This paper provides insights into a probabilistic demand analysis of steel-concrete structures with novel dissipative and replaceable components conceived to pursue repairability in the structures they equip. Incremental Dynamic Analyses (IDAs) were conducted to investigate the impact of incorporating two different dissipative seismic devices: the Dissipative Replaceable Link Frame (DRLF) and the Dissipative Replaceable Beam Splices (DRBeS). The benchmark models were validated using the results from full-scale laboratory tests conducted by means of hybrid simulation within the RFCS DISSIPABLE project. Additionally, the behaviour of these innovative frames was compared to that of a Reference moment-resisting frame, designed according to current standards. Probabilistic demand models were developed, and seismic fragility curves were derived to compare the performance of the analysed structural systems. The findings of this comparative analysis will illustrate that, from a performance perspective, structures equipped with replaceable devices exhibit a seismic behaviour comparable to that of a frame designed according to traditional criteria. Consequently, from an economic viewpoint, despite an initial installation cost, devices enhancing structural resilience permit reduced costs and times associated with restoration activities.

In the last decades, high priority has been given to enhancing the seismic resilience of structures by reducing the damage of structural and non-structural elements after a disaster. In this context, the European Research Fund for Coal and Steel (RFCS) project DISSIPABLE was funded to perform large demonstration tests of steel frames equipped with easily repairable seismic dissipative devices. The paper extensively describes the experimental campaign carried out at the University of Trento on a steel frame equipped with innovative Dissipative Replaceable Link Frame (DRLF) systems, composed of two rigid columns connected by weakened beams at their ends. Hybrid Simulation was employed, enabling to physically test the first floor of the building yet allowing for considering the response of the remaining five floors, which were numerically simulated. A bidimensional frame was tested under increasing seismic intensity levels: Damage Limitation, Significant Damage and Near Collapse limit states. The experimental results proved that the DRLF system was able to dissipate energy and protect the primary elements of the structure from plasticisation. Moreover, the structure's re-centring capability was verified to ensure the components' replaceability. Finally, the calibration of the nonlinear model was performed following the tests, which allowed to develop a high-fidelity model suitable for further numerical investigation.

A novel device based on the energy transfer concept, named impact mass damper (IMD), is presented for the mitigation of large structural vibrations due to horizontal seismic excitations. To achieve the optimal performance of the nonlinear device, coupled with different standard steel buildings, an optimization procedure is set both employing the design of experiments (DOEs) method and the Kriging surrogate modelling. Concerning the seismic input, site-specific ground motions and record-to-record variability are taken into account, in agreement with the new European standards. The validated performance of the IMD device demonstrates its benefits, in particular for short-period steel buildings.

The paper describes the results of an experimental campaign conducted on full-scale steel frames equipped with dissipative components within the European Research Fund for Coal and Steel (RFCS) pilot project DISSIPABLE. Dissipative Replaceable Link Frame (DRLF), whose characteristic is the large energy dissipation combined with ease of replacement, were installed on the frame and coupled through high-strength steel (HSS) beams characterised by an elastic response to increase the overall frame stiffness and to improve the re-centring capability after a major seismic event. The seismic performance of the steel frame was investigated by means of Hybrid Simulation (HS) at three different limit states, i.e., damage limitation (DL), significant damage (SD) and near collapse (NC). In particular, the first floor of the frame was physically built, whilst the response of the remaining five floors was numerically simulated. The results of the tests highlighted the large dissipation capabilities of the DRLF system. In addition, the high-strength steel coupling beams remained elastic even at the NC limit state and provided excellent behaviour in increasing stiffness and re-centring capabilities. Finally, the repairability of the DRLF components was demonstrated.

In the last decades, high priority has been given by the research community to the development of low-damage structures, and reparability has become fundamental for minimizing the environmental and economic impact of reconstruction. In this context, the European Research Fund for Coal and Steel (RFCS) project DISSIPABLE was carried out, with the aim to test large-scale structures where the dissipation is concentrated on replaceable components introduced in the structure. In this paper, the performance of a six-storey braced steel frame with dissipative systems is analysed. The capacity of withstanding seismic actions relies on Dissipative Replaceable Bracing Connections (DRBrC), used for the brace-column joints. The energy dissipation is ensured by wide hysteresis loops experienced by DRBrC, whose configuration enables an easy replacement after a medium-high intensity earthquake. Results of a wide experimental test campaign on full-scale structures and numerical analyses on refined models are presented and compared. In particular, experimental data were used to validate and to calibrate the simplified numerical laws used to represent the cyclic performance of the dissipative components and it was proved the effectiveness of using a simplified formulation from both a theoretical and a practical point of view.

Pipelines periodically supported by rack structures (PPRs) are common in chemical and petrochemical plants, among others, and conventional tools such as dampers and hysteretic absorbers are commonly used to mitigate large vibrations in these systems. In this study, we explore two alternative strategies: (i) enhancing the attenuation rate of PPR vibrations through structural internal damping, and (ii) using nonlinear vibro-impact systems (VIS) to reduce seismic vibrations in a PPR. To shed light on the first strategy, we develop analytical dispersion relations for a PPR and show how damping can improve the mitigation capabilities of the periodic system. As for the second strategy, we consider a 9-node beam, i.e., a single span (SS) of a PPR equipped with a VIS, and combine the central composite design (CCD) and Kriging metamodelling to maximize dissipation energy and minimize the number of impacts. This multi-objective optimization problem aims to find the most effective design solution for the VIS in terms of gap and coefficient of restitution (COR). Additionally, we consider the stochastic nature of seismic input and the possible chaotic behavior of the VIS. To account for the sensitive variability of the number of impacts in seismic records, we perform incremental dynamic analyses and calculate fragility functions for various engineering demand parameters, including the number of impacts. We define a 3D surface for selecting the optimal gap-COR pair. When impacts occur, transient results can be chaotic, and we compute the largest Lyapunov exponents of a few representative trajectories.

