摘要：
To address the specific demands for early-strength materials in ecological slope emergency restoration projects and ecological slope construction in cold regions, this study has developed Ecological Porous Concrete (EPC) with low-alkali characteristics and enhanced early-strength advantages through a synergistic mechanism of alkalinity regulation and strength enhancement. This provides new material support for advancing the ecological restoration technology system within the context of carbon neutrality . In this study, we systematically investigated the influences of triethanolamine (TEA) and nano-silica (NS) on the mechanical properties and CO 2 absorption capacity of EPC cementitious materials . The results indicate that the incorporation of TEA and NS effectively mitigates the issue of reduced early strength in EPC caused by oxalic acid , leading to a significant improvement of 33.3 % in the early mechanical properties. Furthermore, the addition of TEA and NS promotes crystal nucleation and growth during the hydration reaction of EPC cementitious materials, facilitating the transition from the nucleation and growth (NG) process to the impingement (I) process, and enhances the CO 2 sequestration capacity of the EPC cementitious materials. Planting tests demonstrate that the early-strength EPC exhibits excellent vegetation performance, fulfilling the practical needs of the project. These research findings offer robust technical support for accelerating the construction speed of EPC and ensuring project quality. They are of considerable significance in promoting the industrialized application of EPC in green building and ecological restoration fields, particularly in cold region engineering and emergency ecological slope restoration projects.
To address the specific demands for early-strength materials in ecological slope emergency restoration projects and ecological slope construction in cold regions, this study has developed Ecological Porous Concrete (EPC) with low-alkali characteristics and enhanced early-strength advantages through a synergistic mechanism of alkalinity regulation and strength enhancement. This provides new material support for advancing the ecological restoration technology system within the context of carbon neutrality . In this study, we systematically investigated the influences of triethanolamine (TEA) and nano-silica (NS) on the mechanical properties and CO 2 absorption capacity of EPC cementitious materials . The results indicate that the incorporation of TEA and NS effectively mitigates the issue of reduced early strength in EPC caused by oxalic acid , leading to a significant improvement of 33.3 % in the early mechanical properties. Furthermore, the addition of TEA and NS promotes crystal nucleation and growth during the hydration reaction of EPC cementitious materials, facilitating the transition from the nucleation and growth (NG) process to the impingement (I) process, and enhances the CO 2 sequestration capacity of the EPC cementitious materials. Planting tests demonstrate that the early-strength EPC exhibits excellent vegetation performance, fulfilling the practical needs of the project. These research findings offer robust technical support for accelerating the construction speed of EPC and ensuring project quality. They are of considerable significance in promoting the industrialized application of EPC in green building and ecological restoration fields, particularly in cold region engineering and emergency ecological slope restoration projects.
摘要：
The research aimed at evaluating the creep properties of glulam beams connected with steel joining plates and bolts (GBSBs) made of Larix gmelinii. Three GBSBs and three intact Glulam beams of identical dimensions were subjected to long-term service loads, with their mid-span deflection behavior monitored and analyzed to understand the creep mechanisms and material performance impacts over an extended period. After 900 days of loading, the average mid-span deflection of the intact Glulam beams and the GBSBs were 18.55 mm and 27.70 mm, respectively. Three existing creep models and a modified Burger model were adopted to fit the long-term deflection curves of the specimens. The modified Burger model provided satisfactory accuracy capturing the trend of creep behavior and demonstrated superior capability in predicting the trend throughout the service life period. It was also found that the elastic deformation emerged as the main deformation form within the beams, and the viscoelastic deformation may potentially govern the deformation. Additionally, theoretical calculations of the long-term deformation using the timber long-term deformation calculation method specified in Eurocode 5 were conducted. These results are in good agreement with the calculation results according to Eurocode 5.
The research aimed at evaluating the creep properties of glulam beams connected with steel joining plates and bolts (GBSBs) made of Larix gmelinii. Three GBSBs and three intact Glulam beams of identical dimensions were subjected to long-term service loads, with their mid-span deflection behavior monitored and analyzed to understand the creep mechanisms and material performance impacts over an extended period. After 900 days of loading, the average mid-span deflection of the intact Glulam beams and the GBSBs were 18.55 mm and 27.70 mm, respectively. Three existing creep models and a modified Burger model were adopted to fit the long-term deflection curves of the specimens. The modified Burger model provided satisfactory accuracy capturing the trend of creep behavior and demonstrated superior capability in predicting the trend throughout the service life period. It was also found that the elastic deformation emerged as the main deformation form within the beams, and the viscoelastic deformation may potentially govern the deformation. Additionally, theoretical calculations of the long-term deformation using the timber long-term deformation calculation method specified in Eurocode 5 were conducted. These results are in good agreement with the calculation results according to Eurocode 5.
通讯机构：
[Wang, HD ] C;Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.
