The stress analysis of the cable-pylon anchorage zone is usually calculated using solid finite elements.However,due to the complex structure and diverse types,it is not easy for general engineering designers to use.Therefore,this paper analyzed the transmission characteristics of the built-in steel anchor box anchoring system based on the actual project of a cable-stayed bridge and proposed a simplified calculation method based on the plane frame theory.Nonlinear analysis methods were used to establish an ANSYS finite element model of the anchorage zone to correct the formula.The results show that the error between the calculation results of the simplified formula before correction and the finite element model calculation results is about 10%.Considering the influence of the thickness of the pylon wall,the calculation height of the pylon,and the thickness of the anchor box side plate,the method of reducing the elastic modulus of concrete is used to compensate and correct the stress distribution of the bridge pylon,and the specific concrete reduction coefficient is determined by the method of nonlinear regression.Finally,the corrected formula was compared with the finite element model data.The results show that the error between the calculation results of the corrected formula and the finite element model calculation results is within 2%,indicating the corrected formula can well analyze the cable force distribution in the cable-pylon anchorage zone and has a certain practical engineering value.

The fatigue life and relaxation life of bolts affect their service life. Under the joint action of fatigue and relaxation, the connection at the column base is deteriorating. In order to explore the influence of the relaxation of connecting bolts on the fatigue life of high-speed railway sound barrier, bolts with asymmetrical and symmetrical arrangements used for high-speed railway sound barrier at a train speed of 400 km/h are taken as the research objects, and the finite element models of column base bolts are established using ANSYS. The preload is applied by cooling method, positive and negative unit bending moment loads are applied to calculate the stress amplitude of the most unfavorable bolt at the column base under different preloads, and the fitting relationship between the stress amplitude and preload is proposed. Moreover, based on Midas, a whole model of noise barrier is established to analyze the dynamic response characteristics of the barrier structure at the train speed of 400 km/h.The bending moment time history results of column base bolts are extracted to compare the bolt life considering fatigue failure only and the bolt life considering relaxation and fatigue together. Results show that the bolt relaxation will reduce the preload and increase the bolt stress amplitude of bolt base models in both cases of asymmetrical and symmetrical arrangements. In the existing time history calculation of column base bolts, the fatigue life considering the combined effect of relaxation and fatigue is much lower than that only considering the fatigue effect. When the preload is reduced to 55% due to the relaxation, the fatigue effect will occur. The results can provide a reference for designers of connection structures to quantitatively evaluate the bolt life and the maintenance of bolts.

甬舟铁路西堠门公铁两用大桥主桥为主跨1 488 m斜拉-悬索协作体系桥,主梁由3个流线型扁平钢箱梁组成,斜拉索梁端采用内置于边箱风嘴部位的钢锚箱锚固,钢锚箱与箱梁纵腹板双侧连接.为研究该桥索梁锚固结构的受力特性和焊缝传力机理,确保锚固结构承载安全可靠,选择全桥索力荷载最大的S26号钢锚箱索梁锚固结构进行局部受力研究.采用Abaqus软件建立索梁锚固区域多尺度有限元模型,分析不同施工阶段对索梁锚固结构受力状态的影响,以及索梁锚固结构处于不同索力工况下,锚固区域应力分布和焊缝传力机理.结果表明:钢锚箱锚固结构设计合理、安全可靠;锚箱结构受力相对独立,基本不受梁段施工阶段边界条件变化影响,而与锚箱相连内腹板则存在约17％的应力变化;索梁锚固区域整体应力水平较低,但存在明显的应力集中现象,主要分布在锚箱与腹板相连的6条焊缝附近,且随着索力荷载增大,应力集中现象更为突出;锚箱与腹板相连的6条焊缝分配索力合理,但不同焊缝等效应力沿焊缝方向呈现不同分布形式,且随着索力荷载增大,焊缝等效应力分布特征更加显著.

