风工程数值模拟中平衡大气边界层的研究与应用

杨　伟¹ 金新阳² 顾　明² 陈素琴²
（1.中国建筑科学研究院，北京100013；2.同济大学，上海200092）

摘要：基于RANS方法构造满足水平均匀性的自保持平衡大气边界层是计算风工程中一个非常重要但尚未得到很好的解释和解决、同时也经常被忽略的前提问题。本文从描述湍流流动的模型方程角度对这个问题进行了研究。首先基于湍流平衡假设，从两方程标准k-ε模型导出一类近似满足大气边界层自保持要求的湍流来流边界条件；接着将本文建议的此类边界条件运用到模拟钝体建筑结构分离流动具有较好适用性的SST k-ω湍流模型中，通过数值风洞模拟对比算例，验证了作者提出的边界条件在构造自保持平衡边界层中的适用性。通过本文的理论和数值研究，一方面对研究平衡大气边界层的模拟问题提供了一种新的方法，另一方面也为风工程数值模拟提供了一类新的适用的来流湍流边界条件，将对增进计算风工程中模拟平衡边界层的理解有所帮助，因此具有理论和实用价值。
关键词：计算风工程；平衡大气边界层；标准k-ε模型；SST k-ω 模型

A study on the self-sustaining equilibrium atmosphere boundary layer in computational wind engineering and its application

Yang Wei¹　 Jin Xinyang¹　 Gu Ming²　 Chen Suqin²
(1. China Academy of Building Research, Beijing 100013, China;
2. Tongji University, Shanghai 200092, China)

Abstract: Constructing the equilibrium atmosphere boundary layer is an important yet still unsolved problem in the numerical simulation based on Reynolds Averaged Navier-Stokes (RANS) method for Computational Wind Engineering(CWE). This problem is reinvestigated from a new viewpoint using turbulence models. A set of new inflow turbulence boundary conditions is presented based on the standard k-ε model after an approximate solution is derived from the Turbulence Kinetic Energy(TKE)equation. The fact that the suggested inflow turbulence boundary conditions may produce horizontally homogeneous equilibrium ABL in SST k-ω model is verified and validated. Therefore, the proposed approach is more suitable for numerical simulation of the bluff body flows. A new method of modeling equilibrium ABL is introduced and a set of inflow turbulence boundary conditions are presented for practical applications.
Keywords: computational wind engineering; equilibrium atmosphere boundary layer; standard k-ε model; SST k-ω model

E-mail: yangwei@cabrtech.com

基于IFC标准的建筑结构模型的自动生成

邓雪原   张之勇   刘西拉
（上海交通大学，上海200030）

摘要: 当前，在各种商业软件盛行的环境下，设计单位最紧迫的问题是要解决本单位各专业之间的信息交互，而在这些信息交互中，建筑与结构专业的信息交互最为急需。针对这一需要，本文介绍了现今国际上建筑信息模型的数据共享与交换的IFC标准，分析了建筑模型与结构模型信息的组成与特点，研究了通用建筑结构有限元模型的表达方法，建立以IFC标准为基础，通过建筑模型自动生成符合多种结构分析与设计软件的结构模型的基本方法。通过实例验证本研究方法的实用性与可行性，结果表明本方法为各种设计软件间信息的共享与交换提供了一种通用解决方案，为企业内部实现建筑设计集成化提供了技术保障。最后，文章讨论了该研究方向中基于IFC标准的建筑模型的结构构件偏心、节点连接、荷载处理等方面的问题和后续研究方向。
关键词：计算机辅助建筑设计；建筑结构模型；集成化建筑设计；有限元模型；数据交换；IFC标准

Automatic generation of structural model from IFC-based architectural model

Deng Xueyuan　Chang Tse·Yung P　Liu Xila
(Shanghai Jiao Tong University, Shanghai 200030, China)

Abstract:One of the common problems in the building design industry is the direct information exchange and data sharing without relying on manual interpretations among various disciplines in building design.  Of these information exchange and sharing, that between the architectural and structural professions is the most critical one. Realizing such a demand, this paper introduced the IFC standard for building information modeling, compared the representations and features of architectural and structural models, and studied the general representation technique of finite element model of buildings. An algorithm for structural model construction from the IFC-based architectural model was proposed together with an illustration example. The example shows that the proposed method represents a general solution for the information sharing and exchange between multiple CAAD and structural design software applications.  The technical support for the implementation of an integrated building design approach is presented. A number of issues in the related area, such as representation of member offsets, clear identification of connected joints, loading extraction in the IFC-based architectural model, are discussed with some details for the extension of the present work.
Keywords: CAAD；structural model；integrated building design；finite element models；data exchange；Industry Foundation Classes (IFC)

E-mail: dengxy@sjtu.edu.cn

结构简化弹塑性撞击分析模型及新型防撞吸能器初步试验研究

朱  斌
(浙江大学，杭州 310027)

摘要：通过引入防撞吸能器的力-位移关系，建立了用于结构防撞设计的简化弹塑性撞击分析模型。同时对新型蜂窝状加气混凝土吸能器开展了系列静压试验，结果表明该吸能器具有良好的塑性变形吸能特性。通过改变水灰比、骨料配比及模具的形状与大小，可制作不同强度及不同几何构型的蜂窝状加气混凝土吸能器。对安装该吸能器的结构模型进行了撞击试验，实测的结构振动响应与简化弹塑性撞击分析模型的仿真结果吻合良好，从而验证了所提出的简化撞击分析模型的有效性。进一步的撞击能量转移及结构振动响应分析表明：吸能器强度越大，则撞击持续时间越短，而直接作用在结构上的撞击能量越大；撞击过程中结构的动力响应主要受吸能器的强度及结构自身刚度的影响；采用拟静力法分析撞击过程中结构的位移响应时需考虑合适的放大系数。
关键词：弹塑性；撞击；吸能器；结构防撞

