A method for examining the seismic performance of steel arch deck bridges

To examine the seismic resistance performance of a steel arch bridge during a strong earthquake, an approach is proposed in this paper to determine the ultimate strain of an arch rib using the static elasto-plastic large deformation theory. A steel fixed-end deck arch bridge with a span length of 200 m was used as an example in this study. The ultimate strain of the arch rib was calculated using the elasto-plastic finite element model. The seismic responses of the arch bridge exposed to strong earthquakes in two and three directions were also simulated. Moreover, the effect of earthquake motion in the lateral direction on the elasto-plastic earthquake response was discussed, and the seismic resistance of the structure was analyzed. The results show that steel arch bridges have preferable seismic resistance under strong earthquake conditions. While lateral earthquake motion has some influence on the damage to an arch bridge, it has little effect on the displacement, axial force, and bending moment responses of the arch rib. It is feasible to examine the seismic performance of the arch bridge by ascertaining the out-of-plane and in-plane earthquake responses of the bridge.     

上承式钢管混凝土拱桥车桥耦合研究

对于车桥耦合振动的研究,目前比较多的是以移动荷载和移动质量这两种简化方法来模拟车辆通过桥梁时的情况,移动荷载简化模型由于计算方便,所以在目前车桥耦合振动分析中应用得比较多,但是由于移动荷载的研究方法没有考虑质量的惯性力的作用,所以该分析方法与实际情况存在一定的差距,本文以落步溪大桥荷载试验为依据,分析了移动荷载作用下桥梁结构的加速度,分析了移动荷载模型这种计算方法对于钢管混凝土拱桥车桥耦合分析的可靠性和适用条件。     

Fatigue test of an advanced orthotropic steel deck system using high performance steel for bridges

Magnificent elongation of bridge span length, especially of recently constructed cable stayed bridges and suspension bridges, can be achieved by technological as well as new material development of orthotropic steel deck systems. One such effort is to install curved bulkhead plates inside longitudinal u-ribs, which was analytically and experimentally demonstrated to reduce significant amount of concentrated stresses without sacrificing self-weight of the whole structure. In this paper, the optimal shape of more effective bulkhead plates is characterized by computational analysis. And it is verified from fatigue tests of a 3-dimensional full-scale structure that the fatigue performance can be significantly improved by installing the optimal bulkhead plates and by fabricating the structure out of recently developed high performance steel for bridges.     

大跨径桥梁钢桥面铺装设计

由于大跨径钢箱梁桥面铺装的使用条件、施工工艺、质量控制与要求的特殊性,因此对于特定的桥梁的桥面铺装均需作针对性的专题研究,以保证铺装设计和施工成功。总结了作者近10年对大跨径钢桥面铺装设计理论与方法设计的研究成果,包括铺装材料与结构、钢桥面铺装体系受力特性、疲劳特性、设计指标、轴载换算原则与方法、铺装体系整体优化设计方法、工程实施等技术,研究成果已在南京长江第二大桥、南京长江第三大桥、润扬长江公路大桥、苏通长江大桥和杭州湾大桥等10多座大型钢箱梁桥桥面铺装设计和铺装工程中应用。     

钢桥面铺装层结构设计指标近似计算新方法

在行车荷载作用下,钢桥面铺装层的受力与变形较一般公路沥青路面或机场道面复杂得多,也是钢桥面铺装层结构设计的一个重要因素。从使用条件、工程实践、试验研究和受力特点等角度出发,提出钢桥面铺装层结构设计指标:一是铺装层拉应力,二是铺装层表面局部挠跨比。采用有限元方法建立在车载作用下钢桥面铺装层的力学响应计算模型。在结构设计参数常用取值范围内,对不设纵隔板和设置纵隔板两种常用钢桥面铺装层的结构设计指标关键影响因素进行正交敏感性分析。同时,通过逐步线性回归方法拟合出钢桥面铺装层结构设计指标的近似计算公式。得到的近似计算公式的精度检验和工程实例分析结果表明,近似计算公式精度很好,满足工程设计和理论研究的需要。研究结果可为钢桥面铺装层结构设计提供近似计算的新方法。     

