Comparative assessment of mechanical properties of HPS between electrochemical corrosion and spray corrosion
作者：
Xiao, Linfa;Peng, Jianxin* ;Zhang, Jianren;Ma, Yafei;Cai, C. S.
期刊：
Construction and Building Materials ,2020年237:117735 ISSN：0950-0618
通讯作者：
Peng, Jianxin
作者机构：
[Ma, Yafei; Xiao, Linfa; Peng, Jianxin; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;[Cai, C. S.] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.
通讯机构：
[Peng, Jianxin] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
High performance steel;Mechanical property;3D scanning technology;Corrosion;FEM
摘要：
An experimental study was conducted to compare the deterioration of mechanical properties of HPS specimens subjected to electrochemical corrosion and neutral salt spray accelerated corrosion. Twenty seven 460D steel specimens were designed and subjected to these two kinds of corrosion. The geometric features of the specimens were evaluated by using 3D scanning technology. Mechanical properties and corrosion damage were discussed after tensile tests. FEM was developed to investigate the effects of different corroded cross sections and their spacing on the degradation of mechanical properties. Experimental results show that specimens subjected to the electrochemical accelerated corrosion have more obvious non-uniformity. Shape of big pits in terms of the electrochemical accelerated corrosion can be regarded as a flat semi-ellipsoid, and part of a full semi-ellipsoid for salt spray accelerated corrosion, and cone for the small pits. Corrosion method has an effect on the ductility, strength, and failure behaviors. Compared with thickness loss, width loss has a greater impact on structural strength and stiffness. (C) 2019 Elsevier Ltd. All rights reserved.
语种：
英文
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锈蚀钢筋混凝土梁斜截面抗剪失效分析
作者：
马亚飞;刘彬;王磊;张建仁
期刊：
长安大学学报(自然科学版) ,2019年39(1):90-98 ISSN：1671-8879
作者机构：
长沙理工大学土木工程学院,湖南长沙,410114;[马亚飞; 刘彬; 张建仁; 王磊] 长沙理工大学
关键词：
桥梁工程;钢筋混凝土梁;斜筋;箍筋;锈蚀;抗剪性能
摘要：
为了研究锈蚀对钢筋混凝土构件抗剪性能的影响,设计并制作了7根配有箍筋和斜筋的钢筋混凝土矩形梁,其中1根为未锈蚀的对比梁,采用电化学快速锈蚀方法对其余6根钢筋混凝土梁进行加速锈蚀试验。开展相同剪跨比下钢筋混凝土梁的斜截面抗剪性能试验,讨论钢筋混凝土梁表面初始锈胀裂缝的分布特征,分析箍筋锈蚀、斜筋锈蚀和主筋锈蚀对钢筋混凝土梁斜裂缝的形成与发展、荷载-挠度曲线、剪压区混凝土压力传递过程以及钢筋的内力变化情况,研究不同锈蚀程度钢筋混凝土梁斜截面极限承载能力与失效特征。研究结果表明:弯剪斜裂缝的数量随着钢筋锈蚀水平的增长逐渐减少,斜裂缝的延伸长度变短,主拱传递压应力路径逐步由直线变为抛物线形;锈胀引起的剪压区混凝土截面损伤对钢筋混凝土构件的抗剪强度有很大影响;箍筋锈蚀和斜筋锈蚀对斜裂缝的发展影响较大,而对钢筋混凝土梁的破坏形态影响相对较小,但其截面面积的减小会导致箍筋和斜筋过早的发生断裂,进而降低钢筋混凝土梁的斜截面抗剪强度;随着主筋锈蚀程度的增长,临界斜裂缝的倾角变大,并且与仅箍筋锈蚀梁相比,其倾角增幅更为显著。该研究可为钢筋混凝土梁的抗剪强度预测模型的建立以及有限元分析提供试验基础。
语种：
中文
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MECHANICAL PROPERTIES OF CORRODED HIGH PERFORMANCE STEEL SPECIMENS BASED ON 3D SCANNING
作者：
Xiao, Lin-fa;Peng, Jian-xin* ;Zhang, Jian-ren;Cai, Chun-sheng
期刊：
Advanced Steel Construction ,2019年15(2):129-136 ISSN：1816-112X
通讯作者：
Peng, Jian-xin
作者机构：
[Zhang, Jian-ren; Peng, Jian-xin; Xiao, Lin-fa] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha, Hunan, Peoples R China.;[Cai, Chun-sheng] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.
通讯机构：
[Peng, Jian-xin] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha, Hunan, Peoples R China.