Elasto-plastic impact model and experimental study of new absorber for
structural collision protection

Zhu Bin
(Zhejiang University, Hangzhou 310027, China)

Abstract: An elasto-plastic impact model based on the quasi-static load-compression relationship of an absorber is presented for the collision protection of structures. Using the proposed model, the entire impact process of the impactor-absorber-structure system can efficiently and automatically be predicted. A cost effective Cellular Reinforced Concrete Absorber (CRCA) is designed to soften the impact and absorb the impact energy. Quasi-static tests show that this concrete absorber has excellent plastic deformation characteristics. To verify the proposed impact model and investigate the energy absorbing characteristics of the present absorber, impact experiment of a frame model with installed CRCA is carried out. The simulated results of the elasto-plastic impact model are in good agreement with the experimental ones. Due to the plastic deformation of the absorber, the impact force and responses of the structure during the impact are considerably reduced. Further structural impact analysis indicates that the time duration of the impact decreases and the impact energy directly applied to the structure increases with the increase of strength of the absorber, and the dynamic response of the structure during the impact mainly depends on the strength of the absorber and the stiffness of the structure.
Keywords: elasto-plastic; impact; absorber; structural collision protection

E-mail:binzhu@zju.edu.cn

体外CFRP筋预应力混凝土箱梁长期受力性能试验研究

曹国辉¹²　方　志¹
（1．湖南大学，湖南长沙410082；2．湖南城市学院，湖南益阳413000）

摘要：碳纤维(CFRP)筋具有优异的物理力学性能，可用于替代传统的预应力钢筋。制作了体外配置碳纤维筋预应力混凝土箱梁模型，对持续均布荷载作用箱梁的截面应力重分布、长期挠曲变形及裂缝发展等规律进行了1001 d的试验观测。基于素混凝土柱体的实测徐变系数，运用双线性法和曲率法分别对试验箱梁的长期挠曲变形进行预测。试验结果表明：受压钢筋应变较初值增长225%~268%，受拉钢筋的应变较初值增长36.2~38.6%，混凝土表面压应变较初值增长164%~224%。按现行设计规范计算长期荷载作用特征裂缝宽度较实测值偏小11.8%~55.5%。跨中长期挠曲变形实测值为初始变形的2.32~2.42倍，较现行设计规范取值偏大18.5%。
关键词：碳纤维筋；预应力混凝土箱梁；收缩徐变；双线性法

Experimental study on the long-term behavior of concrete box
girders prestressed with external CFRP tendons

Cao Guohui¹²　Fang Zhi¹
(1. Hunan University,Changsha 410082,China；2. Hunan City University,Yiyang 413000,China)

Abstract: Carbon fiber reinforced polymer(CFRP)tendons, due to excellent physical and mechanical performance, may be employed to replace conventional prestressed steel bars. A concrete box girder model prestressed with externally CFRP tendons was cast, and the stress redistribution, deflection and crack development of the girder model were tested for 1001d under sustained uniform load. Based on the creep coefficient of plain concrete columns, the long-term deflection of the box girder was predicted applying both the bilinear method and the curvature method. The test results indicated that the strain of the compressive bars would be increased by 225%～268%, the strain of the tensile bars increased by 36.2%～38.6%，and the surface strain of the compressive concrete increased by 164%～224%, as compared with the initial values, respectively. The long-term characteristic crack width calculated by using the present design code would be 11.8%～55.5% less than the test value. The long-term deflection at mid-span in the test would be 2.32～2.42 times of the initial value, and the deflection in the test is 18.5% larger than that adopted by the present design code.
Keywords: carbon fiber reinforced polymer tendon; prestressed concrete box girder; shrinkage and creep; bilinear method

E-mail: cgfcivil@163.com

铝合金焊接节点力学性能的试验研究

李静斌¹　张其林² 丁洁民²
（1.郑州大学，河南郑州450002；2.同济大学，上海200092）

摘要：为满足国家标准“铝合金结构设计规范”编制的需要，对铝合金焊接节点的力学性能进行系统的试验研究。试验内容包括铝合金对接焊缝节点和角焊缝节点。通过试验得出对接焊缝临界失效面距焊缝中心及焊缝边缘的距离、焊接热影响区及折算强度区的范围；确定临界失效面强度折减系数的取值大小；分析焊件厚度、焊丝型号、焊接工艺对焊缝强度、临界失效面强度折减系数、焊接热影响区范围及折算强度区范围的影响；验证角焊缝强度计算β公式。部分试验结果同欧洲及英国铝合金结构规范值进行对比分析。研究成果为我国首部铝合金结构规范相应章节的制定提供必要依据，是国内首次对铝合金焊接节点力学性能完成的基础性试验研究。
关键词：铝合金；焊接节点；力学性能；试验研究

Experimental study on the mechanical properties of aluminum welded joints

Li Jingbin¹ Zhang Qilin² Ding Jiemin²
(1．Zhengzhou University，Zhengzhou 450002，China；
2．Tongji University，Shanghai 200092，China)

