Strong ground motion data serve as the basis for establishing ground motion models. It is difficult to establish ground motion models in areas lacking sufficient strong motion data. This paper reviews several methods for establishing ground motion models in areas lacking strong motion data, including the numerical simulation method, the hybrid empirical method, and the referenced empirical approach. The numerical simulation method employs high-frequency and low-frequency ground motions simulated by stochastic and deterministic methods, respectively, to develop ground motion models. The hybrid empirical method can effectively solve the problem of lack of data by combining numerical simulation and actual observation data and applying the empirical ground motion model of the reference area to the target area by using the adjustment factor. The referenced empirical approach is based on the small earthquake records in the study area and adapts the existing empirical ground motion model to suit the specific regional situation with simplicity and effectiveness. Each of these three types of methods has its own characteristics, numerical simulation methods can take into account the characteristics of the seismic source, complex geological and site conditions, and the calculation results depend on the accuracy and precision of the source model and the subsurface velocity structure. The hybrid empirical method combines the flexibility of numerical simulation methods and the statistical characteristics of observed data, and can establish a relatively reliable model. The referenced empirical approach is quicker and simpler but is dependent on the data of the small earthquakes. Finally, this paper suggests that artificial intelligence and multi-source data fusion can be used to improve the accuracy and reliability of ground motion model in areas lacking strong motion data.

The response spectrum is a crucial foundation for seismic design. The constitutive models of traditional numerical simulation methods fail to adequately capture the complex site conditions and dynamic processes of soil with high uncertainty, which causes significant discrepancies between calculated and measured response spectra. This paper used 2428 sets of bedrock and surface seismic records from horizontal site stations by KiK-net in Japan. It established a BO-XGBoost-SS model for predicting ground acceleration response spectra, taking soil layer information and bedrock input as primary features through a stratified sampling training strategy guided by site categories. Results demonstrate that the constructed model exhibits good predictive performance, with an R² evaluation metric of 0.87 for surface acceleration response spectrum, with R² values above 0.8 for various periods. Applying dynamic time warping (DTW) distance analysis to assess the prediction match of individual response spectrum, the model proposed shows stability across different site categories, overcoming the deficiencies of numerical methods in underestimating high-frequency ground motion and anomalously amplifying long-period response spectrum. Validation with the latest ground motion records as an external dataset further confirms the model’s generalization ability. Through shapley additive explanations (SHAP) analysis, the contributions of features to model predictions are elucidated, revealing key features influencing response spectrum predictions, consistent with existing knowledge. The study’s findings provide training strategies and assessment guidance for the development of site response prediction models, offering new insights into the application of machine learning in seismic zoning and earthquake-resistant design of engineering structures.

There are various liquefaction assessment methods empirically based on test data used both domestically and internationally. Among them, the cone penetration test (CPT) has become a common method due to its inherent advantages. This paper elaborates on four commonly used CPT-based liquefaction assessment methods from both domestic and international sources: the NCEER method, the Code for investigation of geotechnical engineering method, the Specification for geotechnical invesitgation in soft clay area method, and the General rules for performance-based seismic design of buildings method. It compares the assessment results of these methods and utilizes data-driven classification and regression tree (CART) and random forest (RF) algorithms to study and analyze the importance of liquefaction influencing factors and the interplay among them. A new set of standards for determining liquefaction occurrence was developed, showing that: The General Rules method proposed by YUAN Xiaoming et al. is balanced with the highest accuracy for liquefaction assessment, achieving over 94% accuracy in seismic intensity zones of 7, 8 and 9, which is higher than the NCEER method, and significantly better than the Geotechnical Specification and Soft Soil Procedure methods. The NCEER method, though ranking second best, tends to misclassify a large quantity of non-liquefaction data as liquefaction in deeper layers of intensity zone 9, which is not consistent with reality. The performance of the Geotechnical Specification and Soft Soil Procedure methods is the worst. The accuracies of the two machine learning methods are 97.6% and 97.5% respectively, with the importance ranking of predictive variables being largely consistent. Factors such as relative density (D_r), soil behavior type index (I_c), fines content (FC), and cover thickness (CT) have a significant impact on triggering liquefaction, whereas peak ground acceleration (PGA), groundwater table (GWT), and critical thickness of the liquefiable layer (CTL) have a lesser impact. The proposed new standards for liquefaction triggering are in line with the impact trends of various influencing factors, providing references and support for the prediction and assessment of liquefaction triggering.

