Giacomo Tempesta

Equilibrium analysis of masonry domes. on the analytical interpretation of the Eddy-Lévy graphical method

ABSTRACT The 19th century graphic method of Eddy-Lévy is analyzed and proposed in an analytical form as an assessment tool for masonry domes. The method determines the neutral hoop that separates the upper part of the dome that behaves as a compressed membrane from and the bottom that behaves as independent arches, due to the presence of vertical cracks. This method allows determining a no-tension equilibrated solution, accounting for the natural behavior of masonry domes of fracturing along meridian planes. Six case studies were investigated, considering spherical and pointed dome, complete, with hole and with hole and lantern. A modified version has been studied to model the biaxial stress of upper part properly through the membrane theory, and compared to the solution obtained by a numeric discrete block model. Limit thickness-to-radius ratio was identified, and a parametric analysis was carried out to investigate the extension of meridian fracture varying dome shape and thickness.

Pompeii’s Stabian Baths. Mechanical behavior assessment of selected masonry structures during the 1st century seismic events

ABSTRACT The eruption of Mount Vesuvius in 79 AD buried and preserved the Stabian Baths building in the exact configuration which the archaeological excavations carried out in the second half of the 19th century recovered. By combining archeologists’ studies with the analysis of deformations and cracking pattern due to the 1st century seismic events, in this article numerical models have been formulated which allowed the formation of some hypotheses coherent on the timeline of the events, the damage to as well as the change of the shape and stylistic language of the thermal building. Specifically, through global seismic analyses and kinematic analyses of masonry portions of the “destrictarium” block, it is proven that during the 1st century not only a sole catastrophic earthquake occurred but, at least, two important seismic events took place. The purpose of this article is to identify and parameterize the responsible earthquake by the analysis of seismic effects detectable in the damages and archaeological remains of the masonry walls of the Stabian Baths. The identification of the earthquake and the grading of provoked damages represent a useful knowledge tool that provides information about the vulnerability of ancient buildings and can be suitably used also to safeguard architectural heritage from seismic risk.

A Novel Numerical Tool for Seismic Vulnerability Analysis of Ruins in Archaeological Sites

ABSTRACT Ancient masonry constructions in archaeological sites are often ruins or remains of wider portions. Therefore, archaeological artifacts generally occur as a discontinuous set of walls or columns detached from the original context. The absence of most of the original structural portions makes them much more vulnerable. Indeed, even if their current existing condition is an indicator of their equilibrium condition under gravitational loads, this condition is not sufficient to guarantee their preservation in the case of an unexpected earthquake. Furthermore, the cracking patterns and collapses make them even more vulnerable. For these reasons, the vulnerability of ruins should be addressed as regard to the possible failure mechanisms that can be activated by seismic actions. Accordingly, in this article a novel and targeted numerical tool for seismic vulnerability assessment of remains in archaeological sites, that considers collapse mechanisms occurrence as the main cause of masonry constructions being lost, is presented. Results of the numerical procedure proposed are compared with the results obtained by the canonical formulation of virtual works. Finally, the seismic vulnerability level of selected masonry constructions in the archaeological sites of Pompeii and Arpino (Italy) has been assessed by the use of this procedure.

Seismic Performance Evaluation of Timber—Framed Masonry Walls Experimental Tests and Numerical Modelling

The Borbone constructive system used in Calabria at the end of the 1700s consisted of a particular composite structure realized by means of a timber frame suitably embedded inside masonry walls. This system used with similar purposes, although in different ways, in other places in the world (especially in seismic regions), can represent, with good reason, the synthesis of scientific knowledge in eighteenth century seismic engineering. The aim of the paper is to investigate and evaluate the seismic performance of the structure described above through a comparison between experimental tests, carried out by means of cyclic tests on 1:1 scale models, and the results obtained by the numerical modeling of the mechanical system that is capable of interpreting the actual contribution of the wooden structure, as well as that of the masonry, to the overall stiffness of the wall. In the numerical procedure, the masonry infill is modeled by rigid blocks connected by unilateral elastic contact constraints. A convenient way to define the contact device which links the blocks, through which a mortar joint or dry joint could be simulated, is to consider a set of elastic links, orthogonal to the contact surface between two adjacent blocks, and an additional link, parallel to the interface through which the shear forces can be transmitted. Reasonable hypotheses can be assumed for the link parallel to the contact surface in order to calibrate both the shear behaviour and the influence of the friction between the blocks. Furthermore the timber frame is modeled by using finite elements with elastic and bilateral behaviour. Unilateral contact constraints are again used in the contact interfaces between elements in wood and masonry blocks which take into account the actual contribution of friction. The mechanical parameters used in the numerical model were deduced from the experimental laboratory tests.

Ruins and Archaeological Artifacts: Vulnerabilities Analysis for Their Conservation Through the Original Computer Program BrickWORK

Architectural ruins in archeological sites constitutes cultural heritage of a country. Every day there is the risk of archaeological artifacts being lost or of undergoing a slow and progressive deterioration, for at least three reasons: the presence of visitors who are often the cause of damage, the material vulnerabilities and the intrinsic vulnerabilities of ruined constructions. Leaving aside the first type, material vulnerability is primarily due to chemical and physical transformations undergone by the artifact which has been buried for a long time. After excavation, their prolonged exposure to weathering, frost-thaw alternate cycles, humidity variation, etc., reduce mechanical properties of materials such as stones and mortars. Furthermore, ruined constructions are lacking in most of the original structural portions which acted as constraints and therefore they are in the condition of unstable equilibrium and are very vulnerable under seismic actions. Indeed, (timber) floors are the first members which undergo decay or collapse. Therefore, archaeological artifacts generally appear as a discontinuous set of walls or columns and consequently easily vulnerable. Lastly, ruins retain “memory” of past events, visible in the cracking patterns and collapses provoked by seismic events which make them even more vulnerable. In this paper the analysis of main vulnerabilities of ruined constructions is performed. The analysis is carried out on meaningful case studies in the archeological site of Pompeii and Arpino (Italy), using a structural software suitably developed by the authors, and provides data to allow one to propose targeted methodologies for protection and conservation.