The paper describes the failure scenario of a precast building that collapsed during the 2012 Emilia earthquake. By means of time-history analyses on a detailed finite-element model, the dynamic behavior of the structure was investigated and the most reliable causes producing the seismic collapse were established. All collapse mechanisms (column failures induced by exceeding the shear force capacity, attainment of ultimate chord rotation, equilibrium instability of columns due to second-order effects and loss of support due to sliding at the double-tee slab-beam and beam-column friction-based supports) were monitored for the whole earthquake duration. The collapse scenario obtained from the interpretation of numerical results was compared with that suggested by the in situ inspection, confirming that friction-based supports (with absence of connection mechanical devices), typically adopted in Italy in precast technology when no seismic design provisions were prescribed, are inadequate to carry medium-high horizontal seismic loading. The modeling criteria and the procedure adopted for safety checks until the attainment of a collapse condition are presented and discussed.

The interacting boson approximation model, extended by allowing one boson to break and form a quasiparticle pair, is investigated in the SU(3) limit. Electromagnetic properties of yrast states are studied for the algebraic analogs of both the decoupling and strong-coupling limits. The effects of a pair-breaking interaction that mixes states with different numbers of quasiparticles are investigated for E2 transitions between yrast states. For the algebraic analog of the decoupling limit, it is shown that the mixing interaction has a strong influence on transitions in the region of crossing between the ground-state band and the lowest two-quasiparticle (2qp) band. The mixing interaction does not change the electromagnetic properties of the states of the ground-state band. This effect is due to the approximate cancellation between self-energy and vertex corrections, which corresponds to the nuclear Ward identity. For the algebraic analog of the strong-coupling limit, the K forbiddeness of E2 transitions between the ground-state band and the lowest 2qp band is high, and therefore the influence of the mixing interaction is negligible.

Recent earthquakes have highlighted a general inadequacy of the existing building stock in Italy and the need to address this critical issue by increasing its structural resilience. At the same time, the problem of energy consumption in existing residential and commercial buildings is increasingly significant and incompatible with the environmental targets set by governments. Considering all the aforementioned aspects, the seismic upgrading of existing buildings, based on the use of an eco-friendly and sustainable technology, has become more and more relevant and different intervention approaches have been developed. This paper aims to provide a multidisciplinary approach for the performance assessment of an eco-friendly and sustainable RC-framed skin for integrated refurbishment of existing buildings. A preliminary description of such skin technology is provided with particular attention to the simultaneous improvement of structural (e.g., seismic) and non-structural (e.g., energy, acoustic) performances and to issues concerning the limitation of invasiveness and interruption of use of the building. Technological details and in situ installation phases are described with special regard to connection and interaction with the existing building. Procedures for the assessment of upgraded building performances, in terms of seismic capacity and thermo-hygrometric and acoustic performances, are defined and applied to a selected basic cell structure. The feasibility and sustainability of the proposed upgrading intervention is finally investigated by means of a holistic Life Cycle Assessment for environmental impact and Life Cycle Cost for an economic evaluation. Finally, results from a multidisciplinary performance assessment are critically discussed by relating the performance aspects to the technological and installation issues.

Assessing the seismic vulnerability of existing buildings at the territorial scale is a crucial aspect for seismic-prone regions to properly plan effective strategies for disaster risk management. This paper presents a simplified methodology for the seismic vulnerability assessment of existing masonry and reinforced concrete buildings. The main purpose is to provide a tool able to evaluate the vulnerability of large building stocks, with the aim of defining priorities for further investigations or interventions. The procedure, inspired by methods in the literature devoted to the large-scale evaluation of structural vulnerability, allows defining the collapse peak ground acceleration (PGA_c) through the evaluation of the resisting shear force, the latter being estimated by mechanical considerations and by taking expert judgment into account to consider the real structural complexities involved. A classification is proposed, which aims to categorize buildings within homogenous groups characterized by a level of seismic vulnerability belonging to given intervals. The method was calibrated with reference to several case studies in order to reach a sufficient level of reliability in the vulnerability estimate and was then applied to a significant number of school buildings in the province of Ravenna, Italy. For some of them, the simplified methodology was validated through comparisons with results obtained by means of vulnerability assessment procedures based on finite element analyses.