作者：
Wang, Xinzhong;Li, Linshu;Xiang, Yi;Wu, Yuexing;Wei, Mei
期刊：
Frontiers in Materials,2024年10 ISSN：2296-8016
通讯作者：
Wang, XZ
作者机构：
[Li, Linshu; Wang, XZ; Wang, Xinzhong; Wu, Yuexing; Xiang, Yi] Hunan City Univ, Sch Civil Engn, Yiyang, Peoples R China.;[Wei, Mei] Hunan Arts & Crafts Vocat Coll, Sch Digital Arts, Yiyang, Peoples R China.
通讯机构：
[Wang, XZ ] H;Hunan City Univ, Sch Civil Engn, Yiyang, Peoples R China.
关键词：
concrete-filled steel tube;basalt fiber;short columns;finite element analysis;bearing capacity;ductility coefficient
摘要：
<jats:p>With rapid economic and social development, both concrete-filled steel tube (CFST) composite structures and basalt fiber (BF) have been widely applied in the field of civil engineering. To investigate the laws and characteristics of the influence of chopped BF on the mechanical properties of CFST columns and further promote the application of BF in CFST structures, the axial compressive bearing capacity test of 18 CFST short columns was carried out, and the influence of BF of different lengths on their structural mechanical properties was analyzed. The test results were compared with the theoretical calculation results and the finite element analysis results to verify the reasonableness of the test results. The results reveal that the axial compressive bearing capacity of the CFST short column after adding BF is significantly improved compared to the ordinary CFST short column, in which the bearing capacity and the ductility coefficient are increased by approximately 8.1% and 31.6%, respectively, on average. In addition, changing the length of BF has less effect on the bearing capacity of CFST short columns, the rate of increase in bearing capacity decreases with an increase in the steel ratio of CFST, and the coefficient of ductility increases with the increase in the steel ratio.</jats:p>
期刊：
International Journal of Structural Stability and Dynamics,2024年 ISSN：0219-4554
通讯作者：
Wang, L
作者机构：
[Wu, Yuexing; Wang, Xinzhong] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Chen, Zhaowei; Wu, Yuexing; Zhou, Jianting] Tunnel Engn Chongqing Jiaotong Univ, State Key Lab Mt Bridge, Chongqing 400074, Peoples R China.;[Zhang, Jinquan] Minist Transport, Res Inst Highways, R China, Beijing 100088, Peoples R China.;[Wang, Lang] Southeast Univ, Sch Civil Engn, Nanjing 211189, Peoples R China.
通讯机构：
[Wang, L ] S;Southeast Univ, Sch Civil Engn, Nanjing 211189, Peoples R China.
关键词：
Long-span cable-stayed bridges;bridge system excitation;train-track-bridge dynamic interaction;mapping relationship
摘要：
Urban rail transit is rapidly evolving, with long-span cable-stayed bridges becoming increasingly popular among engineers because of their adaptability. However, as the operation time of bridges with tracks increases, the combined effects of repeated wheel loads and various bridge system excitations, including temperature changes and shrinkage-creep, gradually alter the alignment of the main beam. Similarly, the track structure on the bridge deck also undergoes vertical displacement, leading to corresponding degradation in rail alignment. This study applies singular function theory and verifies its effectiveness in bridge mechanical analysis. For the steel spring floating plate track cable-stayed bridge system, the mapping relationship between the deformation of the bridge's main beam and the track's deformation under bridge system excitation is derived, integrating singular function theory with the theory of train-track-bridge dynamic interaction. By analyzing the force transfer mechanism of the track-bridge system under system excitation, this research examines the effects of different excitations on the coupled dynamic response of the train-track-bridge. These findings suggest that system excitations increase the dynamic response of the train-track-bridge system, which is crucial for improving the durability and reliability of urban rail transit infrastructure.