Abstract: The first edition of the code for design of aluminum structures is being prepared in China. A series of experiments on properties of aluminum welded joints, including aluminum alloy butt welds and fillet welds, have been carried out to provide the basic data for the code. The distances from the failure planes of a HAZ (heat affected zone) to the center and the toe of the weld, and the extensions of a HAZ and a RSZ (reduced strength zone) are measured. The reduced strength coefficient in the failure planes is determined. The influence of such parameters as the thickness of the welded plate, the type of the welding wire and the welding technology on the weld strength, the reduced strength coefficient in the failure planes and the extensions of a HAZ and a RSZ is studied. The accuracy of the β formula in calculating the strength of the fillet welds is experimentally checked. The test results are compared with the characteristic strength values determined by EC9 and BS8118. The present study, as the first of its kind in China, provides the experimental basis for the Chinese code.
Keywords: aluminum alloy; welded joint; mechanical property; experimental study

E-mail: lijingbin@zzu.edu.cn

八边形中空夹层钢管混凝土轴压短柱力学性能的研究

杨俊杰¹ 徐汉勇² 彭国军¹
（1.浙江工业大学，浙江杭州 310014；2.浙江建设职业技术学院，浙江杭州311231）

摘要：在总结圆中空夹层钢管混凝土和方中空夹层钢管混凝土柱受力性能与工程应用优缺点的基础上，提出采用八边形中空夹层钢管混凝土结构的合理性。对八边形中空夹层钢管混凝土轴压短柱力学性能进行试验分析，得到构件各组成部分的荷载-应变关系曲线和极限承载力值，由试验现象与试验结果发现八边形截面中空夹层钢管混凝土柱的承载能力比方形截面柱承载能力高，比圆形截面柱承载能力稍低，且与八边形直边与斜边之比相关。为拓展此类构件应用的几何尺寸范围，在确定材料合理的应力-应变关系模型后，采用有限元方法进一步分析此类构件的力学性能，由此得到的荷载-应变关系曲线以及构件承载力与试验结果能较好地吻合。通过对影响构件承载能力各主要参数的分析，利用试验与数值模拟结果，提出轴压条件下八边形中空夹层钢管混凝土短柱极限承载力的计算公式，供工程设计人员参考。
关键词：中空夹层；八边形；轴压；应力-应变关系；承载力

A study on the behavior of concrete-filled double skin steel tubular
columns of octagon section under axial compression

Yang Junjie¹ Xu Hanyong² Peng Guojun¹
（1.Zhejiang University of Technology, Hangzhou 310014, China;
2. Zhejiang College of Construction, Hangzhou 311231, China）

Abstract: Based on a summary of two types of CFDSST (concrete-filled double skin steel tube) members of circular or square section, a new type of CFDSST, with the outer tube being octagon section and the inner tube circular section, is proposed. Test studies are conducted for the behavior of the CFDSST members of octagon section subjected to axial compression, and the load-strain curves of the steel tubes and the confined concrete and the bearing capacity of the members are obtained. It is found that the bearing capacity of the columns of octagon section is larger than that of square sectioned columns, a little lesser than that of circular sectioned columns, and the bearing capacity of the members is related to the ratio between the length of the straight edge and that of the bevel edge of the octagon. With the suitable stress-strain model, results are obtained by using the general finite element software, ANSYS. A simplified formula is proposed, and the calculated results are in good agreement with the test results.
Keywords: octagon section；axial compression；stress-strain relationship；bearing capacity

E-mail: yjinjie@163.com

高压输电塔-线体系抗灾研究的现状与发展趋势

李宏男 白海峰
（大连理工大学海岸及近海工程国家重点实验室，辽宁大连116024）

摘要：以输电塔-线体系的环境荷载特性和结构动力响应特性为出发点，分析目前高压输电塔-线体系的发展现状及人们对环境荷载缺乏认识而经常造成灾害事故的原因，论述了输电塔-线体系在现有设计水准下抵抗地震和环境荷载作用的能力和现阶段输电塔-线体系设计的可靠性。全面系统地总结了高压输电塔-线体系抗震抗风研究的动力分析建模方法、模型种类与适用性，以及试验研究所采用的方法、达到的水平和解决的问题，抗震抗风研究的理论成果和发展动向，结构振动控制理论体系和控制手段，结构设计理论的发展趋势等。指出了现阶段输电塔动力响应研究与设计中存在的缺陷和不足，从环境荷载建模、结构动力响应分析方法、试验测试手段和结构控制理论与措施等方面提出了当前迫切需要进行研究的内容与方向。根本目的旨在提高输电塔-线体系结构设计理论和设计水准，增强抵抗地震和环境荷载灾害性破坏的能力。
关键词：高压输电塔-线体系； 动力计算模型； 试验研究； 抗震抗风； 振动控制； 设计理论

State-of-the-art review on studies of disater resistance of high-voltage
transmission tower-line systems

Li Hongnan　Bai Haifeng
（State Key Lab of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China )

Abstract: With regard to the characteristics of environmental loads and structural dynamic responses, the design standard and reliability of power transmission line systems under earthquake and environmental loads are assessed. The state-of-the-art of high-voltage power transmission line systems and relevant disasters caused by environmental loads is analyzed. Mechanical modeling methods, types and utilities of dynamic analysis, test measurements, available standards and results of experimental investigations, advances and improving directions of anti-seismic and windproof theoretical analysis, structural control theories and developments of corresponding measurements, and structure design theories are systematically summarized. The shortcomings in power transmission line system design and corresponding research needs are pointed out. The research content and direction are provided for systems with respect to environmental load modeling, structural response analytical method, experimental and test measurement, structural vibration control theory and structural design concept.
Keywords:high-voltage power transmission tower-line system; dynamic analysis modeling; experimental research; earthquake and wind resistance; vibration control; design theory

