FRP与混凝土界面黏结-滑移本构关系的试验研究

郭樟根¹　孙伟民¹　曹双寅²
（1. 南京工业大学，江苏南京210009；2. 东南大学，江苏南京210096）

摘要：FRP与混凝土的黏结性能是外贴纤维增强聚合物加固钢筋混凝土结构技术的关键问题。采用修正梁模型，对9个外贴FRP条带加固混凝土受弯构件的黏结性能进行了试验研究，考察混凝土强度和FRP黏结长度对黏结性能的影响，分析了FRP应变以及局部黏结剪应力发展规律以及沿黏结长度在各级荷载下的分布规律，计算得到了局部黏结剪应力-滑移关系曲线。通过对试验结果的统计回归分析，提出3种不同复杂程度的局部黏结剪应力-滑移本构关系模型，3种本构关系模型与试验结果都吻合较好，可供实际加固改造工程应用以及完善相应规范的编制参考。
关键词：FRP； 加固； 黏结性能； 滑移； 本构模型

Experimental study on bond-slip behavior between FRP and concrete

Guo Zhanggen¹　 Sun Weimin²　 Cao Shuangyin¹
(1. Nanjing University of technology, Nanjing 210009, China;
2. Southeast University, Nanjing 210096, China)

Abstract: FRP laminates, because of their superior properties, are being successfully used for the strengthening of existing reinforced concrete structures. Critical to strengthening a concrete structure through externally bonded FRP plates is the bond behavior between FRP and concrete. A modified beam test specimen was employed to study the bond behavior and the force transfer of the composite material plates adhered to concrete. The influences of the bond length, and concrete strength on the bond behavior was investigated, the strain development and distribution in GFRP sheet along the bond length was obtained, and the direct shear bond stress distribution and local bond stress versus slippage relationship were analyzed. Based on the test results, three local bond stress-slip constitutive models were proposed. These models matches the experimental results well，and are valuable references for the corresponding codes and engineering applications.
Keywords: FRP；strengthening；bond behavior；slip；constitutive model

E-mail: zhgguo@163.com

锈蚀钢筋混凝土梁疲劳性能试验研究

易伟建　孙晓东
（湖南大学，湖南长沙410082）

摘要: 通过锈蚀钢筋混凝土梁的疲劳试验，分析了主筋锈蚀与混凝土梁疲劳性能的关系。疲劳试验包括1根钢筋未锈蚀的对比梁和8根钢筋锈蚀率介于4%～12%的试验梁。试验结果表明锈蚀钢筋混凝土梁的刚度在疲劳过程中表现出“下降—平稳—上升”三阶段特性。由于钢筋混凝土梁中钢筋的不均匀锈蚀，钢筋表面产生明显的坑蚀，锈蚀梁的疲劳破坏在应力幅最大且表面有坑蚀的钢筋截面发生。随着主筋锈蚀率的增加，梁的疲劳寿命急剧缩短，其破坏形式为受拉钢筋脆性断裂，破坏前没有预兆。振动测试表明，梁的基本频率并不是随疲劳损伤积累而单调下降，实测基本频率不能可靠地预报锈蚀钢筋的疲劳断裂破坏。同时，在相同疲劳循环次数下，随疲劳应力幅的增大，钢筋锈蚀的性能逐渐由软钢向硬钢转变。
关键词：钢筋腐蚀；锈蚀主筋；钢筋混凝土梁；疲劳试验；疲劳寿命

Experimental investigation on the fatigue behavior of corroded RC beams

Yi Weijian　Sun Xiaodong
(Hunan University, Changsha 410082, China)

Abstract: The fatigue property RC beams, including its relationship with the rusted main bars, was studied. A control RC beam without steel corrosion and eight RC beams with steel corrosion rates ranging between 4%～12% were tested under fatigue loading. The results of fatigue test showed that the stiffness of the beams performs with three distinctive stages under the fatigue cycle loads, i.e., decline-stabilize-rise stages. There were large amount of spot corrosions resulting from uneven corrosion of the main bars. Generally, the failure of the corroded RC beams occurred at locations with a high stress amplitude and with spot corrosions on the tensile steel bars. With the increase in the corrosion rate for the main bars, the fatigue lifespan of the corroded RC beams is shortened considerably. The fatigue failure of corroded RC beams occurred in the form of brittle fracture of tension steel bars without any precursors. The dynamic testing results showed that the fundamental frequency of corroded RC beams did not decrease monotonously with the cumulated fatigue damage. So the fundamental frequency obtained from the vibration test can not be used to predict the failure of the rusted main bar of the RC beams under fatigue loads. It was also shown that the rusted main bars were converted from the soft steel into hard steel with an increase in the fatigue stress amplitude under the same fatigue cycle loads.
Keywords: steel corrosion; corroded main bar; reinforced concrete beam; fatigue test; fatigue lifespan