摘要：
Self-stressing steel tube concrete is a novel composite structure created by substituting ordinary concrete with self-stressing expansion concrete within a steel tube. Compared to regular steel tube concrete, self-stressing steel tube concrete structures can overcome the limitation that ordinary steel tube concrete is prone to voids. Many engineering studies have shown that these structures are prone to fatigue damage at the welded joints of steel tubes under repeated loads. Factors such as welding residual stress, welding defects, and stress concentration contribute to this susceptibility, which could potentially lead to catastrophic accidents. In this study, fatigue tests and finite element analysis were conducted on self-stressed concrete-filled steel tube joints of DY-type joints. The fatigue behavior of the joints under alternating loads was investigated through experiments and validated with the finite element analysis results. The impact of concrete's self-stress on joint fatigue performance was examined, including the stress concentration factor (SCF) and geometric parameters such as the ratio of the branch pipe outer diameter to the main pipe outer diameter, the ratio of the main pipe's outer radius to its wall thickness, the ratio of the branch pipe wall thickness to the main pipe, and the correlation between the angle of the main pipe and the branch pipe. The research results show that the node can withstand 2 million alternating loads without failure under a fatigue stress amplitude of 47.2 MPa. Additionally, the fatigue life of the test model under variable amplitude loads is converted into that under constant amplitude loads. The fatigue life of the node indicates that it can withstand 4.16 million cycles under the given fatigue amplitude before fatigue cracks appear. Additionally, variations in geometric parameters can impact the fatigue life of the node, but do not lead to changes in the initiation position of fatigue cracks. Moreover, as self-stress increases, the fatigue performance of the tube node will decrease, although the effect of self-stress on the stress distribution around the weld is minimal.
作者机构：
[Wu, Yuexing; Wang, Xinzhong] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Fan, Yonghui; Fan, YH; Shi, Jun; Wu, Yuexing; Luo, Chao] Chongqing Jiaotong Univ, State Key Lab Mt Bridge & Tunnel Engn, Chongqing 400074, Peoples R China.;[Wang, Xiangchuan] Huasheng Testing Technol Co Ltd, Chongqing 400039, Peoples R China.
通讯机构：
[Fan, YH ] C;Chongqing Jiaotong Univ, State Key Lab Mt Bridge & Tunnel Engn, Chongqing 400074, Peoples R China.
关键词：
concrete-filled steel tube arch bridge;ultimate span;strain energy minimization method;finite element analysis;response surface method
摘要：
In order to study the ultimate span of a concrete-filled steel tube (CFST) arch bridge, taking the structural strength, stiffness, and stability as the limiting conditions, the finite element analysis method is adopted to carry out research on the influence law of a single parameter of the pipe diameter, wall thickness, and cross-section height on the ultimate span of the arch axial shape. The result is used as a sample point to determine the ultimate span of the CFST arch bridge under multifactor coupling based on the response surface method. The finite element method is used to check the strength, stiffness, stability, number of segments and maximum lifting weight, steel content rate, and steel pipe concrete constraint effect coefficient of the CFST arch bridge under the ultimate span diameter. The results show that, when analyzed using a single parameter, the ultimate span diameter of the CFST arch bridge increases with the increase in the steel pipe diameter and the cross-section height, and then decreases. Moreover, it increases with the increase in the wall thickness of the steel pipe, and the CFST arch bridge reaches the ultimate span with the increase in the steel pipe wall thickness. When the pipe diameter is 1.38 m, the CFST arch bridge reaches the ultimate span; according to a multi-parameter coupling analysis, when the pipe diameter is 1.49 m, wall thickness is 37 mm, and cross-section height is 17 m, the CFST arch bridge reaches the ultimate span of 821 m, which meets all of the limiting conditions, and, at this point, the arch axial coefficient is 1.2. The results of the finite element calculation show that the structural strength, prior to the stiffness, stability, and other limitations, just reaches the critical value of the limiting conditions.
摘要：
Degradation of bond strength due to corrosion of steel strands is of great importance for serviceability of prestressed concrete structures. An analytical model is proposed to demonstrate the effect of corrosion of steel strand on reduction of bond strength. Corrosion expansion force generated by steel strand corrosion before and after corrosion cracking is firstly estimated. Then, the reduced gripping effect of the concrete, change of friction coefficient between the corroded strand and reduction force on the bearing face are considered in calculating the pre-rib extrusion force. Finally, the enhancement of bond strength due to transverse confinement of stirrups is considered and the ultimate bond strength of corroded steel strand is calculated. Comparison of results between the prediction and experimental result shows the proposed model can be used to reasonably evaluate the bond strength. The prediction result of the bond strength model is affected by the degree of strand corrosion, but almost not by the drawing method.
