塔式容器结构抗震设计的动力可靠性研究

本文运用随机有限元原理提供了结构系统在地震力作用下的可靠性分析方法，并运用该方法对现行规范抗震设计的几种典型塔式容顺进行动力可靠性研究，其结果可为制订塔式容器结构抗震可靠性设计标准作为参考。     

结构健康监测系统设计标准化评述与展望

阐述了结构健康监测的概念和内涵。详细介绍了结构健康监测系统的功能、组成和应用现状。结构健康监测系统设计标准化能够促进健康监测的应用和发展,具有重要的工程意义。对世界范围内相关研究进展进行了综述和评价。强调在我国建立监测系统设计标准的重要性,并提出了相应的说明和建议。设计标准可以分为总则、外观检查与无损检测、传感器的选择与布置、信息采集与处理系统、通信与传输系统、损伤识别和评估系统、应用实例等7部分。结构健康监测系统设计标准的实现将有力地推动健康监测的研究。     

广畅国际大厦磁流变和粘滞阻尼器抗震分析

针对上海广畅国际大厦的抗震问题，通过对不同控制装置的优缺点和适用范围进行比较分析后，采用磁流变阻尼器和粘滞阻尼器相结合的方式，探讨了该结构在无控和安装控制装置后在地震作用下的动力响应和控制效果。文中通过建立结构的力学模型，首先分析了无控结构的动力特性；此后分析了无控结构以及安装磁流变阻尼器和粘滞阻尼器的结构在多遇地震以及罕遇地震作用下的动力响应。分析结果表明，采取磁流变阻尼器以及粘滞阻尼器相结合的方式，能够有效地控制该结构在地震作用下的响应。     

基于位移的减震结构设计方法研究

针对减震结构的设计, 其振型分解反应谱方法不能反映阻尼器的非线性和结构在大震下的性能;时程分析法需要多次试算、十分繁琐的情况,采用以结构构件设计为主、线性粘滞阻尼器为强度补充的设计思想,将结构等效为单自由度体系,利用基于位移的设计方法对线性粘滞阻尼减震结构进行设计,并利用该方法设计1栋13层框架剪力墙结构,最后通过动力时程分析验证了该方法的可行性.     

结构分灾抗震设计:概念和应用

详细论述了结构分灾抗震设计的产生背景、设计思想、优化模型和基本原则，指出结构分灾设计是在分析基于投资—效益准则的结构抗震设计模型的基础上，对工程实践中一些成功经验的提炼和概括而形成的设计方法，工程领域中一些现行设计方法和措施就是分灾设计的具体应用。当工程师们待处理的问题必须考虑高度不确定性因素时，将分灾设计作为一种可能选用的设计理念，将有助于工程师们实现设计创新。分灾设计符合基于性能的抗震设计思想，可以方便地实现基于性能的设计。     

百米级高层隔震结构一体化设计及风振舒适度评估研究

《建筑隔震设计标准》（后简称《隔标》）是我国第一部专门指导隔震设计的国家级标准。由于目前基于新规范完成隔震设计的实际工程较少,尤其是百米级高层隔震结构在我国还尚属少见,为此针对某百米级住宅公寓楼实际工程展开研究,根据《隔标》完成隔震设计,并从经济性的角度出发,对比了一体化直接设计法与传统分部隔震设计法的配筋结果;最后结合现行规范对高层隔震结构的风振舒适度进行了评估。研究结果表明：一体化直接设计方法在显著提升隔震结构安全的同时还具有较好的经济性,即使隔震结构设防目标由小震提升至中震,即地震作用提升约3倍的前提下,该高层隔震结构总用钢量的增加仍控制在15%以内;百米级高层隔震结构在1年、10年风荷载作用下均出现了舒适度问题,最大风振加速度响应分别达到了10.3 gal和18.0 gal,超出规范限值71.7%和20%,在未来的隔震结构抗风设计中,高层隔震结构的风振舒适度问题应引起足够重视。     