SummaryAs a new type of lateral load‐resisting system in SPSW systems, corrugated SPSWs (CSPSWs) have been gradually researched and applied. Corrugated plates offer various advantages over flat plates including higher energy dissipation capacity, ductility, out‐of‐plane stiffness, and improved buckling stability. For seismic control and isolation techniques, low yield point (LYP) steels (LY100, LY160, and LY225) are the reliable and ideal energy‐dissipating materials. The low yield point CSPSWs combine high energy‐consuming materials with high‐performance structures to provide a better solution for ductile and seismic resistance of high‐rise and super tall buildings. Currently, there are no design codes addressing the seismic performance of LYP corrugated steel plate shear walls (CSPSWs). This study investigates cyclic behavior and energy dissipation performance of corrugated steel plate yield point (100, 160, 225, 235, and 345 MPa) of different thickness CSPSWs and determine the plate yield point that provides the optimum performance. Results and findings of this study reveal that compared with the ordinary yield strength corrugated steel plates, the low yield point CSPSWs have a larger safety factor of lateral bearing capacity, a fuller hysteresis curve, a strong energy dissipation coefficient, a larger ductility coefficient and a smaller fluctuation range of strength degradation coefficient, and better strength stability. The initial equivalent stiffness of CSPSWs with different yield strengths is the same.

To study the mechanical characteristics and live load effect of the ultra-wide steel box girder of the cable-stayed rail-cum-road bridge, based on the study of the ultra-wide steel box girder section of Yibin Lingang Yangtze River Bridge with a width of 63.9 m, a model of the composite structure with a scale of 1∶10 was designed and constructed for static load model tests and finite element analysis, where the mechanical characteristics, longitudinal and transverse normal stress distribution and beam deformation characteristics of the ultra-wide steel box girder were investigated under the dead load condition, road vehicle load condition, railway train load condition and combination of different live load conditions. The results show that the box girder of the bridge has a significant lateral bending force behavior, with the girder body exhibiting the mechanical properties and deformation characteristics of a shoulder-supported girder under the live load conditions. The middle box shows the mechanical characteristics of a simply supported beam with positive bending moment under the load of the railway train, while the side boxes of the beam show the mechanical characteristics of the cantilever beam with a negative bending moment under the load of the road vehicles, pedestrians and non-motor vehicles, showing reasonable design of the cross-section of the girder body, clear live load action mechanism, and clear force transmission of the middle and side box structures. The research results provide important reference and design basis for the design and construction of ultra-wide steel box girders, and provide guidance for the design of similar bridges.

The stability of stiffened plates has always been an important research issue in bridge engineering. The application of stiffened curved plates (SCPs) in the field of bridge engineering is gradually increasing, but the corresponding research needs to be more comprehensive. Guidelines have yet to be established in bridge design codes for the stability design of SCPs. To study the failure mode and ultimate resistance of SCPs with trapezoidal longitudinal stiffeners under uniaxial compression, six test specimens with a scale ratio of 1:2 were designed in this work, and static loading tests were conducted on three kinds of SCPs with different curvatures. The influence of curvature on the ultimate resistance and failure mode of SCPs was analyzed, and a calculation method for the ultimate resistance of SCPs was discussed. Results showed that the SCPs with trapezoidal longitudinal stiffeners have sufficient overall and local stability. The failure of the SCPs occurred locally in the subpanels between stiffeners, and the ultimate resistance of specimens with different bending radii was insignificantly different. The ultimate compressive resistance calculated following the effective section of the main plate was close to the test results. When the subpanels are locally buckled, the stiffened flat plate calculation method can be used to analyze the ultimate resistance of SCPs, and the calculated results deviate conservatively.

为了研究低屈服点波形钢板剪力墙(corrugated steel plate shear wall,CSPSW)新型抗侧向荷载系统减震耗能性能,利用有限元软件ABAQUS,对 16个CSPSW有限元模型进行横向单调和循环荷载作用下的减震耗能性能数值分析,并以波形钢板屈服强度和板厚为关键参数,综合分析其对结构抗侧性能、滞回性能、刚度退化、延性和能量耗散等性能的影响规律.研究结果表明:低屈服点CSPSW与普通钢板剪力墙初始刚度相同,但抗侧性能弱于后者;与普通屈服强度CSPSW相比,低屈服点CSPSW滞回曲线更饱满,耗能性能更好,且延性更好;随着波形钢板屈服强度降低,低屈服点CSPSW延性和耗能性能均提高,结构水平刚度退化加快;随着波形钢板厚度增大,低屈服点CSPSW初始刚度和结构耗能性能均提高,承载能力变化较小.