关键词：
Metro train;building vibration;secondary noise;numerical analysis;vibration control
摘要：
With the rapid development of urban rail transit, the environmental vibration and secondary noise induced by metro train operation have become increasingly serious, posing stricter requirements on the vibration and secondary noise of sensitive building office (SBO) and sensitive building school (SBS). To predict and control the vibrations and secondary noise in sensitive buildings along the metro line induced by metro train operations. A prediction method for the vibration and secondary noise of sensitive buildings along the metro line during metro train operation has been proposed. The sub-model of train-track system coupled dynamics and the sub-model of track-tunnel-soil-building system dynamics are included. The influence of metro train operation on the vibration and secondary noise of SBO and SBS is studied. The influence of the distance between the metro line and the building on the vibration and secondary noise of the sensitive building is discussed, and an effective control scheme of vibration and secondary noise is proposed. Results show that the vibration frequencies of the SBS and the SBO caused by the metro train operation are concentrated at about 8Hz and 63Hz. The vibration below the second floor of SBO caused by the metro train operation exceeds the limit, and the secondary noise below the third floor of SBS exceeds the limit. The secondary noise inside the building of each floor of SBO exceeded the limit. Using secondary noise to evaluate the environmental impact of metro train operations is more stringent than relying solely on vibration assessments. secondary noise is recommended in engineering to assess the impact of metro train operation on sensitive buildings along line. Combined with vibration, secondary noise and construction requirements, SBS and SBO are recommended to be no less than 72m and 74m away from the metro line, respectively.
摘要：
To investigate the influence of cross-sectional parameters and the rigid skeleton length on the structural mechanics behavior of reinforced concrete arch bridges, this study focused on the Yelanghu Bridge with a span of 210 m. The sensitivity of the main arch rib's instability mode to cross-sectional parameters such as width, spacing between adjacent webs, height, and concrete thickness was examined by combining the finite element method and the theoretical derivation. Subsequently, research was conducted on the impact of the rigid skeleton length during construction on the static and dynamic performance of the structure relying on the Midas Civil software. The findings indicate that for the Yelanghu Bridge, the risk of in-plane instability is greater than that of out-of-plane and local instabilities. In-plane instability is most sensitive to the section height and the out-plane instability is most sensitive to the thickness of the roof and floor concrete. Under ultimate load-bearing conditions, the axial force in the critical sections of the bridge increases with the length of the rigid skeleton. The fundamental frequency of the Yelanghu Bridge is approximately 0.32, which is significantly lower than that of more rigid arch bridges but higher than those of structurally softer structures such as cable-stayed or suspension bridges. This indicates that large-span reinforced concrete arch bridges exhibit unique dynamic characteristics and belong to moderately flexible structures.
通讯机构：
[Zhu, X ] H;Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;Changsha Univ Sci & Technol, Natl Engn Res Ctr Highway Maintenance Technol, Changsha 410114, Peoples R China.
关键词：
construction solid waste;recycled aggregate;brick slag content;subgrade
摘要：
In road engineering, road construction requires a large amount of natural aggregate; its substitution with recycled construction-solid-waste aggregate not only saves resources but also reduces the burden on the environment. The main components of construction solid waste are concrete blocks and brick slag; the breakability of the latter can affect the performance of mixed recycled aggregate, which hinders the use of construction solid waste in road engineering applications. To analyze the applicability of recycled construction-solid-waste aggregate containing brick slag aggregate in the subgrade layer, the effect of brick aggregate content on the CBR (California bearing ratio) and crushing value of mixed recycled aggregates was evaluated based on laboratory tests, and the field compaction quality of the recycled aggregates was analyzed. The results show that the 9.5–19 mm mixed recycled aggregate samples were crushed to a higher degree during the compaction process. A brick aggregate content less than 40% had little effect on the performance of mixed recycled construction-solid-waste aggregate. It is recommended to use a 22 t road roller for five passes (two weak vibrations + two strong vibrations + one weak vibration) at a speed of 3 km/h in the main compaction stage of the subgrade filling.
摘要：
In the present study, 104 sets of flexural tests on corroded prestressed concrete (CPC) beams were gathered from different publications. A flexural strength database for CPC beams was created by incorporating standardized concrete strength and the corrosion rate of prestressed steel. This database enables the analysis of the impact of different factors on the flexural capacity, such as the beam's width and effective depth, concrete compressive strength, shear span ratio, the prestressed steel's corrosion level, prestressing ratio (PPR), and the effective prestress. The findings show that the flexural strength of the CPC beams is notably influenced by variations in beam width, shear span ratio, and the prestressed steel's corrosion level and prestressing ratio compared to other parameters. Furthermore, a comparison was conducted of the Chinese code, Eurocode and ACI standard for evaluating the flexural strength of CPC beams using the established database. It shows that the three design codes overestimate the flexural strength of CPC beams, and it is unsafe to predict flexural strength using these three codes without taking into account the impact of corrosion. Finally, a practical model based on the ACI standard is suggested to provide precise and reliable predictions across a diverse set of test data.
