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The number of buildings with passive control systems is steadily growing worldwide. For this reason, this study focuses on the reliability analysis of these systems employing fragility curves. The structural performance evaluation is obtained for a 10-story steel building with two different sections (trimmed and conventional). The trimmed section of the building was evaluated with hysteresis and oil dampers, while the conventional section of the building was evaluated without damper. The fragility curves were obtained from the incremental dynamic analysis using 20 ground motion records. Spectral acceleration response at the fundamental period of the building was considered and used as the intensity measure for the ground motion records. The maximum inter-story drift ratio of the building was employed as the damage measure. In addition, the seismic energy absorption rate was compared between hysteresis and oil dampers. As a result, hysteresis dampers were found to be more effective for high ground motion intensities. On the other hand, the oil damper dissipates energy immediately, even for low ground motion intensities. Furthermore, the combination of different types of dampers improved the seismic performance of the trimmed section of the building to almost the same level as the conventional section of the building. Eventually, a combination of hysteresis and oil dampers in a building is suggested to improve structural performance.

Offshore wind turbines in seismic active areas suffer from earthquake impacts. In this study, seismic fragility analysis of a monopile offshore wind turbine considering different operational conditions was performed. A finite element model for a 5 MW monopile offshore wind turbine was developed using the OpenSees platform. The interaction between the monopile and the seabed soil was modeled as a beam-on-nonlinear-winkler-foundation (BNWF). A nonlinear time history truncated incremental dynamic analysis (TIDA) was conducted to obtain seismic responses and engineering demand parameters. Potential damage states (DSs) were defined as excessive displacement at the nacelle, rotation at the tower top, and the allowable and yield stresses at the transition piece. Fragility curves were plotted to assess the probability of exceeding different damage states. It was found that seismic responses of the wind turbine are considerably influenced by environmental wind and wave loads. Subject to earthquake motions, wind turbines in normal operation at the rated wind speed experience higher levels of probability of exceeding damage states than those in other operational conditions, i.e., in idling or operating at higher or lower wind speed conditions.

City centres of Europe are often composed of unreinforced masonry structural aggregates, whose seismic response is challenging to predict. To advance the state of the art on the seismic response of these aggregates, the Adjacent Interacting Masonry Structures (AIMS) subproject from Horizon 2020 project Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe (SERA) provides shake-table test data of a two-unit, double-leaf stone masonry aggregate subjected to two horizontal components of dynamic excitation. A blind prediction was organized with participants from academia and industry to test modelling approaches and assumptions and to learn about the extent of uncertainty in modelling for such masonry aggregates. The participants were provided with the full set of material and geometrical data, construction details and original seismic input and asked to predict prior to the test the expected seismic response in terms of damage mechanisms, base-shear forces, and roof displacements. The modelling approaches used differ significantly in the level of detail and the modelling assumptions. This paper provides an overview of the adopted modelling approaches and their subsequent predictions. It further discusses the range of assumptions made when modelling masonry walls, floors and connections, and aims at discovering how the common solutions regarding modelling masonry in general, and masonry aggregates in particular, affect the results. The results are evaluated both in terms of damage mechanisms, base shear forces, displacements and interface openings in both directions, and then compared with the experimental results. The modelling approaches featuring Discrete Element Method (DEM) led to the best predictions in terms of displacements, while a submission using rigid block limit analysis led to the best prediction in terms of damage mechanisms. Large coefficients of variation of predicted displacements and general underestimation of displacements in comparison with experimental results, except for DEM models, highlight the need for further consensus building on suitable modelling assumptions for such masonry aggregates.

