Based on the viscoelasticity interconversion of short-term creep and damping, this paper aims to study the load history-dependent material damping of recycled aggregate concrete (RAC) by monitoring the evolution of mechanical parameters under sustained loading. The present study employed fractional order and recoverability coefficients to characterize the influence law of sustained loading on material properties, which effectively addressed the long-standing technical challenge of in-situ damping measurement during continuous load application. To begin, short-term creep and recovery experiments were conducted. The resulting data were interpreted with a fractional three-parameter model (FTPM) to quantify how prior loading history alters the viscoelastic constants. Next, static-dynamic viscoelastic correspondence was exploited to convert creep compliance into loss moduli, yielding the material’s inherent damping capacity. Because these dynamic attributes evolve with age, free-vibration tests repeated at successive maturities were used to update the damping spectrum. Integrating the age and history-dependent trends, a predictive expression for the RAC damping was advanced, and the meso-mechanical origins of its temporal variation were dissected. The results indicate that load history exerts a significant influence on material damping by changing the viscoelastic properties. An increase in load level shows a positive correlation with material damping, which exhibits a downward trend with extended load holding duration. Meanwhile, material damping decreases specifically after unloading. The influence of load history on the material damping of concrete is the result of the combined action of different factors at the mesoscale.

Prefabricated bridge frame structures are widely adopted for their construction efficiency and quality, yet their seismic design mainly relies on ductility, often resulting in costly demolition and reconstruction after severe earthquakes. To enhance seismic performance and facilitate post-earthquake repair, this study proposes a repair method using replaceable double-wall corrugated steel tubes and energy-absorbing steel plates (DCST-EAS). Through quasi-static loading tests, the study systematically investigates key seismic performance indicators of the repaired structures-such as failure modes, hysteretic behavior, ductility, energy dissipation capacity, stiffness degradation, and residual deformation-and compares them with those of the original structures. Additionally, a validated three-dimensional finite element model was developed to conduct a sensitivity analysis of relevant parameters. The experimental results indicate that the DCST-EAS repair method increases the ductility of the prefabricated frame structure by 14.5 % and the ultimate displacement ratio by 28.6 %, thereby significantly improving the structure's deformation capacity and seismic performance. In conclusion, the DCSTEAS repair technique offers an effective solution for restoring earthquake-damaged prefabricated frame structures. It not only enhances seismic safety and maintainability but also provides a theoretical and practical foundation for the design and maintenance of prefabricated bridges in seismic regions.

Soil-steel composite bridges (SSCBs) are commonly utilized as overpasses. In the majority of existing studies, the transverse structural performance of SSCBs is primarily focused on, while neglecting their longitudinal structural performance. The aims of this paper are to clarify the longitudinal properties and compensate for the paucity of research on the longitudinal structural performance of SSCBs. In current study, field tests were conducted on a SSCB case bridge in a mining area, both in the construction stage and post-construction stage. Subsequently, longitudinal differences in the structural settlements, deformations, and hoop strains were analyzed. Additionally, a refined three-dimensional finite element model was developed and verified to analyze the transfer behavior of soil pressure above the structure along the longitudinal direction. The results indicate that in the construction stage, the difference in the soil-covered height primarily account for the differences in structural performances along the longitudinal direction. At the end of backfilling, the settlements, deformations, and hoop strains in the middle section are all greater than those in the end sections. In the post-construction stage, further developments of longitudinal structural characteristics occur due to creep deformation of the foundation soil and disturbances from mining trucks. One year after construction, the structural characteristics have stabilized. The maximum settlement reaches -1.014m and the maximum settlement difference reaches 0.365m. The differential settlement ratio, at 0.62%, remains within the 1% limit specified in the CHBDC code. Due to longitudinal settlement differences, the soil pressure in the higher settlement zone is transferred to the lower settlement zone by the longitudinal soil arching effect, which benefits the load-bearing capacity of SSCBs.

