Search Results (353)

To investigate the effects of end-plate thickness on the seismic performance and damage evolution of K-shaped eccentrically braced frames with end-plate connections (EPEBFs), two scaled specimens with different end-plate thicknesses were tested under low-cycle reversed loading. The influence of end-plate thickness on mechanical behavior and seismic response was evaluated from failure modes, hysteretic response, skeleton curves, ductility, energy dissipation, and stiffness degradation, together with damage assessment using different models. Refined finite element models were then established for parametric analysis. The results show that EPEBFs exhibit a well-defined plastic development path. Damage in the reference specimen was mainly concentrated in the link and its end-plate connection region, thereby protecting the frame columns, beams, and braces. For the two thicknesses tested, the specimen with thicker end plates showed higher lateral resistance, greater ultimate deformation capacity, and better late-stage resistance retention, but lower displacement ductility, indicating enhanced absolute deformation capacity but reduced post-yield deformation reserve. Thicker end plates also altered stress transfer and plastic development in the connection regions, causing damage to extend toward the frame-beam ends. Among the damage models considered, the elastic–plastic energy dissipation ratio model better captured the accumulation of energy dissipation and plastic deformation. The finite element results agreed well with the tests. Within the investigated range, increasing end-plate thickness mainly improved ultimate deformation capacity and late-stage resistance retention, without a clear monotonic effect on lateral resistance. The findings provide a basis for prefabricated design, damage control, and post-earthquake replacement and repair of EPEBFs. Full article

Tower cranes are highly vulnerable to seismic excitation owing to their slender geometry and pronounced dynamic behaviour. Although carbon fibre reinforced polymer (CFRP) materials offer significant lightweight potential, and damping devices are widely adopted for seismic protection, their combined application to tower cranes has received limited attention. This study numerically investigates the seismic response of a rearing jib tower crane equipped with a CFRP jib and base joint dampers. A finite element model was developed and analysed under four critical operating configurations through static structural, modal and response spectrum analyses in accordance with the Italian Building Code (NTC 2018). The performance of the CFRP solution was compared with that of a conventional steel crane, while two damper configurations with different stiffness values were also assessed. The proposed lightweight design reduced the total crane mass by 34% and the jib weight by 77%. Compared with the steel configuration, the CFRP solution decreased static displacements by 38–56% and equivalent stresses by 22–44%. Under seismic loading, the adoption of joint dampers reduced the maximum equivalent stress by up to 35%, while increasing structural displacements by 5–19% because of the lower support stiffness. The results demonstrate that combining CFRP lightweight design with seismic damping devices effectively improves the earthquake performance of tower cranes while maintaining structural safety. Full article

This paper investigates the seismic performance of a nonlinear passive control device, namely a Bi-Stable Mass Damper–Inerter (BSMDI), designed to mitigate structural displacements. The system combines a mass damper connected to the primary structure through a bistable (snap-through) nonlinear element with a grounded inerter, enabling the exploitation of both nonlinear energy transfer mechanisms and enhanced inertial effects. The main objective of the study is to assess the effectiveness of the proposed BSMDI in reducing the maximum displacement response of structures subjected to seismic excitation. The novelty of the work lies in the synergistic integration of bistable nonlinear dynamics and inerter-based inertial amplification, together with a systematic parametric investigation aimed at identifying effective configurations in terms of both bistable parameters and inertance. The study is carried out on a two-degree-of-freedom system, in which the primary structure to be protected is represented by an equivalent single-degree-of-freedom model. This system is coupled to a mass damper through a bistable element, which is in turn connected to a grounded inerter device. A comprehensive parametric study is performed by varying the dimensionless stiffness and cubic coefficients of the bistable element, as well as the inertance ratio, while keeping the damper mass ratio small. The system performance is assessed using a displacement-based index defined as the ratio between the peak response of the controlled structure and that of the uncontrolled configuration. Performance maps and corresponding optimal curves are derived for three different seismic inputs. The present results suggest that the inerter plays a crucial role in achieving effective vibration mitigation, being significantly more effective than the damper mass alone. Overall, the proposed device appears to provide an efficient solution for seismic displacement mitigation. Full article