E-mail: hnli@yahoo.com

体外预应力筋极限应力和有效高度计算方法

李国平　沈　殷
（同济大学，上海200092）

摘要：为了建立体外预应力混凝土梁抗弯承载力简化计算方法，通过系列模型试验形成体外预应力筋极限应力和有效高度的基础数据；基于试验验证的非线性有限元计算方法，分析试验加载方式与我国桥梁规范设计荷载的差异以形成 相应的修正系数；根据试验结果分析体外预应力筋极限应力和有效高度随试验参数的变化规律，研究有效高度变化产生的抗弯承载力的二次效应；基于上述分析结果，采用施工方法、跨高比、体内受拉钢筋配比等参数，建立体外预应力筋极限应力和有效高度的回归计算公式，并通过试验数据进行验证；最后按照我国公路桥梁设计可靠度水平和现行规范要求对计算公式进行修正，提出体外预应力筋极限应力和有效高度计算方法。该计算方法能较有效的反映各主要因素对体外预应力筋极限应力和有效高度的影响规律。
关键词：体外预应力筋；极限应力；极限有效高度；简化计算；整体式梁；节段式梁

Calculation methods for the ultimate stress and effective height of external prestressing tendons

Li Guoping Shen Yin
（Tongji University, Shanghai 200092, China）

Abstract: In order to establish a simplified calculation method for the flexural bearing capacity of externally prestressed concrete beams, a series of model tests were conducted to obtain the basic data for analyzing the ultimate stress and effective height of external prestressing tendons. By using the nonlinear finite element method, as verified by the test results, the difference between test loading system and the design load in the Chinese code is compared and a corresponding modification coefficient is introduced. Based on the test results, the variations of ultimate stress and effective height of external prestressing tendons with the test parameters are analyzed, and the second-order effect of effective height variation on the flexural bearing capacity is also studied. With construction method, span-to-depth, area ratio of internal reinforcements as the parameters, the regression formulas for ultimate stress and effective height of external prestressing tendons are established and validated by using the test results. According to the requirements of the current Chinese code and its reliability level for design of highway bridges currently in effect, suitable calculation methods of ultimate stress and effective height for external prestressing tendons are proposed. Use of the proposed methods may reflect the effects of the main factors on the ultimate stress and effective height of external prestressing tendons.
Keywords: external prestressing tendon; ultimate stress; ultimate effective height; simplified calculation; monolithic beam; segmental beam

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

体外预应力混凝土连续梁弯曲性能试验研究

李国平　张国泉
（同济大学，上海200092）

摘要：为了研究体外预应力混凝土连续梁的弯曲性能、极限受力状态及内力重分布规律，以施工方法和体内外预应力筋配比为参数，对1根整体式（体内外配筋）和2根节段式（体内外配筋和全体外配筋）体外预应力混凝土连续梁进行了模型试验。通过试验数据分析，得到了模型梁挠度、混凝土应变、体外预应力筋应力与有效高度随荷载变化规律，以及混凝土裂缝发展与分布情况。结果表明：整体式梁的混凝土极限压应变和挠度最大、延性较好但体外预应力筋有效高度减少最大，节段式体内外预应力梁的体外预应力筋极限应力最大，节段式全体外预应力梁的混凝土极限压应变和挠度最小、延性较差、体外预应力筋极限应力及有效高度减少也最小。节段式梁的裂缝主要集中在接缝位置、无斜裂缝，接缝位置的塑性变形使内力重分布更充分。整体式梁内力重分布的区域集中而节段式全体外预应力梁的范围较大，各梁控制截面弯矩增、减幅值不超过10％。
关键词：体外预应力；连续梁；弯曲性能；弯矩重分布；模型试验

Experimental study on the flexural behavior of externally prestressed
concrete continuous beams

Li Guoping　Zhang Guoquan
（Tongji University, Shanghai 200092, China）

Abstract: To study the flexural behaviour, limit bearing state and internal force redistribution of externally prestressed concrete continuous beams, a monolithic (externally and internally prestressed) and two segmental (one externally and internally prestressed and the other externally prestressed) concrete continuous model beams were tested with the construction method and the ratio of internal tendons to external tendons as the parameters. From the test results, the deflection of concrete beams, strain of concrete, stress and effective height of external tendons with variations of loading are analysed, and the development and distribution of cracks investigated. It is shown that the monolithic beam has the largest deflection and ultimate compressive strain of concrete, best ductility and the smallest effective height of external tendons; the ultimate stress of externally prestressing tendons of the segmental externally and internally prestressed beam is the largest; the segmental externally prestressed beam has the smallest deflection and ultimate compressive strain of concrete, worst ductility, smallest ultimate stress and the largest effective height of externally prestressing tendons. In addition, for the segmental beams, cracks are concentrated near the joints and no oblique cracks are detected, the internal force distribution is more sufficient due to plastic deflections at the joints. The internal force redistribution in the monolithic beam is more concentrated, whereas that in the segmental externally prestressed beams is more widely spread. The range of bending moment redistribution in critical sections of the model beams is below 10%.
Keywords: external prestressing; continuous beam; flexural behavior; bending moment redistribution; model test

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

体外预应力混凝土简支梁剪切性能试验研究

李国平
（同济大学，上海200092）

摘要：为了研究节段式体外预应力混凝土梁的剪切性能，采用剪跨比、配箍率、接缝类型、体内外预应力筋配比等参数进行了13根整体式和14根节段式（胶接缝和干接缝）体外预应力混凝土简支模型梁试验。描述了模型梁箍筋应力、体外预应力筋应力、挠度随荷载变化规律，以及破坏裂缝形成过程和破坏形态；分析了剪跨比、体内外预应力筋配比、接缝位置和数量及类型对梁剪切性能的影响。研究表明，节段式体外预应力混凝土梁的剪切性能和整体式梁有很大差异，接缝决定着剪切破坏形态与破坏裂缝的形成、较大削弱了梁的抗剪承载力、明显增大了破坏裂缝的宽度和梁体破坏时的变形；配置体内预应力筋能有效改善体外预应力混凝土梁的剪切性能；整体式体外预应力混凝土梁的剪切性能和一般预应力混凝土梁也有一些差异。
关键词：体外预应力；整体式梁；节段式梁；剪切性能；模型试验