Updating the finite element (FE) model has great implications for follow-up FE-based analysis. The traditional updating method of FE models based on static surrogate models is ill-suited for the above task due to its high calculation cost and low updating accuracy. Therefore, the Continual Learning with Query-By-Committee (CLQC) model is proposed to determine the number of samples and improve the efficiency and accuracy of the model. First, the Sobol global sensitivity method is used to select the update parameters with higher sensitivity. Second, the maximin Latin Hypercube Sampling (LHS) method is used to select the initial sample set of the input within the specified range, and the residual between the calculated response and the test response is used as the output of the CLQC model to construct a multivariate continuous learning model. The FE model updating problem is directly converted into a machine learning model optimization problem. Then, the Query-By-Committee (QC) active learning method is used to conduct adaptive sampling in the alternative input sample set. The weight loss is recorded in each iteration, and the iteration stopping rule is set through early stopping to avoid redundant calculation. Finally, the effectiveness of the proposed method is validated using field-measured data from a long-span cable-stayed bridge. The advantages of the proposed method are demonstrated through ablation experiments and comparative analysis. Results show that this method can not only obtain the updated parameters with physical significance but also meet users' needs for high fitting accuracy without wasting computing resources.

In vibration-based structural health monitoring, frequency is widely used to judge the occurrence of damage, which is quite efficient and convenient. However, besides damage, variations of environmental factors, such as temperature and humidity can also cause the changes of frequency. To eliminate the effects of environmental factors, co-integration analysis method in the field of econometrics is adopted. First of all, the concept of co-integration analysis is presented. Then dynamic tests on a two-way curved arch bridge and three concrete simply supported model beams were introduced. The frequency, environmental temperature and humidity were recorded every one or 2 hours. After that, co-integration analysis was carried out and the co-integration equation among frequency, environmental temperature and humidity was determined. Finally, the effects of environmental temperature and humidity on the frequency were eliminated by the co-integration equation, which makes the vibration-based structural health monitoring method more accurate and reliable.

In recent years, prefabricated bridges have gained significant attention for their advantages in reducing construction time, costs, and environmental impact. However, the seismic performance of substructure connections, particularly their load transfer mechanisms during earthquakes, remains a critical challenge. This study proposes a novel prefabricated bridge frame structure incorporating corrugated steel tube-confined connections and columns. To evaluate its seismic behavior, a 1:4 scaled pseudo-static test was conducted, focusing on failure modes, hysteresis characteristics, energy dissipation, and stiffness degradation. A three-dimensional finite element model was developed to validate the experimental results and perform a parametric sensitivity analysis, providing insights into load transfer mechanisms and failure patterns. Based on these findings, a seismic design method tailored for the proposed structure is introduced. Results demonstrate that the use of corrugated steel tubes significantly improves seismic performance and enhances the stability of prefabricated bridge substructures. The proposed frame structure and seismic design method offer both theoretical and practical guidance for the implementation of prefabricated bridges in seismically active regions, contributing to the advancement of seismic design theory and practice.

Prefabricated frame structures are widely used in bridge construction for their efficiency and quality, but current seismic designs focus mainly on ductility, often resulting in costly repairs after earthquakes. To address this, the paper proposes a new repair method using double wall corrugated steel tube-fiber reinforced rubber concrete (DCST-FRuC) components for earthquake-damaged prefabricated frames. Through pseudo-static load tests, the key seismic performance indicators of the repaired structure-including failure mode, hysteresis performance, ductility, energy dissipation, and performance degradation-were systematically evaluated and compared with those of the unrepaired structure. Additionally, an experimentally verified three-dimensional finite element model was established, and parameter sensitivity analysis was conducted to explore the influence of key geometric and material parameters on structural performance. The research findings indicate that, compared to the unrepaired structure, the DCST-FRuC repair method significantly improved the lateral strength (by 58.4 %), initial stiffness (by 66.4 %), and energy dissipation capacity (by 29.3 %) of the frame structure. The DCST-FRuC repair technology offers an effective, rapid solution for restoring prefabricated bridges in earthquake-prone areas, enhancing both seismic performance and post-earthquake repairability, with important implications for bridge design and maintenance.