E-mail: hunuyi@public.cs.hn.cn

大直径薄壁钢管压弯构件的稳定分析

潘汉明^1,2 郭彦林¹ 梁　硕²梁伟盛²裴胜兴²　王乐文²
（1. 清华大学，北京100084；2. 广州新电视塔建设有限公司，广东广州510310）

摘要：针对我国现行钢结构设计规范未对径厚比为100以上的大直径薄壁钢管压弯构件的稳定计算作相应规定，采用非线性有限元方法，分析初始缺陷、长细比及两端作用不等弯矩等因素对该类构件稳定承载力的影响。研究结果表明，随着径厚比的逐渐增大，该类构件的稳定承载力显著降低。通过有限元分析结果及参照相关规范提出了该类压弯构件稳定承载力的建议计算公式。最后，对3根薄壁钢管压弯构件进行了试验研究，得到每个试件的荷载位移曲线、破坏屈曲和压弯极限承载力，试验荷载位移曲线与有限元方法计算得出的曲线基本吻合，实测极限荷载值与建议公式计算值偏差幅值控制在20%之内，进一步验证了该理论分析方法是有效的、可靠的，研究成果可为类似构件的设计提供依据。
关键词：大直径薄壁钢管；压弯稳定承载力；初始缺陷；长细比

A stability analysis of major diameter thin-walled tube beam-columns

Pan Hanming^1,2　Guo Yanlin¹　Liang Shuo¹
　Liang Weisheng¹Pei Shengxing² Wang Lewen²
(1. Tsinghua University, Beijing 100084, China；
2.Guangzhou New TV Tower Development CO.,Ltd., Guangzhou 510310, China）

Abstract: For major diameter thin-walled tube beam-columns (MDTTB) with diameter-thickness ratios exceeding 100, there exists no corresponding regulation and reference in the current design standard of steel structures. The influences of initial imperfection, slenderness ratio and unequal end moment on the stability capacity of MDTTB are investigated by using nonlinear finite element analysis. The results indicate that with the increase in diameter-thickness ratio, the stability bearing capacity of MDTTB is clearly reduced. According to the related design standard of steel structures, and on the basis of the numerical analysis results, the formulas for calculation of the stability bearing capacity of MDTTB are presented. Three tests of thin-walled steel tube beam-columns are reported. The deformation and ultimate strength from the tests are found to be in good agreement with the corresponding formula-calculated values, indicating that the proposed method is effective，reliable and convenient for design applications.
Keywords: major diameter thin-walled steel tube; stability bearing capacity of beam-column; initial imperfection; slenderness ratio l

E-mail: chinap@mail.tongji.edu.cn

铝合金工字形截面的抗剪承载力研究

董　震　张其林
(同济大学，上海200092)

摘要：提出了考虑腹板屈曲后强度和翼缘约束效应的铝合金工字形截面的抗剪设计方法，并给出实用的建议设计公式。采用有限元方法模拟铝合金工字形截面的受力变形，并对已有工字形截面的抗剪承载力计算理论进行分析。有限元方法得出的荷载-位移曲线反映出铝合金工字形截面腹板弹性剪切屈曲力相当低，而构件整体抗剪承载力却相对较高，传统钢构件的设计方法不能准确反映其实际抗剪能力。在此基础上指出对于铝合金材料制成的工字形截面，抗剪设计公式应准确、方便的计算腹板受剪屈曲后承载力和翼缘对截面抗剪承载力的贡献。经数据比对，建议设计公式的计算结果和Hamoodi M J、Burt C A和Evans H R的试验资料及现行的欧洲铝合金规范公式计算结果吻合，且公式计算简捷。
关键词：铝合金；工字形截面；抗剪承载力；有限元分析；设计研究

A study on the shear resistance of aluminum alloy 工 sections

Dong Zhen　Zhang Qilin
(Tongji University, Shanghai 200092, China)

Abstract: The design method for the shear resistance of aluminum alloy 工 sections is presented, taking into consideration of the post-buckling strength of webs and the restraint effect of flanges, and the practical design formulas are proposed. The deflection of aluminum alloy 工 sections under concentrated load is simulated by using the finite element method, and several design theories are discussed. The shear resistance vs. the maximum web displacement curve reflects that the web of aluminum alloy 工 sections is under less shear buckling force, while the entire member has rather high shear resistance. However, the traditional design method is not able to give the real shear resistance of aluminum alloy 工 sections. The analysis shows that the proposed design formulas for the shear resistance of aluminum alloy 工 sections ought to calculate accurately the post-buckling resistance of webs and the shear resistance contribution of flanges. The proposed design formulas are simple and convenient, and the calculation results are consistent with the test data of Hamoodi M J, Burt C A, Evans H R and the calculation results from using Eurocode 9 formulas.
Keywords: aluminum alloy；section；shear resistance；finite element analysis；design study

