Seismic wave propagation is mainly studied by two paradigms: empirical research based on in-situ observation and model test, theoretical research based on mathematical deduction and numerical simulation. However, these paradigms face challenges such as sparse data samples, weak generalization of results, and insufficient understanding of laws. To address these challenges, we propose a coupling neural network that embeds both physical information and constrains physical laws. We use this neural network to learn the law of seismic wave propagation from a combination of theoretical equations and test records. We develop a prediction model of seismic wave propagation that jointly constrains multi-type sparse data, which improves the physical interpretability and extrapolation ability. The results demonstrate that the physical-guided coupling neural network can effectively and flexibly integrate theoretical, simulated, and experimental data, and generate the full waveform data and spatial distribution patterns of various physical quantities, thereby reducing the uncertainty of sparse sensor test data and solving the problem of data interaction of independent research paradigms.

The current research focuses on creating a Conditional Variational Autoencoder designed for encoding and reconstructing 5% damped spectral acceleration (S_a). This model integrates parameters related to the characteristics of the seismic source, propagation path, and site conditions, utilizing them as conditional inputs through the bottleneck layer. Unlike conventional Ground Motion Models, which typically use these parameters in a deterministic fashion, our model captures complex, nonlinear interactions between these parameters and ground motion through a probabilistic framework. The model is trained on an extensive data set comprising 23,929 ground-motion records from both horizontal and vertical directions, sourced from 325 shallow-crustal events in the updated NGA-West2 database. The input parameters encompass moment magnitude (M_w), Joyner-Boore distance (R_JB), fault mechanism (F), hypocentral depth (H_d), average shear-wave velocity up to 30 m depth (V_s30), and the direction of ground motion (dir). To validate the model's reliability, both interevent and intraevent residual analyses are conducted, affirming its robustness and applicability. Furthermore, the model's performance is assessed through residual analyses. Thus, this study contributes to advancing techniques in ground motion modeling, specifically enhancing seismic hazard assessment and the reconstruction of ground-motion data.

Bridge piers in deep reservoirs with canyon terrain boundaries are subject to complex hydrodynamic effects during earthquakes. In this study, a framework with added mass is adopted to calculate the effects of canyon terrain boundaries. This approach is demonstrated to be effective and accurate after the results from the fluid-structure interaction model and the model with the added mass method are compared. Then, the impacts of canyon terrain boundaries on the seismic response of bridge piers in deep reservoirs are numerically investigated. The effects of key parameters such as the pier-to-boundary distance, terrain slope angle, and water depth are also thoroughly studied. The results indicate that the canyon tunnel boundaries have larger influence zones along the height of the bridge pier when it has a larger terrain slope angle and a lower water depth. Although the dynamic characteristics did not change much after the specific topographic conditions were considered, the dynamic response greatly increased in terms of base forces and deformation. Moreover, this study underscores the critical importance of canyon terrain boundary conditions in the seismic design of bridges in mountainous reservoir regions.

Spectrally matched records are commonly evaluated based on the tightness of the match of the record response spectrum (PSA) with the target design spectrum and the preservation of the seed motions essential features. When used for seismic design and assessment of nuclear facilities, the US Nuclear Regulatory Commission (NRC) also requires verifying that the motions exhibit an adequate power distribution along the frequencies of interest. This requirement is typically validated by comparison of the motion power spectral density (PSD) with a target PSD function. This article proposes an extension of the continuous wavelet transform based spectral matching methodology to develop spectrum compatible records that comply with a minimum power distribution prescribed by a target PSD function. It is shown that the proposed algorithm is capable of generating records that comply with both, the PSA and PSD requirements, while preserving most of the seed records nonstationary features. The article also presents recommendations for the selection of seed motions that increase the likelihood of a successful match.

This study evaluates the optimum combination of the parameters that affect the seismic behavior of self-centering concrete bridge piers. Finite element models of these bridge piers under cyclic loading are developed in this study and validated based on the available experimental data set in the literature. A factorial analysis is performed to understand the effects of various parameters on the strength loss of the low and high aspect ratio piers under monotonic lateral loading as demonstrated in past experimental program. The interaction among different parameters such as the pier aspect ratio, concrete strength, prestress force level, longitudinal steel ratio and thickness of the confining steel jacket was evaluated for 4% drift level and their contribution to the degradation of the pier strength has been determined. The results show that concrete strength, prestress force level, and steel jacket thickness affect seismic behavior for both low and high aspect ratio piers. Steel jacket thickness is found to be the most sensitive for strength loss of high aspect piers, and initial prestress force level is the most sensitive for low aspect piers. The longitudinal steel ratio of the piers does not have any effect on strength degradation. Based on factorial analysis, optimum design parameters and a set of regression equations are proposed for the strength degradation estimation. Optimum design parameters result in 3.68% strength reduction for high-aspect piers and no strength reduction for low-aspect piers. The proposed optimum pier design ensures minimum strength degradation and enhances seismic resilience in the self-centering concrete bridge piers.