Experimental study on the shear behavior of
simply-supported externally prestressed concrete beams

Li Guoping
（Tongji University, Shanghai 200092, China）

Abstract: In order to study the shear behavior of segmental externally prestressed concrete beams, 13 monolithic and 14 segmental (epoxy jointed and dry jointed) simply-supported externally prestressed concrete model beams were tested with the shear-span ratio, stirrup ratio, joint type, ratio of internal tendons to external tendons, etc., as the parameters. Stress variations in the stirrup and the external tendons and deflection during loading are described, the failure crack generation and failure mode are also explained. The effects of shear-span ratio, ratio of internal tendons to external tendons, joint position, joint number and joint type on the shear behaviour of beams are analysed. The study indicates that there is significant difference in shear behaviour between segmental externally prestressed concrete beams and monolithic beams. The joint, a key factor affecting the failure crack generation and shear failure mode, causes great decrease in the shear bearing capacity, increase in the crack width and deflection of beams at failure. Internal tendons can effectively improve the shear behaviour of externally prestressed concrete beams. The shear behaviour of monolithic externally prestressed concrete beams also differ, in some aspects, from traditional prestressed concrete beams.
Keywords: external prestressing; monolithic beam; segmental beam; shear behavior; model test

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

体外预应力混凝土简支梁抗剪承载力计算方法

李国平　沈　殷
（同济大学，上海200092）

摘要：将已进行的13根整体式和14根节段式（胶接缝和干接缝）体外预应力混凝土简支模型梁剪切性能模型试验成果，作为建立抗剪承载力简化计算方法的基础资料。根据模型梁剪切性能试验的研究结果，以施工方法（整体式和节段式）、剪跨比、配箍率、接缝类型、体内外预应力筋配比等为参数建立斜截面抗剪承载力的回归计算公式，基于混凝土双轴强度理论和接缝截面极限平衡条件推导接缝截面抗剪承载力计算公式，利用试验数据对计算公式进行验证。按照我国公路桥梁设计可靠度水平和现行规范的要求对计算公式进行修正，提出可用于体外预应力混凝土梁截面抗剪承载力设计的简化计算方法。研究表明，简化计算方法能有效反映体外预应力混凝土梁剪切破坏特点和各主要因素对抗剪承载力的影响规律。
关键词：体外预应力；整体式梁；节段式梁；抗剪承载力；简化计算

Calculation method for the shear bearing capacity of
simply-supported externally prestressed concrete beams

Li Guoping　Shen Yin
（Tongji University, Shanghai 200092, China）

Abstract: Test results for the shear behavior of 13 monolithic and 14 segmental (epoxy jointed and dry jointed) simply-supported externally prestressed concrete model beams are employed for formulating a simplified method of calculating the shear bearing capacity. Based on the test results, a regression formula for the oblique section shear bearing capacity is established with the construction type(monolithic or segmental), shear-span ratio, stirrup ratio, joint type, ratio of internal tendons to external tendons, etc., as the parameters. The shear bearing capacity of joint section is also derived by using the biaxial concrete strength theory and the limit equilibrium condition on joint sections. The two formulas are validated by using the test results. According to the requirements of the current Chinese code and its reliability level for design of highway bridges, a suitable simplified calculation method for the shear bearing capacity in the design of externally prestressed concrete beams is put forward. It is shown that the shear failure behavior and the effects of the main factors on the shear bearing capacity of externally prestressed concrete beams can be represented in the simplified calculation method.
Keywords: external prestressing; monolithic beam; segmental beam; shear bearing capacity; simplified calculation

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

大跨径钢桥面铺装体系多目标优化设计

明图章¹　 胡光伟^1,2 黄　卫²
(1.江苏省交通规划设计院，江苏南京210005；2.东南大学ITS中心，江苏南京210096)

摘要：将大跨径钢桥的正交异性钢桥面和其上的铺装层作为钢桥面铺装体系整体进行多目标优化设计。取大跨径钢桥面铺装体系造价及铺装层表面极限应力最小化两类指标构造目标函数，在此基础上建立多目标优化设计的数学模型。采用评价函数中的线性加权和法进行求解，开发了钢桥面铺装体系结构多目标优化设计程序，以国内某大跨径钢桥为对象，采用多目标优化设计方法，给出钢桥面铺装体系中各参数的合理界限。应用国际通用有限元软件SPA93程序对其进行验证，结果表明，应用多目标优化设计方法对大跨径钢桥面铺装体系设计是可行的。研究成果可为大跨径钢桥面铺装体系结构的设计提供理论依据。
关键词：大跨径钢桥；各向异性钢桥面板；铺装体系；多目标优化；有限元

Multiple-objective optimum design of pavement system for
long-span steel bridges

Ming Tuzhang¹   Hu Guangwei¹   Huang Wei²
(1.Jiangsu Provincial Communication Planning and Design Institute, Nanjing 210005, China
2.Intelligent Transportation Systems Institute，Southeast University，Nanjing 210096, China)

