Giulia Bettiol

A Bayesian approach to rapid seismic vulnerability assessment at urban scale

ABSTRACT The seismic vulnerability of city centers is commonly assessed by extending the study methods applied to single buildings to urban aggregations. This approach is not always applicable at territorial scale, as it is uneconomical in terms of time and costs. An innovative method provides reasonable large-scale a priori estimation of parameters not directly evaluable from the exterior of buildings by elaborating values which can be measured from the outside. Those parameters are treated as continuous variables, by assigning them a suitable probability density function. The Bayesian approach is adopted, which allows the update of initial hypotheses by using new data gathered during on-site surveys. In this regard, a rapid survey form for the on-site data collection is proposed. An example of its application to a façade of a building structural unit in Santo Stefano di Sessanio in L’Aquila province (Italy) is proposed, showing promising preliminary results for buildings belonging to Italian historical centers.

Effect on the Structure in Elevation of Wood Deterioration on Small-Pile Foundation: Numerical Analyses

ABSTRACT Wooden pile foundations are quite common in Venice historical building. Very short, small-diameter piles are embedded into the soft shallowest soil layer under the groundwater level, but wood degradation is not prevented as anaerobic bacteria can flourish even in anoxic condition. This study couples the behavior of the masonry structure and the foundation as result of pile degradation. The numerical analyses, relative to the ancient piling, consider wood decay and secondary settlement of soil. The effect of deterioration as a function of the pile spacing and the possible presence of a stiff layer under pile tips are also investigated. The geotechnical results are then used as input for the structural model. The behavior of the masonry as result of different states of wood conservation along the wall is studied numerically.

Preliminary studies for the recovering of the Armstrong, Mitchell & Co. hydraulic crane of the Arsenal of Venice

In this paper, the preliminary study of intervention on puddle iron and cast iron Hydraulic crane, situated in the “Arsenale” of Venice is described. The crane was built by Armstrong, Mitchell & Co. in 1885. It is one of the most important and the last remaining example of XIX century innovation of English engineering, after the disposal of other Armstrong Company cranes. Thanks to the interest of the Superintendency of Venice and The Venice in Peril Fund UNESCO Committee, the crane is now undergoing restoration works. To design and execute the restoring interventions of the crane, a preliminary study was necessary. The first fundamental step consisted on performing a detailed historical research, focused in particular of the past interventions and on identifying the most important causes of damage.