This work presents the experimental campaign performed on a full-scale 6-storey steel concentrically braced frame equipped with the so-called Dissipative Replaceable Braced Connection (DRBrC) made with plates of mild steel and high-strength steel. Such component, constituting the brace-column joint, is capable of dissipating large amounts of energy through wide hysteretic loops, while providing the possibility of being easily replaced after the building undergoes medium-high intensity earthquakes. To reduce the costs and, at the same time to obtain a representative response of the full frame, hybrid simulation tests were employed, in which only the ground floor was physically built in the laboratory. In contrast, the remainder of the structure was numerically simulated. The innovative frame was subjected to three different natural ground motions at the Damage Limitation (DL), Significant Damage (SD) and Near Collapse (NC) limit states, respectively. The outcomes highlighted the high potential of the DRBrC component in dissipating large amounts of energy and, at the same time, in protecting the remaining parts of the structure, by exhibiting very small residual displacements that enhance self-centring and repairability capabilities. Moreover, the numerical models were calibrated by including the non-negligible effect introduced by the bolt-hole clearances. All results are thoroughly described in the manuscript.

This paper deals with the seismic response assessment of a steel–concrete moment‐resisting frame (MRF) equipped with special dissipative replaceable components (DRCs): the dissipative replaceable beam splices (DRBeS), which combine large energy dissipation with ease of replacement. The evaluation of the full potential of DRBeS requires a system‐level investigation, that is, a six‐story MRF, whereby the hysteretic effects of beam splices partial‐strength joints are considered on the global response of the structural system. Therefore, an OpenSees finite element (FE) frame model, based on previous experimental campaigns with cyclic displacements on partial‐strength joints, and a Matlab model validated on OpenSees, were used for a more complex experimental activity via hybrid simulation (HS). The aim of the simulations was twofold: (i) to increase knowledge of the non‐linear behaviour of steel‐concrete composite partial‐strength MRFs; and (ii) to study the effectiveness of the DRBeS components for increasing the recovery of functionality after a major seismic event. Therefore, to appreciate the performance of the partial‐strength MRF at damage limitation (DL), significant damage (SD) and near collapse (NC) within the performance‐based earthquake engineering (PBEE) approach, HSs were carried out. In such instances, the ground floor was physically tested at full scale in the laboratory and the remainder of the structure was numerically simulated. Relevant results showed that the DRBeS were capable of dissipating a significant amount of hysteretic energy and of protecting the non‐dissipative parts of partial‐strength joints and the overall structure with an ease of replacement.

In the last decades, high priority has been given to community disaster resilience owing to seismic events with a particular focus on the post‐disaster restoration. Therefore, damage reduction of structural and non‐structural elements after a disaster is fundamental for costs and for functionality aspects. In this context, the European RFCS project DISSIPABLE was funded with the aim to perform large demonstration tests of steel frames equipped with easily repairable seismic dissipative devices. In this paper, the experimental tests performed according to dynamic substructuring are described. The capacity of withstanding seismic actions as well as the energy dissipation relies on the Dissipative Replaceable Link Frame system, composed of two rigid columns connected by weakened beams. Two different configurations of frames equipped with DRLF systems were tested: i) frames made of only mild steel and ii) frames made of both mild and high‐strength steel. Bidimensional frames were tested under different seismic intensity levels: Damage Limitation, Significant Damage and Near Collapse.

This paper provides insight into a probabilistic demand analysis of a steel‐concrete structures equipped with novel dissipative components. DISSIPABLE components were studied in the framework of a European Research Fund for Coal and Steel (RFCS) project, funded to test large‐scale structures in which the dissipation is concentrated in specifically designed elements that act like a fuse and can easily be replaced after a seismic event. Incremental Dynamic Analyses (IDAs) were performed to investigate the influence of equipping steel frames with two different dissipative seismic devices, namely the Dissipative Replaceable Beam Splice (DRBeS) and the Dissipative Replaceable Link Frame (DRLF). The benchmark models were calibrated on the results of laboratory full‐scale tests, carried out in the project framework. In addition, the DISSIPABLE frame behaviour was compared with a state‐of‐the‐art moment‐resisting frame, designed according to the capacity design philosophy. Probabilistic demand models were developed, and seismic fragility curves were then derived to compare the behaviour of the analysed structural systems.

Modern techniques of structural design are effective in preventing structural collapse due to earthquake actions. Nevertheless, repairability has become an important issue to deal with in order to minimise the economic and environmental impact of structural damage. In this respect, this paper presents the design of experimental tests on full‐scale specimens of steel frames to be tested according to hybrid simulation. This work is conducted within the ongoing European research project DISSIPABLE that seeks to test easy to replace structural components installed in steel buildings. In fact, by including these Dissipative Replaceable Devices (DRD) into the building, it is possible to provide full post‐earthquake functionality after damage. Three are the devices that will be tested, namely DRD1, DRD2 and DRD3, which are going to be briefly presented in the paper. Five hybrid tests will be performed and major details will be given to the numerical modelling of the components and the identification of the substructures to be employed in the tests. Finally, the design of the physical substructure and the test setup will be briefly described.