关键词：
Concrete-filled steel tube;Hydration heat;Mechanical response;Temperature field
摘要：
As the span of concrete-filled steel tube (CFST) arch bridges increases, the hydration heat temperature effect of concrete inside steel tube becomes more severe, which increases the safety risk during the construction process. Therefore, a numerical simulation of the mechanical response of a long-span CFST arch bridge under the influence of hydration heat was carried out. First, based on the hydration heat conduction theory, a finite element model of the transient temperature field of a CFST arch rib was established. The temperature distribution of the CFST arch rib and its variation with time were revealed, and an approximate formula for the distribution of the hydration heat temperature along the radial direction of the CFST was provided. Subsequently, the variation law of the thermal stress of a CFST during hydration heat release was investigated. Finally, based on the principle of temperature equivalence, a finite element model of the overall CFST arch rib was established to examine the effect of hydration heat on the deformation of the arch rib. The results reveal that the hydration heat temperature field of the CFST arch rib exhibits nonlinear and axisymmetric characteristics. The maximum temperature of the section and the maximum temperature difference can reach 73.5°C and 33.2°C, respectively. Because of the influence of the hydration heat, there is a significant stress gradient in the cross section of the arch rib. A maximum radial stress of 2.08MPa is attained, indicating a risk of concrete cracking. Additionally, the displacement along the transverse and vertical directions of the chord tube exhibits an initial increase, followed by a decrease over time. The maximum transverse displacement of the chord tube reaches 70.6mm, while the vertical displacement reaches 117.8mm.
通讯机构：
[Yang, YM ] H;Hunan City Univ, Coll Civil Engn, 158 Yinbindong Rd, Yiyang 413049, Peoples R China.
关键词：
Prestressed concrete structures;Bonding behavior;Corrosion of steel strands;Pull -out experiment;Empirical formula
摘要：
Degradation of bonding behavior due to chloride-induced corrosion of steel strands is critical for serviceability of prestressed concrete structures. In this paper, total thirty-one central and eccentric pull-out specimens were tested to study the effects of strand corrosion, combined with stirrups or position of steel strand on global force-slip response, bond strength and failure pattern. Experimental results show that the bond strength of the eccentric pull-out specimen without corrosion or slight corrosion is greater than that of the centrally loading ones, and the opposite is true once the corrosion rate reaches 6%. Stirrups in bonding specimens can effectively restrain the transverse deformation of concrete, and significantly improve the bond strength between corroded strand and concrete. As the corrosion rate of steel strand increases, the bond-slip curves of specimens with stirrups tend to be similar to those without stirrups. Compared with the corroded deformed bar, the degradation of bond behavior caused by deformed bar corrosion is more serious than that of steel strand corrosion. By considering the combined effects of steel strand corrosion, stirrups and position of steel strand, an empirical model is proposed to predict the bond strength between corroded steel strand and concrete with reasonable accuracy.
期刊：
Magazine of Concrete Research,2022年75(4):163-175 ISSN：0024-9831
通讯作者：
Yiming Yang
作者机构：
[Tang, Huang; Wang, Xinzhong; Yang, Yiming] Hunan City Univ, Sch Civil Engn, Yiyang, Hunan, Peoples R China.;[Yang, Yiming] Minist Educ, Key Lab Safety Control Bridge Engn, Changsha, Hunan, Peoples R China.;[Yang, Yiming] Hunan City Univ, Hunan Engn Res Ctr Struct Safety & Disaster Preve, Yiyang, Hunan, Peoples R China.
通讯机构：
[Yiming Yang ] S;School of Civil Engineering, Hunan City University, Yiyang, Hunan, China<&wdkj&>Key Laboratory of Safety Control of Bridge Engineering, Ministry of Education, Changsha, Hunan, China<&wdkj&>Hunan Engineering Research Center of Structural Safety and Disaster Prevention for Urban Underground Infrastructure, Hunan City University, Yiyang, Hunan, China
关键词：
corroded concrete structures;failure probability;scale of fluctuation;spatial variability;stochastic resistance deterioration
期刊：
Journal of Engineering Science and Technology Review,2017年10(1):55-60 ISSN：1791-9320
通讯作者：
Xinzhong, Wang(wxz0419314@163.com)
作者机构：
[Chuanxi, Li] School of Civil Engineering and Architecture, Changsha University of Science and Technology, Changsha, 410114, China;[Wei, Zhou; Heliang, Xie] School of civil engineering, Hunan City University, Yiyang, 413000, China;[Xinzhong, Wang] School of Civil Engineering and Architecture, Changsha University of Science and Technology, Changsha, 410114, China<&wdkj&>School of civil engineering, Hunan City University, Yiyang, 413000, China
通讯机构：
School of Civil Engineering and Architecture, Changsha University of Science and Technology, Changsha, China