An insufficient separation distance between adjacent buildings is the main reason for structural pounding during severe earthquakes. The lateral load resistance system, fundamental natural period, mass, and stiffness are important factors having the influence on collisions between two adjacent structures. In this study, 3-, 5- and 9-story adjacent reinforced concrete and steel moment resisting frames (MRFs) were considered to investigate the collision effects and to determine modification factors for new and already existing buildings. For this purpose, incremental dynamic analysis was used to assess the seismic limit state capacity of the structures using a developed algorithm in OpenSees software including two near-field record subsets suggested by FEMA-P695. The results of this paper can help engineers to approximately estimate the performance levels of MRFs due to pounding phenomenon. The results confirm that collisions can lead to the changes in performance levels, which are difficult to be considered during the design process. In addition, the results of the analyses illustrate that providing a fluid viscous damper between adjacent reinforced concrete and steel structures can be effective to eliminate the sudden changes in the lateral force during collision. This approach can be successfully used for retrofitting adjacent structures with insufficient in-between separation distances.

The paper presents an assessment framework aimed at evaluating seismic fragility and residual capacity of masonry infilled reinforced concrete (RC) frames subject to mainshock/aftershock sequences. A double incremental dynamic analysis (D-IDA) approach is used, based on the combination of a mainshock (MS) signal at different intensities with a set of spectrum-compatible aftershocks (AS) scaled in amplitude with respect to peak ground acceleration. Limit state functions, specifically defined for infilled frames, are used to detect chord-rotation exceeding and shear collapse of RC members during standard and double incremental dynamic analyses. Intact and aftershock fragility curves are obtained for a reference full-scale RC frame specimen, by simulating seismic response with and without infills through a fully fiber section model developed in OpenSees. D-IDA results allow also defining aftershock residual capacity domains and loss diagrams, which are used to compare responses of bare and infilled frames subject to increasing MS intensities. Results show that masonry infills can drastically reduce seismic fragility of RC frame structures during main events and AS, and also limit and economic losses for the mid-low intensity earthquakes. Such beneficial contributions, however, depend on the capacity of RC members to support additional shear demand due frame-infill interaction and avoid sudden failures which conversely occur.

In the seismic design specification of each country, the displacement of reinforced concrete frames is a significant parameter for evaluating structural safety. For structures designed according to traditional methods, the maximum story drift ratios of some stories are obviously larger than those of other stories, which threatens structural safety. This paper proposes a uniform displacement optimization method for reinforced concrete frames to address the weak story issue. This method can be implemented through the automatic operation of MATLAB and OpenSEES. It is presented based on four reinforced concrete frames with different heights. The design formulas of optimal component reinforcement ratios were obtained by fitting the design results. The universality of the design formulas was verified through nonlinear time history analysis, incremental dynamic analysis, and seismic fragility analysis. The results indicate that the story drift ratio distributions were closely related to the reinforcement ratios of components. The story drift ratio distributions of reinforced concrete frames subjected to various earthquake records were similar. The design formulas can therefore make story drift ratio distributions more uniform when structures are subjected to earthquake records with different intensities.

This paper presents a novel method for rapidly addressing the earthquake-induced damage identification task in historic masonry towers. The proposed method, termed DORI, combines operational modal analysis (OMA), FE modeling, rapid surrogate modeling (SM) and non-linear Incremental dynamic analysis (IDA). While OMA-based Structural Health Monitoring methods using statistical pattern recognition are known to allow the detection of small structural damages due to earthquakes, even far-field ones of moderate intensity, the combination of SM and IDA-based methods for damage localization and quantification is here proposed. The monumental bell tower of the Basilica of San Pietro located in Perugia, Italy, is considered for the validation of the method. While being continuously monitored since 2014, the bell tower experienced the main shocks of the 2016 Central Italy seismic sequence and the on-site vibration-based monitoring system detected changes in global dynamic behavior after the earthquakes. In the paper, experimental vibration data (continuous and seismic records), FE models and surrogate models of the structure are used for post-earthquake damage localization and quantification exploiting an ideal subdivision of the structure into meaningful macroelements. Results of linear and non-linear numerical modeling (SM and IDA, respectively) are successfully combined to this aim and the continuous exchange of information between the physical reality (monitoring data) and the virtual models (FE models and surrogate models) effectively enforces the Digital Twin paradigm. The earthquake-induced damage identified by both data-driven and model-based strategies is finally confirmed by in-situ visual inspections.

