On 14 August 2018 at 11:35 AM, a relevant portion (about 243 m) of the viaduct over the Polcevera river in Genoa collapsed, killing 43 people. 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. This paper aims to reminisce the complete story of the bridge, from the Italian construction boom in the 1960s to some of the issues that soon arose thereafter: the strengthening intervention in the 1990s, the subsequent structural monitoring and, finally, the strengthening project never brought to fruition. Potential reasons for the collapse are discussed, together with some of the possible inadequacies of the bridge, its maintenance and loading history based on critical reflection, comparison with specific features of bridge construction practice today and results obtained using numerical models with different levels of refinement. Since the entire matter (specifically the debris) was considered classified by the investigating magistrate in the immediate aftermath of the bridge collapse, this work is based entirely on publicly available material.

In this paper, an innovative displacement-based adaptive pushover procedure, whereby a set of laterally applied displacements, rather than forces, is monotonically applied to the structure, is presented. The integrity of the analysis algorithm is verified through an extensive comparative study involving static and dynamic nonlinear analysis of 12 rein-forced concrete buildings subjected to four diverse acceleration records. It is shown that the new approach manages to provide much improved response predictions, throughout the entire deformation range, in comparison to those obtained by force-based methods. In addition, the proposed algorithm proved to be numerically stable, even in the highly inelastic region, whereas the additional modelling and computational effort, with respect to conventional pushover procedures, is negligible. This novel adaptive pushover method is therefore shown to constitute an appealing displacement-based tool for structural assessment, fully in line with the recently introduced deformation- and performance-oriented trends in the field of earthquake engineering.

The recent drive for use of performance based methodologies in design and assessment of structures in seismic areas has significantly increased the demand for the development of reliable nonlinear inelastic static pushover analysis tools. As a result, the recent years have witnessed the introduction of the so-called adaptive pushover methods, which, unlike their conventional pushover counterparts, feature the ability to account for the effect that higher modes of vibration and progressive stiffness degradation might have on the distribution of seismic storey forces. In this paper, the accuracy of these force-based adaptive pushover methods in predicting the horizontal capacity of reinforced concrete buildings is explored, through comparison with results from a large number of nonlinear time-history dynamic analyses. It is concluded that, despite its apparent conceptual superiority, current force-based adaptive pushover features a relatively minor advantage over its traditional non-adaptive equivalent, particularly in what concerns the estimation of deformation patterns of buildings, which are poorly predicted by both types of analysis.