Abstract: This study is concerned with the multiple objective optimum design of long-span orthotropic steel bridge deck and its pavement system．The price of material of the pavement system and the maximum tensile stress on the pavement are selected as the design objectives. The mathematical model of multiple objective optimum design is established, the solution is sought by using the linear weighted sum method of the evaluation functions, and a multiple objective optimum design program for the long-span orthotropic steel bridge deck and its pavement system is developed. The rational limits of parameters for steel bridge pavement systems are obtained through multiple-objective optimal design for a long-span steel bridge in China. The result is validated as reasonable, and the multiple-objective optimum design of long-span steel bridge pavement system is proven to be reasonable and may be used to provide a theoretical basis for the design of the pavement system of large-span steel bridges.
Keywords: long-span steel bridge; orthotropic steel bridge deck; pavement system; multiple objective optimization; FEM

E-mail: mingtuzhang@jsjsy.com

挡土墙墙趾地震作用的波动分析

陈学良¹ 金 星^1,2,3,4 陶夏新^1,5 陈宪麦⁶袁一凡¹
（1.中国地震局工程力学研究所，黑龙江哈尔滨150080；2.福建省地震局，福建福州350003；
3.南京工业大学，江苏南京210009；4.福州大学，福建福州350002；
5.哈尔滨工业大学，黑龙江哈尔滨150008；6.铁道科学研究院，北京100081）

摘要：目前国内外规范中对挡土墙墙趾处地震作用的规定很不一致，给工程设计及工程评价带来诸多困难，如何合理考虑其作用已成为岩土工程中的重要课题之一。针对强震地区的重要挡土工程，以墙前2 m覆盖土层的挡土墙为例进行了设计和讨论；基于近场波动数值模拟技术，输入El Centro波、Taft波、河北迁安滦河桥波和天津医院宁河波这四种不同场地条件的地震动进行动力分析，对比墙趾及墙背处的土动剪力时程发现，墙趾土动剪力对挡土墙的动态稳定性起着重要作用；墙趾覆盖土层所产生的动土压力，较有益于挡土墙的抗倾覆、抗滑稳定性。用简化估计的方法，对动土压力及剪力的合力作用点进行分析，发现相同位置的动土压力和剪力的合力作用点比较接近，其值分别是，墙趾处约距墙底0.62 H2（H2为墙前覆土厚度），而墙背处约为H1/3，这与以往研究并不相同。最后对地震作用效应折减系数进行讨论，并建议了墙趾地震作用的合理设计取值。这些结果为改进挡土墙的抗震设计、指导工程实践提供了有益的基础。
关键词：墙趾；地震作用；动土压力；土动剪力；合力作用点

Wave motion analysis of earthquake action on the toe of retaining walls

Chen Xueliang¹　　Jin Xing^1,2,3,4　　Tao Xiaxin^1,5　　Chen Xianmai⁶ Yuan Yifan¹
(1. Institute of Engineering Mechanics, China Earthquake Administration, Harbin 150080, China；
2. Earthquake Administration of Fujian Province, Fuzhou 350003, China;
3. Nanjing University of Technology, Nanjing 210009, China;
4. Fuzhou University, Fouzhou 350002, China;
5. Harbin Institute of Technology, Harbin 150008, China;
6. China Academy of Railway Sciences, Beijing 100081, China)

Abstract: It is difficult to design and evaluate retaining walls, due to the disagreement regarding the treatment of earthquake action on the toe of retaining walls in design codes in China and other countries. For example, a 2m-soil layer covered at the front of a retaining wall is considered and, the effective design and analysis of the associated retaining walls under strong earthquake motions are explored. Based on the numerical simulation of near-field wave motion, the dynamic response of the retaining wall is analyzed with four records-El Centro, Taft, Qi’an(Luan he), Tianjin Hospital(Ning he)waves under different site conditions. By comparing the shear force history of the back with that of the toe, it is found that the shear forces of the toe of wall are significant to the dynamic stability of the retaining wall, and they provide resistances to the overturning and sliding actions resulting from the dynamic earth pressure. Using a simplified method, the resultant force action points of pressure and shear on both the toe of wall and the back are obtained. At a given location, the resultant force action points of both pressure and shear are close to each other, about 0.62H2(H2 denoting the buried thickness at the front of retaining wall) and 1/3H on the toe and the back, respectively. A reliable value of earthquake action on the toe of wall is proposed in design and the reduced coefficient of seismic action effect is discussed.
Keywords: toe of wall; earthquake action; dynamic earth pressure; dynamic earth shearing strength; action point of resultant force

E-mail: xueliang_chen@yahoo.com.cn

天津某深基坑工程施工监测及数值模拟分析

姜忻良¹   宗金辉²　 孙良涛¹
(1.天津大学，天津300072；2.河北工业大学，天津300130)

摘要：介绍了天津铜锣湾广场深基坑工程开挖实例。通过对深基坑开挖过程中的支护结构内力、坑周土体水平位移等的现场监测和数值模拟分析，讨论了基坑开挖过程中支护结构受力的特点及其对周围环境的影响，得到基坑周边土体水平位移的变化规律，为考虑施工因素的深基坑开挖及支护结构设计提供了依据。分析表明：土方开挖对基坑周围土体的影响范围约为两倍的开挖深度；开挖过程中土体及围护桩最大位移位置基本上都处于基坑开挖面附近；在基坑施工过程中，应该尽量减小无支撑暴露的时间，加快底板浇注，防止因土体流变而产生过大的位移；对于环梁支撑体系，如果支撑布置不规则，会造成受力不均，容易产生较大的弯矩值，会对环梁支护结构产生不利影响。
关键词：基坑；双环梁支护体系；监测；支撑内力；土体水平位移；数值模拟

Construction monitoring and numerical simulation for a deep excavation in Tianjin

Jiang Xinliang¹　Zong Jinhui²　Sun Liangtao¹
(1.Tianjin University, Tianjin 300072, China；
2.Hebei University of Technology, Tianjin 300130, China)