Roller compacted concrete gravity dams have developed rapidly since the 1980s due to their advantage of fast construction speed. Generally, induced joints are set between the dam sections of roller compacted concrete gravity dams and the joints are cut discontinuously with a slotting machine, with the joint surface being non-exposed. The overall seismic response and safety of the dam considering the influence of induced joints are worth attention. This paper proposed a simulation method for the induced joints of roller compacted concrete gravity dams. Established a three-dimensional finite element model of a certain roller compacted concrete gravity dam. Calculated and analyzed the stress, deformation and plastic damage behavior under static and dynamic loads of the overall model of the roller compacted concrete gravity dam and compared it with a single dam section model to study the influence of induced joints on the dam seismic response. The results showed that the stress level and damage degree of the highest dam section in the riverbed are similar under the two models and the seismic responses of the single dam section model were greater in some parts. In addition, the overall model can simulate the damage and cracking process of the induced joints of the roller compacted concrete gravity dam and can more reasonably simulate the overall response of the dam, especially the stress distribution of the dam sections at both dam abutments.

To investigate the seismic response of single-hole with two-track shield tunnels and inside prefabricated internal structures, this paper adopts stratum-structure method and viscous-spring artificial boundaries, utilizing the concrete damage plasticity (CDP) model to structures and establish the finite element models based on the Shanghai airport link line. After simulating, analyzing, and comparing, the seismic response of single-hole with two-track shield tunnels under five earthquakes has obtained. The results reveal that: internal structures, which can effectively increase the lateral stiffness of tunnel and reduce the diameter deformation rate, are beneficial to the seismic performance of tunnel. However, due to the internal structures, the most severely damaged part of the tunnel will change. Although the under-track structure increases the transverse stiffness of tunnel, the side walls on both sides of middle box culvert will be the first damaged parts under seismic wave. The seismic performance of partition walls is the worst among all components, and its response is controlled by the medium to long periods of seismic wave. Damage to the middle partition wall is mainly concentrated on the top and bottom. The seismic performance of the tunnel structure is relatively good, while the seismic performance of the internal structure is relatively poor, especially the middle partition wall. Future design and research should focus on the partition walls.

Currently, the construction of concrete filled steel tube (CFST) arch bridges in China is developing rapidly, and a large number of CFST arch bridges are located in the high-seismicity zones. The seismic resistance issues of CFST arch bridges have received widespread attention. This article first surveyed 360 domestic and foreign research literatures related to the seismic resistance of CFST arch bridges, and provided a macro discussion on their research direction and trends based on the number of publications. Afterwards, the current research progress and shortcomings were summarized in detail from four aspects: seismic simulation and analysis methods, seismic response characteristics, seismic damage analysis, and seismic isolation of CFST arch bridges. Finally, an outlook was made on the issues worth further research on the seismic resistance of CFST arch bridges in the future. The results show that the dynamic analysis method can accurately obtain the seismic response of structures, the coupling behavior of dynamic response amongst components, the optimization and reasonable design method of structural design parameters, the reasonable deployment method of seismic reduction and isolation measures and the mechanism of their impact on structural response, as well as the universal damage assessment process are of great significance for the seismic resistance of CFST arch bridges. In addition, seismic risk assessment, the application of digital technology, and universal research methods and data analysis methods are key areas worth studying in the future. The research can provide a reference for the engineering and academic communities in the seismic analysis, design, and evaluation of existing and pending CFST arch bridges.

To address the issue of the single energy dissipation form of traditional metal dampers, this paper proposes a new type of metal-double hinge friction hybrid damper, leveraging the characteristics of large yield displacement in bending metallic dampers and small yield displacement in rotational friction dampers. The construction principles and main parameter calculation methods of the hybrid damper are elaborated to achieve the objective of phased energy dissipation from frequent earthquakes to the maximum considered earthquakes. Experimental research on the mechanical performance of the hybrid damper was conducted, comparing the hysteresis curves, strain development, stiffness degradation and energy dissipation capabilities of dampers made of LY160 and Q355 steel materials and in different construction forms. The results show that the hybrid damper has good energy dissipation performance, with fuller hysteresis curves compared to traditional metal dampers. Within the range of metal yield displacement deformation, the damper primarily dissipates energy through friction, exhibiting multi-level yielding characteristics and a higher equivalent viscous damping ratio. The restoring force model for the hybrid damper is proposed and verified with experimental results. By adjusting the parameters of the metal damper and the double hinge friction damper, a performance-based design can be achieved to meet the seismic demands of various application scenarios. A new type of metal-double hinge friction hybrid damper has been developed.