关键词：
High performance steel;Mechanical property;3D scanning technology;Corrosion;FEM
摘要：
An experimental study was performed to investigate the impact of corrosion on the mechanical properties of high performance steel (HPS) specimens. Fifteen HPS specimens were designed and subjected to electrochemically accelerated corrosion. The geometric features of the specimens were quantified by using 3D scanning technology. Then, tensile tests were employed to study the mechanical properties of the corroded HPS specimens. The relationship between the mechanical properties of the corroded HPS specimens and corrosion damage was discussed in detail. Meanwhile, a three-stage constitutive model was proposed to evaluate the mechanical behaviors of the degraded HPS specimens. Finally, a finite element model based on 3D scanning technology was developed and verified to investigate the stress distribution and failure of the tensile specimens. Results show that the maximum cross-sectional loss ratio rho(A) is a suitable parameter for describing the mechanical properties of the degraded HPS specimens. The failure modes of the HPS specimens gradually vary from ductile to brittle as rho(A) varies from 0% to 50.28%. It is found that the yield or ultimate load decreases linearly as the rho(A). increases. The corrosion-induced ductility reduction has an exponential relationship with rho(A). A comparison between the numerical results and experimental results shows that the proposed three-stage constitutive model is rational. Copyright (c) 2019 by The Hong Kong Institute of Steel Construction. All rights reserved.
语种：
英文
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Reliability evaluation of reinforced concrete columns designed by Eurocode for wind-dominated combination considering random loads eccentricity
作者：
Jiang, Youbao* ;Peng, Suixiang;Beer, Michael;Wang, Lei;Zhang, Jianren
期刊：
Advances in Structural Engineering ,2019年23(1):146-159 ISSN：1369-4332
通讯作者：
Jiang, Youbao
作者机构：
[Jiang, Youbao; Peng, Suixiang; Wang, Lei; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China;[Beer, Michael] Leibniz Univ Hannover, Inst Risk & Reliabil, Hannover, Germany;[Beer, Michael] Univ Liverpool, Inst Risk & Uncertainty, Liverpool, Merseyside, England
通讯机构：
[Jiang, Youbao] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
contribution analysis;Eurocode-based design;random loads eccentricity;reinforced concrete columns;reliability evaluation;wind-dominated combination
摘要：
With the capacity models in the 2004 edition of the European Committee for Standardization's Standard Design of Concrete Structures, a more realistic limit state function is obtained for reinforced concrete columns with random loads eccentricity. Using this function, the applicability of the code-based design factors is discussed. Taking the wind-dominated combination as an example, the probabilistic distribution of loads eccentricity and the statistics of column resistance are analyzed for representative cases. The analysis indicates that the possible loads eccentricity is scattered over a large range, and the probabilistic model of column resistance varies from case to case, which is largely different from the resistance model assumed in previous reliability calibration. With Monte Carlo simulation, the column reliability and the contributions of both tension failure and compression failure to the total failure probability are calculated and obtained for different cases. The results show that the fixed loads eccentricity criterion underestimates differences in the reliability of columns for different loads eccentricity cases and overestimates the column reliability in some tension failure cases. Furthermore, it is found that the tension failure mode contributes most to the total failure probability for not only some columns designed to fail in tension failure but also for some columns designed to fail in compression failure. To attain a robust design, a group of optimum wind load factors varying with cases is recommended. The new calibration results prove that the recommended wind local factors can achieve a better goal.
