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Within seismology, geology, civil and structural engineering, deep learning (DL), especially via generative adversarial networks (GANs), represents an innovative, engaging, and advantageous way to generate reliable synthetic data that represent actual samples' characteristics, providing a handy data augmentation tool. Indeed, in many practical applications, obtaining a significant number of high-quality information is demanding. Data augmentation is generally based on artificial intelligence (AI) and machine learning data-driven models. The DL GAN-based data augmentation approach for generating synthetic seismic signals revolutionized the current data augmentation paradigm. This study delivers a critical state-of-art review, explaining recent research into AI-based GAN synthetic generation of ground motion signals or seismic events, and also with a comprehensive insight into seismic-related geophysical studies. This study may be relevant, especially for the earth and planetary science, geology and seismology, oil and gas exploration, and on the other hand for assessing the seismic response of buildings and infrastructures, seismic detection tasks, and general structural and civil engineering applications. Furthermore, highlighting the strengths and limitations of the current studies on adversarial learning applied to seismology may help to guide research efforts in the next future toward the most promising directions. [ABSTRACT FROM AUTHOR]

Addressing the seismic vulnerability of infrastructures is critical, especially for those built before the introduction of the current seismic regulations. One of the primary challenges lies in retrofitting these buildings without interrupting their functionality. In this context, the use of exoskeletons for seismic retrofitting represents an effective solution. This approach increases the seismic resistance and ensures the continuous operation of the building during retrofitting. This advantage is especially crucial for critical infrastructures, such as airports. Nevertheless, traditional seismic assessment methods based on pushover analyses might not accurately predict the seismic capacity of complex infrastructures dominated by local vibration modes. To bridge this gap, the study proposes refining the multimodal pushover analysis tailored for seismic vulnerability assessments of large infrastructures with exoskeletons characterized by low modal participation ratios. The Foggia Airport case study exemplifies these points and highlights the practical applications of the discussed advancements. The authors compared two force distributions for push-over analysis, addressing the fine-tuning of exoskeletons to maximize their seismic resistance. [ABSTRACT FROM AUTHOR]

Inclined screws represent a typical connection solution for timber structures. They can provide higher capacity and stiffness due to the combined axial-shear interaction. This paper investigates the effect of engineering wood products choice (glued-laminated timber and cross-laminated timber), fibre inclination, friction, and interlayers on the capacity and deformation energy of timber-to-timber screwed connection with inclined screws. First, the authors carried out thirty push-out tests with inclined screws considering six structural configurations. Then, through X-ray computed tomography (CT) and threshold-based image segmentation, they assessed the deformed configuration of the screws to isolate the screw and timber contributions to the total deformation energy. The deformed shape of the connectors, fitted by a six-order polynomial, provides an estimate of the connection bending deformation assuming an elasto-plastic stress–strain constitutive for steel. By subtraction, the authors separately evaluated the role of timber embedment and steel deformation in the overall energy deformation in all the tested configurations. The experimental results revealed that most deformation energy comes from the screwed connection without interlayer, while the remaining can be attributed to timber plasticization. Conversely, the presence of the interlayer significantly unbalances such contribution, considerably reducing the role of timber plasticization. [ABSTRACT FROM AUTHOR]

The flexibility of the foundation system significantly affects the seismic and operational performance of integral abutment bridges (IAB). The so-called pile isolation system can lead to higher flexibility in pile foundations. It consists in backfilling the pile hole with high-damping materials up to a certain depth from the surface level. However, the impact of this solution in increasing the lateral flexibility and reducing the seismic demand strongly depends on the scale factor and pile diameter. Most investigations on this topic are based on experimental tests on scaled pile specimens. This paper explores the pile isolation system's effectiveness by conducting a multivariate sensitivity analysis of the seismic demand of an IAB structural archetype. The IAB archetype is modelled as a Winkler beam with a piece-wise definition of the subgrade stiffness and equivalent viscous damping, simulating the responses of the soil and high-damping particles. The simulated data are then used to calibrate a probabilistic formulation of the seismic demand reduction due to the pre-hole. The formulation, calibrated following a Bayesian approach, is used to derive estimates of the q-factor associated with the damping pre-hole for possible use in engineering practice. The analyses demonstrate that pile isolation with high-damping material can be effective but possesses a limited dissipating capacity, with a seismic reduction factor of approximately 1 and 2. [ABSTRACT FROM AUTHOR]