The implementation of dissipative dampers between adjacent buildings can effectively mitigate structural vibration responses, with inerter dampers offering distinct advantages for controlling coupled structures. However, the performance of different types of inerter dampers in adjacent buildings requires further investigation. This study aims to determine the optimal parameters of various control devices for multi-story adjacent structures. A global optimization solver is employed, with displacement and acceleration of the flexible structure as the primary control objectives, while constraining the response of the rigid structure. Three damper types, namely, viscoelastic dampers (VED), tuned inerter dampers (TID), and tuned viscous mass dampers (TVMD), are individually applied to adjacent structures to evaluate the influence of structural period ratio and damper placement on seismic response. The control efficacy of VED, TID, and TVMD is systematically compared, and a novel hybrid control scheme combining TID and TVMD is proposed. Time-history analysis confirms the effectiveness of the optimized design. Numerical results indicate that inerter dampers (TID and TVMD) significantly reduce the seismic response of adjacent structures while requiring considerably smaller damping parameters than VED. Although the hybrid TID-TVMD system demands higher parametric requirements than single-damper configurations, it achieves superior balance in controlling both displacement and acceleration of the flexible structure.

This paper proposes a novel prestressed reinforced concrete (RC) column reinforcement method by replacing traditional angle steel with spatial special-shaped steel structures, which enhances constraint effectiveness and construction efficiency through prestressing technology and bolt connections. Four specimens were designed and subjected to axial compression tests to obtain failure modes, load-displacement curves, and strain distribution patterns of different configurations. The study found that post-earthquake damaged RC columns exhibited a 24% reduction in ultimate axial compressive bearing capacity and 46% stiffness degradation. After prestressed lattice steel reinforcement, concrete crack propagation was effectively controlled with significantly reduced damage severity. The bearing capacity and stiffness reached 141% and 115% of the original column’s values respectively, accompanied by a 20% improvement in deformation capacity, demonstrating excellent reinforcement performance. The prestressed lattice steel provides substantial lateral confinement, inducing compressive stresses in reinforced components that enhance material properties and retard crack development. Finally, based on the section equilibrium method, a calculation formula for axial compressive bearing capacity of fully bolted prestressed lattice steel-reinforced seismic-damaged RC columns was established, laying a theoretical foundation for engineering applications of this innovative reinforcement technique.

On December 18, 2023, a magnitude 6.2 earthquake occurred in Jishishan County, Gansu Province, with a maximum intensity of Ⅷ degrees. In order to analyze the damage characteristics of different structural types of buildings constructed by the standard and self-built methods in the townships, a seismic damage survey was conducted on the buildings in the macro-seismological center of the earthquake-Dahejia Town. The typical seismic damage characteristics of reinforced concrete shear wall structures, masonry-concrete composite structures, reinforced concrete frame structures, and other structural types were summarized, and the causes of damage were analyzed. The results of the investigation and analysis show that the standard-built masonry-concrete composite structures and reinforced concrete shear wall structures suffered minor damage as a whole, which does not affect the continued use of the buildings. The load-bearing columns and beams of the standard-built frame structures are basically intact, but the infill walls are severely damaged, which affects the use of the building and the cost of later repair is relatively high. The self-built buildings are more severely damaged than the standard-built buildings, and the damage patterns are complex and diverse, which seriously affects the production and life of the residents. In view of the many problems in the earthquake-resistance of township houses, it is suggested that the relevant government departments organize professional units to carry out appraisal of existing buildings and provide multiple sets of repair and reinforcement schemes. For new and under-construction self-built houses, the regulatory intensity should be increased, and the professional skills of the personnel involved in house construction should be enhanced through training. For the urgently developing and constructing township areas, the relevant departments should strictly follow the relevant regulations of the seismic code, take the lead in the construction of civil houses, and improve the overall seismic capacity of the region.