语种：
英文
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Modelling guidelines for corrosion-fatigue life prediction of concrete bridges: Considering corrosion pit as a notch or crack
作者：
Guo, Zhongzhao;Ma, Yafei* ;Wang, Lei;Zhang, Jianren
期刊：
Engineering Failure Analysis ,2019年105:883-895 ISSN：1350-6307
通讯作者：
Ma, Yafei
作者机构：
[Ma, Yafei; Wang, Lei; Zhang, Jianren; Guo, Zhongzhao] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Ma, Yafei] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
Bridge engineering;Fatigue crack growth;Pitting corrosion;Probabilistic method;Stress concentration
摘要：
Corrosion accelerates the fatigue damage accumulation and decreases the fatigue life of reinforced concrete bridges. A critical issue in the corrosion-fatigue life prediction is to deal with the relationship between fatigue crack and corrosion propagation. This paper proposes two modelling methods for fatigue life prediction of reinforced concrete bridges subjected to coupled corrosion-fatigue effect: model I considers the corrosion pit as a notch and model II treats the corrosion pit as a surface crack. The chloride ingress, cyclic load, corrosion pit growth, fatigue crack growth and concrete severe cracking are systematically considered. Following that, a probabilistic analysis is also performed to include various uncertainties in the two models, and the effects of environment aggressiveness level and traffic frequency on the prediction results are investigated. The results show that corrosion pit-induced stress concentration has a significant effect on the fatigue behavior, and modelling the corrosion pit as a notch is the preferred method for theoretical prediction. For the extreme aggressiveness environment and low traffic frequency conditions, considering the corrosion pit as a crack is an alternative modelling method for the fast assessment of aging reinforced concrete bridges due to its simplicity. © 2019 Elsevier Ltd
语种：
英文
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基于EIC增长的锈蚀钢筋混凝土梁疲劳寿命评估
作者：
马亚飞;王磊;张建仁
期刊：
公路交通科技 ,2019年36(4):80-87 ISSN：1002-0268
作者机构：
长沙理工大学 土木工程学院,湖南 长沙,410114;[马亚飞; 张建仁; 王磊] 长沙理工大学
关键词：
桥梁工程;疲劳;等效初始裂纹原理;锈蚀;裂纹扩展
摘要：
锈蚀和疲劳荷载共同影响下的材料复合损伤机理十分复杂,会显著降低既有钢筋混凝土桥梁的使用寿命。为了能够准确地预测锈蚀钢筋混凝土梁的疲劳寿命,通过从材料到钢筋混凝土构件的跨尺度分析,提出了一种基于材料失效机理的锈蚀钢筋混凝土梁疲劳寿命评估方法。该方法以断裂力学和等效初始裂纹理论为基础,并且可以同时考虑钢筋的不同锈蚀形态。结合锈蚀钢筋的疲劳拉伸试验结果,提出了不同锈蚀水平下的应力集中因子表达式,结果表明随锈蚀率的增长,应力集中因子先增大后减小。然后将局部锈蚀导致的应力集中的影响融入到应力强度因子计算模型中;通过对试验数据进行拟合得到了钢筋疲劳裂纹速率增长分析模型,对该模型从等效初始裂纹尺寸到临界裂纹长度进行积分来实现钢筋混凝土梁的疲劳寿命预测。为了验证本评估方法的有效性,开展了电化学快速锈蚀钢筋混凝土梁的疲劳性能试验,试验梁失效形式均为受力主筋的疲劳断裂;采用扫描电子显微镜对疲劳失效后的锈蚀钢筋断口形貌进行了微观分析,对比了不同锈蚀程度下钢筋疲劳裂纹扩展形式的差异。将理论计算结果与本研究试验和已有文献中的试验值进行了比较,二者吻合较好,可为日后钢筋混凝土桥梁的腐蚀疲劳寿命评估提供科学依据。
语种：
中文
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服役桥梁构件随机场参数估计及估计方法比较分析
作者：
阳逸鸣;彭建新;张建仁
期刊：
公路交通科技 ,2019年36(2):85-94 ISSN：1002-0268
作者机构：
长沙理工大学 土木工程学院,湖南 长沙,410114;[彭建新; 张建仁; 阳逸鸣] 长沙理工大学
关键词：
桥梁工程;波动系数;ACF法;SVF法;钢筋混凝土结构;锈蚀;弯矩
摘要：
为了估计服役钢筋混凝土结构材料性能和结构尺寸参数的波动系数,以3片服役36 a的RC梁为研究对象,首先对样本梁的保护层厚度和混凝土抗压强度进行了测量,运用普通Kriging法对实测结果进行了空间插值以获取更多的有效数据。其次,采用自相关函数(ACF)法和半变异函数(SVF)法对保护层厚度和混凝土抗压强度的波动系数进行了估计。然后,基于246根锈蚀钢筋不同位置的点蚀系数实测值,得到钢筋锈蚀不均匀系数的波动性质,且基于一维随机场理论对梁进行离散,根据不同估计方法得到的相关系数将随机变量转化为空间相关变量,得到各个离散单元的参数值,进而得到各离散梁单元和整梁的抗弯承载能力。最后,结合锈蚀梁的理论弯矩值与承载力试验结果,对上述两种估计方法进行了比较分析。结果表明:由SVF法得到的混凝土抗压强度和保护层厚度的波动系数均值分别为2. 242和2. 467,均大于由ACF法得到的对应值,且混凝土抗压强度的波动范围随着波动系数值的增加而减小;同一锈蚀钢筋表面蚀坑之间的分布并未存在很强的相关性;基于SVF法估计得到的理论弯矩值较基于ACF法估计得到的对应值与试验结果更为接近,且前者的平均相对误差为6. 52%,比后者的对应值低33. 19%,说明与ACF法相比,SVF法更能精确估计参数的波动性质。
语种：
中文
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坭洲水道桥圆形地连墙支护体系监测与分析
作者：
贺炜;凡子义;崔剑峰;罗超云;张建仁
期刊：
地下空间与工程学报 ,2019年15(2):549-555 ISSN：1673-0836
作者机构：
长沙理工大学土木工程学院,长沙,410114;湖南省交通规划勘察设计院,长沙,410008;广东长大公路工程有限公司,广州,510620;[罗超云] 广东省长大公路工程有限公司;[贺炜; 凡子义; 张建仁] 长沙理工大学
关键词：