关键词：
Calcareous sand;EICP;Stress-strain curve;Calcium carbonate content;Statistical damage constitutive model
摘要：
The enzyme-induced calcium carbonate precipitation (EICP) technique was utilized to cement calcareous sand. The mechanical properties of EICP-cemented calcareous sand at various cementation degree were investigated using consolidated drained triaxial compression tests. A statistical damage constitutive model tailored for EICP-cemented calcareous sand was also developed based on damage mechanics theory. The findings are as follows: (1) The EICP technique significantly enhances the cementation of calcareous sand. As the number of grouting operations increases, the peak deviator stress of the cemented material gradually increases, with the maximum enhancement approaching 2.5 times. Moreover, during the stress decay phase following the peak stress, the decay rate of the cemented sand accelerates, displaying a more pronounced brittle characteristic. (2) With the increased calcium carbonate content, the peak eccentric stress of the cemented body increases significantly, and there is an obvious nonlinear exponential correlation between them. (3) The statistical damage constitutive model, formulated based on Lemaitre's strain equivalence principle combined with a log-normal distribution and the Drucker–Prager strength criterion, accurately predicts the stress–strain curves, effectively simulating the complete stress–strain evolution of EICP-cemented sand under different numbers of grouting operations and varied confining pressure conditions. (4) At higher cementation levels or lower confining pressures, the internal damage process of the EICP-cemented calcareous sand specimens intensifies, indicated by the rapid increase of the damage variable D with axial strain. The research findings can provide a crucial theoretical foundation for the application of EICP technology in the treatment of island reef or roadbed foundations, aiding in the analysis and prediction of the mechanical properties of EICP-cemented calcareous sands.
摘要：
This paper proposes beam-only connected steel plate shear walls (BSWs) and composite shear walls (BCWs) to mitigate the seismic risk of concrete-filled double-steel tube (CFDST) frames. As a new type of structural system, limited works have been reported on the performance limit definitions and risk-informed assessment of them due to the lack of experimental and analytical data. According to the cyclic tests results performed by the authors and the guidance of FEMA 356, three stage of limit states are defined and the corresponding results are recommended. Then, an elaborate numerical model is developed that considering the nonlinear behaviour of materials, panel zone, beam-column joints and shear walls, and the model is validated by the test results. Besides, three CFDST buildings with different height and two CFDST buildings with BSW or BCW are modeled based on the validated numerical model. Finally, seismic fragility analyses as well as seismic risk assessments are conducted on these models, and the annual occurrence probability and collapse probability of the structure within 50 years are calculated. The results show that both BSWs and BCWs can effectively mitigate the seismic responses and risks of CFDST buildings, and the collapse probability of buildings within 50 years decreases from 7.7 % to 1.39 % and 1.24 % due to the equipped BSWs and BCWs, respectively.
This paper proposes beam-only connected steel plate shear walls (BSWs) and composite shear walls (BCWs) to mitigate the seismic risk of concrete-filled double-steel tube (CFDST) frames. As a new type of structural system, limited works have been reported on the performance limit definitions and risk-informed assessment of them due to the lack of experimental and analytical data. According to the cyclic tests results performed by the authors and the guidance of FEMA 356, three stage of limit states are defined and the corresponding results are recommended. Then, an elaborate numerical model is developed that considering the nonlinear behaviour of materials, panel zone, beam-column joints and shear walls, and the model is validated by the test results. Besides, three CFDST buildings with different height and two CFDST buildings with BSW or BCW are modeled based on the validated numerical model. Finally, seismic fragility analyses as well as seismic risk assessments are conducted on these models, and the annual occurrence probability and collapse probability of the structure within 50 years are calculated. The results show that both BSWs and BCWs can effectively mitigate the seismic responses and risks of CFDST buildings, and the collapse probability of buildings within 50 years decreases from 7.7 % to 1.39 % and 1.24 % due to the equipped BSWs and BCWs, respectively.
摘要：
Due to the complex and diverse terrains in China, the unequal height piers are commonly used for high-speed railway track-bridge system (HSRTBS). The unequal pier height may amplify the seismic responses of the components in HSRTBs. Besides, the energy dissipation steel device (EDSD) is suggested to control the damages. Therefore, how to balance the effect of the unequal pier height and the arrangement of these devices is an essential issue. This paper proposed U-shaped EDSD, and investigates how the device arrangements affect the seismic responses of 5-span 4-pier HSRTBs with three typical pier height configurations. The cases of HSRTBS are equal height piers, symmetrical piers, and asymmetrical piers. The results show that the peak response on the rail of the HSRTBS with unequal height piers is about 10% higher than the equal height cases. A proper arrangement of the proposed U-shaped EDSD could reduce the response of the HSRTBS by approximately 50%. However, a negative influence may occur if the devices are placed on only several piers of the HSRTBS with asymmetrical unequal height piers, which needs attention from designers. Similar findings are observed in the seismic fragility results. This research could provide insights into the seismic response control of HSRTBS with unequal height piers.
摘要：
Fatigue damage in steel–concrete composite structures frequently initiates at welded joints due to stress concentrations and inherent defects. This study investigates the stress intensity factors (SIFs) associated with fatigue cracks in the welds of steel longitudinal beams, employing the FRANC3D–ABAQUS interactive technique. A finite element model was developed and validated against experimental data, followed by the insertion of cracks at both the weld root and weld toe. The influences of stud spacing, initial crack size, crack shape, and lack-of-penetration defects on Mode I SIFs were systematically analyzed. Results show that both weld root and weld toe cracks are predominantly Mode I in nature, with the toe cracks exhibiting higher SIF values. Increasing the stud spacing, crack depth, or crack aspect ratio significantly raises the SIFs. Lack of penetration defects further amplifies the SIFs, especially at the weld root. Based on the computed SIFs, fatigue life predictions were conducted using a crack propagation approach. These findings highlight the critical roles of crack geometry and welding quality in fatigue performance, providing a numerical foundation for optimizing welded joint design in composite structures.
期刊：
Theoretical and Applied Fracture Mechanics,2025年139:105089 ISSN：0167-8442
通讯作者：
Lan, M
作者机构：
[Shao, Zuliang; Zhang, Shenchen; Lin, Qibin; Lan, Ming] Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Lin, Hang; Huang, Chao] Cent South Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China.;[Zhang, Ke] Kunming Univ Sci & Technol, Fac Elect Power Engn, Kunming 650500, Peoples R China.;[Zhang, Ke] Hebei Univ Technol, Sch Civil & Transportat Engn, Tianjin 300401, Peoples R China.;[Fan, Wenchen] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.
