多点输入下大跨结构反应谱分析方法研究进展

在大跨度结构的抗震研究领域,多点输入反应谱方法因其形式简洁、物理意义明确、应用方便等优点而获得了广泛重视和迅速发展,并已在一些重大工程项目的抗震分析中得到了应用。本文首先详细阐述了近年来国内外多点输入反应谱分析方法的研究现状;然后介绍了多点输入反应谱法的应用情况,包括基于该方法进行的大跨度结构地震反应分析和抗震可靠度分析;最后,提出了今后研究中一些需要进一步解决的问题。     

长联大跨摩擦摆支座隔震连续梁桥多维地震反应分析

结合长联大跨连续梁桥的特点,以1座(65+123+156+123+10×90+55)m长联大跨摩擦摆支座隔震连续梁桥为背景,建立了全桥三维有限元模型,运用非线性时程分析法,分析了地震动输入模式、地震动强度、摩擦摆支座参数对该桥内力、位移和能量响应的影响。研究结果表明:(1)长联大跨连续梁桥布置摩擦摆支座,可有效延滞固定墩顶有效主梁质量效应,实现全桥协同抗震。大部分地震能量可通过支座滞回耗能散耗,大幅降低了该桥固定墩地震能量耗散需求。(2)长联大跨连续梁桥减隔震设计中,建议采用水平单向+竖向地震组合进行内力设计,采用三向地震组合进行位移设计。(3)强震作用下,支座摩擦因数取0.029~0.034时该桥隔震性能最优。     

Numerical simulation of aerodynamic derivatives and critical wind speed for long-span bridges based on simplified steady wind field

Combining the computational fluid dynamics-based numerical simulation with the forced vibration technique for extraction of aerodynamic derivatives, an approach for calculating the aerodynamic derivatives and the critical flutter wind speed for long-span bridges is presented in this paper. The RNG k-ε turbulent model is introduced to establish the governing equations, including the continuity equation and the Navier-Stokes equations, for solving the wind flow field around a two-dimensional bridge section. To illustrate the effectiveness and accuracy of the proposed approach, a simple application to the Hume Bridge in China is provided, and the numerical results show that the aerodynamic derivatives and the critical flutter wind speed obtained agree well with the wind tunnel test results.     

四渡河大跨悬索桥空间地震响应分析

非一致激励输入对大跨结构响应有着较大影响。本文以四渡河悬索桥为背景,首先根据该桥动力特性对规范反应谱进行调整,基于修正反应谱并考虑相位非平稳性合成地震动位移;然后编制了调索程序来确定有限元模型的初始平衡构型;采用时程法,分别分析了在纵桥向、横桥向以及竖向的非一致激励(行波输入、多点输入)下的悬索桥地震响应。计算结果表明,纵向非一致激励输入增大了悬索桥的地震响应,横向、竖向非一致激励输入的影响有增有减。     

某大型复杂结构地震响应与控制研究

针对某大型复杂结构的地震响应及控制策略进行了研究。首先,建立该结构的整体有限元模型,采用Ritz向量法对结构进行模态分析,研究该复杂结构的振动特性,基于位能加权平均法求解了该复杂结构等效阻尼比;随后,研究了不同布置型式下粘滞消能支撑的受力特点和计算模型;最后.对该结构进行减振设计,分析了不同消能支撑布置形式下的减振效果。结果表明,采用消能减震装置能有效降低复杂结构的地震响应,且并不改变结构体型;同等减震效果前提下,采用人字形支撑比采用斜撑更为经济。本文工作可供类似的大型复杂结构减震设计参考和借鉴。     

Modeling of cable vibration effects of cable-stayed bridges

The analysis of dynamic responses of cable-stayed bridges subjected to wind and earthquake loads generally considers only the motions of the bridge deck and pylons. The influence of the stay cable vibration on the responses of the bridge is either ignored or considered by approximate procedures. The transverse vibration of the stay cables, which can be significant in some cases, are usually neglected in previous research. In the present study, a new three-node cable element has been developed to model the transverse motions of the cables. The interactions between the cable behavior and the other parts of the bridge superstructure are considered by the concept of dynamic stiffness. The nonlinear effect of the cable caused by its self-weight is included in the formulation. Numerical examples are presented to demonstrate the accuracy and efficiency of the proposed model. The impact of cable vibration behavior on the dynamic characteristics of cable-stayed bridges is discussed. Supported by: Natural Science and Engineering Research Council of Canada     

大跨度空间网格结构在地震行波作用下的响应

本文对地震行波三向正交分量分别独立作用和联合作用下的大跨度空间网格结构的地震响应（包括结构控制点的位移，杆件内力，柱底弯矩等）进行了数值分析，结果表明，与一致地震振动相比，地震动的行波效应可使大跨度空间网格结构的控制点位移增大21%，柱脚弯矩增大79%，杆件内力增大100%，因此，在大跨度空间结构的抗震分析中必须进行详细的抗震分析。     

The Concept and Development of Smart Structures Technologies for Long-span Cable-supported Bridges

This article presents an overview of smart structures technologies in connection with long-span cable-supported bridges. Considering the broad scope of the smart structures technologies, two subareas, namely, structural health monitoring and structural control technologies, and their applications in long-span cable supported bridges, are identified as the focus of this review. It is believed that by, adopting the smart structures technologies, reliable operation and hazard management of long-span bridges can be achieved much more efficiently and can be made economically feasible, especially for bridges located at sites with high risks of severe natural hazardous events, such as those facing the bridges of the Taiwan Strait Crossing project. The feasibility of and practical issues in implementing the smart structures technologies in the design and construction of long-span cable-supported bridges are also discussed here. Considering the time span of the construction of the Taiwan Strait Crossing, some of the innovative technologies with a high potential for future long-span bridge applications, while still at the stage of exploratory research at the time of writing, are also examined as it is believed these technologies might have become prevalent by the completion time of the Taiwan Strait Crossing project.     

自适应卡尔曼滤波在大跨径桥梁安全监控中的应用

对由卡尔曼滤波理论建立的数据模型进行了研究,建立了自适应动态滤波模型,并用该模型对南京长江某大跨径桥梁的实际监测资料进行了分析,结果表明该模型能正确反映桥梁变化.     

Cluster computing-aided model updating for a high-fidelity finite element model of a long-span cable-stayed bridge

Accurate and high-fidelity finite element (FE) models are in great demand in the design, performance assessment, and life-cycle maintenance of long-span cable-stayed bridges. The structural system of a long-span cable-stayed bridge is often huge in size and complex with many components connected and various materials constituted. Therefore, the FE model of a long-span cable-stayed bridge involves a large number of elements and nodes with many uncertainties. The model updating of the FE model to best represent a real bridge is necessary but very challenging. One of the challenging issues is that the numerical computation needed for searching the global optimum of a large set of structural parameters is so extensive that the existing FE (not surrogate) model-based updating methods cannot fulfill this task. In this study, a cluster computing-aided FE model updating framework is proposed for the high-performance FE model updating of large and complex structures. In the framework, several computer software packages, including MSC.Marc, Python, and MATLAB, are interconnected for making use of their respective functions of strength. The shake table test of a scaled physical structure of the Sutong cable-stayed bridge in China is used to validate the accuracy and efficiency of the proposed framework. The simulated bridge responses based on the updated FE model are in good agreement with the measured ones from the shake table test. The successful application of the proposed framework provides a reference for the model updating of other types of large and complex structures.