深基坑工程;圆形地连墙;弹性地基梁;环向刚度;监测
摘要：
对虎门二桥坭洲水道桥直径90 m、深29 m东锚碇工程进行了监测,实测得到开挖过程中地连墙墙后土压力、墙体径向位移、竖向弯矩等。同时,设计并实施了地连墙槽段接缝的单元体试验,探讨了圆形地连墙环向刚度折减系数的取值方法,并结合轴对称弹性地基梁法对监测数据进行了对比分析。计算与实测分析结果表明,圆形地连墙支护体系墙体最大位移值为开挖深度的0.018%,远小于工程预警值,说明其可有效控制基坑变形;施工过程中土体开挖及内衬施工对地连墙应力影响最大,是相应深度地连墙应力达到峰值的主要原因,其影响范围为上下两倍当层开挖深度;圆形地连墙墙后土体具有空间效应,实测土压力值小于主动土压力理论计算值;由计算对比可知,考虑环向效应及环向刚度折减的弹性地基梁法可较好地反映圆形地连墙支护体系的受力变形特性。
语种：
中文
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自密实混凝土加固碳化混凝土界面剪切性能试验
作者：
罗育明;张建仁;张旭辉;彭建新
期刊：
长安大学学报(自然科学版) ,2019年39(2):65-72 ISSN：1671-8879
作者机构：
长沙理工大学土木工程学院,湖南长沙410114;湖南交通职业技术学院路桥工程学院,湖南长沙410132;长沙理工大学土木工程学院,湖南长沙,410114;湘潭大学土木工程与力学学院,湖南湘潭411105;[彭建新; 罗育明; 张建仁; 张旭辉] 长沙理工大学
关键词：
桥梁工程;自密实混凝土;直剪试验;混凝土碳化;剪切性能
摘要：
为研究混凝土构件长期暴露大气中表面形成的碳化层对自密实混凝土加固混凝土黏结界面剪切性能的影响,为该类结构加固设计提供依据,设计不同碳化程度Z形黏结试件进行直剪试验,考察混凝土碳化深度、混凝土强度和界面处理方式等对黏结试件破坏形式和抗剪强度的影响,并在试验基础上建立碳化混凝土黏结界面抗剪强度预测模型。研究结果表明:混凝土碳化引起黏结界面剪切裂缝分布形式的改变;混凝土碳化后强度和弹性模量均有所增强,在黏结界面间形成一个局部强化区域,剪切裂缝由原来的界面裂缝逐渐向老混凝土内部转移,扩展至碳化强化区与未碳化区交界面;混凝土碳化使得黏结界面抗剪强度增强,碳化初期,黏结界面抗剪强度增长迅速,达到一定碳化深度后,其增长幅度变小;黏结界面抗剪强度与新老混凝土的强度、界面处理方式等也密切相关,对于Ⅰ类和Ⅱ类界面,一定范围内增大新混凝土强度对于提高界面抗剪强度具有积极作用;当新老混凝土强度相差超过2个标号时,继续提高新混凝土强度作用不大;Ⅲ类界面植筋能有效提高抗剪强度,且其抗剪强度由较低强度混凝土控制。
语种：
中文
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Flexural behavior of corroded HPS beams
作者：
Peng, Jianxin;Xiao, Linfa* ;Zhang, Jianren;Cai, C. S.;Wang, Lei
期刊：
Engineering Structures ,2019年195:274-287 ISSN：0141-0296
通讯作者：
Xiao, Linfa
作者机构：
[Xiao, Linfa; Peng, Jianxin; Wang, Lei; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;[Cai, C. S.] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.
通讯机构：
[Xiao, Linfa] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
3D scanning technology;Analytical model;Flexural behavior;High performance steel (HPS);Random corrosion
摘要：
Experimental research is conducted to investigate the flexural behavior of corroded High Performance Steel (HPS) beams. Four beams with various corrosion damage are designed and subjected to electrochemical accelerated corrosion process. 3D scanning technology is employed to analyze the geometric features affected by the corrosion damage. Flexural tests are carried out, and the impact of corrosion on the flexural response is discussed. Considering the randomness of corrosion pits in each area, predictive models are proposed for the flexural strength of corroded beams with an idealized elastic-plastic and linear-hardening constitutive relationship model. An analysis comparing the proposed models with Chinese and American codes is made. Results show that increasing the corrosion damage leads to a decrease of discreteness in the residual sectional area and causes a transformation in the compressed flange from noncompact to slender. A corrosion loss less than 10% leads to slight deterioration of both strength and stiffness degradation, while further corrosion damage results in a significant decrease. The depth and length of the buckling wavelength for corroded beams decreases gradually as the corrosion damage become more serious. The analytical models IEM and LHM or the GB50017-2017 may be suitable for predicting the lower and upper limit values of the ultimate flexural moment, respectively, and results predicted by AISC are conservative. © 2019 Elsevier Ltd
语种：
英文
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Experimental Investigation of Bond between Near-Surface-Mounted CFRP Strips and Concrete under Freeze-Thawing Cycling
作者：
Peng, Hui;Liu, Yang;Cai, C. S.;Yu, Jun;Zhang, Jianren*
期刊：
Journal of Aerospace Engineering ,2019年32(1) ISSN：0893-1321
通讯作者：
Zhang, Jianren
作者机构：
[Liu, Yang; Zhang, Jianren; Peng, Hui] Changsha Univ Sci & Technol, Sch Civil Engn, Natl Local Joint Engn Lab Technol Long Term Perfo, Changsha 410004, Hunan, Peoples R China.;[Cai, C. S.] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.;[Cai, C. S.] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410004, Hunan, Peoples R China.;[Yu, Jun] Cent S Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.