E-mail: dz_china@126.com

圆钢管约束高强混凝土轴压短柱的试验研究与承载力分析

张素梅 刘界鹏 马 乐 邢 涛
（哈尔滨工业大学，黑龙江哈尔滨150090）

摘要：进行6组共18个圆钢管约束高强混凝土短柱在循环或单调轴压荷载作用下的试验研究。试验中的主要参数为混凝土强度（fcu=88.14~94.17）和钢管径厚比（D/t=21.62~43.01）。试验结果表明，圆钢管约束高强混凝土短柱的轴压承载力高于同条件的普通钢管混凝土构件，但两种构件的延性无显著差异；随钢管中纵向应力的降低，构件的轴压承载力提高。对构件的应力分析结果表明，圆钢管约束高强混凝土轴压短柱的峰值荷载点对应于钢管的屈服点。在应力分析结果的基础上建立圆钢管约束混凝土的轴压承载力公式，公式结果与试验结果吻合较好。基于试验结果对Mander约束混凝土模型进行修正，使模型适合于约束高强混凝土。
关键词：圆钢管约束高强混凝土；循环轴压荷载；径厚比；轴压承载力

Axial compression test and analysis of circular tube confined HSC stub columns

Zhang Sumei Liu Jiepeng Ma Le Xing Tao
(Harbin Institute of Technology, Harbin 150090, China)

Abstract: A total of 18 circular tube confined high strength concrete (HSC)stub columns were tested under cyclic or monotonic axial compression. The parameters in the study include the compressive strength of concrete (fcu=88.14~94.17 MPa) and diameter-to-thickness ratio of the steel tube (D/t=21.62~43.01). The experimental results indicate that the axial bearing capacity of a steel tube confined concrete stub column is greater than that of a CFT column with equivalent parameters, while difference in ductility is insignificant. The axial bearing capacity of the columns increases as the longitudinal stress of the steel tube decreases. The results of elasto-plastic analysis of the steel tube indicate that the steel yields at the peak load. A design equation is proposed to calculate the axial bearing capacity of circular tube confined concrete columns. The results from the proposed equation for stub columns are consistent with the test results. A modified Mander’s model that is suitable for confined HSC is proposed based on the test results.
Keywords: circular tube confined HSC; cyclic axial compression; diameter-to-thickness ratio; axial load strength

E-mail: smzhang@hit.edu.cn

钢筋混凝土T形柱的耐火极限研究

吴 波¹　 徐玉野²
(1. 华南理工大学，广东广州 510640；2. 华侨大学，福建泉州 362021)

摘要：利用数值模拟程序分析了荷载比、计算长度、截面尺寸、荷载偏心率、配筋率和荷载角等参数对ISO834标准升温过程下钢筋混凝土等肢T形柱耐火极限的影响规律。针对不同荷载比、计算长度、截面尺寸、荷载偏心率、配筋率和荷载角共5400种工况进行了四周受火时等肢T形柱的高温反应分析。在此基础上，定量给出了该类构件耐火极限的实用计算方法。研究表明：(a) 严格控制荷载比是提高T形柱耐火极限的有效措施。(b) 随着计算长度的增加，T形柱耐火极限近似呈直线降低。(c) 当荷载偏心率在0和1.0之间变化时，T形柱耐火极限随荷载偏心率的增大而减小。当荷载偏心率在1.0和2.0之间变化时，荷载偏心率改变对T形柱耐火极限影响较小。(d) 荷载角对T形柱耐火极限影响较大且影响规律较为复杂。
关键词：钢筋混凝土柱；耐火极限；T形截面；实用计算方法

Fire resistance of reinforced concrete columns of T-shaped cross section

Wu Bo¹　　Xu Yuye²
(1. South China University of Technology, Guangzhou 510640, China;
2. Huaqiao University, Quanzhou 362021, China)

Abstract: Analyses were performed to study the influence of several parameters, such as load ratio, effective length, section dimension, load eccentricity ratio, reinforcement ratio and load angle, on the fire resistance of reinforced concrete columns of T-shaped cross section exposed to the ISO834 standard fire. 5400 hypothetical cases of columns subjected to fire in all sides were selected for fire response analysis. Different load ratios, effective lengths, cross section dimensions, load eccentricity ratios, reinforcement ratios, and load angles were considered in the analyses. Based on the simulation results, a practical method is proposed for calculating the fire resistance of columns of T-shaped cross section subjected to fire in all sides. The simulation results indicate that:(a)reducing the load ratio is an effective measure to improve the fire resistance of columns of T-shaped cross section;(b)the fire resistance of columns of T-shaped cross section decreases linearly with the increase of effective length;(c)the fire resistance of columns of T-shaped cross section decreases significantly with the increase of load eccentricity ratio from 0.0 to 1.0, whereas varies only slightly for a load eccentricity ratio between 1.0 and 2.0; and(d)the influence of load angle on the fire resistance of columns of T-shaped cross section is significant and complex.
Keywords: reinforced concrete column; fire resistance; T-shaped cross section; practical calculation method

E-mail: yuyexu@tom.com

核心筒部分悬挂结构振动台试验及分析

曹万林 卢智成 张建伟 常卫华 赵长军
(北京工业大学，北京100022)

