Computational & Technology Resources
an online resource for computational,
engineering & technology publications
PROCEEDINGS OF THE EIGHTH INTERNATIONAL CONFERENCE ON COMPUTATIONAL STRUCTURES TECHNOLOGY
Edited by: B.H.V. Topping, G. Montero and R. Montenegro
Dynamic Analysis of Age-Old Masonry Constructions
S. Degl'Innocenti, C. Padovani, A. Pagni and G. Pasquinelli
Institute of Information Science and Technologies "A. Faedo", Italian National Research Council, Pisa, Italy
S. Degl'Innocenti, C. Padovani, A. Pagni, G. Pasquinelli, "Dynamic Analysis of Age-Old Masonry Constructions", in B.H.V. Topping, G. Montero, R. Montenegro, (Editors), "Proceedings of the Eighth International Conference on Computational Structures Technology", Civil-Comp Press, Stirlingshire, UK, Paper 79, 2006. doi:10.4203/ccp.83.79
Keywords: masonry constructions, non-linear elasticity, dynamic analysis, finite element method.
In order to perform dynamic analyses of real masonry structures many researchers model the masonry as a linear elastic material and apply the mode superposition method to integrate the equations of motion [1,2,3]. Alternatively, the dynamic behaviour of very simple structures has been investigated using an elastic-plastic constitutive model imbedded into a direct integration method [4,5,6].
In this paper masonry is modelled as a non-linear elastic material with zero tensile strength and infinite compressive strength [7,8,9]. The resulting constitutive equation, known as the equation of masonry-like or no-tension material, is able to account for some of masonry's peculiarities, in particular, its inability to withstand large tensile stresses. Assumptions underlying the model are that the infinitesimal strain is the sum of an elastic part and a fracture part, and that the stress, negative semi-definite, depends linearly and isotropically on the former and is orthogonal to the latter, which is positive semi-definite. Thus, the stress is a non-linear function of the infinitesimal strain. In order to study the structural behaviour of existing masonry structures, both the static and dynamic problem can be solved via the finite-element method [9,10]. The equation of masonry-like materials has been implemented into the finite-element code NOSA, developed entirely at ISTI-CNR with the purpose of studying the behaviour of masonry solids and modelling restoration and reinforcement operations on constructions of particular architectural importance. The code has been successfully applied to the analysis of some buildings of historical interest: the S. Nicolò Motherhouse in Noto, the Medici Arsenal in Pisa, the Baptistery of the Volterra Cathedral, the Church of S. Pietro in Vinculis in Pisa, the Buti bell tower and the dome of the Church of S. Maria Maddalena in Morano Calabro.
As far as numerical solution of the dynamic problem is concerned, the equations of motion must be integrated directly. In fact, due to the non-linearity of the adopted constitutive equation, the mode-superposition method is meaningless. We instead apply the Newmark method implemented in NOSA  to perform the time integration of the system of ordinary differential equations obtained by discretising the structure into finite elements.
In this paper, the numerical method presented in  is applied to age-old masonry constructions, in particular to the dome of a church located in the Calabria Region, Italy. We present the numerical method implemented in the NOSA code for the dynamic analysis of masonry structures, with particular focus on vaults and domes. Subsequently, we study the damaged dome and tambour of the Church of Santa Maria Maddalena in Morano Calabro. The structure has been discretised with shell elements and analyses performed using the NOSA code. Initially, the structure is at rest, in static equilibrium under the action of its own weight. Subsequently, the base of the tambour, which is clamped, is subjected to a cyclic horizontal acceleration acting over a given time interval, and then the construction is left to oscillate freely. The results obtained considering the masonry to be a non-linear elastic material are compared with the results of an analogous dynamic analysis carried out on the same structure, while however assuming linear elastic material behaviour. This comparison has highlighted the profound differences between the results obtained using the two assumptions.
purchase the full-text of this paper (price £20)