Eurocode-based seismic assessment of modern heritage RC structures: The case of the Tower of the Nations in Naples (Italy)

Abstract

Given the interest earned recently by modern heritage structures, seismic assessment criteria of Eurocode 8 for ordinary reinforced concrete structures are applied to a modern heritage RC building. This case study, the Tower of the Nations in Naples, was designed at the end of 1930s. Modal dynamic identification, in situ inspections and testing provided the necessary knowledge of the structure in terms of geometry, structural details, and material properties. Two nonlinear models of the structure are built up in both the hypotheses of accounting and not accounting for tuff infills’ stiffness and strength contribution. Lumped plasticity model for reinforced concrete elements and equivalent strut macro-models for tuff and concrete infills are employed. Seismic assessment through nonlinear dynamic analyses is carried out for both limit states of Significant Damage and Damage Limitation. Assessment of bare and infilled models emphasizes a lower demand in terms of maximum interstorey drift of the infilled model with respect to the bare model, for both limit states considered. Record-to-record variability for the sets of seven records becomes larger if infills strength and stiffness contribution is taken into account. Outcome of the assessment is not affected by infills, i.e. the structure can be considered safe (according to EC8 provisions) for both limit states, and in both modeling hypotheses. On the other hand, the ratio demand over capacity, for both the limit states considered, is strictly influenced by infills’ contribution. Assessment tools provided for ordinary RC structures can be addressed to modern heritage buildings as shown in this case study, even if specific care is necessary for nonlinear structural modeling in case of non-conventional structural elements and non-conventional structural materials (e.g., tuff infills in lieu of clay hollow brick infills).