Displacement-Based Simplified Seismic Loss Assessment of Italian Precast Buildings

Abstract

Economic losses associated with the structural and non-structural damage occurring after an earthquake are of particular importance in the case of industrial buildings due to the consequences of such losses on the local economy and employment level. The seismic sequences that hit the industrial area of Emilia-Romagna region of Italy in 2012 represent an emblematic example. In this earthquake event, major damage on poorly performing precast structures was recorded: many buildings were severely damaged and experienced partial or full collapse. The level of the recorded damage was related to a design lacking modern seismic detailing and to a non-up-to-date evaluation of the seismic hazard: in fact, several industrial buildings, typically one storey precast reinforced concrete (RC) structures, were designed to transfer horizontal loads (i.e. between roof elements and supporting beam or main girder and supporting columns) through either friction or under-designed mechanical connections.The aim of this paper is to provide insights on the evaluation of direct losses in the case of precast RC structures typical of the Italian industrial sector, particularly for buildings built before the enforcement of modern seismic codes. A simplified displacement-based seismic loss assessment procedure is proposed and applied to a selected case study and comparisons are made with the results obtained from non-linear time history analyses on simplified (i.e. single column models) and complete three dimensional models. Retrofit solutions are proposed and their influence on the collapse probability of the structural elements and on the economic losses is evaluated.

Influence of Modelling Assumptions on the Seismic Risk of Industrial Precast Concrete Structures

“…Therefore, the previous formulation of the building models is suitable for the collapse rate evaluation. The main advantage of detailed 3D models is related to the possibility of detecting local damages in a more comprehensive way suitable, for instance, for a detailed loss assessment (Bosio et al, 2020).…”

“…The last earthquakes in Italy, particularly the ones that struck Emilia Romagna region (Northern Italy) in 2012, highlighted major vulnerabilities in reinforced concrete (RC) precast industrial buildings designed before the entry into force of modern anti-seismic provisions and accurate seismic zonation of the Italian territory (Belleri et al, 2015a;Belleri et al, 2015b;Ercolino et al, 2016;Bournas et al, 2014;Minghini et al, 2016;Nastri et al, 2017;Palanci et al, 2017;Savoia et al, 2012;Toniolo and Colombo, 2012). The main collapses observed were due to failure of the RC fork supporting the beams, the development of short columns due to ribbon glazing, or to the loss of support of the main structural elements due to underdesigned or friction-based connections (Brunesi et al, 2015;Casotto et al, 2015;Demartino et al, 2018;Titi et al, 2018;Bosio et al, 2020). On the beam-to-column faying surface, a neoprene bearing pad is generally included both for spreading the vertical load and to allow for thermal expansions; the neoprene pads lead to a reduction of the coefficient of friction from 0.5, typical of concrete-to-concrete contact, to values also in the order of 0.1 (Magliulo et al, 2011), therefore facilitating relative displacements during earthquakes.…”

Crescent-Moon Beam-To-Column Connection for Precast Industrial Buildings

“…Such buildings have highlighted considerable vulnerability to recent seismic events (Bournas et al, 2014;Magliulo et al, 2014;Belleri et al, 2015a;Belleri et al, 2015b;Ercolino et al, 2016;Minghini et al, 2016;Belleri, 2017;Nastri et al, 2017;Palanci et al, 2017). These vulnerabilities are related to multiple local collapse mechanisms and vulnerabilities such as the loss of support of the roof elements and/or beams, the overturning of the RC cladding panels and the collapse of RC columns or forks at the top of the columns (Brunesi et al, 2015;Belleri et al, 2016;Belleri et al, 2017a;Dal Lago et al, 2018;Ercolino et al, 2018;Torquati et al, 2018;Iervolino et al, 2019;Bosio et al, 2020).…”

Displacement-based design of precast hinged portal frames with additional dissipating devices at beam-to-column joints

“…Besides these advantages, existing buildings designed before the enforcement of modern anti-seismic building codes may show several criticalities, particularly in the Italian territory (Magliulo et al 2014a;Belleri et al 2015a;Ercolino et al 2016;Minghini et al 2016), mainly related to the lack of efficient connections between structural elements and to the displacement incompatibility between structural and non-structural elements, such as cladding panels, arising as a consequence of the high flexibility of the building typology (Belleri et al 2015b(Belleri et al , 2016(Belleri et al , 2018Dal Lago et al 2019;Scotta et al 2015). The seismic assessment and risk analysis of such structural system highlight the influence of these vulnerabilities (Belleri et al 2015b;Palanci et al 2017;Torquati et al 2018;Bosio et al 2020).…”