Concrete filled steel tubes (CFSTs) are widely used in critical load-bearing structures, such as piers. However, in medium-to-high seismic zones, CFST columns often face challenges such as insufficient energy dissipation and premature buckling of external steel tubes. To address these challenges, we propose a novel prefabricated frame structure using rubberized concrete double-column piers confined by corrugated steel tubes. A 1:4 scale model was tested under quasi-static loading, and a nonlinear finite element model was developed to analyze load transfer and failure mechanisms. Results indicate that damage is concentrated at the column ends, while the joint, cap beam, and foundation remain largely unaffected. The ultimate failure mode is characterized by circumferential tearing of the corrugated steel tube, resulting in ductile bending failure. A proposed calculation method for the compression-bending bearing capacity of the section, validated through numerical and experimental data, accurately predicts structural capacity. In conclusion, the proposed prefabricated frame structure offers a practical and innovative solution for accelerating bridge construction in seismic zones, enhancing structural resilience, and advancing sustainable seismic engineering.

Structure health monitoring systems (SHMs) play a crucial role in understanding the condition of structures. However, owing to various uncertain factors, sensor data may be anomalous, posing a great challenge to the real-time capture of dynamic characteristics of bridges. Hence, detecting anomalous data is crucial for SHM systems. This paper proposes a lightweight model to enable SHMs to detect anomalous data automatically and efficiently. This method combines three modules: Bridge Signal Transformer (BST), Mobile Vision Transformer (MobileViT), and Mixture of Bridge Experts (MoBE). Firstly, the acceleration data is converted to an image, and the MobileViT module is used to detect the anomalous data in the converted image. Since the converted image loses the absolute information of the data, this paper proposes a BST module, which uses directly the information of the data to identify the data type. MoBE module combines perfectly the advantages of the two modules to detect various types of anomalous data accurately. Experiments on an acceleration dataset from an extra-long-span railway cable-stayed bridge validate the advantages of the proposed method. This method performs well in any period, proving its generalization ability.

In this study, a wear-resistant ultra-thin wear layer was fabricated with polyurethane as an adhesive to investigate its durability for pavement applications. Its road performance was investigated based on indoor tests. First, the abrasion test was performed using a tire–pavement dynamic friction analyzer (TDFA), and the surface elevation information of the wear layer was obtained by laser profile scanning. The relationship between the anti-skid properties of the wear layer and the macro-texture was analyzed. Second, a Fourier infrared spectrometer and scanning electron microscope were employed to analyze the evolution of polyurethane aging properties in the pull-out test and accelerated ultraviolet (UV) aging test. The results showed that the mean profile depth (MPD), arithmetic mean wavelength of contour (λa), surface wear index (SBI), stage mass loss rate (σ), and total stage mass loss rate (ω) of the abrasive layer aggregate had significant multivariate quadratic polynomial relationships with the skidding performance of the abrasive layer. The tensile strength of the polyurethane ultra-thin abrasive layer decreased by only 2.59% after 16 days of UV aging, indicating a minimal effect of UV action on the aggregate and structural spalling of the polyurethane abrasive layer.

In the construction of building structures, numerous components simultaneously experience axial pressure and lateral bending moments. This concurrent influence plays a pivotal role in structural design considerations. This paper presents an experimental investigation of the compression-bending performance of rubberized concrete-filled corrugated steel tubes (RuCFCST). Twenty-two specimens were tested to evaluate the effect of eccentricity, length-diameter ratio, and confinement factor on the failure mode, load-displacement response, stiffness, compression-bending capacity, and ductility of the columns. The study also conducted a stress analysis on the corrugated steel tube to understand its confinement effect on the core rubberized concrete. The results demonstrate that the confinement factor emerges as a pivotal and sensitive parameter that impacts the compression-bending bearing capacity of RuCFCST columns. The study further elucidated the non-uniform confinement and failure mechanisms of the RuCFCST column, and subsequently assessed the applicability of the specimen's compression-bending bearing capacity as calculated by current specifications. The proposed RuCFCST columns offer new insights and serve as a reference for developing composite member systems with large hoop stiffness, small wall thickness, and environmental sustainability.