变截面屈服L形金属阻尼器力学性能试验研究

针对常规金属阻尼器设计位移较小、抗疲劳性能差和制作安装复杂等不足,基于变截面塑性屈服设计思想提出一种L形金属阻尼器。在初步给出其工作机理及构造形式的基础上,设计并制作3组不同设计参数的L形钢阻尼器试件,通过拟静力试验研究其滞回规律、耗能能力和抗疲劳特性,分析了各项工作性能指标对设计参数的敏感性。试验结果表明:L形钢阻尼器能够实现变截面屈服及大位移变形,其滞回曲线呈饱满纺锤形,恢复力退化小,黏滞阻尼系数可稳定在0.5附近,具有良好的耗能能力和抗疲劳性能;该阻尼器初始刚度大,可满足结构不同抗震位移设计需求;影响该阻尼器滞回特性及抗疲劳性能的主要参数为L形耗能钢板高度和厚度。本文工作对结构抗震加固和减震设计提供了一种新的选择。     

钢筋混凝土框架结构直接基于损伤性能的抗震设计方法研究

在现有抗震设计方法研究的基础上，提出了直接基于损伤性能的设计方法。首先，建立等效位移延性系数与结构损伤指标的关系，得到了反映不同设防水准损伤目标的结构等效位移延性系数；其次，运用R-μ关系模型，根据等效位移延性系数确定地震折减系数，从而计算出结构弹塑性地震作用；然后，建立结构的需求曲线与推覆曲线，对结构在强震作用下的性能进行评价；最后，通过算例说明了该方法的设计步骤及其可行性。     

基于结构性能的抗震设计理论研究与展望

基于结构性能的抗震设计理论进90年代国际地震工程提出的新概念，是抗震设计理念上的一次变革。本文阐述了基于结构性能的抗震设计理论产生的背景，基本内容，主要特点及发展概况，并结合我国抗震设计理论和实际的现状就其研究和应用前景进行了展望。     

基于位移的底部框架-抗震墙房屋抗震能力分析

在基于性能/位移抗震设计思想下,通过动力时程分析,研究了底部两层框剪砖房结构在不同地震强度作用下的弹塑性反应和变形特征;针对《规范》中对底部两层框剪砖房结构侧向刚度比的限定条件,研究了不同侧向刚度比条件下结构的抗震能力,得到了相关结论。     

Seismic analyses of conventional and improved marginal wharves

Marginal wharves are key components in providing functionality of port facilities. Ports are central components of the US economy. Earthquake damage to a port can disrupt the economic stability. Therefore, port facilities must be able to quickly return to full operation shortly after a seismic event. Prior studies have shown that integrity of marginal wharves may be compromised by excessive soil movement and structural damage. The latter is often localized at pile‐to‐wharf connections and in the pile body buried within the soil. Recent research has resulted in an improved connection design that mitigates damage. This study was undertaken to evaluate the full seismic performance of marginal wharves including both conventional and damage‐resisting connections. A series of finite element models of a representative pile‐supported wharf facility were created. The models varied in their moment‐resisting pile‐to‐wharf connections. A total‐stress analysis approach was used to capture the soil response along with p–y, t–z, and Q–z soil–structure interaction springs. Validated connection interface elements were integrated with non‐linear frame elements to simulate the marginal wharf structure and substructure. Non‐linear static pushover and dynamic time history analyses, for three different hazard levels, were performed. The results of the numerical simulations were used to assess the performance of the marginal wharf including estimates of crane damage and port downtime. Copyright © 2013 John Wiley & Sons, Ltd.     

Probabilistic assessment for seismic performance of port structures

Past experience has shown that ports are often susceptible to severe damage during earthquakes. From field damage data of 1995 Kobe earthquake, it is observed that the seismic behavior of port structures shows significant variability. In this study, a 2D numerical model, representing PC1 berth located in Port Island, Kobe and damaged in the 1995 Kobe earthquake, has been developed and used to simulate seismic behavior. It has been found that the uncertainties in the friction angle and the shear modulus of reclaimed soil contribute most to the variability of the residual horizontal displacement (RHD) response of the quay wall of port structures. To investigate the propagation of uncertainties of soil–structure system to the quay wall, a tornado diagram and a first-order second-moment analysis are used. Uncertainty of ground motions has also been investigated. Based on the results, design considerations have been provided.     