因材料导热系数的显著差异,高海拔地区钢-混组合桥梁可能出现超出规范的环境温度效应.针对拟建藏区某40 m跨径简支钢-混组合梁桥,通过热-结构耦合分析,研究了环境因素作用下的温度场以及结构温致效应,并对桥梁结构选型提出了建议.研究表明,在高海拔环境中,钢-混凝土组合梁存在较大温差梯度,且温差值、温差曲线与现有设计规范存在一定差异;环境温度下混凝土板应力分布极不均衡,温致拉应力超过材料抗拉强度;温致应力峰值多位于钢-混交界面,此处易成为结构薄弱环节;钢箱组合梁箱内、外混凝土应力水平差异较大,且温致结构竖向变形较大,从结构温致效应角度推荐采用钢板组合梁.

运用有限元软件ANSYS建立钢管混凝土桁架焊接T型管节点模型,进行支管轴向拉力作用下管节点热点应力集中系数(Stress Concentration Factor,SCF)研究.结果表明:T型管节点的主管冠点处SCF与管径比、径厚比和壁厚比均成正相关,而主管鞍点处SCF虽与径厚比和壁厚比成正相关,但与管径比呈负相关;相比于主管,支管SCF整体水平较低,且随几何参数变化幅度较小;主管SCF沿管节点相贯线的分布模式与管径比、径厚比相关,但受壁厚比的影响很小;管节点SCF最大值与径厚比、壁厚比成正相关,随管径比的变化规律与径厚比的取值有关;基于有限元计算结果,可推导出钢管混凝土桁架焊接T型管节点SCF最大值计算式.

为研究悬挂式轨道梁在无车情况下的抗震能力,以某悬挂式轨道交通试验线为研究对象,利用MIDAS/CIVIL建立模型并采用反应谱法,研究不同地震峰值加速度(0.1g、0.15g、0.2 g、0.3 g、0.4 g)对Y型墩柱的影响.研究结果表明:该桥横向刚度较小;相较于横向地震,Y型墩柱在顺桥向地震作用下的内力响应更大;当地震加速度大于0.1g时,4号混凝土墩柱开始出现裂缝;当地震加速度大于或者等于0.25 g时,3号混凝土墩柱开始出现裂缝;在所讨论的地震峰值加速度中,Y型钢墩和混凝土墩柱均未出现屈服现象,但混凝土墩柱弯矩增长速率更快,有先屈服的趋势.

为了研究不同开口形式的封闭式声屏障在高速列车所产生风压作用下的受力特征,以某高铁声屏障为研究对象,利用有限元软件Midas建立顶部不同开口间距的双侧封闭式声屏障及顶部不同覆盖长度的单侧封闭式声屏障整体模型;将速度为350 km/h的列车驶过时产生的脉动风压激励时程作用于声屏障结构整体模型,计算得到声屏障结构的静力响应和动力时程曲线;最后计算动力放大系数.研究结果表明:双侧封闭式声屏障顶部增加开口间距和单侧封闭式声屏障顶部覆盖长度减小都有利于风压的释放,改善结构受力情况,随着开口间距增加或覆盖长度减小,有利作用愈加明显;对于双侧封闭式声屏障,开口2 m时立柱最大动应力是开口8 m时立柱最大应力的1.15倍,放大系数也增加0.12;对于单侧封闭式声屏障中,覆盖8 m时立柱的最大动应力是覆盖2 m时立柱的最大动应力的1.28倍,放大系数也增加0.37.

随着高速铁路的发展,行车速度不断提升,对于声屏障的结构性能要求也逐步提高.基于数值分析方法,运用有限元软件Midas Civil,建立6种常用结构形式插板式声屏障模型,进行380 km·h-1以上高速铁路插板式声屏障动力特性及响应研究.结果表明:不同结构形式的插板式声屏障在增设1m高通透隔声板后自振基频减小;在车速为380,400和420 km·h-1条件下,插板式声屏障立柱的横向位移、组合应力和纵向弯矩放大系数在未设置1m高通透隔声板时均随车速的增大而增大,而在增设1m高通透隔声板后则随车速的增大先增后减;在相同车速下,增设1m高通透隔声板后,立柱的横向位移、组合应力和纵向弯矩放大系数均增大.针对增设1m高通透隔声板的声屏障,设计时除需重点关注420 km·h-l车速时的结构动力响应外,还需额外关注400 km·h-1车速时的结构动力响应.