Compared with circular, arched, and pipe-arched soil–steel structures, box-type soil–steel structures (BTSSSs) have the advantages of high cross-section utilization and low cover depth. However, the degree of influence of the crown and haunch radii on the mechanical performance of BTSSSs is still unclear. Therefore, two full-scale BTSSS models with a span of 6.6 m and a rise of 3.7 m but with different crown and haunch radii were established, and the mechanical properties during backfilling and under live load were tested. Afterward, 2D finite element models (FEMs) were established using the ABAQUS 2020 software and verified using the test data. The influence of cross-section geometric parameters on mechanical performance was analyzed by using the FEM, and a more accurate formula for calculating the bending moment during backfilling was proposed. The results show that the BTSSS with a smaller crown radius has a stronger soil–steel interaction, which promotes more uniform stress on the structure and makes the structure have smaller relative deformations, bending moments, and earth pressure. The span and arch height greatly influence the bending moment and deformation of the structure. Based on the CHBDC, the crown and haunch radii were included in the revised calculation formula.

The use of concrete-filled steel tube (CFST) piers has attracted widespread attention due to their high load-bearing capacity, excellent ductility, and superior seismic performance. Given their role as bridge substructures responsible for transmitting seismic loads, the ability of CFST piers to dissipate energy under seismic conditions significantly impacts bridge safety. This study investigates rubberized concrete-filled corrugated steel tube (RuCFCST) pier as a solution for addressing issues such as local buckling, bulging, or tearing damage in CFST columns during seismic loading. Four 1:4 scale pier specimens were subjected to pseudostatic tests to determine the effects of the axial compression ratio, filling concrete type, and connection method on the damage development, failure mode, strain distribution, and seismic performance of the pier specimens. In addition, a reliable nonlinear finite element model was established to evaluate sensitive parameters such as the length–diameter ratio, axial compression ratio, diameter-to-thickness ratio, and confinement factor. The influence of each parameter on this type of composite pier was revealed. The results showed that the flexural strength of corrugated steel tubes filled with rubber concrete was 17.4

A rubberized-concrete-filled corrugated steel tube composite column-foundation connection is proposed as a solution to mitigate local buckling, bulging, or tearing damage of concrete-filled steel tube columns during seismic load. This proposal aims to improve the ductility and energy dissipation capacity of the column. Experimental studies have been conducted to investigate the axial compressive strength of this novel column and the side shear performance of its connection to the foundation. A quasi-static experiment was carried out on three specimens to facilitate the application of the proposed connection. The influence of embedded depth on the seismic strength of such composite column-foundation connection was studied, and the cast-in-place specimen was used as a reference. The failure modes of the specimens were observed, and the evaluation indicators such as strength, stiffness, and ductility were analyzed. The results show that the connection of the composite column foundation can provide sufficient connection strength under seismic load. Furthermore, seismic design methods are explored and proposed, combined with the side shear database. These investigations aim to inform the design and application of such column-foundation connections.

Thin-walled galvanized helical corrugated steel tubes (HCSTs) filled with concrete are promising composite members, consisting of concrete, an anti-corrosion shell, and a multifunctional exterior corrugated steel tube. To investigate the synergistic working mechanism of concrete-filled HCSTs (CFHCSTs), six specimens were designed for axial compression tests, with the inner diameter of the column and the volumetric steel ratios of the longitudinal reinforcement as the variation parameters. The results show that HCSTs can better confine the concrete core and increase its strength. The failure mode of HCSTs is significantly influenced by the column’s diameter, and those with a smaller diameter are prone to slide failure and lock seam tearing. The strains and stresses on HCSTs are discussed in detail to elucidate the confinement effect. This paper proposes a suitable design method to predict the ultimate axial compression load capacity of CFHCST columns based on early studies on steel tube-confined concrete.