Current geological site assessment models focus on examining stable natural features and neglect measuring surrounding industrial and environmental hazards. This methodological deficiency is clearly evident in the management of technological heritage in existing or abandoned mining areas. This research presents the modified GAM_GES geo-environmental assessment model to address this practical gap in the regional planning of industrial geoparks. The proposed model integrates the geo-environmental safety (GES) block as a mathematical discount factor that measures the risks of surface deformation, seismic activity, gas emissions, and pollution from mining waste. The research applies the developed criteria to the Kirov Mine database in the Kuzbass Basin, renowned for its combined technological and geodynamic characteristics. The numerical results demonstrate a lower overall site value compared to the conventional model due to the detection of active ground fissures and continuous methane migration across tectonic faults. The model provides planners with a quantitative decision support framework for dividing industrial heritage sites into multiple safety zones that ensure visitor protection and the security of sustainable tourism facilities. Full article

Offshore wind power has expanded rapidly in recent decades and is expected to continue growing through the deployment of larger turbines in deeper waters. The safe and stable operation of offshore wind turbines (OWTs) depends critically on foundation performance, which is severely threatened by seabed scour. To better understand these threats, this paper reviews recent studies on the effects of seabed scour on the structural performance and safety of fixed-bottom offshore wind turbine foundations (OWTFs), focusing on four aspects: (1) the changes induced by scour in both the seabed morphology and the soil mechanical state, which form the basis for the subsequent analyses; (2) the effects of scour on the bearing capacity and natural frequency of the foundation, covering both its static and dynamic performance; (3) the behavior of scoured foundations under long-term cyclic loading during normal operation and under transient seismic action during extreme events; and (4) the role of scour protection in enhancing structural safety. Several future research directions are also highlighted. This review offers helpful insights for assessing scour-induced risk and for designing scour protection from a structural safety perspective, thereby supporting the safe operation of OWTs. Full article

This paper proposes an urban-scale dynamic screening method for the preliminary seismic-risk prioritization of masonry buildings. The method is based on the integration of rapid surveys, relational databases, geographic information systems, and accelerometric data recorded during seismic events. It is not intended to replace comprehensive seismic vulnerability or risk assessment procedures. In its present formulation, it provides an event-specific preliminary dynamic-priority indicator, derived from recorded ground motions, to support post-event inspections and subsequent detailed analyses at the urban scale. The procedure combines a rapid visual survey (on average covering ca. 300 buildings per day) with a database management system (DBMS) linked to a three-dimensional cartographic database of the building stock. The geometric and structural information collected in the field is integrated with the processing of ground acceleration records, from which the pseudo-acceleration spectra, peak ground acceleration (PGA), and spectral amplification ratios (DAF) are derived. Through the relationship between spectral period and building height, the method identifies height classes and number of storeys corresponding to the highest spectral amplification ratios derived from the recorded ground motions. Buildings belonging to these classes are not classified as vulnerable in absolute terms, but are considered priority buildings for subsequent checks, inspections, or detailed analyses. The method was applied to the municipalities of Umbertide and Gubbio, in the province of Perugia, which were affected by the seismic sequence of 9 March 2023. The processed accelerometric records identified Classes I, II and III, corresponding to one-, two-, and three-storey masonry buildings. The illustrative GIS application focused on Classes II and III; 27 of the 33 masonry buildings included in the damaged-building sample (82%) belonged to these two classes. The main contribution of the study is the definition of an integrated, rapid, and replicable workflow that can support local authorities, technicians, and civil protection operators in the preliminary management of seismic risk at the urban scale. Full article