通讯机构：
[Zhang, Jianren] C;Changsha Univ Sci & Technol, Sch Civil Engn, Natl Local Joint Engn Lab Technol Long Term Perfo, Changsha 410004, Hunan, Peoples R China.
关键词：
Carbon fiber reinforced plastics;Compressive strength;Concrete additives;Concretes;Debonding;Deterioration;Durability;Fiber reinforced plastics;Freezing;Friction;Frost resistance;High performance concrete;Reducing agents;Reinforced concrete;Reinforced plastics;Reinforcement;Thawing;Air entraining agents;Carbon fiber reinforced polymer;Experimental investigations;Freeze-thaw cycles;High strength concretes;Near surface mounted;Structural strengthening;Water-reducing agents;Bond length
摘要：
The technique of prestressing near-surface-mounted (NSM) carbon fiber-reinforced polymer (CFRP) has good potential and future prospects for structural strengthening due to its improvement of the bond between the CFRP and concrete. However, notably few investigations have been conducted to study the bond durability of the NSM CFRP-concrete interface. The present study was undertaken to increase the understanding of the durability of the bond between the NSM CFRP and concrete under freeze-thaw cycles. Pull-out tests were conducted to investigate the influence of freeze-thaw cycles on the interfacial bond with ordinary concrete and concrete with high strength or additional frost resistance. The mechanism of freeze-thaw cycles degrading the bond of the NSM CFRP is discussed. Additionally, the influence of the distance between concrete edge and groove (edge distance) and the bond length on the bond durability was studied. It was found that, first, freeze-thaw cycling results in a significant decrease in compressive strength of ordinary concrete but a unremarkable degradation of strength of high-strength concrete and concrete with water-reducing agents and admixtures of air-entraining agents. Second, freeze-thaw cycling also leads to a relatively significant decrease in the bond of the NSM CFRP systems with ordinary concrete; however, it has no substantial impact on the bond of specimens of concrete with high strength or frost resistance. This indicates that the deterioration of the bond of NSM CFRP under freeze-thaw cycles is caused by the degradation of concrete. Third, a decrease in the edge distance results in cone-shaped cracks at the loaded end. Finally, when the failure mode remains debonding at the NSM CFRP-concrete interface, the NSM CFRP system with a longer bond length exhibits more significant degradation in bond capacity compared with that with a shorter bond length. This is because the residual friction stress at the debonding interface also decreases due to freeze-thaw cycling; thus, a longer bond length corresponds to a great loss of residual friction force at the debonding zone. © 2018 American Society of Civil Engineers.
语种：
英文
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钢板加固锈蚀钢筋混凝土梁抗弯性能试验研究
作者：
郭诗惠;唐皇;张建仁;戴理朝
期刊：
桥梁建设 ,2019年49(4):46-51 ISSN：1003-4722
作者机构：
[郭诗惠] School of Civil Engineering, Nanyang Institute of Technology, Nanyang, 473000, China;[唐皇] School of Civil Engineering, Hunan Institute of Technology, Yiyang, 413000, China;[郭诗惠; Dai, Li-Zhao; 唐皇; 张建仁] School of Civil Engineering, Changsha University of Science and Technology, Changsha, 410114, China
关键词：
钢筋混凝土梁桥;钢筋锈蚀;钢板加固;承载力;破坏模式;试验研究;有限元法
摘要：
