Performance-Based Nonlinear Response History Analysis Framework for the "Proindustry" Project Case Studies

Abstract

Within the PROINDUSTRY project a Performance-based analysis framework is defined for seismic assessment of industrial structures, based on Nonlinear Response History Analysis (NL RHA) using in particular the Incremental Dynamic Analysis (IDA) method. This paper describes the choice of the PBEE and IDA analysis methods starting from an overview of state-of-the-art methods. The choice is analyzed in relation to: analysis goals for the selected case studies (design-based vs. risk-based), availability of databases/tools for hazard analysis and GMs selection, accuracy of criteria to scale and match GMs to a target spectrum (UHS, CMS, etc.) and treatment of record components. Three possible approaches of GMs selection are described and analyzed: (1) UHS-coherent Unscaled (Design), (2) UHScoherent GMs scaled to Sa(T1) (Risk/Loss), (3) CMS-coherent GMs scaled to Sa(T1), (Risk/Loss). Within the scopes of PROINDUSTRY, the approach (1) is proposed, as a tradeoff between simplicity of conventional PBEE design methods and probabilistic robustness for a heterogeneous portfolio of structures/facilities.

Reducing the seismic vulnerability of existing elevated silos by means of base isolation devices

“…The first set is characterized by low-to-moderate seismicity (Table 3), while the second set is characterized by high seismicity (Table 4). The hazard curves have been estimated within the PROINDUSTRY project [3,36] according to the Italian Building Code [48].…”

“…For each group of accelerograms, 9 scale factors (SF) have been defined, which are associated with peak ground acceleration values of annual probability of exceedance. Scaled a g values are reported in Table 5 and Table 6 for low-to-moderate and high seismicity data [36]. Probability curves for both sets are shown in Fig.…”

“…The European Research project PROINDUSTRY (Seismic Protection of Industrial Plants By Enhanced Steel Based Systems) aimed to develop innovative seismic protection systems, both for the design of new industrial plants and for the retrofit of existing ones, based on seismic isolation and energy dissipation techniques [3,12,13,35,36]. This paper presents the efficiency of curved surface sliders for an elevated silo structure studied in the PROINDUSTRY project.…”

Performance Based Earthquake Assessment of an Industrial Silos Structure and Retrofit With Sliding Isolators

“…The friction devices have been modeled with nonlinear link elements with parameters reported in Table 1. The seismic action has been modeled with a set of unscaled Ground Motions ( Figure 5) [9] and various scale factors calculated dividing the probabilistic hazard curve in regular steps. The hazard curve has been calculated from the hazard definition of the Italian Code NTC08 [11][12].…”

“…The silos are modelled through elastic shell elements with distributed mass so to correctly account for their deformability. Static and dynamic analyses, which considered the variability of the action through through a suite of earthquake records [9], were used to establish the main damage causes, which were due to a fragile failure of the steel columns, caused by buckling effects, resulting in a complete collapse of the system. The silos remained fully elastic, consistent with observation found in the literature [6][7][8].…”