India’s building stock remains highly vulnerable to seismic hazards, with conventional retrofitting strategies often limited in their applicability under varying earthquake intensities. This study investigates the effectiveness of the Yielding Brace System as a novel lateral load–resisting mechanism for improving the seismic resilience of mid-rise reinforced concrete buildings. A six-storey special moment-resisting frame was analysed in bare and Yielding Brace System (YBS)-integrated configurations using a comprehensive multi-analysis framework, including nonlinear static pushover analysis, nonlinear time history analysis, incremental dynamic analysis, and probabilistic fragility assessment. Results demonstrate that the incorporation of YBS significantly reduces inter-storey drift demands by 30–53% and increases normalized base shear capacity from 0.30 in the bare frame to 0.75 in the YBS frame. Ductility improved from 3.20 to 3.98, while residual drift ratios consistently remained below the FEMA P-58/ASCE 41 threshold of 0.5%. Fragility analysis revealed that the bare frame reached a 50% probability of collapse at 5.1 m/s², whereas the YBS-equipped frame required 15 m/s², highlighting a threefold enhancement in collapse safety margin. By reducing collapse probability and ensuring functional recovery after earthquakes, Yielding Brace System advances resilient infrastructure development and aligns with global sustainability objectives under UN SDG 9 (Infrastructure), SDG 11 (Sustainable Cities), and SDG 13 (Climate Action).

Non-structural components represent a major portion of building investment and experience significant damage during earthquakes, leading to functional loss and economic costs. This study develops a nonlinear multi-parameter model to predict floor acceleration amplification (FAA, defined as the ratio of peak floor acceleration to peak ground acceleration), which is crucial for designing acceleration-sensitive non-structural elements. Incremental Dynamic Analysis was performed on diverse structural systems (reinforced concrete, steel, and steel-concrete composite structures) subjected to scaled ground motions. The research quantified the influence of relative height, fundamental period, strength ratio (representing ductility demand), and structural system type on FAA distribution. The proposed fundamental period, distinct from conventional code approaches relying solely on the relative height. Validated against 59 instrumented building records and compared with numerical simulations and existing models, the model demonstrated superior predictive accuracy across different structural fundamental periods, nonlinear states, and system types. This provides enhanced theoretical understanding and practical support for seismic design, addressing limitations in current code provisions for non-structural components.

This study presents a displacement-based seismic fragility assessment of a high-rise reinforced cement concrete (RCC) building designed in compliance with Indian seismic codes. The selected structure, a G+19 ordinary moment-resisting frame (OMRF), is modelled in ETABS with realistic material properties, geometric irregularities, and design loads as per IS 875 and IS 1893 provisions. Seismic performance evaluation is conducted through Incremental Dynamic Analysis (IDA) using a suite of ground motion records from FEMA P695, scaled progressively to capture structural response from elastic behaviour to collapse. Peak Ground Acceleration (PGA) and spectral displacement serve as intensity measures, while inter-storey drift ratio is adopted as the primary damage parameter. Fragility curves are developed for key performance levels based on maximum allowable drift limits. The results reveal significant sensitivity of the high-rise frame to torsional irregularities, with drift concentration occurring predominantly in the mid-height storeys. Probabilistic fragility functions indicate that the probability of exceeding life safety limits increases sharply beyond a PGA of 0.25g. Comparison with previous studies confirms that displacement-based assessment provides a more accurate representation of seismic vulnerability than force-based methods, particularly for irregular high-rise configurations. The findings emphasize the necessity for enhanced design considerations, including stiffness regularity and supplemental damping systems, to improve resilience in Indian high-rise RCC buildings. This research contributes a performance-based seismic assessment framework adaptable for both new designs and retrofitting strategies in similar structural systems.