为了研究锈蚀钢筋混凝土(RC)梁采用钢板加固后的承载性能,设计制作5片试验梁,采用电化学腐蚀方法对其进行腐蚀。其中3片梁采用梁底粘贴钢板的方法进行抗弯加固,1片梁采用粘贴钢板和U形箍的方法进行抗弯抗剪组合加固,通过抗弯试验研究加固梁的承载力、破坏模式、荷载~跨中挠度曲线,采用Abaqus软件对试验梁进行有限元分析。结果表明:2种加固方式均能显著提高锈蚀RC梁的承载力和刚度,组合加固时效果更好;抗弯加固试验梁的破坏模式为斜拉脆性破坏,抗弯抗剪组合加固试验梁的破坏模式为支座处混凝土压碎破坏。
语种：
中文
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钢-混凝土叠合梁自锚式悬索桥动力特性测试分析
作者：
王天鹏;张建仁;肖宏彬;孙赟
期刊：
地震工程与工程振动 ,2019年39(1):206-212 ISSN：1000-1301
作者机构：
长沙理工大学土木工程学院,湖南长沙410114;中南林业科技大学土木工程学院,湖南长沙410004;长沙理工大学土木工程学院,湖南长沙,410114;中南林业科技大学土木工程学院,湖南长沙,410004;[肖宏彬; 孙赟] 中南林业科技大学
关键词：
自锚式悬索桥;钢-混凝土叠合梁;动力特性;有限元分析;测试
摘要：
针对钢-混凝土叠合梁自锚式悬索桥的结构特点,在总结以往大跨径桥梁有限元模型的基础上,采用组合有限元法以梁、板、杆、索单元建立邵阳市桂花大桥三维有限元模型,计算分析获得结构的主要频率和振型。通过现场测试获得大桥环境激励和行车激励作用下的响应时程,分析得到结构的主要频率、振型和阻尼比,引入模态置信因子对计算模态信息和实测模态信息进行比较分析,以验证数值模型和实测结果的准确性。研究结果可为全面了解钢-混凝土叠合梁自锚式悬索桥的动力特性、准确预测结构的动力响应以及类似桥梁的抗震、抗风设计提供重要依据。
语种：
中文
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Influence of cracks on chloride diffusivity in concrete: A five-phase mesoscale model approach
作者：
Peng, Jianxin;Hu, Shouwang* ;Zhang, Jianren;Cai, C. S.;Li, Long-yuan
期刊：
Construction and Building Materials ,2019年197:587-596 ISSN：0950-0618
通讯作者：
Hu, Shouwang
作者机构：
[Peng, Jianxin; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha, Hunan, Peoples R China.;[Hu, Shouwang] Dongguan Univ Technol, Dept Civil Engn, Dongguan 523808, Guangdong, Peoples R China.;[Cai, C. S.] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.;[Li, Long-yuan] Plymouth Univ, Sch Marine Sci & Engn, Plymouth, Devon, England.
通讯机构：
[Hu, Shouwang] D;Dongguan Univ Technol, Dept Civil Engn, Dongguan 523808, Guangdong, Peoples R China.
关键词：
Chloride diffusion;Concrete;Crack;Mesoscale model;Multi-phase;Numerical simulation
摘要：
This paper presents a mesoscale numerical approach to investigate the chloride diffusivity in cracked concrete. Concrete is treated as a five-phase material, including cement paste, aggregate, interfacial transition zone (ITZ), crack, and damaged zone (DZ), for its heterogeneity. In the mesoscale model, the randomly distributed aggregates were treated as impermeable, whereas all other phases are assumed permeable but with different diffusion coefficients. It is assumed that the crack is located in the middle of the DZ, and there is a liner relationship of the chloride diffusion coefficients between the DZ and the crack. The developed mesoscale model is validated by comparing the simulation results with the experimental data. Finally, the influence of the DZ, such as the chloride diffusion coefficient, the width and length of the DZ, the width and length of the crack, on the penetration of chlorides in cracked concrete is examined and discussed. © 2018 Elsevier Ltd
语种：
英文
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不同持荷下自密实混凝土加固既有RC梁抗弯性能试验
作者：
张建仁;罗育明;张旭辉;彭建新
期刊：
长安大学学报(自然科学版) ,2019年39(4):62-72 ISSN：1671-8879
作者机构：
长沙理工大学土木工程学院,湖南长沙,410114;长沙理工大学土木工程学院,湖南长沙410114;湖南交通职业技术学院路桥工程学院,湖南长沙410132;湘潭大学土木工程与力学学院,湖南湘潭411105;[彭建新; 罗育明; 张建仁; 张旭辉] 长沙理工大学
关键词：
桥梁工程;自密实混凝土;混凝土梁加固;试验研究;持荷水平;抗弯性能
摘要：
针对自密实混凝土加固既有混凝土桥梁时结构初始损伤和持荷加固等对加固梁抗弯性能的影响,设计和制作了8片钢筋混凝土T梁,对其进行加载造成初始损伤,然后在不同持荷水平下对其进行自密实混凝土增大截面加固,并对加固梁进行抗弯性能测试,以明确持荷水平和自密实混凝土加固厚度对RC梁抗弯性能的影响,包括构件裂缝分布形态、破坏形式、挠度变形和混凝土应变发展等,最后探讨了加固梁抗弯承载力计算方法。研究结果表明:该试验采用的自密实混凝土增大截面加固方法能有效提高构件的抗弯刚度,增大抗弯承载力约1倍,并且加固梁均表现出良好的延性破坏特征;混凝土梁底加固厚度能在一定程度上提高构件抗弯承载力,但效果不明显,其提高程度小于加固截面自重的增长;低持荷水平对加固梁抗弯承载力退化影响不大,甚至略有提高,但高持荷水平会引起加固梁抗弯承载力在一定程度退化,持荷水平对加固梁抗弯刚度的影响依赖于其引起的梁表面裂缝张合情况,裂缝闭合时,一定的持荷对于加固梁的抗弯刚度具有促进作用,但高持荷加固梁表面存在开口裂缝时会引起其抗弯刚度退化;对于适筋加固梁,基于平截面假定和塑性极限方法,忽略二次受力的影响,直接按受拉钢筋屈服对加固梁抗弯承载力计算具有较高的精度。