通讯机构：
[Lan, M ] U;Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.
关键词：
Jointed rock mass;Compressive-shear load;Strain field evolution;Digital image correlation;Pixel evolution model
摘要：
The instability of jointed rock masses under compressive-shear loading poses significant challenges to the safety of underground engineering structures. This study investigates the crack propagation mechanism in jointed rock masses with a circular hole using compressive-shear tests and digital image correlation (DIC) analysis. Cement mortar specimens with varying joint dip angles were designed to simulate jointed rock masses. The results reveal that joint dip governs strain field evolution and failure modes: specimens with 30° and 75° joints exhibited anomalous failure stability, characterized by high-frequency displacement fluctuations and rapid strength degradation post-peak. The interaction between holes and joints reduced the bearing capacity by 38–52% compared to intact specimen, with shear stress dominating the failure process. A novel pixel evolution model was developed to quantify crack propagation process. Identified three strain evolution phases: rapid development during initial loading, gradual progression approaching peak stress, and stabilization post-failure. Three failure modes were classified based on joint dip angles: tensile-dominated fracture below 30°, hybrid tensile-shear failure between 45° and 60°, and shear-controlled rupture above 70°. DIC analysis captured displacement discontinuities at crack tips and localized strain patterns preceding macroscopic cracks. Specimens with critical joint dip angles exhibited over 70% residual strength reduction after failure, highlighting their engineering vulnerability. This research establishes a quantitative framework for predicting crack evolution in rock masses, thereby facilitating precursor identification through strain field quantification. The findings provide valuable insights into stability assessment and disaster mitigation in underground engineering projects.
The instability of jointed rock masses under compressive-shear loading poses significant challenges to the safety of underground engineering structures. This study investigates the crack propagation mechanism in jointed rock masses with a circular hole using compressive-shear tests and digital image correlation (DIC) analysis. Cement mortar specimens with varying joint dip angles were designed to simulate jointed rock masses. The results reveal that joint dip governs strain field evolution and failure modes: specimens with 30° and 75° joints exhibited anomalous failure stability, characterized by high-frequency displacement fluctuations and rapid strength degradation post-peak. The interaction between holes and joints reduced the bearing capacity by 38–52% compared to intact specimen, with shear stress dominating the failure process. A novel pixel evolution model was developed to quantify crack propagation process. Identified three strain evolution phases: rapid development during initial loading, gradual progression approaching peak stress, and stabilization post-failure. Three failure modes were classified based on joint dip angles: tensile-dominated fracture below 30°, hybrid tensile-shear failure between 45° and 60°, and shear-controlled rupture above 70°. DIC analysis captured displacement discontinuities at crack tips and localized strain patterns preceding macroscopic cracks. Specimens with critical joint dip angles exhibited over 70% residual strength reduction after failure, highlighting their engineering vulnerability. This research establishes a quantitative framework for predicting crack evolution in rock masses, thereby facilitating precursor identification through strain field quantification. The findings provide valuable insights into stability assessment and disaster mitigation in underground engineering projects.
期刊：
International Journal of Structural Stability and Dynamics,2025年Accepted Papers ISSN：0219-4554
通讯作者：
Qin, HX
作者机构：
[Qin, Hongxi; Wang, Da; Lv, Xiaoyong; Liu, Fan; Zhang, Qishu] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Peoples R China.;[Liu, Fan; Zhao, Yan] Dalian Univ Technol, State Key Lab Struct Anal Optimizat & CAE Software, Dalian, Peoples R China.;[Zhao, Yan] Dalian Univ Technol, Sch Mech & Aerosp Engn, Dalian, Peoples R China.;[Zhao, Yan] Ningbo Res Inst Dalian Univ Technol, Ningbo, Peoples R China.
通讯机构：
[Qin, HX ] C;Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Peoples R China.
关键词：
Train riding comfort evaluation;surrogate model;polynomial dimensional decomposition;train-bridge coupled system
摘要：
This paper efficiently realizes train riding comfort evaluation of a random three-dimensional train-bridge coupled system (TBCS) subjected to random track irregularities by constructing a surrogate model of the power spectral density (PSD) of the acceleration response of the train. The response PSD is regarded as a random function above random system parameters, and the dimensional decomposition and polynomial expansion are performed on random functions. The surrogate model of system response PSD is constructed using the expansion coefficients and polynomial basis. To avoid high-dimensional integration in probability space and reduce random vibration analysis of the TBCS, the dimension-reduction integration and Gaussian quadrature are introduced to calculate the expansion coefficients. Furthermore, the PSD of the system response required at each integration point is efficiently calculated by the pseudoexcitation method. Finally, the riding comfort evaluation of the train is achieved by calculating the Sperling index of each time instant using the surrogate model of the acceleration PSD of the train. In numerical examples, results of the proposed method are verified, the parameter sensitivity analysis is conducted, and the influence of variations of system parameters and train running velocity on the riding comfort is further studied.