This paper compares the performance of probabilistic and deterministic capacity models for reinforced timber members under compression perpendicular to the grain. A database collecting approximately 60 test results has been compiled by reviewing research papers and master's and doctoral theses from the past twenty years. The capacity model proposed for the next generation of Eurocodes assesses the capacity as the minimum between the values associated with two failure modes, one at the contact plate and one at the screw tips. The main drawbacks of the model are the excessive elaborateness, given its limitation in accuracy and the fallacy in predicting the observed failure modes. In detail, the failure by the screw tips seldom occurs, although it was expected in more than half of the selected specimens. The authors attempted to simplify the capacity equation by proposing a generalized expression corresponding to the failure mode at the contact plate, corrected by a factor including the effects of load and screw arrangement and geometric details of the specimen. A deterministic mechanical model obtained by multiplying the timber strength by the contact area with a given coefficient performs better than the Eurocode model, which attempts to include the effect of load diffusion (R 2 ≈ 0.27 ). A constant factor equal to 2 yields a suitable fitting (R 2 ≈ 0.76 ). The best performance is achieved with a four-term polynomial, with adimensional addends, leading to an optimum fitting (R 2 ≈ 0.82 ). [ABSTRACT FROM AUTHOR]

The dynamic response of post-tensioned rocking walls in a mass timber building can be reduced to a single-degree-of-freedom (SDOF) model. In this model, the rocking wall panel is simplified as a rigid block, while the base rotation represents the degree of freedom of the entire structure. The paper presents an analytical approach to develop and calibrate this nonlinear model using shake table tests of a full-scale two-story building with CLT rocking walls. The experimental data are used to estimate the parameters of the governing equation using least-squares optimization. The correlation between the obtained parameters and the cumulative dissipated energy led to a nonlinear model with degradation behavior captured. After that, the calibrated model was used to assess the fragility functions of the structure under repetitive seismic events. [ABSTRACT FROM AUTHOR]

This paper focuses on the optimum design of the e-CLT technology. The e-CLT technology consists in adding cross laminated timber (CLT) walls to an existing reinforced concrete (RC) infilled frame via asymmetric friction connection (AFC). The authors carried out quasi-static and nonlinear dynamic analyses. The RC frame is modeled in OpenSees by fiber-section-based elements with force-based formulation. The contribution of the infill is simulated using a degrading data-driven Bouc–Wen model with a slip-lock element while the AFC is modelled with a modified Coulomb model. Different types of infill, aspect ratio, scaling, and member size are considered. The benefits of using e-CLT technology are discussed and the ranges of optimum performance of the AFC are estimated. A comparison of the performance of traditional infills with the e-CLT system is presented. The authors provide optimum intervals of the ratio between slip force and in-plane stiffness of the CLT panel, following energy and displacement-based criteria. The seismic displacement demand under various seismic scenario is investigated. Correlations between the RC characteristics and the optimum design ratios bestow possible criteria for the design of the AFC. [ABSTRACT FROM AUTHOR]

The energy dissipation phenomenon of a high-temperature superconducting (HTS) magnetic levitation (Maglev) transport system is investigated by using a single degree of freedom generalized Bouc–Wen hysteresis model. The Maglev system under test consists of a bogie with HTS skaters, which interacts with permanent magnets distributed on the guideways; thanks to a passive and self-balanced magnetic interaction, the vehicle is suspended and guided in all phases of the motion, including zero speed. The response of the HTS skate is tested under pseudo-static cyclic load in the vertical and lateral directions. The parameters of the generalized Bouc–Wen (GBW) model are calibrated on the experimental hysteresis loops using an ordinary least squares–based algorithm. The vertical dynamics of the levitating HTS skate is affected by the magnetic field discontinuities of the guideway. The dissipated hysteretic energy is simulated to assess the dependence on the velocity and pattern of the magnetic field. The displacement response is obtained by solving the nonlinear differential equation representative of the moving HTS skater, modelled as a single degree of freedom system, whose interactions with the magnetic guideway are described by the identified GBW hysteresis law. [ABSTRACT FROM AUTHOR]