摘要：提出核心筒部分悬挂结构体系，该体系将框架-核心筒结构有多道抗震防线的优势与核心筒悬挂结构减震性能好的优势相结合：在地震反应相对较小的底部采用框架-核心筒结构，在地震反应相对较大的上部采用核心筒悬挂结构，并采取在悬吊结构楼板与核心筒之间设置阻尼器和设置素混凝土连接键的构造措施，实现对结构地震反应的有效控制。进行了一个8层1∶10比例的核心筒部分悬挂结构模型的模拟地震振动台试验研究，分析了结构在弹性阶段、弹塑性阶段的动力特性以及该结构在不同峰值加速度的El Centro地震波作用下的地震反应，建立结构分析模型，用SAP2000程序对该结构进行了弹性和弹塑性时程地震反应分析，计算结果与试验结果吻合较好。试验及分析表明，该结构具有良好的减震性能。
关键词：核心筒；部分悬挂结构；振动控制；振动台试验

Shaking table test and analysis of core-tube partial suspension structures

Cao Wanlin Lu Zhicheng Zhang Jianwei Chang Wehua Zhao Changjun
(Beijing University of Technology, Beijing 100022)

Abstract: A type of core-tube partial suspension structure is proposed. It take advantage of both the core-tube suspension structure that is good in earthquake resistant performance and the frame core-tube structure that has more lines of seismic resistance, consisting of core-tube suspension with dampers and pure concrete blocks between core tube and suspension floors in the upper four-storey for strong seismic responses and frame core-tube in the bottom four-storey for weak seismic responses .The system can achieve effective control over earthquake responses. A shaking table test of a 1/10 scale model of this type of structure, involving elastic and elasto-plastic stages, is described. A dynamical model is formulated and the dynamic characteristics and earthquake responses of the structure under the El Centro wave are analyzed. The experimental results indicate that the structure performs well under seismic conditions. The elastic and elasto-plastic time-history analyses of the structure are conducted by using SAP2000, and the simulation results agree well with those of the experiment.
Keywords: core tube; partial suspension structure; vibration control; shaking table test

E-mail: wlcao@bjut.edu.cn

框架结构能量流网络及其初步应用

张雷明 刘西拉
(上海交通大学，上海 200030)

摘要：从考察框架结构在各种荷载条件下的能量流动出发，考虑结构杆件以及节点的能量流动状况，建立框架结构的能量流动网络。比较各杆件和节点的能量流动方向及大小，按图论方法得到框架结构内能量流动的关键路径，即结构的最大传力途径；通过比较拆除不同杆件对结构系统总体应变能影响的大小，确定结构杆件的重要性；通过跟踪结构杆件的破坏顺序以及结构杆件重要性的变化，确定结构最重要破坏模式。对唐山大地震中倒塌的一个3层框架作了分析，结果表明这种方法可以充分考虑结构受不同荷载作用的影响，可以确定框架结构的杆件重要性、最大传力途径以及最重要破坏模式。
关键词：能量流网络；杆件重要性；最大传力途径；最重要破坏模式

Network of energy transfer in frame structures and its preliminary application

Zhang Leiming Liu Xila
(Shanghai Jiaotong University, Shanghai 200030, China)

Abstract: Based on the energy transfer in frame structures under various loading conditions, a network of energy transfer is constructed for structural members and joints. Using the graph theory, the key path of energy transfer in frame structures, namely the most important loading-carrying path, is determined in accordance with the energy transfer in and out of members and joints. By comparing the change of strain energy in the structure with different members removed, the index of member importance is introduced. By tracing the change of the index of member importance due to failure of members, the most important failure mode is determined. A three-story frame collapsed during the Tangshan earthquake is analyzed, illustrating that the presented procedure is effective in determining the index of member importance, the most important load-carrying path as well as the most important failure mode, with full consideration of different loading conditions.
Keywords: Network of energy transfer; importance of member; most important load-carrying path; most important failure mode

E-mail: lmzhang@sjtu.edu.cn

常规的均匀网格状配筋承台冲切承载力的计算

郭宏磊
（江汉大学，武汉430056）

摘要：目前，相比于承台冲切破坏的空间桁架受力机理研究，承台冲切承载力计算的研究尚显薄弱。采用非线性有限元的电算分析，结合逐次多元最小二乘法的数学推导，得出常规的均匀网格状配筋承台冲切承载力的空间桁架理论表达式。通过对76个桩数有异、布桩形式多变，在国内外文献上公开发表的试验数据的验证，以及与ACI318-05规范中的临界截面应力法、美国CRSI手册方法、中国JGJ94—94与GB50007—2002规范方法的对比计算分析表明：所得公式普遍适用于常规的按均匀网格状布筋承台的冲切承载力计算。
关键词：承台；冲切；空间桁架；承载力；计算

Calculation of the punching shear bearing capacity of
pile caps with ordinary uniform grid reinforcement

Guo Honglei
（Jiang Han University, Wuhan 430056, China）

Abstract: Based on a study on the spatial strut-and-tie bearing mechanism of pile caps, nonlinear finite element analyses are conducted, and combining with a gradual least square method for multiple variables, theoretical formulae are derived for the punching shear bearing capacity of pile caps with ordinary uniform grid reinforcement. Verification study with the published test data of 76 in the literature, including the critical section stress method of the ACI318-05 code, the American CRSI handbook method, the Chinese code JGJ94—94 and GB50007—2002 methods, indicates that the proposed method is suitable for the calculation of the punching shear bearing capacity of pile caps with ordinary uniform grid reinforcement.
Keywords: pile cap;punching shear; spatial strut-and-tie; bearing capacity; calculation