期刊：
Indian Geotechnical Journal,2025年55(3):1863-1872 ISSN：0971-9555
通讯作者：
Liu Sisi
作者机构：
[Zeng Feng; Liu Sisi; Huang Ying] School of Civil Engineering, Central South University of Forestry Science and Technology, Hunan, China;[Wang Shuisheng] China Construction Fourth Engineering Bureau Co., Guangzhou, China;[Lu Yu] Yunnan Tobacco Rebaking Limited Liability Company Shizong Rebaking Factory, Yunnan, China
通讯机构：
[Liu Sisi] S;School of Civil Engineering, Central South University of Forestry Science and Technology, Hunan, China
关键词：
Root mass density (RMD);Flexible reinforcement model;Root-soil composite;Shear strength;Vetiver
摘要：
Vetiver root-soil complexes were utilized, and direct shear tests as well as root weight density (RMD) measurement experiments were conducted on these complexes at the different depths h and growth periods (t), ranging from 1 to 16 months. RMD, different over growth periods and depths, was analyzed for its impact on the shear strength increments. The experimental results demonstrated that the variation rules of the shear strength increments and RMD with respect to the growth periods (t) were essentially identical. With RMD at its core, a meticulous examination of the flexible reinforcement model has been undertaken, combined with an empirical understanding of RMD’s evolution over time (t), we’ve crafted an enhanced flexible reinforcement model. This model includes growth periods (t) and depths (h) as critical parameters, thereby offering a comprehensive depiction of the dynamic impact of plant root systems on soil reinforcement across different stages of development and depths. The established model was employed to calculate and analyze the shear strength increments for the different growth periods (t) and depths (h), which were compared and analyzed against the experimental outcomes. The results indicate that both the measured and model-calculated shear strength increments exhibit a largely consistent of trend over different growth periods (t). The measured shear strength increment is all within the range predicted by the new calculation model, thereby indicating that the model calculation method is reasonable.
期刊：
Case Studies in Construction Materials,2025年22:e04772 ISSN：2214-5095
通讯作者：
Jinyang Fu
作者机构：
[Xiang, Maolong; Yang, Junsheng; Fu, Jinyang] School of Civil Engineering, Central South University, Changsha 410075, China;[Liu, Zhiqiang] China Railway Southwest Research Institute Co. Ltd., Chengdu 611731, China;[Zhang, Cong] School of Civil Engineering, Central South University of Forestry and Technology, Changsha 410004, China
通讯机构：
[Jinyang Fu] S;School of Civil Engineering, Central South University, Changsha 410075, China
关键词：
3D printing technology;Gypsum-based material;Elaborated tunnel model;Stratified rock mass;Physical model test
摘要：
This study proposed and applied innovative methods for constructing elaborated tunnel models and stratified rock masses, utilizing 3D printing technology and gypsum-based materials. In the test, three types of elaborated tunnel models and a traditional model are constructed and their application effects are compared in physical model tests. Experimental results indicate that elaborated models with base structures, such as inverted arch filling, more accurately represent the deformation and damage observed in actual tunnels. The precision of these elaborated models is enhanced by 3D printing technology, while gypsum-based materials effectively simulate the failure of tunnel structures under high in-situ stress. Additionally, horizontally soft-hard stratified rock masses are well replicated by employing the self-leveling characteristics of the slurry of gypsum-based similar materials. Furthermore, the failure characteristics of tunnel structures and stratified rock masses are investigated in the test. Under high horizontal in-situ stress, cracks in tunnel structures and failures in surrounding stratified rocks are concentrated in the vault and base of the tunnel, and the damage to the surrounding rocks manifests as the bending of rock layers and shear-slip failure of the rock mass. Therefore, to prevent damage to tunnels in nearly horizontally stratified strata subjected to high in-situ stress, it is crucial to reinforce the structures and surrounding rocks at both the bottom and vault of the tunnel.
This study proposed and applied innovative methods for constructing elaborated tunnel models and stratified rock masses, utilizing 3D printing technology and gypsum-based materials. In the test, three types of elaborated tunnel models and a traditional model are constructed and their application effects are compared in physical model tests. Experimental results indicate that elaborated models with base structures, such as inverted arch filling, more accurately represent the deformation and damage observed in actual tunnels. The precision of these elaborated models is enhanced by 3D printing technology, while gypsum-based materials effectively simulate the failure of tunnel structures under high in-situ stress. Additionally, horizontally soft-hard stratified rock masses are well replicated by employing the self-leveling characteristics of the slurry of gypsum-based similar materials. Furthermore, the failure characteristics of tunnel structures and stratified rock masses are investigated in the test. Under high horizontal in-situ stress, cracks in tunnel structures and failures in surrounding stratified rocks are concentrated in the vault and base of the tunnel, and the damage to the surrounding rocks manifests as the bending of rock layers and shear-slip failure of the rock mass. Therefore, to prevent damage to tunnels in nearly horizontally stratified strata subjected to high in-situ stress, it is crucial to reinforce the structures and surrounding rocks at both the bottom and vault of the tunnel.
作者机构：
[Zhan, Xue-fang; Zhao, Tian-pu; Wang, Fang; Wang, Hao-lei; Zhao, Yi-bin] Cent South Univ Forestry & Technol, Civil Engn Dept, Shaoshan South Rd 498, Changsha 410004, Peoples R China.
通讯机构：
[Zhao, YB ] C;Cent South Univ Forestry & Technol, Civil Engn Dept, Shaoshan South Rd 498, Changsha 410004, Peoples R China.
