Keywords: masonry structure, cellular automata, corrector factor, failure load, failure pattern, zone similarity.

Research in the University of Plymouth by Zhou [1] and Rafiq et al [2], has proposed a novel approach for the analysis of masonry panels subjected to lateral loading, which gives a much closer prediction of both failure load and failure patterns. This method is based on the proper modelling of the variation in masonry properties in various locations within the panel and more importantly, properly modelling the effect of panel boundaries, which has been proved by this research to have a dominant effect on the behaviour of panels subjected to lateral loading. The research has introduced a new concept, "stiffness/strength corrector" [1], which quantifies the boundary effects and properly models the variation in masonry properties at various locations (zones) within a masonry wall panel. Derivation of these correctors was based on a closer mapping of laboratory experimental results, carried out by Chong [3], to those obtained from a non-linear finite element analysis of full-scale masonry wall panels subjected to a uniformly distributed lateral loads. The finite element program was originally developed by May and Ma [4] and further developments were introduced by Chong [3] and Zhou [1].

In this paper the results of the above research are discussed, with particular emphasis on the use of the cellular automata (CA) technique to model boundary effects from a panel whose correctors are known (the base panel) to any unseen panel, with and without openings. Examples of the use of this method are presented and the results are compared with the laboratory results to demonstrate the accuracy and robustness of the proposed techniques.

In order to determine a corrector value for a zone on a new panel, it is necessary first to identify a zone on a base panel, which has similar characteristics to the zone on the new panel (i.e. similar boundary types and similar position with respect to each boundary). The corrector value from the base panel is then assigned to the new panel for use in the finite element model. This paper also describes the concept of zone similarity and associated rules for defining zone similarity, developed by Zhou [1].

Finally the results of using correctors in finite element analysis of laterally loaded masonry wall panels is examined. It is discovered that by using this method considerable improvement in the prediction of failure loads and failure patterns of masonry panels, in comparison with their experimental results, is achieved.

1

Zhou, G. C. (2002). "Application of Stiffness/Strength Corrector and Cellular Automata in Predicting Response of Laterally Loaded Masonry Panels". Thesis (Ph.D). University of Plymouth, UK.

2

Rafiq, M.Y., Zhou, G.C. and Easterbrook, D.J., 2003. "Analysis of wall panels subjected to lateral loading using correctors", Journal of Masonry International, Vol. 16, No. 2, pp75-82. ISSN 0950-2289.

3

Chong, V.L. (1993). "The Behaviour of Laterally Loaded Masonry Panels with Openings". Thesis (Ph.D). University of Plymouth, UK.

4

May, I.M. and Ma, S.Y.A., (1986). "Design of Masonry Panels under Lateral Load", Proc of 1st Int. Mas. Conf., British Masonry Society, pp 118-120.

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