Vulnerable coastal urban margins face overlapping pressures from erosion, climate change, and plastic-waste accumulation. This study presents a screening-level numerical assessment of a hollow modular unit made of a recycled polyethylene terephthalate (PET)–concrete composite, proposed for coastal slope protection and stabilisation in Chucuito, Callao, Peru. A limit-equilibrium baseline indicates that the unprotected slope is marginal to unstable under the site’s seismic demand, motivating the evaluation of a surface-protection concept through a parallel, one-way finite element analysis–computational fluid dynamics (FEA–CFD) framework applied at three slope angles (60°, 53°, 45°). The FEA structural-response screening indicates consistent trends across configurations under an equivalent impact load and the adopted basal restraint. For the hydraulic comparison, inlet velocities of 3, 5 and 7 m/s were anchored to the site-specific Delft3D inundation modelling (site maximum 5 m/s), with a conservative 10 m/s upper bound; relative to a rip-rap reference, the hollow configuration suggests midpoint run-up velocity reductions of approximately 52% at θ = 53° under the conservative scenario and ≈57% at 3 and 5 m/s, falling to ≈25% at 7 m/s with overlapping ranges and the simulated free surface exceeding the crest. The CFD free-surface elevations show order-of-magnitude consistency with an indicative EurOtop-based run-up benchmark used as a consistency check rather than as hydraulic validation. Independent of this hydraulic comparison, the hollow geometry saves ≈ 62% of the material volume relative to an equivalent solid concrete block, valorises ≈ 793 post-consumer PET bottles per unit at a 10% dosage, and suggests a 42–58% embodied-CO₂ reduction relative to the same solid-concrete reference, driven mainly by the hollow geometry rather than by the PET substitution itself. The results are internally consistent but not experimentally validated and are intended as a comparative baseline to guide subsequent experimental and field studies, in line with Sustainable Development Goals (SDG) 11, 12 and 13. Full article

This study examines the post-earthquake reconstruction framework adopted in the Mt. Etna region, where the ordinances issued by the Extraordinary Commissioner provided the operational structure enabling the integration of technical, geological, and landscape-protection requirements. Geological, geophysical, and geognostic investigations were mandated to characterize local subsurface conditions and ensure that repair or reconstruction works complied with safety standards and regulatory requirements, particularly where retaining walls support buildings, roads, and infrastructure. A distinction was made between traditional dry-stone retaining walls—an essential component of the rural Etnean landscape—and reinforced concrete walls, which are adopted in contexts requiring higher structural performance. Their reconstruction involved differentiated technical approaches aimed at ensuring deformation-compatible behavior and mitigating the effects of permanent ground deformation while preserving the historical and cultural value of dry-stone constructions, recognized as UNESCO intangible heritage. The resulting reconstruction model integrates high-resolution geostructural and geophysical surveys, Active and Capable Fault (ACF) zoning criteria, and performance-based geotechnical design within a unified governance and technical protocol. This approach provides a replicable methodology for the post-seismic reconstruction of retaining walls in areas affected by permanent ground deformation and complex volcano-tectonic settings. Full article

In southern Kazakhstan, landslide control is highly relevant for settlements located in areas with mountainous terrain. This study was conducted to observe the results of applying electrical, seismic and magnetic surveys to investigate a landslide-prone slope in the Almaty Region. The aim was to improve the reliability of geophysical data when assessing the state of the landslide body. For the first time for this landslide, based on a joint analysis of geoelectric and velocity characteristics, the structural heterogeneities associated with unconsolidated and water-saturated soils, as well as fractures, were identified. The combination of data on the elastic, electrical and magnetic properties of the studied medium significantly improved the clarity of the interpretation of geophysical data when studying the landslide massif. This made it possible to refine the internal structure of the landslide and identify areas with an increased likelihood of deformation. The obtained results provide a reliable basis for assessing slope stability and demonstrate the need for integrated geophysical surveys to reduce the risk of landslides. Along with engineering–geological methods, geophysical surveys will be an integral component of monitoring landslide-prone areas, which will enable timely implementation of organizational measures to protect infrastructure facilities. Full article