关键词：
Fully jointless bridges;Microcracked R-ECC road-bridge link slabs;Seasonal temperature variation;Traffic loads;Crack development;Rebound deflection;Sensitive parameter finite element analysis
摘要：
A novel road-bridge link slab utilizing rubberized engineered cementitious composites (R-ECC) has been proposed for fully jointless bridges (FJBs). Preliminary research has shown that R-ECC road-bridge link slabs possess superior deformation absorption capacity, tensile strength, and crack control capabilities. However, micro-cracks developed on the surface of these slabs due to seasonal temperature fluctuations. While R-ECCs demonstrate improved bending ability compared to conventional ECCs, they exhibit lower compressive strength. Further research is necessary to investigate the crack development and bending deflection of microcracked R-ECC road-bridge link slabs under vehicle loads, which will help determine the suitability of R-ECCs for this application. The microcracked R-ECC slab has a great crack control capacity, and the rebound deflection measured in the experiment is less than the allowable value, indicating that the microcracked R-ECC slab meets the durability and strength standard. A sensitivity parameter finite element analysis was conducted considering the effects of slab thickness and equivalent elasticity modulus of the foundation on the R-ECC road-bridge link slab. Two evaluation indexes 'C(t)' and 'C(e)' are proposed to evaluate the performance and construction cost of the R-ECC slab. To improve performance and minimize construction costs, a design thickness of 180mm and an equivalent elasticity modulus of the foundation of 800MPa were recommended for the R-ECC road-bridge link slab.
摘要：
To enhance the axial compressive ultimate strength (ACUS) and corrosion resistance of cold-formed steel composite columns, this paper proposes a novel type of foam concrete-filled cold-formed sorbite stainless steel composite T-shaped column (FC-CSSS-T). Axial compression tests were conducted on eight composite columns with different parameters to analyze their buckling behavior, failure modes, and load-displacement relations. An elaborated finite element model was established to simulate the performance of these specimens. The results indicate the following:(1) All specimens failed due to local distorted buckling, with no evidence of overall buckling. (2) The S600E sorbite stainless steel exhibited a significant strain hardening effect, a property that suggested excellent load-bearing properties in high-strength conditions. (3) As the cross-sectional size increased, the ACUS had almost no change for the hollow section specimens. It increased by 44.80 % ∼ 76.40 % for FC-CSSS-T specimens compared to hollow ones. (4) The proposed numerical model considered the nonlinear behavior of material, buckling deformation, contacting interactions, and screw connections. The predicted results agreed well with the tests, the error was less than for most of the specimens. (5) No specific calculations are recommended for the FC-CSSS-T column, the relevant six codes in different countries were used to calculate the ACUS of them. The results were compared to the test results, and the errors between them are 15 % ∼ 62 %, indicating the inefficiency of current codes in the design of the novel sections proposed in this paper. This novel composite column is suitable for applications in industrial structures, marine engineering, chemical plants, and environments with complex corrosive conditions.
To enhance the axial compressive ultimate strength (ACUS) and corrosion resistance of cold-formed steel composite columns, this paper proposes a novel type of foam concrete-filled cold-formed sorbite stainless steel composite T-shaped column (FC-CSSS-T). Axial compression tests were conducted on eight composite columns with different parameters to analyze their buckling behavior, failure modes, and load-displacement relations. An elaborated finite element model was established to simulate the performance of these specimens. The results indicate the following:(1) All specimens failed due to local distorted buckling, with no evidence of overall buckling. (2) The S600E sorbite stainless steel exhibited a significant strain hardening effect, a property that suggested excellent load-bearing properties in high-strength conditions. (3) As the cross-sectional size increased, the ACUS had almost no change for the hollow section specimens. It increased by 44.80 % ∼ 76.40 % for FC-CSSS-T specimens compared to hollow ones. (4) The proposed numerical model considered the nonlinear behavior of material, buckling deformation, contacting interactions, and screw connections. The predicted results agreed well with the tests, the error was less than for most of the specimens. (5) No specific calculations are recommended for the FC-CSSS-T column, the relevant six codes in different countries were used to calculate the ACUS of them. The results were compared to the test results, and the errors between them are 15 % ∼ 62 %, indicating the inefficiency of current codes in the design of the novel sections proposed in this paper. This novel composite column is suitable for applications in industrial structures, marine engineering, chemical plants, and environments with complex corrosive conditions.
期刊：
European Journal of Education,2025年60(2):e70078 ISSN：0141-8211
通讯作者：
Qian Wang
作者机构：
[Qian Wang; Shiwang Hou; Sixian Wan] School of Advanced Interdisciplinary Studies, Hunan University of Technology and Business, Changsha, People's Republic of China;[Xin Feng] School of Civil Engineering, Central South University of Forestry and Technology, Changsha, People's Republic of China;[Hao Feng] Engineering Department, Country Garden Group, Foshan, People's Republic of China
通讯机构：
[Qian Wang] S;School of Advanced Interdisciplinary Studies, Hunan University of Technology and Business, Changsha, People's Republic of China
摘要：
To prepare undergraduates for complex careers, interdisciplinary higher education is gaining popularity. However, implementing interdisciplinary learning in engineering management is challenging due to the complex and intertwined knowledge structures. While smart education platforms provide access to extensive knowledge bases, the intricate web of relationships can overwhelm undergraduates. Therefore, innovative technologies are needed to create a coherent knowledge system. Knowledge graphs, derived from artificial intelligence, are pivotal tools for connecting knowledge points across courses. This study begins by explaining the necessity of constructing interdisciplinary knowledge graphs. It then uses engineering management as a case study to outline a strategic framework for developing a knowledge graph. Finally, it analyses the benefits and challenges of applying knowledge graphs in interdisciplinary higher education.
作者机构：
[Chen, Ying; Huang, Jingxiang; Cheng, Xiang; Liu, Lei; Wang, Shuaifeng; Liu, Peng] Cent South Univ, Sch Civil Engn, Changsha 410000, Peoples R China.;[Huang, Jingxiang; Cheng, Xiang; Liu, Lei; Yu, Zhiwu; Wang, Shuaifeng; Liu, Peng] Natl Engn Res Ctr High Speed Railway Construct, Changsha 410000, Peoples R China.;[Li, Qizhi; Shao, Guangqiang] China Construct Second Engn Bur Ltd, Beijing 100160, Peoples R China.;[Yu, Zhiwu; Liu, Peng] China Railway Grp Ltd, Beijing 100039, Peoples R China.;[Wang, Lingling] Guizhou Univ, Sch Civil Engn, Guiyang 550025, Peoples R China.