E-mail: ghl5186@yahoo.com.cn

河床冲刷深度变化对大型桩基桥梁地震反应的影响

叶爱君^1,2 张喜刚² 刘伟岸¹
（1.同济大学，上海200092；2.中交公路规划设计院，北京100010）

摘要：以一座超大跨度斜拉桥为工程背景，采用解析解和有限元模拟计算相结合的方法，对河床冲刷深度变化对大型桩基桥梁地震反应的影响进行初步探索性研究。建立两质点单墩模型，推导地震反应计算公式，用解析法计算桥墩及其基础的地震反应随河床冲刷深度变化的情况，分析高桩承台基础与桥墩的动力相互作用规律，结果表明，由于承台大质量的存在，桥墩的地震反应会表现出显著的共振效应，当桥墩和基础的自振周期相近时，会出现一个峰值。进一步地，建立斜拉桥的全桥有限元模型，计算边墩、主塔及其基础的地震反应随河床冲刷深度变化的情况，验证了解析法得出的影响规律：河床冲刷深度变化对大型桩基桥梁的地震反应有很大的影响，随着冲刷深度的增加，桥梁结构的地震反应并不是单调减小，而可能出现一个峰值。
关键词：河床冲刷；大型桩基桥梁；地震反应；共振

Effects of riverbed scouring depth on the seismic response of bridges on pile foundations

Ye Aijun^1,2　　Zhang Xigang²　　Liu Weian¹
(1.Tongji University, Shanghai 200092, China;
2.China Highway Planning and Design Institute, Beijing 100010, China)

Abstract: Taking a super long-span cable-stayed bridge as the background, a pilot study was carried out to investigate the effect of riverbed scouring depth on the seismic response of a bridge on pile-foundations. A two-particle single-pier model was established to approximately simulate the dynamic behavior of a pier and its high-rise pile cap foundation, the seismic responses corresponding to different scouring depths were calculated, and the dynamic interaction between the pile foundation and the pier was analyzed. The results indicate a significant resonance between the pier and pile foundation because of the large pile-cap mass. Six finite element models corresponding to six riverbed scouring depths of the entire bridge were established, the effects of scouring depth on the seismic response of side piers and towers were analyzed. The conclusion is that the scouring depth has a significant effect on the seismic response of the bridge, and as the scouring depth increases, the seismic response of the bridge does not monotonously decrease, and there possibly is a peak value.
Keywords: Riverbed scouring; bridge on pile foundation; seismic response; resonance

E-mail: yeaijun@mail.tongji.edu.cn

曲线箱梁桥空间预应力效应分析

周绪红^1，2，3 戴 鹏¹ 狄 谨¹ 商岸帆¹
(1.长安大学，陕西西安710064；2.兰州大学，甘肃兰州730000; 3.湖南大学，湖南长沙410082)

摘要：曲线箱形梁桥是空间复杂受力的结构体系，预应力效应一方面能提高构件的承载能力，另一方面也可能对结构带来一些不利的影响。采用三维实体单元和杆单元相结合的空间组合有限元方法，对一座两跨曲线预应力混凝土箱形连续梁桥进行空间受力分析。针对曲线箱形梁的力学特点，对空间曲线钢束摩阻损失的计算方法进行分析。采用组合有限元法和简化方法分析预应力径向力对箱梁腹板的作用效应，比较两者的计算结果差异。采用两种计算模型，分析了预应力对支座受力的影响，对径向支座间距设置和改善支座受力的方法进行了研究。根据预应力效应的分析结果，得到了一些有益的结论，为进一步完善曲线预应力混凝土箱梁桥的设计提供了依据。
关键词：桥梁工程；曲线箱梁；预应力混凝土；箱梁腹板；支座反力；有限元分析

Effect of spatial prestressing for curved box girder bridges

Zhou Xuhong^1,2,3 Dai Peng¹ Di Jin1 Shang Anfan¹
(1.Chang’an University, Xi’an 710064, China; 2.Lanzhou University, Lanzhou 730000, China;
3.Hunan University, Changsha 410082, China)

Abstract: Curved box girder bridge is a complicated spatial structural system. The effect of prestressing may improve the bearing capacity of the members, but may also adversely affect the structure. Using a spatial composite finite element method, combining three-dimensional solid element and bar element, the mechanical analysis of a two-span curved PC continuous box girder bridge is conducted. According to the mechanical characteristics of the bridge, the calculation method for prestress friction loss of the spatial curved prestressed wires is studied. The impact of prestressing radial force on the web plate is analyzed, and the composite finite element method and a simplified method are compared. Two computational models are established to study the influence of prestressing on the bearings, the spatial arrangement between the radial bearings and the approach to promote the performance of the bearings.
Keywords: bridge engineering; curved box girder; prestressed concrete; box girder web; bearing reaction; finite element analysis