为研究变刚度组合连续梁的有效宽度,采用有限元软件AnsysAPDL建立3跨变刚度组合连续梁空间有限元模型,计算组合梁关键截面混凝土板的有效宽度和纵向应力分布,进行4种常用中外规范的适用性评估,以及变刚度区域底板混凝土构造和钢与混凝土界面的抗剪刚度对混凝土顶板有效宽度和纵向应力分布的影响分析.结果表明:在边跨跨中截面和中跨支座截面,用英国规范和日本规范计算出的混凝土顶板有效宽度与有限元的计算结果较为吻合,差距在15％以内;在中跨支座附近的变刚度段内,底板的栓钉抗剪刚度变化只对中跨截面顶板的有效宽度有影响;全桥栓钉的抗剪刚度退化至0.1倍初始刚度之前,对顶板的有效宽度和纵向应力分布影响较小,变化在5％以内;当各关键截面栓钉抗剪刚度分别降低时,仅相应截面处的有效宽度和顶板纵向应力分布受影响,相同退化条件下,支座截面受影响最大.

高速铁路声屏障受通行高速列车的列车风反复激励,连接螺栓会发生松弛.为预测反复横向剪切荷载长期作用下高速铁路声屏障螺栓的松弛程度,利用软件ANSYS建立考虑螺纹螺旋效应的三维有限元模型,利用降温法施加预紧力,加载交变横向力,研究不同横向力幅值、初始预紧力及螺纹螺距相应的松弛速率.结果表明,横向力幅值越大、初始预紧力越小、螺纹螺距越小,松弛速率越快.通过引入部分假设,建立了一种简易方法用于预测确定荷载谱下声屏障螺栓的松弛程度,研究成果对声屏障螺栓维护有指导意义.

为解决传统桥梁病害信息管理过程中数据采集过程复杂、可视化效果不佳及缺乏时间关联要素的问题,结合BIM(building information modeling)技术实现了某钢桁梁桥裂纹病害的可视化,基于可视化编程软件Dynamo研发了一种裂纹病害信息快速批量更新的方法,且将更新代码模块化;通过引入病害时间参数,创建了4D裂纹病害信息模型,实现了裂纹病害信息与三维图形在时间序列上的动态关联,呈现了裂纹的扩展规律.研究结果表明:在桥梁病害管理系统中引入BIM技术可以提升病害信息管理的效率,实现裂纹病害信息的可视化,通过4D裂纹病害信息模型的创建可以直观地对裂纹病害的发展历程加以呈现,帮助桥梁运维管理人员科学地预测裂纹发展趋势.

In order to investigate the local stress distribution and hot spot stress concentration factors (HSCF) of welded tubular joints of concrete-filled steel tube (CFST) truss under different contact characteristics of steel-concrete interfaces, the Y-shaped welded tubular joints of CFST truss (the angle between the chord and the branch was 60°) were set as the research object. Utilizing the finite element software ANSYS, a finite element model of the tubular joint was established by using Solid45, Mass21, Targe170 and Conta173 elements. Considering nonlinear surface-surface contact relationship between the steel tubular wall and the filled concrete, internal squeezing or detachment caused by local deformation were simulated. Local contact deformation and stress state such as the contact gap, penetration depth, normal contact stress and tangential friction stress between the steel tubular and the filled concrete were obtained. The HSCF distributions of the chord and branch under three friction coefficients (0, 0.35, 0.60) were analyzed. The research results showed that the HSCF at the weld toe of the chord had a minimum value at the crown heel and a maximum value at the midpoint between the saddle point and the crown toe. Compared with the chord, the HSCF of the branch was generally smaller and the minimum value appeared at the crown heel. The maximum appeared between the saddle point and the crown toe. Under the action of the axial tension of the branch, the steel and concrete near the welding seam of the Y-shaped tubular joint were separated from each other, and the void area near the crown point was larger than that near the saddle point. The periphery of the void area of the saddle point was the most violent contact and compression area between the steel tubular and the concrete. The pressure was the greatest, and the concrete showed the most obvious supporting effect on steel tube. The friction coefficient had little effect on the distribution trend of the HSCF of tubular joint, and had a certain effect on the maximum value of HSCF.