Abstract: A test section was designated for a deep foundation pit for the Tianjin Causeway Bay Plaza. Bracing force and lateral displacement of soils were measured. Construction monitoring and numerical analysis were conducted to obtain the internal force of the bracing system and soil horizontal displacement. The characteristics of the internal force variation in the ring beam and the influence on the environment are discussed. The results of field measurement and numerical simulation indicate that the range of soil influenced by the excavation is about two times of the excavation depth and that the maximum soil displacement for a braced excavation usually occurs near the excavation surface. The analysis results also show that the reinforced concrete base slab should be poured promptly to reduce pit exposure time. For ring beam bracing system, irregular bracing arrangement may cause uneven force and large bending moment that in turn affects the ring beam bracing system.
Keywords: foundation pit; double ring beam bracing system; construction monitoring; internal force; horizontal soil displacement; numerical analysis

E-mail: jiangxinliang@126.com

地铁振动荷载作用下隧道周围饱和软黏土动力响应研究

张　曦²　唐益群^1，2　周念清^1，2　王建秀^1,2　赵书凯²
（1. 同济大学岩土工程重点实验室，上海200092；
2. 同济大学地下建筑与工程系，上海200092）

摘要：以上海地铁二号线静安寺站－江苏路站区间隧道周围饱和软黏土为研究对象，通过对隧道周围不同位置、不同深度土体中预埋土压力盒和孔压计，进行现场连续动态监测，对地铁振动荷载作用下饱和软黏土的响应频率、土体响应应力幅值随距离地铁隧道远近以及土体响应应力幅值随深度的变化规律进行研究，并提出了土体动力响应衰减计算公式，利用该式可以计算出地铁列车经过时的影响范围及其动力响应值的大小，可以预测与估算地铁列车振动荷载对周围建筑物的影响情况，为地铁设计、施工以及安全运营提供有价值的参考。
关键词：地铁隧道；振动荷载；饱和软黏土；动力响应

Dynamic response of saturated soft clay around a subway tunnel under vibration load

Zhang Xi²　Tang Yiqun^1,2　Zhou Nianqing^1,2　Wang JianXiu^1,2　Zhao ShuKai²
（1.State key laboratory of geotechnical engineering, Tongji University 200092, China；
2. Dept. of Geotechnical Engineering, Tongji University, Shanghai 200092, China）

Abstract: The subject of concern is the saturated soft clay around the running tunnel between Jingan Temple Station and Jiangsu Station of the Shanghai No.2 subway line. Continuous dynamic monitoring is conducted by means of embedded soil pressure cells and pore-water pressure meters around the tunnel. The variations of frequency and amplitude of pressure with the distance from the tunnel due to subway vibration load are studied. A formula is proposed for the attenuation of the dynamic pressure response in the soil. The range of influence and the amplitude of dynamic response are calculated. The influence on the surrounding buildings by subway vibration load is predicted.
Keywords: subway tunnel; vibration load; saturated soft clay; dynamic response

E-mail: zhangxi-1979@163.com

网壳锚喷支护理论分析及其在兖州矿区的应用

姚传勤 庞建勇
（安徽理工大学，安徽淮南232001）

摘要：跨采及软岩巷道地压强度高、变形强烈，支护较为困难。传统支护方式成本高、工艺复杂。根据地面大跨度板壳原理设计出网壳结构，该结构稳定性强，能承受较大变形地压及冲击荷载。钢筋网壳结构是巷道支护工程中一种新型的支护形式，既可在巷道内单独组装对围岩进行连续支撑，又可先撑后喷，在围岩表面形成半刚性钢筋混凝土薄壳衬砌结构。能承受强大变形地压及采动荷载，达到用较少材料又提高喷层支撑能力与让压的目标。介绍了钢筋网壳锚喷支护的技术特色与支护原理，并对其进行理论分析，推导出钢筋网壳锚喷结构的计算模型及其内力与主要应力的计算表达式。完成了室内整架载荷试验，成功应用于兖州矿区跨采巷道。
关键词：网壳支架；理论分析；室内试验；跨采巷道；工程应用

AAnalysis of shell bolting and shotcrete supporting and their application in the Yanzhou mine

Yao Chuanqin Pang Jianyong
（Anhui University of Science and Technology, Huainan 232001, China）

Abstract: It is difficult to provide support to overpass and soft-rock mining drifts because of high ground pressure and excessive deformation. Traditional means of support have the disadvantage of high cost and complex technology. Based on the mechanical principle, shell structures are designed such that improved stability and capacity under deformation earth pressure and impulse load can be achieved. Reinforced shell structure is a new type of support for tunnel engineering in soft rocks in forming a continuous lining to the surrounding rock by itself, or to serve as a half-rigid support before concrete spraying. Features of the technology and supporting theory are introduced and analyzed. The calculation model and expressions for calculating the internal forces and main stresses are derived. Laboratory test is conducted and its application to the Yanzhou mine is successful.
Keywords: shell structure；theory analysis；lab test；dynamic pressure tunnel；engineering application

E-mail: cm1990@sohu.com

基于微粒群算法的工程项目资源均衡优化

陈志勇　杜志达　周　华
（大连理工大学，辽宁大连 116023）

摘要：将微粒群算法运用到工程项目管理的资源均衡优化问题，定义了以活动的实际开始时间作为微粒坐标的微粒群；建立了资源方差与活动实际开始时间直接联系的评价函数；通过微粒群在飞行中位置的进化过程来搜索对应于最优方案的活动实际开始时间。最后通过算例的计算分析，用微粒群算法得到的资源强度比初始方案降低了75.2%，比遗传算法的结果降低了26.97%，验证了该方法在工程项目管理的资源均衡优化中的可行性及有效性，同时还获得了若干个次优方案，对于工程项目管理中的资源均衡优化具有实际应用价值。
关键词：微粒群算法；资源均衡；评价函数；项目管理

