斜拉桥纵向设置粘滞阻尼器参数分析

采用Maxwell阻尼模型模拟了粘滞阻尼器的滞回耗能特性。通过对设置粘滞阻尼器斜拉桥纵向非线性地震反应的分析，讨论了粘滞阻尼器各参数对结构地震响应的影响，并通过计算证实了粘滞阻尼器具有良好的消能减振效果。     

双座串联大跨度斜拉桥粘滞阻尼器参数分析

以双座串联大跨度斜拉桥-珠海洪鹤大桥为背景,根据桥梁自振特性及场地效应,生成了三组人工波,采用纵向+2/3竖向的地震作用组合输入方式,通过非线性时程分析,系统的研究了粘滞阻尼器对双座串联大跨度斜拉桥减震性能的影响。同时为了确定粘滞阻尼器的最优参数,对粘滞阻尼器的阻尼系数C和速度指数α进行了参数敏感性分析。结果表明:设置纵向粘滞阻尼器能够显著减小双座串联斜拉桥的纵向位移响应,减小主梁在串联处发生碰撞的概率,同时改善主塔塔底结构受力情况,具有良好的耗能减震效果。综合考虑安全性、适用性和经济性等方面,最后给出针对洪鹤大桥的最优粘滞阻尼器参数:速度指数α为0.3,阻尼系数C为3 000kN/（m/s）^0.3。     

大跨度斜拉桥阻尼器参数分析

以某大跨度斜拉桥实际工程为依托,研究大跨度斜拉桥线性粘滞阻尼器参数的不同选取对该桥抗震性能的影响。通过线性动力时程分析对线性粘滞阻尼器在大跨度斜拉桥中阻尼系数C进行参数敏感性分析,并与该桥在未设置线性粘滞阻尼器状态下的地震响应进行比较分析。结果表明:斜拉桥纵向设置粘滞阻尼器后,通过调节粘滞阻尼器的参数能有效降低结构在地震作用下关键部位的相对位移;可以有效的控制大跨度斜拉桥纵向位移,但是在高频区,竖向位移放大约为23%;同时也改善了结构构件的地震力响应并为同类工程粘滞阻尼器应用中的参数研究提供参考。     

变间隙粘滞阻尼器的性能分析

基于半主动控制理论,本文提出一种新型的间隙式粘滞阻尼器。通过改变阻尼器缸体内径形成合理的阻尼通道间隙,使阻尼系数具有随位移改变而变化的特性。在幂律流体本构关系的基础上,建立了粘滞阻尼器的阻尼力计算模型。理论计算表明：新型间隙式阻尼器的减振性能显著优于常规间隙式阻尼器。     

单层柱面网壳的粘滞阻尼器减振分析

采用粘滞阻尼器减振系统对单层柱面网壳的减振效果进行了较为系统的分析，分别考虑了阻尼系数C0、结构自身阻尼比ζ、屋面质量和结构自身刚度对结构减振系数δ的影响，同时考察了设置阻尼器的数目以及阻尼器的位置的影响。通过较大规模参数化分析，基本了解了粘滞阻尼器减振系统在单层柱面网壳中的减振规律。     

应用大型TMD抑制崖门大桥RC桥塔的抖振响应

崖门大桥是一座两个独柱桥塔单索面预应力混凝土斜拉桥，桥塔在独立状态气动弹模型风洞试验结果表明，在横桥向施工设计风速作用下需要对桥塔的抖振响应进行控制。本文就TMD对抖振控制的理论分析，TMD优化参数以及抑振倍率进行了推导，设计安装了以粘性剪切阻尼器（VSD）为耗能机构的被动式动力减振装置。通过现场实测，风洞试验及理论分析，三者十分吻合。3     

多阶梯被动变阻尼装置高层建筑风振控制性能化设计方法

多阶梯被动变阻尼装置(multi-stage passive variable damping device, MPVDD)能够随外部激励速度变化机械式实时改变阻尼系数,同时不需要外部能量供给和反馈控制,与粘滞阻尼器相比,MPVDD耗能效果明显。在不同阶数MPVDD控制下的高层结构响应控制效果分析表明,多阶梯被动变阻尼装置出力范围大,可用于风振控制。根据风振分析结果提出了针对多阶梯被动变阻尼装置的风振控制性能水准和性能指标,以及多阶梯被动变阻尼装置高层建筑风振控制性能化设方方法,该设计方法可以对不同重现期的风荷载激励下的结构响应针对性设计,最后通过工程实例设计给出了完整的设计过程,从而证明了该方法对高层建筑风振控制的有效性和可行性。     

基于桥梁抖振分析的自激力计算方法

抖振是桥梁在风荷载作用下的一种经常性的限幅振动。对于长大跨度桥梁在计算其抖振响应时不得不考虑自激力的影响，而自激力的计算方法不一，且其计算过程复杂，繁琐。本文根据抖振计算理论，研究一种自激力的实用计算方法，并对军山斜拉桥进行自激力计算。     

城市桥梁粘滞阻尼器防地震碰撞分析与参数设计

研究了粘滞阻尼器防止城市梁桥地震碰撞反应的效果并提出了其参数设计方法。分析了线性粘滞阻尼器与非线性粘滞阻尼器阻尼系数的等效关系。运用随机振动理论与随机等效线性化理论建立了邻联间安装粘滞阻尼器后最大相对位移及墩顶最大位移的计算方法。以控制邻联最大相对位移小于实际间隙为目标,提出了防碰撞粘滞阻尼器参数设计方法。对1座4跨隔震连续梁桥进行了仿真分析,结果表明:粘滞阻尼器能有效抑制邻联的碰撞反应且不会显著增大桥墩的延性需求。在相同阻尼系数的情况下,粘滞阻尼器的速度指数越小,其防碰撞效果越好。利用人工波进行的时程分析结果验证了参数设计方法的可行性。     

考虑阻尼器极限状态的耗能减震体系 斜拉桥抗震性能分析

在大震或特大震下,黏滞阻尼器可能因某个极限状态的出现而发生破坏。现有在斜拉桥上设置黏滞阻尼器的研究多集中在阻尼器的参数优化上,很少考虑到阻尼器失效对斜拉桥抗震性能的影响。针对这一问题,以某三塔斜拉桥为背景,利用OpenSees平台建立斜拉桥有限元模型和可以考虑承载力及行程极限的黏滞阻尼器模型;分析黏滞阻尼器的阻尼系数和阻尼指数对斜拉桥地震响应的影响,确定阻尼器参数的取值;对不安装阻尼器、安装不考虑极限状态及考虑极限状态阻尼器等多种工况的斜拉桥进行非线性时程分析,对比各工况斜拉桥的地震响应。分析结果表明,在大震下,考虑极限状态阻尼器的耗能能力及减震效果将显著降低;不考虑阻尼器达到极限状态后失效的情况将高估耗能减震设计斜拉桥的抗震能力。     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.     

WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)

正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases     

SCIENCE CHINA Earth Sciences SUBJECT INDEX TO VOLUME 57(2014)

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