E-mail: zxh@lzu.edu.cn

桥梁主梁断面气动耦合颤振分析与颤振机理研究

丁泉顺　朱乐东
（同济大学，上海200092）

摘要：通过对系统竖向和扭转耦合振动运动方程的解耦，将系统振动参数的频率和阻尼比隐式地表达成桥梁断面颤振导数的函数形式，导出了二自由度耦合颤振分析方法。值得注意的是，在临界颤振的情况下颤振运动为等幅的谐波运动，因而在颤振临界点时该颤振分析方法理论上是完全精确的。将该分析方法的结果与系统特征值分析方法的计算结果进行比较，验证了该分析方法的可靠性和适用性。在此基础上，对典型桥梁断面气动耦合颤振的机理进行了研究。分析结果表明，对于典型扁平箱形桥梁断面来说，耦合颤振导数项对系统振动参数中频率的影响均较小，系统模态的气动阻尼比主要由直接颤振导数项和耦合颤振导数项A*1A*3构成。
关键词：桥梁断面；气动耦合；颤振分析；机理研究

Aerodynamically coupling flutter analysis and flutter mechanism for bridge deck sections

Ding Quanshun Zhu Ledong
(Tongji University, Shanghai 200092, China)

Abstract: A 2DOF coupling flutter analysis is presented based on an uncoupling of torsional and vertical coupled motion equations of system, in which the frequencies and damping ratios of the system vibration characteristics are expressed implicitly as functions of flutter derivatives. It has been noted that the results of the presented method at the critical flutter state is theoretically exact since the critical flutter motion is constant-amplitude and periodically. The comparison of the results with the exact ones by a characteristic analysis of system motion equations is performed so the reliability and applicability of the presented method is proved. Moreover, the mechanism of aerodynamically coupling flutter for a typical bridge deck section is investigated. It is noted that the effect of the coupling flutter derivatives on the frequency of the system modes is small and the aerodynamic damping is mainly made up of the terms of direct flutter derivatives and A*1A*3.
Keywords: bridge deck section; aerodynamic coupling; flutter analysis; flutter mechanism

E-mail: qsding@mail.tongji.edu.cn

基于阻尼的地震循环荷载作用下黏土非线性模型

尚守平 刘方成 王海东
（湖南大学，湖南长沙410082）

摘要：提出一种基于阻尼比的黏土动应力应变模型，通过在滞回曲线中显示地引入代表阻尼比大小的形状系数，使得理论滞回曲线真实地反应土体的滞回阻尼性能。首先推导在等幅对称荷载下滞回曲线的理论方程。然后，为将该模型应用于随机地震荷载的情况，对扩展的曼辛不规则加卸载准则进行了改造，提出当沿小圈加载时，滞回曲线奔向曾经到达过的最大加卸载点。最后，介绍对一种粉质黏土进行的等幅循环荷载和不规则荷载作用下的循环单剪试验。试验结果表明，模型能够较好地模拟土在地震循环荷载作用下的滞回特性。
关键词：非线性；应力应变模型；阻尼比；不规则荷载；黏土；循环单剪试验

Nonlinear model based on damping ratio for clays under seismic loading

Shang Shouping Liu Fangcheng Wang Haidong
(Hunan University, Changsha 410082, China)

Abstract:A dynamic stress-strain model based on the damping ratio of clays is proposed. Importing of the shape coefficient, which represents the soil’s damping ratio, into the hysteretic loop curve function, makes that the theoretical hysteretic stress-strain loop reflect the actual damping characteristics of the soil. The theoretical functions of the hysteretic loops under symmetrical constant amplitude loading are deduced first. Then for the usage of the hysteretic loop model based on damping ratio under seismic loading, the rebuilding of the expanded Masing’s rules is discussed. It is proposed that when the loading or unloading path is on the so-called“small loops”, the loop curve points to the maximum or minimum loading point ever reached in the history. Finally, a cyclic simple shear testing of silt clay is introduced, under both constant amplitude loadings and irregular loadings. The test results indicate that the proposed model can simulate the hysteretic behavior of soils well.
Keywords: nonlinear; constitutive relation; damping ratio; irregular loading; clay; cyclic simple shear test

E-mail: sps@hnu.cn

火荷载下沉管隧道结构的热-力耦合分析

张孟喜 黄 瑾 贺小强
（上海大学，上海 200072）

摘要：以上海外环线越江沉管隧道为背景，用有限元程序模拟火荷载作用下沉管隧道结构温度场及应力场，并将计算结果与试验数据对比分析，从而确定最佳的分析模型和边界条件,为该领域的研究提供参考依据。根据沉管隧道的结构形式及其特点建立有限元分析模型；参考隧道火灾的试验资料和研究成果确定模型边界条件；通过分析选取合理的混凝土和周围土体的本构模型；分析时还考虑到混凝土热工参数随温度的变化。通过对火灾时沉管隧道不同温度量级的稳态温度场和瞬态温度场分析，得出温度随空间和时间的变化规律，并把分析结果与试验结果进行对比分析。分别进行常温下和火灾时沉管隧道的热-力耦合分析，从而更直观地了解温度场对应力场的影响，得出沉管隧道各个部位在火灾发生时的应力分布情况以及随着不同温度量级的变化规律，以便更有效地为优化设计和防火救灾提供理论指导。最后根据计算结果，结合大量的隧道火灾资料总结火灾时隧道内部的温度场及应力场的危险区域。
关键词：沉管隧道；火荷载；温度场；应力场；有限元；耦合分析

