Comparison between the forecasts of a numerical model and the results of physical model in roman tuff brick walls

As a result of its very ancient history in Italy there are still a large number of towns whose historic centres were built many centuries ago. Most of the buildings in such centres were constructed using natural stone. As can be easily understood, the lithotechnical characteristics of such materials vary from zone to zone in dependence of the quarry from which they were mined and of the geologie nature of such quarries. In particular in Latium, a Region in Central Italy, the extensive outcrops of pyroclastic volcanic fonnations, prompted ever since the earliest days of history, the widest use of such materials for building purposes. Nowadays, for economie reasons but also for environmental protection, as in the case of restraints aiming at not spoiling the landscape, such use has been heavily restricted even though there is still need for these materials to repair and rehabilitate ancient buildings, a problem which is becoming increasingly urgent. For this reason it was decided to study the characteristics of ancient walls with the aim of defining their static-deformational behaviours, taking into account mainly the "brickbinder unit" in its most typical typologies (materials and mortars most commonly used) so as to draw up a code for interventions on ancient structures. This work was started for this purpose and in its first phase the static and deformational behaviour was characterized of a number of physical models of tuff brick walls constructed using different types of mortars, which were then subjected to traditional laboratory tests. Mathematical finite element models were then constructed to simulate the behaviour of the physical models used in the laboratory. A comparative analysis of the results obtained through these two different investigations is believed to provide useful indications for solving the problem at hand. The pyroclastic materials used in the laboratory tests were dimensioned tuff bricks coming from two quarry areas in northem Latium, the quarries located along Via Tiberina near the built-up area of Riano and those in the Treia River Valley near the built-up area of Civita Castellana, where there is a long-standing quarrying tradition for this type of product. The mathematical model used in the study is a three- dimensional finite element model which, in the course of the study was in turn attributed the physico-mechanical characteristics of each of the various materials used in the traditional physical tests.