Search

The collapse of a relevant portion of the Polcevera river viaduct, located in Genoa (Italy) and also known as Morandi Bridge, is herein object of a numerical investigation. The bridge was designed in the early 1960s by Riccardo Morandi, a well-known Italian engineer, and opened to the public in 1967. The collapsed part of the bridge essentially comprised an individual self-standing structure spanning 171 m and two simply-supported connecting Gerber beam systems, each spanning 36 m from the self-standing structure to the adjacent portions of the bridge. A previous investigation, by Calvi et al. (Calvi et al. in Struct Eng Int 29:198–217, 2019), indicated that the collapse of the bridge could have potentially been triggered by a sudden loss of effectiveness of one stay (e.g. due to the failure of either the deck-stay or the antenna-stay connections), which in turn would have induced a flexural–torsional-shear failure of the bridge deck. In the current work, therefore, the attention is turned into a more detailed study of the latter, through the employment of detailed Finite Element Analysis modelling, with a view to corroborate, or not, the results of the aforementioned previous study. As in the latter, the development of such model was based entirely on publicly available material that has so far been rendered online accessible. It is shown that should the support provided by one of the bridge stays be removed, the ensuing flexural–torsional-shear demand on the deck would be such that the latter would be led to the type of collapse observed in the field.

An innovative discontinuum-based micromodeling approach, the Applied Element Method, is used in this work to investigate explicitly potential failure mechanisms that might have contributed ...

This research work is related to the evaluations of some modelling assumptions of the stick–slip phase of the Friction Pendulum™ System (FPS) on the seismic response of base-isolated buildings. Although several theoretical and experimental research findings show the complexity of the FPS nonlinear behaviour, the current international seismic design codes allow the designer to model the FPS nonlinear response using simple bilinear constitutive relationship in order to reduce the computational effort for modelling and performing the analyses. Therefore, the problem that has to be faced by practitioners and researchers is related to the way of modelling the stick–slip phase and the corresponding friction phenomena with a simple bilinear constitutive model. This research work has been encouraged by some experimental evidence and performed for investigating, through a large parametric study, the influence that many modelling assumptions may have on the global and local responses of buildings. The study has been carried out without claiming to be innovative but for being a valuable tool in the design practice and, mainly, in modelling the nonlinear response of the FPS with the bilinear simplification allowed by design codes.

Base isolators are effective tools that favor a high level of building performance under lateral load, providing protection to both structural and non-structural elements. In this context, this paper discusses the possibility of employing materials with different frictional properties to enhance the response of flat- and curved-surface base isolators. Two innovative devices, referred to as “BowTie” and “BowC”, are introduced and discussed in some detail. A series of non-linear time history analyses is then conducted using a customized computer program and considering a number of case study structures, designed applying a displacement-based approach. The results of the analyses are used to discuss the key differences between variable friction and constant friction sliding isolation devices. It is shown that the newly proposed isolators may represent an improvement on classic base isolation solutions, in light of their higher energy absorption capacity, which contributes to significantly enhancing their performance.