Francesco Porco

Monumental buildings are characterized by elements (such as columns, vaults, arches …) that can suffer significant damage even under moderate earthquakes. Unfortunately, the available modeling approaches require a huge amount of computing resources. The chapter presents a multi-level strategy that is able to overcome these difficulties by a rational adoption of different computational approaches. As a case study, the non-linear seismic assessment of the medieval “Maniace Castle”, in Syracuse (Sicily, Italy) is developed, by using different numerical models. First, the linear behavior of the building is studied by means of two 3D Finite Element models. Then, results are used to calibrate a 2D plane Rigid Body and Spring Model (RBSM), specifically formulated for approximating the macroscopic behavior of masonry texture with a small number of degrees of freedom. In order to account for the variability of the material characteristics, parametric non-linear analyses have been performed and compared.

The modelling of infilled frames is generally very difficult because of the several parameters influencing their response. Specifically, the macro-models have many uncertainties related to the definition of the Equivalent Rod that simulates the panel. Main parameters involved in the definition of the Equivalent Strut Models (the width of the strut, the constitutive Force-Displacement law of the panel and the number of struts adopted to simulate the panel) induce a great variability of the structural global response. Consequently, the quantification of the uncertainties that influence the building safety verification becomes very important. In order to investigate this issue, three examples of buildings were developed and the characteristic points of the nonlinear law of the struts (yield and maximum strength) were changed within a range of allowable values. The objective is to appraise the sensitivity of the structural capacity (in terms of displacement) of infill models.

In many countries, seismic-hazard maps were adopted. These maps allow to evaluate the elastic spectrum shape which defines the reference seismic action. The verification of the seismic vulnerability of existing structures by nonlinear methods allows to evaluate the seismic demand starting right from the spectral shapes. However, it is not quite immediate the assessment of the return period of the seismic action corresponding to the actual structural capacity (i.e. the maximum displacement at each limit state). This paper proposes a simplified algorithm for the evaluation of the seismic return period corresponding to the actual capacity of the structure. The structural response, as capacity curve, is defined once only known the elastic stiffness, yield and ultimate displacement at the prefixed limit state. The methodology was validated by means the comparison between the periods obtained with the proposed algorithm and the pushover analysis on a reinforced concrete existing building.

A Multi-Level Approach for the Numerical Modelling of Complex Monumental Buildings: Seismic Assessment of the “Maniace Castle” of Syracuse: 10.4018/978-1-4666-8286-3.ch018: Monumental buildings are characterized by elements (such as columns, vaults, arches …) that can suffer significant damage even under moderate earthquakes.

Purpose: – The purpose of this paper is to collect the numerical elaboration of resistances measured on cubes made during the concrete casting and on cores extracted after the completion of the structure, for the concrete used in the construction of the “Esaro” Dam facilities (Cosenza, Italy). In addition to the statistical treatment of the sample, aimed at assessing the analytical congruence with the homogeneous classes provided in the design, the influence of compaction degree on in place strength value was qualitatively evaluated. Design/methodology/approach: – The reliability of the concrete during the construction phases was evaluated by two analytical control types according to Italian and European technical rules: “production controls” based on statistical processing of resistance values; “laying controls” that serve to assess the compaction degree with a statistical approach. Findings: – Results highlighted in the assessing of compliance checks of the mixture, the fundamental relation between statistical approach and concrete laying control. They become important when is necessary to quantify, especially in the case of great infrastructure, the gap between “potential” and “structural” concrete. Originality/value: – The advantage obtained by controlling the compaction degree in the construction phase is unquestionable. Specifically, it might allow a reduction of the drilling cores, and so minor structural damage, especially for relatively recent structures favouring extensive non-destructive tests.