研究目的:郑北大桥索梁锚固结构采用锚拉板结构形式,该区域构造复杂,焊缝交错,部分位置存在明显的应力集中现象,恒载作用下易发生塑性破坏,反复荷载作用下易产生疲劳破坏.通过建立精细化有限元模型,分析锚拉板式索梁锚固结构的易损部位,对局部细节进行设计参数优化,从而改善其恒载和活载下的受力性能.提取疲劳易损部位热点应力,通过热点应力S-N曲线和线性累积损伤理论计算其疲劳寿命,验证参数优化效果. 研究结论:(1)在原设计的基础上适当优化锚拉板厚度能有效改善锚拉板式索梁锚固结构恒载下受力性能,防止材料塑性破坏;(2)经热点应力法计算疲劳寿命验证,在原设计的基础上适当优化圆形过渡区半径、锚拉板厚度、锚筒厚度能提升锚拉板的疲劳寿命;(3)本文研究结论可运用于今后的斜拉桥锚拉板式索梁锚固结构的设计中,以供相关设计人员参考.

为分析城市轨道交通W型槽梁在顶推施工过程中的时变剪力滞效应,该文以某轨道交通W型槽梁桥为工程背景,建立Ansys和Midas三维有限元实桥模型,计算得到顶推过程中梁体内力变化情况及关键截面纵桥向正应力分布状态,研究得到W型槽型梁截面剪力滞系数的时变规律.研究表明:底板在顶推施工过程中同位置剪力滞效应可能出现正负性质的改变;中间腹板和两侧腹板处剪力滞效应的正负性质大多相反;底板最大剪力滞系数与截面正弯矩存在一定程度正相关;最大悬臂截面剪力滞系数约在0.79～1.58范围内出现,该类桥型设计时需要考虑施工阶段应力状态.

钢-混凝土组合结构是土木工程中一种主要组合结构,能充分发挥混凝土和钢材的性能,可作为一种可持续发展的桥梁结构.近年来,随着绿色建造以及可持续建造理念的普及,钢-混组合结构桥梁在公路、铁路桥梁中所占比例逐步提高,学者们从多个方面开展了对钢-混组合结构桥梁的科学研究和工程应用.为了促进对该结构更加全面、深入的研究,指导钢-混凝组合结构在桥梁建设中更切合实际的应用与推广,对2019年度钢-混组合结构整体力学行为、钢-混组合结构剪力键、钢-UHPC组合结构、钢管混凝土结构及波形钢腹板-混凝土组合结构5个方面的最新研究进行梳理与总结,并对未来钢-混组合结构研究热点和方向进行展望.

为研究主管支撑条件及支管与主管夹角对钢管混凝土桁架(CFST)Y型管节点热点应力分布的影响,利用ANSYS采用20节点实体单元,考虑相贯线焊缝建立Y型管节点空间有限元模型,计算分析在一端固定,一端铰接、两端固定、两端铰接3种边界条件下,支管不同角度变化时(20°,40°,60°,80°,90°),支管轴压作用下主管和支管焊趾处,热点应力集中系数沿相贯线焊缝分布情况.有限元分析结果与已有试验结果进行对比,验证模型的可靠性.研究结果表明:相同约束条件下,随支管角度增大,主管和支管沿焊缝的热点应力集中系数表现为增大,主管热点应力集中系数最大值始终发生在冠点,支管热点应力集中系数最大值由冠点向鞍点移动;同一角度时,随着主管两端约束的加强,主,支管热点应力集中系数分布有所减小,主管鞍点附近受约束条件影响很小.由于局部和整体的刚度同时影响SCF,可以考虑改变节点形式或者减少计算长度、加强固端约束达到降低SCF的目的.