Coupling analysis of thermal field and stress field for immersed tunnels under fire load

Zhang Mengxi Huang Jin He Xiaoqiang
（Shanghai University，Shanghai 200072, China）

Abstract: The analysis of thermal field and stress field for the immersed tunnel of the Outer-Ring Expressway in Shanghai under fire load was carried out by using the finite element method. Analytical theory and variation of the mechanical behavior of concrete with time were introduced. On the basis of experimental study of tunnel fire, the analytical model along with the boundary conditions was established. The appropriate structural equations were provided. From the results of the finite element analysis, the coupling of thermal field and thermal stress under different temperatures was presented. The analytical results were compared with experimental ones.
Keywords: immersed tunnel; fire load; thermal field; stress field; finite element method; coupling analysis

E-mail: mxzhang@shu.edu.cn

钢拱架柔性支撑稳定性预测判别方法探讨

沈才华^1，2 童立元¹
(1.东南大学，江苏南京210096；2.河海大学，江苏南京210098)

摘要：新奥法思想引入后，以型钢钢拱架锚喷支护为主的柔性支撑在大跨公路隧道中得到广泛运用，但由于缺乏柔性支撑安全性预测有效的系统方法，新奥法理念很难真正实现，事故仍时有发生。通过柔性支护钢拱架作用特点研究，在现场钢拱架上应变计监控量测数据基础上，利用力学原理，对钢拱架初支弯矩与轴力综合考虑，结合隧道开挖中事故发生过程的特点，进行分等级判别安全性，提出钢拱架锚喷支护安全性预测判别方法，该方法计算程序简单，现场操作方便，能及时准确反映围岩稳定性状态。工程实例表明，该方法能基本显示隧道开挖过程中初支作用下围岩稳定性安全性级别，并反映初支内力变化规律，可为有效控制施工安全及时提供参考信息。
关键词：新奥法；柔性支撑；拱效应；安全性判别

Discussions on predicting the stability of flexible shotcrete and
steel arch frame support for tunnels

Shen Caihua^1，2 Tong Liyuan¹
（1.Southeast University, Nanjing 210096，China；2.Hohai University, Nanjing 210098，China）

Abstract: Since the introduction of the New Austria Tunneling Method (NATM) into China, flexible support composed of anchor, sprayed concrete and steel frame is widely employed in the excavation of large-span road tunnels. Due to lack of a systematic method for forecasting the stability of flexible support, the principles of NATM, however, can not be realistically carried out, resulting in some accidents. In the study of the characteristics of flexible support, a method is proposed for forecasting the stability of the support, based on measurement of strain of the steel arch. With the bending moment and axial and shear forces of the primary support taken into consideration, along with the characteristics of accidents in excavation, the forecasting method evaluates safety by using different ranks, which makes it easier to employ on site. The field testing indicates that this method can reveal the safety and stability levels of surrounding rocks and the primary support.
Keywords: New Austrian Tunneling Method；flexible support；arching-effect；safety evaluation

E-mail: shencaihua@163.com

行人影响下的信号交叉口通行能力研究

陈晓明 邵春福 聂 伟
（北京交通大学，北京100044）

摘要：为量化行人交通对信号交叉口通行能力的影响，分析了行人-机动车冲突点处的行人行为特征和人车运行规律，并描述了行人成群到达的现象。在此基础上，利用车队分析法建立冲突点车辆通行能力模型，并且利用实测数据标定模型参数，为计算行人影响下的信号交叉口通行能力提供了分析依据。模型计算的冲突车流通行能力很大程度取决于有效绿灯时间内冲突点处人车冲突的平均次数。模型计算通行能力总体上低于HCM2000方法，结果随行人流量增加而呈现的下降趋势渐趋平缓。模型建立在冲突点运行规律基础之上，具有较广泛的适应性。研究为混合交通条件下信号交叉口配时设计与交通管理提供了理论基础。
关键词：信号交叉口；通行能力；行人机动车冲突；车队分析法；行人行为；间隙接受

Studies on capacity of signalized intersections influenced by pedestrian traffic

Chen Xiaoming Shao Chunfu Nie Wei
(Beijing Jiaotong University, Beijing 100044, China)

Abstract: It is a problem of concern to quantify the effect of pedestrian traffic on capacity of signalized intersections. The behaviors of pedestrians and mechanism of pedestrian-vehicle conflict are analyzed in this paper. Pedestrian arrivals in groups are taken into account. Capacity of conflict zone is modeled based on platoon analysis method. The model is calibrated according to field data and lays a foundation for calculating capacity of signalized intersections influenced by pedestrian traffic. Vehicular capacity computed by the proposed model depends much on average conflict times and is generally lower than that by method of Highway Capacity Manual (HCM, 2000). The downtrend of vehicular capacity becomes less and less sharp accompanied by the increase of conflicting pedestrian volume. The proposed model is developed on basis of mechanism of conflict zone, and is more universally applicable. The research provides a theoretical basis for signal timing and traffic management at intersections in mixed traffic condition.
Keywords: signalized intersection; capacity; pedestrian-vehicle conflict; platoon analysis method; pedestrian behavior; gap acceptance

