Engineering Structures 30 (2008) 352–367 www.elsevier.com/locate/engstruct Modelling and analysis of a Romanesque church under earthquake loading: Assessment of seismic resistance Michele Betti ∗ , Andrea Vignoli 1 Department of Civil and Environmental Engineering, University of Florence, I-50139 Florence, Italy Received 17 November 2005; received in revised form 13 March 2007; accepted 14 March 2007 Available online 21 May 2007 Abstract In this paper a Romanesque masonry church is analysed in order to assess its structural behaviour and its seismic vulnerability with respect to the actual state of conservation. Starting from a specific case study, a contribution to the issue of modelling and analysis of monumental masonry buildings under seismic action is provided. A finite element methodology for the static and dynamic nonlinear analysis of historical masonry structures is described and applied to the case study. A quasi-static approach (the seismic coefficient method) for the evaluation of the seismic loads has been used (as indeed is common in many analyses of the seismic behaviour of masonry structures). The comparison demand vs. capacity confirms the susceptibility of this type of building to extensive damage and possibly to collapse, as frequently observed. Moreover the actual efficiency of current techniques for repairing and strengthening are analyzed in order to evaluate their benefits. The analysis of repairing and strengthening techniques show the effectiveness of the usual structural reinforcement in terms of increased seismic capacity. The paper advocates that significant information can be obtained from advanced numerical analysis, namely with respect to the understanding of existing damage and to the minimum and adequate design of strengthening. A clear understanding of the structural behaviour and reliable strengthening, based on sophisticated tools of structural analysis, can therefore reduce the extent of the remedial measures in the restoration of ancient structures. c  2007 Elsevier Ltd. All rights reserved. Keywords: Romanesque church buildings; Earthquake loading; Nonlinear analysis; FE modelling; Seismic vulnerability; Strengthening techniques 1. Introduction A large portion of the Italian cultural heritage is provided by Church masonry building. These historical buildings have demonstrated during the past to be particularly susceptible to damage, and prone to partial or total collapse, under earthquake loads, sometimes due to non-respectful restoration [1,2]. As a matter of fact repairs and retrofitting techniques should always respect the original existence; any intervention not respectful of it could also create incompatibility with the original structural behaviour. Masonry buildings are generally able to carry the vertical loads in a very safe and stable way, while they are rather sensitive, from a structural point of view, to horizontal loads. ∗ Corresponding author. Tel.: +39 055 4796 326; fax: +39 055 495 333. E-mail addresses: mbetti@dicea.unifi.it (M. Betti), avignoli@dicea.unifi.it (A. Vignoli). 1 Tel.: +39 055 4796 214; fax: +39 055 495 433. The high seismic vulnerability of this type of building is due both to the particular configuration (often characterized by open space, slender walls, lack of effective connections among the structural elements) and to the mechanical properties of the masonry material (highly nonlinear behaviour and very small tensile strength). If in principle, the prediction of the structural response of monumental buildings is not different from that of other constructed facilities (e.g. a bridge) it is an even more challenging task for several reasons [3–5]. Each monumental building is by definition a unique building characterised by its own history, often resulting in a composite mixture of added or substituted structural elements, strongly interacting; the dynamic (and static, for that matter) behaviour of ancient buildings is normally too complicated to be interpreted by simple mechanical models. In particular trying to extrapolate analytical procedures specifically developed for modern buildings is in most cases inadequate, since the static diagram is substantially different from the one of modern structures made of trusses and frames. Moreover it is quite 0141-0296/$ - see front matter c  2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.engstruct.2007.03.027