通讯机构：
[Liu, P ] C;Cent South Univ, Sch Civil Engn, Changsha 410000, Peoples R China.;Natl Engn Res Ctr High Speed Railway Construct, Changsha 410000, Peoples R China.;China Railway Grp Ltd, Beijing 100039, Peoples R China.
摘要：
Glued-in rod connections (GIRc) in timber or bamboo joints are characterized by high stiffness, strength, and aesthetic appeal. In this study, pullout tests were conducted on 42 specimens of GIRc in side-pressure laminated bamboo lumber (SPLBL) parallel to grain to investigate their failure modes and characteristics. The effects of edge distance, adhesive layer thickness, and slenderness ratio on the mechanical properties of GIRc in SPLBL were discussed. According to the experimental results, four failure modes were observed: splitting failure of SPLBL, splitting failure of the glue layer of SPLBL, pullout failure of the threaded rod, and yielding failure of the threaded rod. The first two failure modes can be avoided by increasing the edge distance and modifying the production process of GIRc, while the load-bearing capacities of the latter two failure modes are primarily determined by the slenderness ratio and the mechanical properties of the threaded rods. The strength and stiffness of the specimens increased with edge distance and slenderness ratio, reaching a peak at an adhesive layer thickness of 2 mm. One-way ANOVA indicated that the slenderness ratio significantly affects the mechanical properties of the specimens. The applicability of existing load-bearing capacity calculation models was discussed. Based on the existing models and experimental data, a prediction equation for the load-bearing capacity of GIRc in SPLBL was proposed. This prediction equation was validated against a database including various engineered bamboo materials, rod materials, and adhesive layer thicknesses, demonstrating superior generality compared to other equations. Finally, a reliability analysis of the GIRc in SPLBL was conducted using the central point method of the first-order second-moment method, and an approximate solution for the critical anchorage slenderness ratio was obtained. The prediction equation and the reliability analysis results can serve as references for the engineering design of GIRc in bamboo structures.
摘要：
The high alkalinity of silicate cement in Ecological Porous Concrete (EPC) inhibits plant growth, and synergistically regulating alkalinity and strength is challenging. In this study, a ternary composite alkalinity-reducing system of Diatomite-Oxalic Acid-Ferric Sulfate was proposed. The effects of the composite alkali-reducing system on the pH, mechanical properties, porosity, and permeability coefficient of EPC were systematically analyzed, and XRD, FTIR, TG, and SEM multiscale characterization were used to elucidate the mechanism of alkalinity reduction and strengthening. The results indicated that the composite alkali-reducing system accelerated the cement hydration reaction and significantly consumed Ca(OH)₂, and the pH of the EPC decreased to 8.49 after 56 d. Meanwhile, the iron-rich C-(F)-S-H gel with a low Ca/Si ratio generated in the cementation system synergistically reinforced the matrix structure with AFt crystals. The compressive strength and split tensile strength of EPC at 56 days were enhanced to 14.8 MPa and 1.97 MPa, respectively, under the premise of guaranteeing the porosity (20 %-30 %). This study provides a theoretical basis for the alkalinity-strength synergistic modulation of EPC, which promotes its application in ecological restoration projects.
The high alkalinity of silicate cement in Ecological Porous Concrete (EPC) inhibits plant growth, and synergistically regulating alkalinity and strength is challenging. In this study, a ternary composite alkalinity-reducing system of Diatomite-Oxalic Acid-Ferric Sulfate was proposed. The effects of the composite alkali-reducing system on the pH, mechanical properties, porosity, and permeability coefficient of EPC were systematically analyzed, and XRD, FTIR, TG, and SEM multiscale characterization were used to elucidate the mechanism of alkalinity reduction and strengthening. The results indicated that the composite alkali-reducing system accelerated the cement hydration reaction and significantly consumed Ca(OH)₂, and the pH of the EPC decreased to 8.49 after 56 d. Meanwhile, the iron-rich C-(F)-S-H gel with a low Ca/Si ratio generated in the cementation system synergistically reinforced the matrix structure with AFt crystals. The compressive strength and split tensile strength of EPC at 56 days were enhanced to 14.8 MPa and 1.97 MPa, respectively, under the premise of guaranteeing the porosity (20 %-30 %). This study provides a theoretical basis for the alkalinity-strength synergistic modulation of EPC, which promotes its application in ecological restoration projects.
期刊：
Case Studies in Construction Materials,2025年23:e04960 ISSN：2214-5095
通讯作者：
Zhang, QS
作者机构：
[Yang, Qi; Leng, Wuming; Chen, Youwei; Xu, Fang] Cent South Univ, Sch Civil Engn, Changsha 410075, Peoples R China.;[Xu, Fang] Cent South Univ, Mech Teaching Expt Ctr, Changsha 410083, Peoples R China.;[Zhang, Qishu; Dong, Junli] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.
通讯机构：
[Zhang, QS ] C;Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.