E-mail: chenxm11@163.com

密级配沥青混合料集料分形分维与路用性能的关系

杨瑞华 许志鸿
（同济大学，上海 200092）

摘要：从集料结构本身出发，利用分形几何的基本理论，建立沥青混合料集料的粒径分布分形模型、集料体积分形模型和集料孔隙分形模型。集料的体积分形维数是一个饱含丰富信息的重要参数，其与沥青混合料的空隙率存在强相关性，建立AC-16密级配沥青混合料集料体积分形维数与沥青混合料空隙率的回归模型。通过大量路用性能试验，得到AC-16密级配沥青混合料集料的体积分形维数与路用性能指标之间的相关变化规律。集料的体积分形维数增大，沥青混合料的高温性能、抗滑性能呈下降趋势，水稳定性、低温抗裂性呈上升趋势。根据密级配沥青混合料集料体积分形维数与各项路用性能的关系，可对具有不同集料体积分形维数的沥青混合料的路用性能进行预估。
关键词：道路工程；沥青混合料；密级配；分形；路用性能

Relationship between fractal dimension and road performance of dense-gradation asphalt mixture

Yang Ruihua Xu Zhihong
(Tongji University, Shanghai 200092,China)

Abstract: The fractal models of grain size distribution, aggregate volume and aggregate pore are deduced from the composition of aggregation by using the theory of fractal geometry. The fractal dimension of aggregate volume is an important parameter with rich information content. There is a strong correlation between the fractal dimension of aggregate volume and the air void of asphalt mixtures. A regression model for the fractal dimension of aggregate volume and air void of AC-16 is derived. The correlations between road performance and the fractal dimension of aggregate volume of AC-16 are obtained from road tests. With the fractal dimension of volume being increased, the high temperature stability performance and anti-skidding performance of asphalt mixtures are weakened, whereas the moisture susceptibility and the low temperature anti-split performance are improved. The road performances of asphalt mixtures with different fractal dimensions of aggregate volume can be estimated accordingly.
Keywords: road engineering; asphalt mixture; dense-gradation; fractal; road performance

E-mail：yangruihua1995@163.com

基于动力问题的高等级公路沥青路面车辙预估方法

何兆益¹　 雷 婷¹　 王国清² 侯岩峰²
（1.重庆交通大学，重庆 400074；2.河北邯长高速公路建设处，河北石家庄050031）

摘要：基于运动车辆与不平整路面的相互耦合作用，建立车辆动力作用下沥青路面车辙计算与预估方法。提出一种更加符合实际的汽车动载模型；采用室内蠕变试验确定不同级配、不同温度和不同油石比下的沥青面层混合料Burgers黏弹性模型参数；提出以车辙等效的轴载换算及轴载累加作用时间tt计算方法；通过路面温度场观测，综合相应温度场路面材料动稳定度，建立一种新的路面代表温度的计算方法；针对重复与累加作用时间加载的不同，在理论计算基础上，提出不同沥青路面结构加载修正系数；结合有限元方法分析动力轴载累加时间作用下沥青路面车辙及加载修正系数，获得最终车辙预估值。通过邯郸—长治高速公路试验路车辙预估值与实测值对比，误差仅为8%～9.5%。表明沥青路面车辙预估方法的合理性，并具有较高的精度。
关键词：沥青路面； 动载；黏弹性模型；车辙预估

Calculation method for prediction of highway asphalt pavement rutting under dynamic loading

He Zhaoyi¹　　Lei Ting ¹　　Wang Guoqing² Hou Yanfeng²
(1. Chongqing Jiaotong University, Chongqing 400074, China;
2. Hebei HanChang Highway Construction Branch, Shijiazhuang 050031, China)

Abstract: Based on the coupling of vehicle dynamic loading and the pavement surface unevenness, a calculation method is formulated for prediction of highway asphalt pavement rutting under dynamic loading. A simplified vehicle dynamic loading model is established, and the Burgers model parameters of the asphalt pavement mixture are acquired through creep test in the laboratory with different gradations, temperatures and asphalt aggregate ratios. The method for the rutting equivalent axle loading and the time-series of the vehicle loading are proposed. Through measuring the temperature in the pavement and the dynamic stability of the pavement materials, a new method is established for calculating the representative temperatures in the surface of the highway. Through the different time-series of the repetition and progression in pavement loading, revised parameters of asphalt pavement under dynamic loading are proposed on the basis of the calculation. The prediction of rutting is performed by analysis of the asphalt pavement rutting and loading revised parameters by using the finite element method. The error is 8%～9.5% between the calculation and prediction of asphalt pavement rutting for the test road of the Handan—Cangzhi highway. The agreements between the calculation results and the test data indicate that the rutting prediction method is reasonable and reliable.
Keywords：asphalt pavement; dynamic loading; viscoelastic mode; rutting prediction

E-mail: hzyzwb@cquc.edu.cn