Uniform hazard versus uniform risk bases for performance‐based earthquake engineering of light‐frame wood construction

This paper investigates the implications of designing for uniform hazard versus uniform risk for light‐frame wood residential construction subjected to earthquakes in the United States. Using simple structural models of one‐story residences with typical lateral force‐resisting systems (shear walls) found in buildings in western, eastern and central regions of the United States as illustrations, the seismic demands are determined using nonlinear dynamic time‐history analyses, whereas the collapse capacities are determined using incremental dynamic analyses. The probabilities of collapse, conditioned on the occurrence of the maximum considered earthquakes and design earthquakes stipulated in ASCE Standard 7‐05, and the collapse margins of these typical residential structures are compared for typical construction practices in different regions in the United States. The calculated collapse inter‐story drifts are compared with the limits stipulated in FEMA 356/ASCE Standard 41‐06 and observed in the recent experimental testing. The results of this study provide insights into residential building risk assessment and the relation between building seismic performance implied by the current earthquake‐resistant design and construction practices and performance levels in performance‐based engineering of light‐frame wood construction being considered by the SEI/ASCE committee on reliability‐based design of wood structures. Further code developments are necessary to achieve the goal of uniform risk in earthquake‐resistant residential construction. Copyright © 2010 John Wiley & Sons, Ltd.     

海上风电工程基础结构抗震性能研究

为了探讨海上风电工程基础与结构体系的抗震性能,采用ANSYS程序建立了三种基础型式的风电塔架结构数值模型,先采用振型分解反应谱法计算了结构的地震响应,进而分别将传统地震动和最不利地震动作为输入地震动,分析了三种基础结构体系的最大地震响应。结果显示:风电结构属典型的长周期结构,基础型式对结构的振动周期影响明显,单立柱桩式结构振动周期最长,八桩承台结构振动周期最短。地震作用下,单立柱桩结构的顶端位移响应也最大;振型反应谱法与传统地震动作用下结构的响应满足现行建筑抗震规范的要求,但最不利地震作用下结构的位移响应偏大,不满足规范对位移的相关规定;组合三桩结构底部基础与结构连接处是应力集中区。海上风电工程结构抗震设计的重要性应引起充分重视。     

桥梁结构抗震挡块的研究现状与展望

综述了桥梁抗震挡块的几类典型结构形式,对常见挡块的实际震害形式、破坏机理以及力学分析模型的研究现状进行了分析,归纳总结了不同规范中桥梁抗震挡块的设计方法。对当前挡块抗震研究和设计中存在的问题进行了分析和讨论,并提出了一种新型的预应力装配式超高性能混凝土(UHPC)挡块形式。研究结果表明:传统整体式混凝土挡块的主要破坏模式为斜剪和平剪破坏,既有试验中已对两种模式的破坏机理进行了较深入的研究;相比传统整体式混凝土挡块,滑移型混凝土挡块和弹塑性钢挡块在抗震设计中更具可控性,值得进一步在国内推广和应用;美国规范按挡块类型分别给出了不同的设计策略,并对挡块的承载力计算方法和配筋形式进行了说明,值得我国桥梁抗震设计规范借鉴;提出的装配式UHPC挡块具有传力简单明确、自复位和震后修复更换方便等特点,可作为我国中小跨径桥梁结构抗震挡块设计及加固的一种有益补充,值得进一步展开深入的研究。     