Research on the unlimited resource leveling optimization with PSO

Chen Zhiyong Du Zhida Zhou Hua
（Dalian University of Technology, Dalian 116023, China）

Abstract: The PSO (particle swarm optimization) was applied for the unlimited resource leveling optimization of construction engineering in this paper. Defined the particle swarm whose coordinates were used for the activity’s actual start time. Established the appraisal function between the resource variance and the activity's actual start time. Searched the best schedule of project by the evolution of the particle swarm’s position during its flying. Finally, the resource intensity obtained by PSO reduced 75.2% compared to the initial schedule, reduced 26.97% compared to the GA’s (genetic algorithm) result according to the case analysis. Validated the feasibility and the effectivity of the PSO in the unlimited resource leveling optimization , and also obtained several secondary optimum schedules as well as the best one. Therefore, this method has its practical application value for the resource leveling optimization .
Keywords: particle swarm optimization; unlimited resource leveling; appraisal function; project management

E-mail: czydut@163.com

CSG坝筑坝材料特性与抗荷载能力研究

杨首龙
（福建省水利水电勘测设计研究院，福建福州 350001）

摘要：胶凝砂砾石坝（CSG）是介于混凝土面板堆石坝（CFRD）和碾压混凝土重力坝（RCC）之间的一种新坝型。其显著的特点是：胶凝材料用量少，对筑坝材料要求低，坝体和地基受力条件好，是一种环保性能、力学和大坝安全性能都很有竞争力的新筑坝技术。通过福建省龙岩白沙大坝、宁德洪口大坝的围堰以及尤溪街面大坝围堰等3个工程，对CSG坝的筑坝材料和抗荷载能力进行分析研究，并在街面工程的下游围堰进行局部CSG坝的工程实践。研究表明：CSG坝的水泥用量约为RCC重力坝的42.9%~49.1%左右，大坝断面可较CFRD坝减少100%，大坝位移量与RCC坝相当，而只有CFRD坝的1/20~1/10。不仅如此，CSG坝体受力条件明显改善，竣工期与运行期坝体内应力变化不大，大坝抗震能力明显增强。
关键词：CSG坝；材料特性；应力分析；工程实践

Charateristics and load carrying capacity of CSG dam construction materials

Yang Shoulong
(Fujian Institute of Investigation and Design of Water Conservancy and Hydropower,
Fuzhou 350001,China)

Abstract: Cement sand and gravel (CSG) dam is a new type of dam between concrete-faced rock-fill dam(CFRD) and roller compacted concrete dam (RCC). It is obvious that the cement content is low and it is possible to utilize a wide range of materials. CSG is advantageous in environmental protection, internal stress feature and dam safety. The material characteristics and load carrying capacity are studied for the Baisha dam, the Hongkou dam and the Jiemian dam in Fujian province. These studies indicate that the unit cement content is 42.9~49.1 percent of the RCC’s, and the dam section is one half of the CFRD’s . The displacement of CSG is similar to the RCC’s and is 1/10~1/20 of the CFRD’s. In another aspect, CSG is superior in that the internal stress and the load on the foundation do not change significantly under full or empty reservoir conditions and the seismic resisting capacity of the dam is greatly enhanced
Keywords: CSG; material characteristics; stress analysis; engineering practice

E-mail: sdy297@mail.fhid.com

考虑随机腐蚀作用的埋地管线地震反应分析

刘　威　李　杰
（同济大学，上海200092）

摘要：利用齐次马尔可夫过程模拟埋地管线腐蚀的发生，并利用线性腐蚀模型模拟埋地管线腐蚀的发展，将线性腐蚀模型中腐蚀速率考虑为确定性参数，推导给出了管线面积腐蚀率随服役时间变化的概率密度函数，并获得了管线截面面积随服役时间变化的均值和方差。在此基础上，根据弹性地基梁模型，将管线周围土体位移正交展开为余弦级数的形式，获得了地震作用下腐蚀管线位移反应和应力反应的解析表达式。对腐蚀管线地震反应进行线性展开，采用随机摄动理论推导给出了腐蚀管线在地震激励下位移和应力反应的均值和标准差。利用上述分析模型对一根200 m长的埋地管线进行了实例分析，结果表明建议模型可以反映管线面积随服役时间的变化规律，并能反映腐蚀管线在地震作用下位移反应和应力反应的基本概率特征。
关键词：管线；腐蚀；随机摄动；马尔可夫过程；弹性地基梁

Seismic response analysis of buried pipelines with stochastic corrosions

Liu Wei Li Jie
(Tongji University, Shanghai 200092, China)

Abstract: In order to evaluate the corrosions of buried pipelines as the service time increases, Markov process is employed to simulate the occurrence of corrosion of the pipelines. Combining with a linear corrosion development model with deterministic corrosion rate parameters, the evolution of probability density function of the corrosion percentage of buried pipeline section area as service time increases is derived, and the mean and the covariance of pipeline section area are also obtained. Based on such a pipeline corrosion model, an elastic foundation beam model is employed to express the seismic displacement and stress of pipeline as orthogonal cosine series. Using the random perturbation approach, the random seismic response of pipelines is simplified as a linear function of the section areas of pipe segments, and then the mean and the covariance of seismic response are derived. In order to validate the proposed approach, a 200-meter long pipeline is investigated in detail, and the results indicate that the proposed approach can efficiently simulate the evolution of buried pipeline section area as service time increases.
Keywords: pipeline; corrosion; perturbation method; Markov process; elastic foundation beam

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