To investigate the seismic performance and damage evolution of a curved continuous rigid-frame composite girder bridge under near-fault velocity pulse-like ground motions, a refined three-dimensional full-bridge finite element model was established, incorporating pile–soil interaction, expansion joint pounding, shear key damage, and nonlinear hysteretic behavior of high damping rubber bearings (HDRBs). Nonlinear time-history analyses were conducted under E1 and E2 seismic levels using near-field pulse records (short, moderate, and long periods), a near-field non-pulse record, and a far-field record. The fiber section capacity-to-demand ratio method was adopted to assess pier damage. Results show that near-field pulse-like motions govern the structural response, with long-pulse records producing the most unfavorable displacements and internal forces. Under E2, HDRBs exhibit significant yielding and hysteretic energy dissipation, effectively protecting the piers but imposing greater deformation demands on expansion joints and unseating preventers. Continuous girder piers display a transverse frame effect and a longitudinal S-shaped moment distribution with a secondary peak at the upper-middle portion due to higher modes. Rigid-frame hollow thin-walled piers exhibit S-shaped internal force distributions associated with abrupt section changes, and the tallest pier reaches a capacity-to-demand ratio of 0.82, indicating moderate yielding. The vertical seismic component amplifies transverse bending–torsion responses of curved girders through spatial coupling. The findings provide a scientific basis for ductility design and damping detailing of similar complex curved bridges. Full article

The Lombardy Region is characterised by relatively moderate seismic activity, particularly in the Alpine area and its western sector. Significant damage has instead been caused by historical earthquakes with magnitudes greater than M_W 5.0 in the eastern and south-western parts of the region. To enhance preparedness and prevention strategies, the Civil Protection Organisational Unit of Regione Lombardia, together with the Eucentre Foundation and the Civil Protection School of Lombardy (PoliS-Lombardia), organised a regional seismic emergency exercise, the so-called EXE.LOMB.EST 2023, which is an initiative aimed to test and train emergency response capabilities in parts of the region most at risk from seismic events. EXE.LOMB.EST 2023 was a civil protection technical–thematic exercise that involved various groups of participants through tailored training paths. With both educational and practical objectives, the exercise was developed over the course of 2023. In the six months leading up to the final event, approximately 12 training sessions were held to prepare participants according to the identified themes. The final field exercise took place from 9–14 October 2023, during the Italian Civil Protection Week, and included the participation of 15 municipalities. The programme was designed to simulate all key phases of regional emergency management, from activating support functions to assessing damage to cultural heritage. Participants included the Italian Civil Protection Department—as an advisor—the Italian Fire Department; UAS networks, the prefectures and provinces of Brescia, Cremona, and Mantua; municipal officials and certified structural damage assessment experts, with the latter sometimes simply identified as technical personnel and/or technical experts in what follows. The exercise was also a valuable opportunity to test and refine the most advanced emergency management technologies and systems in Italy. The paper discusses notable outcomes, in addition to key steps, and also highlights gaps and issues still open for further/future developments of similar exercises in Italy and abroad. Full article

Towers, as monumental structures with profound cultural and religious significance, have been constructed throughout Chinese history. These buildings are now undergoing natural deterioration and anthropogenic damage, making detailed material studies essential for their conservation. Technical analysis of ancient bricks not only reveals historical manufacturing techniques but also helps in the evaluation of seismic performance, thereby providing vital information for the protection and restoration of ancient towers. This study investigated bricks from 13 ancient towers located in Shaanxi and Sichuan Provinces, China, particularly within the Guanzhong Basin, spanning approximately a millennium from the Sui to the Ming Dynasties. Utilizing techniques like SEM, XRF and XRD, we analyzed the microstructure and composition of the bricks to provide reference data for historical research and future restoration. The results indicate that regional variations had a significantly greater influence on the bricks than temporal changes during this period. Bricks from Shaanxi’s ancient towers exhibit higher Ca content and a more porous, loose microstructure compared to those from Sichuan’s towers. These characteristics merit careful consideration when assessing the weathering resistance of these historic towers and planning future conservation and restoration efforts. Full article