加筋格宾新型组合支挡结构设计研究

依托湖南省湘潭至衡阳西线高速公路K 124＋300～K 124＋895段国内首座加筋格宾组合式挡土墙工程,介绍了以双绞合六边形金属网为筋材的2种新型加筋支挡结构：加筋格宾结构与绿色加筋格宾结构;以极限平衡理论为基础,吸收国外先进加筋土技术,提出了该组合结构的稳定性验算方法与公式;编制相关程序,深入研究了填料粘聚力、内摩擦角、网面拉力、地震力、填土重度、车辆荷载以及加筋间距等重要参数对安全系数的影响。研究表明,各设计参数对安全系数的影响程度不同。同时,也验证了该加筋格宾组合式挡土墙设计的科学性和合理性。研究成果可应用于具体支挡结构设计。     

工程结构抗震设防标准的决策分析

提出了工程结构抗震设防标准的决策方法,该决策方法以结构初始造价分析和地震损失分析为基础。建立了结构初始造价与设计烈度的关系,并提出了地震损失的估计方法。使用该决策方法导出了最佳设计烈度和重现周期的解析表达式,从而得出了对抗震设计具有重要意义的结论。     

最不利设计地震动研究

实际记录到的真实地震动在工程结构的抗震研究、分析和设计中往往作为一种施加到结构上使结构振动，直至破坏的地震荷载．如何合理选择真实的地震动记录作为研究结构地震反应的输入，一直是国内外抗震研究和设计中引人关注的重要问题．本文首先提出了最不利设计地震动的概念；然后在收集到的国内外5000余条被认为有重要意义的地震动记录基础上，利用综合估计地震动潜在破坏势的方法，对４种场地类型分别给出了长周期、短周期和中周期结构的国内外最不利设计地震动；最后通过几类不同结构的地震反应分析，初步验证了本文所确定的最不利设计地震动的可靠性和合理性．      

Peak-over-threshold: Quantifying ground motion beyond design

In performance-based seismic design, as adopted by several building codes worldwide, the structural performance is verified against ground motions that have predetermined exceedance return periods at the site of interest. Such a return period is evaluated by means of probabilistic seismic hazard analysis (PSHA), and the corresponding ground motion is often represented by the uniform hazard spectrum (UHS). The structural performance for ground motions larger than those considered in this design approach is, typically, not explicitly controlled under the assumption that they are sufficiently rare. On one hand, this does not achieve uniform safety at sites characterized by different design ground motions corresponding to the same return period; on the other hand, exceedances of the design spectra are systematically observed over large areas, for example in Italy. The latter issue is because of the nature of UHS, the exceedance of which is likely-to-almost-certain when the construction site is in the epicentral area of moderate-to-high magnitude earthquakes (ie, the design spectrum may be not conservative at these locations), especially if PSHA is based on seismic source zones. The former is partially because of the systematic difference of ground motions for return periods larger than the design one at the different sites. Quantification of the expected ground motion given the exceedance of the design ground motions (ie, the recently introduced as the expected peak-over-threshold or POT) can be of help in quantitatively assessing these issues. In the study, a procedure to compute the POT distribution is derived first; second, POT spectra are introduced and used to help understanding why and how seismic structural reliability of code-conforming structures decreases as the seismic hazard of the site increases; third, expected and 95^th percentile POT maps are shown for Italy to discuss how much high hazard sites are exposed to much larger peak-over-threshold with respect to mid-hazard and low-hazard sites; finally the POT is discussed with respect to the slope of the hazard curve (in log-log scale) at the threshold, a known proxy for ground motion beyond design. All data presented in the maps are made available for the interested reader as a supplemental archive.     

Study on the severest real ground motion for seismic design and analysis

How to select the adequate real strong earthquake ground motion for seismic analysis and design of trucures is an essential problem in earthquake engineering research and practice.In the paper the concept of the severest design ground motion is proposed and a method is developed for comparing the severity of the recorded strong ground motions.By using this method the severest earthquake ground motions are selected out as seismic inputs to the structures to be designed from a database that consists of more than five thousand significant strong ground moton records collected over the world.The selected severest ground motions are very likely to be able to drive the structures to their critical response and thereby result in the highest damage potential.It is noted that for different structures with diffferent predominant natural periods and at different sites where structures are located the severest design ground motions are usually different.Finally.two examples are illustrated to demonstrate the rationality of the concept and the reliability of the selected design motion.