关键词：
Subgrade filler;Dynamic triaxial test;Resilient modulus;Graded variable confining pressure;Prediction model
摘要：
The prestressed subgrade is a novel subgrade reinforcement technique wherein horizontal prestress is applied to the subgrade soil through prestressed reinforcement devices. The applied prestress propagates from the slope to the interior of the subgrade, thereby enhancing the confining pressure ( σ 3 ) of the subgrade filler/soil. A series of dynamic triaxial tests with graded variable confining pressure was performed to assess the impact of horizontal prestress on the resilient behavior of a typical fine-grained subgrade filler. The resilient modulus ( M R ) characteristics and its variation patterns were meticulously analyzed and discussed. The results demonstrate that graded increasing σ 3 could enhance the subgrade filler’s resistance to dynamic elastic deformation, thereby significantly improving its M R , with final increments around 10 MPa. The dynamic loading cycle interval ( N c ) between two adjacent graded confining pressures markedly influences the developmental trend of M R , and earlier increasing σ 3 and smaller N c lead to a higher stable M R of the filler. Each graded increment in the σ 3 initially results in an immediate increase in the specimen’s M R , which is subsequently followed by a decline and eventual stabilization with increasing the dynamic loading cycles. Additionally, the advantages of graded increasing σ 3 may not counterbalance the detrimental effects of increased moisture content on the M R . Subsequently, a prediction model for the M R was developed accounting for the conditions of graded variable confining pressure. The model was validated by a high degree of concordance between the predicted and measured M R values of a stable specimen.
The prestressed subgrade is a novel subgrade reinforcement technique wherein horizontal prestress is applied to the subgrade soil through prestressed reinforcement devices. The applied prestress propagates from the slope to the interior of the subgrade, thereby enhancing the confining pressure ( σ 3 ) of the subgrade filler/soil. A series of dynamic triaxial tests with graded variable confining pressure was performed to assess the impact of horizontal prestress on the resilient behavior of a typical fine-grained subgrade filler. The resilient modulus ( M R ) characteristics and its variation patterns were meticulously analyzed and discussed. The results demonstrate that graded increasing σ 3 could enhance the subgrade filler’s resistance to dynamic elastic deformation, thereby significantly improving its M R , with final increments around 10 MPa. The dynamic loading cycle interval ( N c ) between two adjacent graded confining pressures markedly influences the developmental trend of M R , and earlier increasing σ 3 and smaller N c lead to a higher stable M R of the filler. Each graded increment in the σ 3 initially results in an immediate increase in the specimen’s M R , which is subsequently followed by a decline and eventual stabilization with increasing the dynamic loading cycles. Additionally, the advantages of graded increasing σ 3 may not counterbalance the detrimental effects of increased moisture content on the M R . Subsequently, a prediction model for the M R was developed accounting for the conditions of graded variable confining pressure. The model was validated by a high degree of concordance between the predicted and measured M R values of a stable specimen.
摘要：
The low pozzolanic activity of fly ash (FA) leads to reduced early-age strength in high-volume FA cement systems (HVFAC). While the individual addition of triethanolamine (TEA) or nano-silica (NS) can enhance the mechanical properties of HVFAC, the synergistic effect of their combined incorporation remains unclear. This study investigates the synergistic effect of TEA and NS on the early hydration process and the mechanism of later-stage strength enhancement in HVFAC, using methods including compressive strength testing, isothermal calorimetry , the hydration kinetics model (K-D), TG, Rietveld-XRD, MIP, and SEM-EDS. The results showed that the compressive strength(CS) of mortar with TEA+NS reached 17.0 MPa at 1 day and 56.8 MPa at 28 days, representing increases of 32.8% and 42.0% over the control group, respectively. The 28-day CS improvement (42.0%) significantly exceeded the combined effect of using TEA and NS individually (25.8%). The addition of NS overcame the early hydration inhibition of C 3 S caused by TEA, promoted the formation of calcium hydroxide (CH), and enhanced the pozzolanic reaction(PR) of FA, resulting in a 14.3% increase in early hydration heat release compared to the control. Moreover, TEA+NS accelerated the formation of AFm phases, increased the amorphous phase content, and chemically bound water. MIP results showed that the porosity of the paste decreased from 29.58% to 22.16% with the addition of TEA+NS. SEM-EDS analysis confirmed that TEA+NS promoted the PR of FA and that NS reacted with microcrystalline CH incorporated within the C-S-H gel, reducing the Ca/Si ratio and improving the compactness of the C-S-H structure.
The low pozzolanic activity of fly ash (FA) leads to reduced early-age strength in high-volume FA cement systems (HVFAC). While the individual addition of triethanolamine (TEA) or nano-silica (NS) can enhance the mechanical properties of HVFAC, the synergistic effect of their combined incorporation remains unclear. This study investigates the synergistic effect of TEA and NS on the early hydration process and the mechanism of later-stage strength enhancement in HVFAC, using methods including compressive strength testing, isothermal calorimetry , the hydration kinetics model (K-D), TG, Rietveld-XRD, MIP, and SEM-EDS. The results showed that the compressive strength(CS) of mortar with TEA+NS reached 17.0 MPa at 1 day and 56.8 MPa at 28 days, representing increases of 32.8% and 42.0% over the control group, respectively. The 28-day CS improvement (42.0%) significantly exceeded the combined effect of using TEA and NS individually (25.8%). The addition of NS overcame the early hydration inhibition of C 3 S caused by TEA, promoted the formation of calcium hydroxide (CH), and enhanced the pozzolanic reaction(PR) of FA, resulting in a 14.3% increase in early hydration heat release compared to the control. Moreover, TEA+NS accelerated the formation of AFm phases, increased the amorphous phase content, and chemically bound water. MIP results showed that the porosity of the paste decreased from 29.58% to 22.16% with the addition of TEA+NS. SEM-EDS analysis confirmed that TEA+NS promoted the PR of FA and that NS reacted with microcrystalline CH incorporated within the C-S-H gel, reducing the Ca/Si ratio and improving the compactness of the C-S-H structure.
