications on the congruence between code rules and results from numerical analyses performed according to the code themselves are supplied. The results show that Eurocode 8 provisions seem to be more appropriate and safe, especially in the case of low masonry strength.

    For this paper is available an extended abstract after the text in Italian