This study investigates the impact of rubber aggregates with different particle sizes, volume proportions, and pretreatment methods on the crack resistance and energy dissipation properties of rubberized concrete (RuC). The mechanisms of crack resistance and energy consumption are analyzed from macroscopic, mesoscopic, and microscopic perspectives using static and dynamic performance tests, digital image correlation (DIC), and scanning electron microscopy (SEM). These techniques reveal changes in crack patterns, interface transition zones, and pore characteristics. The findings demonstrate that rubber aggregates significantly slow crack propagation and enhance damping energy dissipation, with the volume content of rubber being the most critical factor. The inclusion of rubber aggregates introduces "cavity defects" into the concrete structure, which accounts for RuC's reduced strength compared to standard concrete while highlighting its advantages in vibration reduction and energy absorption. These insights are essential for advancing research on material modifications and microscopic numerical simulations, contributing to reduced carbon emissions.

为明确波纹钢加固混凝土箱涵的受力性能,本文在考虑原涵洞的二次受力状态以及界面接触属性的基础上利用两步法建模的方法分析了组合程度、波纹钢板的波形参数、混凝土填充层的强度等级、混凝土填充层厚度对结构承载力的影响以及荷载分配规律.结果表明:波纹钢板加固箱涵后承载力提升1倍以上,结构的延性得到进一步的提升;混凝土填充层强度等级的提高对结构承载力的影响甚少;关键位置的凿毛以及全截面的凿毛、植筋和波纹钢板上设置剪力连接件有助于承载力的大幅提高;拱顶位置混凝土填充层厚度增加承载力大幅提高;结构的承载力和延性与波形参数不成正比例关系;各个截面的荷载分配与各部分的抗弯刚度占比成正比例关系.

To comprehensively consider and study the seismic performance of the self-center mortise-tenon segmental pier, its vulnerability under earthquake is evaluated. The reliability of the model is verified by comparing the cyclic pseudo-static test results with the finite element models. The model is used as the basis for vulnerability analysis. Taking the maximum displacement of the pier top as a damage index. Different damage states are described. The damage index limits μcy1, μcy, μc2, and μcmax of different damage levels are determined. The time history analysis of cast-in-place pier and mortise-tenon segmental piers under different earthquake actions is carried out by using finite element software. The probabilistic seismic demand model is established through IDA curves. And the seismic vulnerability analysis is carried out. The influence of various parameters on the seismic vulnerability of mortise-tenon segmental pier is studied by changing the longitudinal reinforcement ratio, axial compression ratio, and aspect ratio. The results show that the seismic vulnerability of the two types of piers designed according to the principle of equivalence is similar under different damage states. It can be considered that it has better seismic performance. The longitudinal reinforcement ratio, axial compression ratio, and aspect ratio have a great impact on the vulnerability of piers.

依托一座5跨圬工拱桥,在考虑原拱桥的二次受力以及界面接触属性的基础上,利用ABAQUS研究采用波纹钢-混凝土组合结构加固的圬工拱桥力学性能的变化.结果表明:加固后混凝土为主要受力构件,波纹钢和原拱圈的内力相当;车辆荷载作用下拱顶轴力降低85.7％,挠度降低79.5％;加固后关键截面应力均小于规范限制,达到了预期的加固效果.此(外,施工过程中波纹钢板可作为混凝土的浇筑模板,施工便捷,工期明显缩短.本文可为现有圬工拱桥加固提供设计参考和工程借鉴.

以研究承插式预制波纹钢管-橡胶混凝土墩的应用为出发点,对某座48m跨度的三跨连续梁桥进行了替代桥墩的力学及细部构造设计,在ABAQUS中建立了多尺度有限元模型,并进行了新型桥墩和几种常规桥墩在动力特性和地震响应方面的对比.结果表明:采用波纹钢管-橡胶混凝土组合桥墩替代后,结构自振频率显著降低,地震响应减小.波纹钢管的截面形式和橡胶混凝土对减小结构响应起到了积极作用.因此,将采用承插式的预制波纹钢管-橡胶混凝土组合桥墩应用于桥梁建造时,可加快建造速度,同时结构地震响应减小.