Expansion of a static analysis-based out-of-plane maximum inelastic seismic response estimation method for steel arch bridges to in-plane response estimation

We have previously proposed a static analysis-based method for estimating the maximum out-of-plane inelastic seismic response of upper-deck steel arch bridges. The method is developed on the basis of the numerical examinations of 6 upper-deck steel arch bridge models. It employs free vibration analysis, response spectrum method and equal energy assumption for the estimation of maximum out-of-plane response. Correction functions are proposed to modify the estimates by the equal energy assumption. In the current study, applicability of the same procedure to the estimation of maximum in-plane response is discussed. It is found that the method can be used also for the maximum in-plane response estimation by only modifying the pushover analysis procedure. The validity of the method is demonstrated for the same parametric models through further numerical evaluations.     

钢管混凝土拱桥多振型组合pushover方法可行性例证

提出采用pushover方法估计钢管混凝土（CFT）拱桥的弹塑性地震响应。由于CFT拱桥地震响应受高阶振型影响较大,故pushover方法需要考虑多振型组合。在阐述了多振型组合的pushover方法的过程步骤后以潮白河大桥为例,对比了pushover方法和杆系模型弹塑性时程分析所得的增量动力时程分析（IDA）曲线。对比结果表明：考虑多振型组合pushover方法能合理的得到结构最大响应;所绘制的IDA曲线与弹塑性时程分析所得曲线很接近,可以用于工程实践;就该例而言,多振型组合结果误差比单一振型结果小10%~15%。     

Reliability-based optimization of steel truss arch bridges

A reliability-based optimization approach is developed and applied to minimize the weight of steel truss arch bridges subject to probabilistic (the overall probability failure of the structure) and deterministic (stress and deflection) constraints. The method intelligently integrates the genetic algorithm (GA), the finite element method and the first order reliability method. A real-coded/integer-coded method is used to realistically represent the values of the design variables. Three GA operators consisting of constraint aggregate selection procedure, arithmetic crossover, and non-uniform mutation are proposed. The finite element method (FEM) and the first order reliability method are used to compute the value of the probabilistic and deterministic constraint functions. A numerical example involving a detailed computational model of a long span steel arch bridge with a main span of 550 m is presented to demonstrate the applicability and merits of the present method. Finally, several important parameters in the present method are discussed.     

Optimum rise design of steel arch bridges

The subject of this paper is the preliminary estimation of the optimum rise of the arch rib in the case of steel arch bridges. This optimum rise is defined in relation to the weight of the construction material used for the arches and columns, while the cost of erection is ignored. A series of arch bridges, having various spans are examined. These bridges have a flexible deck and a stiffened arch rib. For each span the optimum rise is obtained, when the weight of the arches and columns is minimized. The results are given in diagrams in which the variation of the optimum rise with respect to various characteristic parameters, is shown.     

桥梁中抗震限位装置设计方法的研究

为防止桥梁上部结构在地震中发生落梁破坏,通常在伸缩缝处安装限位装置。在调查影响伸缩缝处相邻梁体相对位移因素的基础上,根据线性化模型提出一种限位装置设计方法。该方法既考虑了相邻桥跨不同向振动的动力特性,又考虑了相邻梁体间碰撞对相对位移的影响。运用替代结构法考虑墩柱的弹塑性,使用考虑碰撞效应的相对位移反应谱考虑碰撞对相对位移的影响。通过参数研究对提出的限位装置设计方法的可靠性进行验证,并通过与已有的限位装置设计方法相比,评估了所提出的限位装置设计方法的限位效果。与已有的设计方法相比,本文提出的限位装置设计方法与非线性时程分析结果的相关性更好。     