语种：
中文
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特大跨桥梁安全性设计评定与设计研究进展
作者：
张建仁;彭建新;阳逸鸣
期刊：
中国基础科学 ,2019年21(02):28-32 ISSN：1009-2412
作者机构：
长沙理工大学土木工程学院,湖南,410114;[彭建新; 阳逸鸣; 张建仁] 长沙理工大学
关键词：
国家973计划;特大跨桥梁;安全性评定;安全性设计;研究现状
摘要：
由于特大跨桥梁受力机理和服役环境复杂,现有的特大跨桥梁安全性设计与评定缺乏科学性,导致在多因素作用下特大跨桥梁病害突出,安全事故时有发生.因此亟需对特大跨桥梁评定与设计的相关基础理论和方法展开研究,并编制国家层面的特大跨桥梁安全性设计与评定规范.本文首先对特大跨桥梁安全性评定与设计的理论和方法的研究现状展开介绍,随后系统地介绍了本项目组在特大跨桥梁安全性评定与设计方面完成的各项工作,最后就现阶段研究的不足和存在的问题进行探讨,供同行交流和参考.
语种：
中文
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Concrete cracking prediction under combined prestress and strand corrosion
作者：
Wang, Lei;Dai, Lizhao* ;Bian, Hanbing;Ma, Yafei;Zhang, Jianren
期刊：
Structure and Infrastructure Engineering ,2019年15(3):285-295 ISSN：1573-2479
通讯作者：
Dai, Lizhao
作者机构：
[Ma, Yafei; Wang, Lei; Dai, Lizhao; Zhang, Jianren] Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, Changsha, Hunan, Peoples R China.;[Bian, Hanbing] Univ Lorraine, Lab Etud Microstruct & Mecan Mat, Metz 01, France.
通讯机构：
[Dai, Lizhao] C;Changsha Univ Sci & Technol, Sch Civil Engn & Architecture, Changsha, Hunan, Peoples R China.
关键词：
concrete cracking;corrosion products;crack propagation;Prestressed concrete;rust-expansion ratio;strand corrosion
摘要：
This study investigates strand corrosion-induced concrete cracking under various prestress experimentally and analytically. Experimental data on the critical time of cover cracking, crack width and corrosion loss obtained from the accelerated corrosion test are presented and discussed. The expansion ratio of strand corrosion products is estimated based on the infrared spectroscopy and thermal gravimetry. An analytical model, incorporating the coupled effects of prestress and strand corrosion, is proposed to predict the global process of concrete cracking from initiation to propagation. Strand rust-expansion ratio and the residual stiffness of cracked concrete are also included in the model. Results show that prestress can accelerate the corrosion-induced cracking process. By varying prestress from 0 to 75% strand tensile strength, the critical time of cover cracking decreases 22% and the crack propagation rate increases 9%. It is found that the proposed model is accurate in predicting corrosion-induced crack width in prestressed concrete beams. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
语种：
英文
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Limit equilibrium method-based shear strength prediction for corroded reinforced concrete beam with inclined bars
作者：
Ma, Yafei* ;Lu, Baoyong;Guo, Zhongzhao;Wang, Lei* ;Chen, Hailong;...
期刊：
Materials ,2019年12(7):1014 ISSN：1996-1944
通讯作者：
Ma, Yafei;Wang, Lei;Zhang, Jianren
作者机构：
[Ma, Yafei; Lu, Baoyong; Wang, Lei; Ma, YF; Zhang, Jianren; Guo, Zhongzhao] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;[Ma, Yafei; Wang, Lei; Ma, YF; Zhang, Jianren] Dept Educ, Key Lab Bridge Engn Safety Control, Changsha 410114, Hunan, Peoples R China.;[Chen, Hailong] Univ Kentucky, Dept Mech Engn, Lexington, KY 40506 USA.
通讯机构：
[Ma, YF; Wang, L; Zhang, JR] C;[Ma, YF; Wang, L; Zhang, JR] D;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;Dept Educ, Key Lab Bridge Engn Safety Control, Changsha 410114, Hunan, Peoples R China.