During a severe earthquake, the violent shaking causes freestanding non-structural elements to sway and overturn, potentially injuring occupants or causing the elements themselves to break apart. This study investigates how freestanding contents (FSCs) in buildings respond to various earthquake intensities, detailing their movement through extensive analysis of dynamic performance. The stability of the FSCs on each floor varies depending on the earthquake’s intensity, the building’s structural mode shape, the FSCs’ geometry, and the chosen performance assessment method. A series of multi-level seismic excitation assessments of FSCs were conducted using 30 earthquake records, classified into 50%, 10%, and 2% probabilities of exceedance in 50 years. The floor’s responses, including absolute peak floor acceleration and relative peak floor velocity from both elastic and inelastic analyses, provided the seismic demand. The Ishiyama criterion made it difficult to evaluate FSCs’ seismic capacity because of the ambiguous distinction between rocking and overturning movements. A new criterion, specifically developed to differentiate between rocking and overturning of FSCs, has been proposed to address this issue. The results translate into practical guidance for design and protection: because the demand-to-capacity ratios for overturning are governed by the floor level, content slenderness, and the elastic-versus-inelastic modeling assumption, the proposed criterion identifies which floors and which content geometries are genuinely at risk, allowing anchorage, restraint, or relocation measures to be targeted where they are most needed rather than applied uniformly. This supports more reliable and economical seismic protection of non-structural building contents. Full article

Ancient pagodas are prone to damage or even collapse under seismic loading due to material aging and structural characteristics. To enhance the seismic performance of ancient pagodas, a seismic-strengthening design method for retrofitting ancient pagodas with embedded glass fiber reinforced polymer (GFRP) bars is proposed. The limit values of the story drift angle of ancient pagodas are statistically analyzed to determine the story drift angles at the elastic and elastic-plastic limit points. The corresponding solutions are proposed in view of the primary problems in the seismic reinforcement design of the ancient pagoda, such as the calculation of seismic shear force, the distribution of seismic shear force, and the calculation of shear bearing capacity. The seismic fortification target for the ancient pagoda is proposed with consideration of the special requirements of cultural heritage protection. The two-stage design method is further proposed to achieve the seismic fortification target. Taking the 1/8-scale model of the Xiaoyan Pagoda with cracks as an example, the design method proposed in the paper is used to carry out the reinforcement design with embedded GFRP bars. The proposed design method can provide a theoretical basis and technical reference for the seismic reinforcement of the ancient pagoda. Full article

In the reconstruction problem of compressed sensing, to address the challenge of adapting common sparse constraints to diverse data, we propose a data-driven inverse-weighted regularization for adaptive data matching to enhance the ability of sparse constraints. Specifically, we formulate a weighted regularization term based on the data transform domain, positing that higher values in the sparsity-promoting transform domain correspond to a greater probability of effective signals. Therefore, when solving sparse optimization problems, we inversely weight this portion based on the inverse relationship with the coefficient magnitude, thereby reducing its impact and mitigating damage to effective signals. However, recognizing that noise and other irrelevant signals are sparse and approximately uniformly distributed in the transform domain, we can increase the weight of this portion to boost the sparsity constraint in the transform domain, thereby enhancing noise suppression. Consequently, we presented the corresponding solution algorithm and convergence proof for inverse-weighted sparse regularization, along with an application example in the context of the Radon transform. Experimental data tests indicate that inverse-weighted sparse regularization enhances the capability of sparse constraints, protects effective signals, suppresses noise, and improves the recovery accuracy of compressive sensing algorithms, as demonstrated in natural image enhancement and seismic multiple suppression. Full article