Dynamic analysis of a cable-stayed deck steel arch bridge

A theoretical and experimental research work in relation to the cable-stayed Barqueta bridge is described in this paper. Barqueta bridge, across Guadalquivir river, links the city of Seville with Scientific Park Cartuja 93. During rush hour cars may cover one half of the bridge lanes for more than one hour. Full-scale tests were carried out to measure the bridge dynamic response. The experimental program included the dynamic study for two different live load conditions: the bridge with one half of its lanes full of cars, and the bridge empty of cars. Modal parameter estimations were made based on the acquired data. Ten vibration modes were identified in the frequency range of 0-6 Hz by different techniques, two of these modes being very close to each other. The traffic-structure interaction is also studied. Experimental results were compared with those obtained from a three-dimensional finite element model developed in this work. Both sets of results show very good agreement. Finally, a damage identification technique has been applied to determine the integrity of the structure. Results obtained from a test developed in July 2005 have been correlated with experimental results obtained in October 2006 using the damage index method.     

浅谈钢管混凝土在拱桥中的应用

本文介绍了钢管混凝土具有承载能力强、施工方便、经济效益显著等特点,因此在桥梁工程中得到了广泛的应用。本文列举了钢管混凝土作为拱肋常被采用的几种形式,并配以工程实例进行说明。     

大跨径钢桥桥面铺装材料研究现状

简要介绍了目前世界上主要的几种钢桥桥面铺装材料，并对各种材料的应用现状及前景作了简要分析，为钢桥面铺装材料设计提供一定参考。     

New launching method for steel bridges based on a self-supporting deck system: FEM and DOE analyses

This paper studies a new launching method for steel bridges based on a self-supporting deck system. This new and patent-protected procedure is able to launch bridges of a span length up to 150 m, in an economical and sustainable way. The use of the last span segments to reinforce the critical sections during launching replaces other conventional temporary means applied nowadays. The main objective of this research paper is to numerically analyse the best double deck configuration as well as to define an approach to stiffener distribution in order to avoid the patch loading phenomenon in the slender webs. With this in mind, the pre-design of a triangular cell along the low flange of each web is presented. A three dimensional finite element model (FEM) is built and the design of experiments technique (DOE) is applied to obtain the best bridge configuration. This new construction method can be used together with a continuous launching system in order to increase the velocity of the whole operation and to improve safety during launching. Very good results have been obtained, in terms of deflection, patch loading resistance and vertical load on the pushing device. The comparison with other different construction systems and the application to a real case allows us to ensure the viability of the method described.     

下承式提篮拱桥钢管混凝土顶升法压注施工

钢管混凝土压注是提篮拱桥的关键工序及质量安全控制重点,从混凝土配合比、工艺流程、施工方法等方面做了详细的阐述,总结了混凝土灌注质量控制要点和检验方法,为今后类似工程提供了参考。     

钢管拱桥喷涂防腐施工工艺

以太平湖大桥防腐涂装工程为例,介绍了钢管拱桥喷涂防腐施工工艺,分别对外防腐施工程序及工艺要求和内防腐施工工艺进行了具体阐述,并提出了施工中注意事项,为同类桥梁的防腐施工积累了宝贵经验。     

下部结构对钢管拱桁架抗震性能的影响

通过建立模型,从结构的节点位移、抗震承载力和破坏形式等方面,对三种不同下部结构钢管拱桁架进行了强震下动力弹塑性时程分析,结果表明,三种下部结构拱桁架都能够满足预期的抗震设防目标,下部结构形式会影响拱桁架结构的抗震承载力。     

空中翻身法预制吊运上承式拱箱

从浇筑台座的布置及放样、横板制作安装、钢筋制安、拱箱浇筑介绍了拱箱预制施工方案，阐述了拱箱移位吊装方法，并分析了实施效果，为类似施工积累了经验。     

特大桥钢管拱施工技术

简单归纳了钢管拱桥的特点,重点介绍了特大桥钢管拱施工技术,包括桥上使用的大型吊装设备、拱肋横梁等构件的安装技术和塔架整体横移等施工工艺,为今后同类桥梁施工积累了经验。