关键词：
Bars (metal);Concrete beams and girders;Corrosion;Deterioration;Shear strength;Steel corrosion;Tensile strength;Corroded reinforced concrete beams;Corrosion of reinforcement;Cross sectional area;Deterioration factor;Limit equilibrium methods;Reinforced concrete beams;Shear strength predictions;Shear strength reduction;Reinforced concrete
摘要：
Shear strength is a widely investigated parameter for reinforced concrete structures. The corrosion of reinforcement results in shear strength reduction. Corrosion has become one of the main deterioration factors in reinforced concrete beam. This paper proposes a shear strength model for beams with inclined bars based on a limit equilibrium method. The proposed model can be applied to both corroded and uncorroded reinforced concrete beams. Besides the tensile strength of longitudinal steel bars, the shear capacity provided by the concrete on the top of the diagonal crack, the tensile force of the shear steel at the diagonal crack, the degradation of the cross-sectional area and strength of the reinforcements induced by corrosion are all considered. An experimental work on two groups accelerated corroded beams was performed. Good agreements were found between the proposed theoretical predictions and experimental observations.
语种：
英文
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自密实混凝土浇筑成型方向对新老混凝土界面黏结抗剪强度的影响
作者：
张建仁;罗育明;张旭辉;彭建新
期刊：
铁道科学与工程学报 ,2019年16(3):744-751 ISSN：1672-7029
作者机构：
长沙理工大学土木与建筑学院,湖南长沙,410114;长沙理工大学土木与建筑学院,湖南长沙 410114;湖南交通职业技术学院路桥工程学院,湖南长沙 410132;湘潭大学土木工程与力学学院,湖南湘潭,411105;[彭建新; 罗育明; 张建仁] 长沙理工大学
关键词：
桥梁工程;新老混凝土界面;试验研究;浇筑成型方向;剪切强度;计算方法
摘要：
针对自密实混凝土加固既有混凝土结构时存在不同方位的黏结界面,为研究其对新老混凝土界面剪切强度的影响,设计具有不同混凝土浇筑成型方向的Z型黏结试件进行直剪试验,探究自密实混凝土浇筑成型方向、混凝土强度和界面处理方式等对黏结试件破坏形式和抗剪强度的影响,并探讨不同浇筑成型方向影响下新老混凝土黏结界面抗剪强度计算方法。研究结果表明:混凝土浇筑成型方向对界面抗剪强度影响显著,新混凝土从老混凝土顶面浇筑的效果最好,侧面浇筑次之,底面浇筑最差,差值最大多达到顶面浇筑试件抗剪强度的50%。一定范围内增大新混凝土强度能有效提高黏结界面抗剪强度,底面浇筑时效果尤为明显;当新老混凝土强度相差较大时,继续提高新混凝土强度作用不大。基于本试验结果,建议新老混凝土强度差宜控制在2个标号以内。界面处理方式对其抗剪强度的影响依赖于新老混凝土强度和新混凝土浇筑成型方向。本试验中,II类界面对于强度相同的新老混凝土界面抗剪强度影响不大,但能提高不同强度的新老混凝土界面抗剪强度,尤其是底面浇筑和侧面浇筑的界面。
语种：
中文
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桥梁吊索高强钢丝疲劳裂纹扩展试验与数值模拟
作者：
马亚飞;陈志铖;叶钧;王磊;张建仁
期刊：
Dizhen Xuekan ,2019年39(1):23-30 ISSN：1003-868X
作者机构：
长沙理工大学土木工程学院,湖南长沙,410114;[叶钧; 马亚飞; 张建仁; 陈志铖; 王磊] 长沙理工大学
关键词：
桥梁吊索;高强钢丝;疲劳裂纹扩展;有限元方法
摘要：
反复车辆荷载作用下,斜拉桥斜拉索及拱桥吊杆疲劳损伤问题日益严重。针对大跨桥梁中常用的镀锌高强钢丝,开展了应力比R分别为0.1、0.2、0.3的疲劳裂纹扩展试验,研究了应力比及应力幅对钢丝疲劳裂纹扩展性能的影响,每种应力比下的应力幅分别为140.4、152.1、163.8、175.5MPa。采用分步加载方法,设计不同加载应力幅在试件断裂面留下裂纹扩展时的条纹特征,利用光学显微镜对疲劳断口的疲劳条纹进行观测,得到了不同应力比下裂纹扩展深度与疲劳循环次数的a—N曲线,拟合了高强钢丝的疲劳裂纹扩展速率模型。试验结果表明:钢丝疲劳裂纹呈三阶段扩展,随着应力比R的增大,Paris公式中参数C变小,m变大。运用有限元软件ABAQUS模拟了裂纹扩展过程,定量分析了裂纹扩展径向与表面方向的关系,试验结果与有限元结果吻合较好。试验得到的疲劳裂纹扩展速率曲线,可用于大跨桥梁吊索的抗疲劳、防断裂设计及疲劳寿命评估。
语种：
中文
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