期刊：
Construction and Building Materials,2025年489:142206 ISSN：0950-0618
通讯作者：
Liu, KF;Zhang, K
作者机构：
[Liu, Kefei; Liu, KF; Zhu, Juncai; Wang, Aijun; Li, Wen] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Hunan, Peoples R China.;[Zhu, Juncai] Changsha Univ Sci & Technol, Sch Transportat Engn, Changsha 410114, Hunan, Peoples R China.;[Jiang, Kang] Hunan Commun Res Inst Co Ltd, Changsha 410015, Hunan, Peoples R China.;[Wang, Yuying] Shandong Transport Vocat Coll, Weifang 261206, Shandong, Peoples R China.;[Zhang, Kun; Zhang, K] Calif State Univ, Dept Civil Engn, Chico, CA 95929 USA.
通讯机构：
[Liu, KF ; Zhang, K ] C;Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Hunan, Peoples R China.;Calif State Univ, Dept Civil Engn, Chico, CA 95929 USA.
关键词：
Chemical property;Grey relational analysis;Microscopic characteristics;Rejuvenated asphalt;Rejuvenation Mechanism;Wood tar-base rejuvenator
摘要：
This study conducted a laboratory investigation to assess the effects and rejuvenation mechanism of wood tar-based rejuvenator (WTR) on the properties of aged 70# base asphalt and styrene-butadiene-styrene (SBS) modified asphalt, using a commercial rejuvenator RA-102 as a reference. The conventional physical properties (penetration, ductility, softening point, and viscosity), high and low temperature rheological properties, composition, chemical characteristics, and microscopic characteristics of asphalt under different aging states were tested. The results show that WTR and RA-102 rejuvenator can enhance the penetration, ductility, phase angle δ , and creep rate ( m -value) of aged asphalts, but reduce their softening point, viscosity, complex modulus G* , and creep stiffness ( S -value). Meanwhile, both rejuvenators can reduce the stiffness and increase the proportion of viscous components of aged asphalt, making the values of △T c and the continuous low-temperature grade controlled by the m -value and approach those of the original asphalt. Notably, the joint modification effects of wood tar and bamboo fiber make wood tar-based rejuvenated asphalt (WTRA) have better high-temperature performance but slightly lower low-temperature performance than RA-102 rejuvenated asphalt. The WTR primarily rejuvenates aged asphalt through physical blending by replenishing light components, reducing gel index I C value, and improving microstructural uniformity via the mitigation of wax crystal aggregation and the optimization of bee structure distribution. The results of grey correlation analysis reveal that the rejuvenation of aged asphalt performance by WTR is driven by synergistic changes in composition, chemical structure, and microscopic features, where the regulation of composition and colloidal structure play a dominant role. Overall, WTR demonstrates strong potential as a sustainable and effective rejuvenator for aged asphalt.
This study conducted a laboratory investigation to assess the effects and rejuvenation mechanism of wood tar-based rejuvenator (WTR) on the properties of aged 70# base asphalt and styrene-butadiene-styrene (SBS) modified asphalt, using a commercial rejuvenator RA-102 as a reference. The conventional physical properties (penetration, ductility, softening point, and viscosity), high and low temperature rheological properties, composition, chemical characteristics, and microscopic characteristics of asphalt under different aging states were tested. The results show that WTR and RA-102 rejuvenator can enhance the penetration, ductility, phase angle δ , and creep rate ( m -value) of aged asphalts, but reduce their softening point, viscosity, complex modulus G* , and creep stiffness ( S -value). Meanwhile, both rejuvenators can reduce the stiffness and increase the proportion of viscous components of aged asphalt, making the values of △T c and the continuous low-temperature grade controlled by the m -value and approach those of the original asphalt. Notably, the joint modification effects of wood tar and bamboo fiber make wood tar-based rejuvenated asphalt (WTRA) have better high-temperature performance but slightly lower low-temperature performance than RA-102 rejuvenated asphalt. The WTR primarily rejuvenates aged asphalt through physical blending by replenishing light components, reducing gel index I C value, and improving microstructural uniformity via the mitigation of wax crystal aggregation and the optimization of bee structure distribution. The results of grey correlation analysis reveal that the rejuvenation of aged asphalt performance by WTR is driven by synergistic changes in composition, chemical structure, and microscopic features, where the regulation of composition and colloidal structure play a dominant role. Overall, WTR demonstrates strong potential as a sustainable and effective rejuvenator for aged asphalt.
摘要：
The multi-component long-span bridges are under high-stress state and they are suffering the aging damage caused by adverse environments and loading during the full lifetime. This paper presents a machine learning framework for assessing the reliability of cable-stayed bridge systems. The support vector machine (SVM) method is adopted as a substitute for the complex structural finite element model in reliability analysis. In addition, the GA method is utilized for searching the extreme values of the constrained optimization function, which is used for calculating the time-variant reliability indexes. The beta-bound method is adopted to identify failure modes of structural system. The time-variant influence on system failure mode is considered in this framework. A long-span prestressed concrete cable-stayed bridge in service is proposed to illustrate the proposed framework. The results show that the reliability indexes of beams and cables generally decrease with increasing years of service. Specially, beam reliability decreases significantly as the distance from the tower increases, while cable reliability remains relatively consistent. The system reliability indexes indicate that the bridge is relatively safe before degradation and relatively dangerous after 20 years' service. Therefore, it is imperative to develop an appropriate maintenance strategy based on failure patterns of key components.