Compared with conventional elastomers, silicone elastomers offer superior thermal stability, durability, and enhanced resistance to environmental factors, making them promising candidates for seismic isolation bearing elastomers. However, their relatively low hardness and weak bonding potential have hindered their widespread application. In this context, this study examines the effect of fumed silica as a reinforcing filler on enhancing the mechanical properties of silicone elastomers, as well as the influence of three selected primers on the interlayer bond strength in laminated silicone bearings. Shore A hardness tests revealed that fumed silica increased hardness by up to 185%, with CX32-2036 cured silicone elastomers demonstrating superior performance. Lap shear tests revealed that the AQ1 primer improved the bond strength by up to 400%, particularly when combined with CX32-2036 cured elastomers. Quasi-static shear tests confirmed that prototypes fabricated with optimized filler and primer combinations exhibited excellent hysteretic behavior, consistent damping ratio, and stable shear stiffness. These findings demonstrate the potential of silicone elastomers, enhanced with fillers and primers, as effective materials for next-generation seismic isolation bearings. Further studies are recommended to evaluate long-term durability and dynamic performance under real-world conditions.

Soil liquefaction under seismic loading poses a significant threat to the structural safety of shield tunnels, especially those located in liquefiable interlayered grounds, which are more prone to severe damage. This study employs the CycLiqCPSP model to develop a two-dimensional saturated soil-shield tunnel interaction framework, examining seismic responses of shield tunnels under five spatial configurations of liquefiable soil layers. Resonant column tests and triaxial tests were conducted to calibrate the constitutive model parameters for liquefiable soils in the Beijing area, and the accuracy of these parameters was validated through element test simulations. The results indicate that, compared with shield tunnels in homogeneous liquefiable soils, the spatial distribution of liquefiable interlayers has a significant impact on the seismic response of the soil-structure interaction system. This influence leads to increased deformation, internal forces, and significantly higher damage levels in the tunnel structure. When the tunnel's base crosses the liquefiable layer, lateral deformation is notably amplified, causing severe structural damage and representing the most adverse seismic design scenario. Additionally, during seismic events, drainage channels may form in the middle section of double-track tunnels, heightening the risk of liquefaction. The study also reveals that the internal forces and deformations at the tunnel's haunches and toes are significantly higher than at other locations, necessitating special attention to these areas for potential damage. These findings offer essential theoretical guidance and scientific insights for the seismic design of shield tunnels in liquefiable interlayered grounds under strong earthquakes.

This investigation delves into the essential role of link beams within eccentric braced frames, serving as the key structural element responsible for withstanding the lateral drifts induced by earthquakes, even when subjected to substantial deformation. Due to lack of a wide comparative assessment on the influential variables on the cyclic response parameters and equivalent damping of the link beams with corrugated webs, a comprehensive parametric study was conducted in this investigation. To do so, a selection of 18 distinct case studies has been meticulously curated to consider several influential variables. These include the shape of corrugations, which could be trapezoidal or have a curved web plate, the specific angles at which the corrugated web plate is configured, as well as the number of angles or curvatures present in the web plate. To facilitate a thorough analysis, finite element micro models have been developed and subjected to both monotonic and cyclic shear loading conditions. The outcomes of these analyses reveal a notable improvement in the capacity for rotation and the efficient dissipation of energy as the angles and the number of angles in the corrugated web plates increase. Furthermore, the models with 90-degree corrugation (T-90) demonstrate ductility levels that are either on par with or surpass the benchmark model, as evidenced by ductility factors ranging from 12.34 to 17.85, compared to the F model's factor of 12.62. In addition, the T-90 models exhibit an enhanced cyclic response, as indicated by their higher overstrength Factor (Ω₀) values, which range from 1.36 to 1.41. These findings affirm the superior performance of the T-90 models compared to the F model. Remarkably, one of the case studies featuring a 90-degree web corrugation displays a higher ultimate capacity and a greater capacity for energy dissipation, all while using 4.5% less steel. This highlights the cost-effectiveness of implementing optimized corrugated link beams in structural designs.