Effects of in‐cycle strength degradation on collapse capacity of steel moment frames

In this study, the effects of in‐cycle strength degradation of steel moment connections are investigated on global behavior of multiple degree‐of‐freedom structures. Two types of degrading connection models are defined and compared with a bilinear non‐degrading model. Due to dispersion of the experimental test results on connections performance, two models are considered for each type. A probability assessment is carried out by implementation of incremental dynamic analysis to find the capacity of the structures for various performance levels. A sensitivity study is conducted on hysteresis parameters of connection models to investigate the effect of these parameters on global behavior of the structures. Due to increased dispersion of displacement demands observed in degrading cases, a reliability analysis is carried out to consider the effect of uncertainty on confidence level of the structures. Results show that in‐cycle strength degradation can lead to abrupt dynamic instability and as a consequence decrease in reliability of the system against collapse. Copyright © 2013 John Wiley & Sons, Ltd.     

基于坝肩失稳破坏模式的高拱坝地基体系地震易损性分析

为了开展高拱坝-地基体系整体稳定地震易损性分析,从坝肩潜在滑块滑动失稳破坏模式出发,综合考虑了地震动和材料参数的不确定性,采用增量动力分析方法（Incremental Dynamic Analysis,IDA）,开展了基于概率统计框架的1000次非线性动力响应分析。分别采用特征点残余滑动位移和滑动面积比作为评价结构响应的性能指标,以地震动峰值加速度（peak ground acceleration,PGA）为地震动强度指标,定量的划分了高拱坝-地基体系的不同性能水平,绘制了地震易损性曲线,并对不同极限状态下的地震易损性进行了评估和分析。结果表明,基于特征点残余滑动位移的IDA曲线可以将高拱坝-地基体系分别划分为局部滑动破坏和整体滑动失稳破坏两个破坏等级;基于滑动面积比的IDA曲线可以划分为轻微滑动破坏、中等滑动破坏和整体滑动失稳破坏三个破坏等级;从而根据高拱坝-地基体系的实际地震需求从概率意义上评判结构所处的破坏状态,为高拱坝的抗震优化设计、加固和维修决策提供科学依据。     

一种电力实时监控系统异构数据库访问方法

为了简化异构数据库的访问,提高上层应用程序的复用性和系统的可扩展性,本文介绍一种基于插件动态库的异构数据库访问方法。该方法通过公用中间动态库向应用程序提供动态访问数据库的统一接口,屏蔽数据库的类型差异,使得应用程序和异构数据库之间具有相互独立性,从而有效地解决电力实时监控系统中异构数据库透明高效的访问问题。该方法已在实际系统中得到了有效应用。     

无插件网页快照报表连续显示技术

报表作为一种信息组织和分析的有利手段,广泛应用在各行各业,是企业信息系统的重要组成部分之一。报表应用系统的开发是基于Web结构的信息化系统开发的重点之一,尤其是在客户端,用户在浏览报表时,目前基本上都是通过上下翻页来查看,这样使得报表浏览方式呆板,不够直观。针对这个问题提出了无插件Web报表连续显示的技术并予以实现。该技术同时结合XML和XSLT技术的优势。详细说明了该技术的总体设计,最后介绍了该套方案在实际项目中的应用情况,证实了其可用性和易用性。     

电阻抗式传感器大肠杆菌快速检测方法研究

基于电阻抗法原理,完成了细菌快速检测阻抗式传感器的前端设计,并对叉指式电极进行工艺实现;合理设计实验方案,选取奈奎斯特曲线斜率表征细菌数量的变化,完成了大肠杆菌生长过程的阻抗研究;对测量结果进行分析,并设计实验验证,完成了细菌生长过程中奈奎斯特斜率变化的理论分析,其结果与理论推导吻合。该数据分析方法降低了对测试电极和测量环境的要求,缩短了细菌测定所需要的时间,可用于微生物的快速检测中。     

SRC框架结构失效模式识别与优化

控制结构的失效模式,使结构由于非理想的失效模式向理想的失效模式转化,对提高结构的抗震性能,降低地震时人员伤亡和财产损失,具有重要意义。本文以结构失效模式的识别和优化为研究目标,通过基于OpenSees平台对型钢混凝土结构进行IDA分析,搜索出结构的控制地震波,并获得该地震波作用下的失效模式,并采取一些工程手段对其优化。     

利用FTP和ASP技术 构建资料存储系统 扩

文章主要介绍了SERV-U FTP服务器软件通过插件扩展连接数据库详细记录上载、下载的数据信息,从而利用此特性构建低成本的资料存储管理系统的方法,文章介绍了具体实施步骤和了相应的管理流程、主要数据结构。     

轻钢龙骨房屋抗震性能研究(Ⅱ)——IDA分析

基于数值拟合的滞回曲线和骨架曲线模型,运用增量动力分析法,对结构进行了国内外20条地震记录作用下的动力分析,研究了轻钢龙骨房屋的抗震性能.研究结果表明:轻钢龙骨房屋结构具有承载力高、延性适中、抗震性能好等优点,能够作为普通住宅结构运用于我国广大的抗震设防地区.     

亚氨基二乙腈对合成双甘膦的影响研究

研究了以亚氨基二乙腈为原料制备草甘膦中间体双甘膦的工艺条件,主要探讨了碱解过程中水解温度及氢氧化钠用量对亚氨基二乙腈水解收率的影响,并进一步考察了几个厂家生产的亚氨基二乙腈对合成双甘膦的影响。     

Collapse behavior evaluation of asymmetric buildings subjected to bi‐directional ground motion

This paper discusses the collapse behavior of low‐rise plan‐asymmetric buildings under bi‐directional horizontal ground motions and utilizing strength and stiffness degrading nonlinear models. For this purpose, three‐dimensional three‐story and six‐story reinforced concrete frame buildings with uni‐directional mass eccentricities equal to 0% (symmetrical), 10%, 20% and 30% are subjected to nonlinear static (pushover) as well as incremental dynamic analyses using a set of far‐field two‐component ground motions and their performance are assessed on the basis of the safety margin against collapse and its probability of occurrence. Comparison of the collapse margin ratios as well as the fragility curves demonstrates significant reduction of the collapse‐level ground motion intensity with increasing eccentricity in plan. Results also indicate that current seismic design parameters including the response modification (R), overstrength (Ω) and ductility (μ) factors are not appropriate for buildings with high levels of plan eccentricity. Buildings with high values of plan eccentricity do not meet the design target life safety performance level on the basis of the calculated probability of collapse and safety margin against collapse. It appears that re‐evaluation of their design parameters is necessary. Copyright © 2015 John Wiley & Sons, Ltd.