Grouted sleeve connections are widely used in precast structures due to their excellent connectivity and ease of construction. However, variations in local stiffness within the grouted sleeve region and the relatively weak integrity of the concrete interface at the joint have negatively impacted the seismic performance of precast structures. This paper systematically summarizes the seismic performance tests, theoretical calculations, and numerical analysis of grouting sleeve connection joints, precast assembled components, and precast overall structures. Firstly, this paper elucidates the basic structure and force transmission mechanisms of grouted sleeves while summarizing the critical factors that influence the mechanical performance of sleeve grouted connections. Secondly, the influence laws of the strengthening effect of grouted sleeves on the mechanical properties of precast assembled structures are analyzed. Additionally, the impacts of the arrangement patterns of grouted sleeves and grout defects on the seismic performance of precast structures are investigated. Meanwhile, the calculation methods for the bearing capacities (bending, shear, and torsion) of precast assembled structures connected by grouted sleeves are summarized. Finally, the modeling methods of numerical analysis models for grout sleeve splice and precast assembled components connection with grouted sleeves are analyzed. Based on these, the following researches directions need to be explored: stiffness compatibility between sleeves, steels, and concrete; grouting quality assurance and detection methods; unified constitutive model for grouting material; calculation method for the bearing capacity of precast structure with grouted sleeve connections considering grouted sleeves, concrete, and steels factors.

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.

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.

The cost-effective ratio for the reinforcement of seismic damaged structures is proposed based on the estimated seismic economic loss and reinforcement cost. A performance-based optimal selection method is established. The cost-effective ratio and estimated repair time are adopted as quantitative indexes. Besides, the construction technology, construction time cost, and effect on building functions are qualitative indexes. The technique for order preference by similarity to ideal solution (TOPSIS) and combination ordered weighted averaging (C-OWA) were adopted as the mathematical method for optimal selection. Taking a certain typical concrete frame structure as the research object, based on the incremental dynamic analysis results of different seismic damage reinforcement schemes, a comparative and optimal selection study of the FRP reinforcement scheme, shock absorption reinforcement scheme, and seismic isolation reinforcement scheme for the seismic damaged structure was carried out. Results indicate that the proposed cost-effective ratio can provide a comprehensive and objective insight into promoting seismic performance from an economic perspective. Moreover, the performance-based optimal selection procedure can effectively provide a scientific basis for the construction decision-maker by combining objective situations and subjective willingness.

Real-time hybrid testing is an important test method for exploring the seismic performance of structures incorporating velocity-dependent components. However, current real-time hybrid tests encounter the challenge that the numerical substructure calculation efficiency fails to meet the real-time requirements, thereby restricting the application of this method in seismic tests of large-scale engineering structures. In order to improve the computational efficiency of the numerical substructures, a physical information neural network suitable for real-time hybrid testing is proposed, and a real-time hybrid testing method for neural network surrogate models is implemented. First, a neural network model was constructed based on different physical constraint equations. Then the seismic response of a two-story frame structure with a damper was numerically simulated by finite element software, and these simulation data were employed to train the network model. Finally, the trained physical information neural network was used to carry out real-time hybrid test simulation. The simulation results show that the physical information neural network has high prediction accuracy, among which the physical information neural network using resilience as the loss function has the highest accuracy. The real-time hybrid test method based on the physical information neural network agent model is feasible.

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.

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.

The indirect identification of bridge frequencies through coupled vehicle-bridge dynamics is a critical area of research that underpins the health monitoring of bridges. Traditional methods in this domain, however, impose significant constraints on the parameters and operational velocities of the vehicles involved. These restrictions significantly hamper the real-world applicability of these indirect methods since they cannot be smoothly integrated into the analysis of standard vehicles in normal driving conditions. To bridge this gap in the literature and practice, the current study presents a pioneering approach that capitalizes on the dimensionless response of vehicles in transit to indirectly identify bridge frequencies. The research commences by formulating a set of dimensionless equations characterizing the motion of the vehicle-bridge system. From this theoretical groundwork, the study derives a system state equation and an output signal equation, both predicated upon an enhanced subspace identification technique. This study introduces an innovative equation that captures the dimensionless residual response signal from the dual axles of a single vehicle, incorporating temporal variances in the process. This methodological framework successfully negates the adverse impact of road surface irregularities, effectively sidestepping limitations linked to vehicle parameters within conventional subspace identification methods. The versatility of this approach allows for its application to any typical vehicle in motion across a bridge. Then, the study validates the practicality of the proposed indirect approach for the frequency identification of simply supported beam bridges using the dimensionless response of a dual-axle vehicle. Through rigorous numerical analyses, this study examines the influence of driving speeds, road surface conditions, and stochastic vehicle loads on the indirect identification of bridge frequencies. The results highlight the necessity of adequate load excitation to dependably identify bridge frequencies, especially for eliciting the higher-order modal vibrations of bridges, which are essential for accurately identifying modes at higher frequencies. Finally, empirical evidence is provided through field tests conducted on a high-pier simply supported beam bridge. By inputting the monitored dynamic contact force between the vehicle and bridge into the proposed enhanced subspace identification model, this study validates the feasibility and accuracy of this novel approach. The experimental results affirm that the short-time stochastic subspace identification(ST-SSI) technique effectively isolates the first two modal frequencies of the bridge, outperforming the multivariable output error state space(MOESP) method in identifying higher-frequency modes. This research substantially broadens the scope of bridge frequency identification to include standard vehicles within regular traffic flows, simultaneously improving the precision of frequency detection, especially for higher-order modes.

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.

The construction of underground utility tunnels has developed rapidly, resulting in a large number of interchange utility tunnels, and the interchange nodes of the these tunnels are mostly cast-in-place as a whole. Due to the significant difference in lateral resisting stiffness in two orthogonal directions of the interchange utility tunnel, and the soil deformation is closely related to the buried depth of utility tunnel, the seismic response mechanism of the interchange utility tunnel is complex. In this paper, a response displacement method for the transverse seismic analysis of underground interchange utility tunnel is proposed. Taking a cross interchange cast-in-place utility tunnel as the research project, the load-structure model of the cross interchange utility tunnel is established via the response displacement method. The maximum relative deformation and its occurrence time between the layers of the interchange utility tunnel are studied, and the method in this paper is verified by the time history analysis method. Results indicate that for the underground interchange utility tunnel, the maximum relative deformation between the layers of interchange node does not occur simutaneously. Considering only the maximum relative deformation of the top slab and bottom slab of the interchange node may not be the most unfavorable condition for seismic analysis of the structure. It is necessary to calculate the maximum relative deformation between the layers of the interchange node to determine the most unfavorable condition of the overall structure. The method in this paper can accurately calculate the internal force and deformation response of underground cross interchange utility tunnel under seismic action, which is of reference value for the transverse seismic design of the underground interchange utility tunnel.