对《建筑工程抗震性态设计通则(试用)》的评述

《建筑工程抗震性态设计通则（试用）》（以下简称《通则》）是一部对我国抗震设计规范修订具有重大指导意义的试用标准.本文对《通则》和现行规范的某些不同和改进之处进行了比较,讨论了《通则》所具有的先进性和行业指导性,同时也对应用《通则》的原理,对修订和完善下一代规范还需要研究的问题提出了若干建议.     

《建筑工程抗震性态设计通则》与《规范》中地震作用的比较

《建筑工程抗震生态设计通则(试用)》是一部对我国抗震设计规范修订具有重大指导意义的试用标准。地震作用是抗震设计的首要问题,《通则》中地震作用计算方法与现行规范的差异引人关注。首先分析了《通则》和规范的场地设计谱,然后比较了二者地震作用计算方法,最后引入2个算例计算了水平地震作用的差别。对《通则》的应用,对修订和完善下一代规范有一定的参考作用。     

基于性态的建筑工程抗震设计——《建筑工程抗震性态设计通则》述评

《建筑工程抗震性态设计通则(试用)》对抗震设计具有重要的指导意义,其中的抗震设计理念同以往的抗震设计规范在抗震设防的思路、概念和方法上有较大的区别。从工程实践的角度,比较了《通则》和现行抗震设计相关规范的区别并对具体应用提出一些看法。     

我国首部《高标准农田建设通则》出台

耕地是农业生产的重要物质基础,高标准农田是耕地中的精华。我国首部高标准农田建设国家标准——《高标准农田建设通则》（以下简称《通则》）于2014年6月25日起正式实施。 国家发展改革委农经司司长高俊才表示,高标准农田建设涉及多个部门和各个地方,目前各相关部门都各自围绕行业需求制定了行业标准,许多地方也制定了地方标准,但建设标准参差不齐、难以统一考核评价的问题突出。     

评估地震预报方法的统计检验

本文讨论了零假设检中包括后效在内的影响。应用中心极限定理的通则使零假设检验中含有非等预报概率。为此，我们系统阐述了一种统计检验。     

基于地震作用和场地影响确定广东省设计地震动参数

在对《建筑抗震设计规范(GB50011-2001)》和《建筑工程抗震性态设计通则(试用,CECS 160:2004)》研究的基础上,根据广东地区的场地和地震作用特点,确定出了广东省甲、乙、丙类建筑不同设防水准的地震动峰值加速度,以及广东省91个城镇的特征周期分区值,为广东省建筑物抗震设计提供了更加可靠的地震动参数。     

首部高标准农田建设国家标准——《高标准农田建设通则》发布

正由国土资源部牵头,会同农业部、国家发展改革委、财政部、水利部、国家统计局、国家林业局、国家农业综合开发办公室等部门共同编制的国家标准《高标准农田建设通则》(GB/T30600-2014)近日经质检总局、国家标准委批准发布,将于2014年6月25日"全国土地日"起正式实施。这是我国首部高标准农田建设国家标准。     

对《结构力学非常解法》第九章(伸臂结构抗震验算)的讨论

《工程结构上界地震力理论及其应用》(地震出版社2000年出版)一书的作者将该书第四章静定模型的上界地震力第一节竖直悬臂式结构,作了修改和补充,再次发表于新书《结构力学非常解法》(地震出版社2004年出版)第九章。     

农田“评什么”是高标准? 解读《高标准农田建设评价规范》

正继《高标准农田建设通则》发布实施后,我国高标准农田建设领域的另一项国家标准《高标准农田建设评价规范》(以下简称《规范》)于10月13日发布,高标准农田建设评价是强化高标准农田建设监测监管、促进国家高标准农田建设任务落实的一项重要手段。《规范》规定了高标准农田建设评价的目的、任务、内容、程序、方法和成果要求等,适用于各级行政区内高标准农田建设完成后的整体评价工作。     

浅埋地下结构顶板在竖向地震作用下的动力响应

采用结构动力学的方法研究了浅埋地下箱形结构在竖向地震作用下的动力响应。鉴于土与结构动力相互作用分析的复杂性,为了简化分析,整个分析过程分为2步。第1步把结构看作是刚体,利用刚体与地基的相互作用分析求得刚体在竖向地震分量作用下的动力响应;第2步首先考虑到了侧墙对于顶板的抗弯约束作用,求得了顶板的固有频率及振型,并把第1步刚体的动力响应作为输入求解顶板梁的受迫振动,进而求得了顶板弯矩。     

竖向质量分布对框架结构动力特性影响的研究

在框架结构动力分析中,往往是把填充墙质量集中在楼层处进行求解.文中考虑填充墙实际分布对结构自振特性的影响,通过传递矩阵法求解结构自振频率和振型,并进一步分析了高阶频率的分布规律.结果表明,与采用集中质量模型的振型叠加法相比,填充墙的竖向质量分布会对框架结构高阶频率产生很大影响;框架结构的高阶模态具有局部性和密集分组的特...     

新20号井井水位动态分析及地震预测效能评价

对新20号井井水位动态观测资料进行了全时间过程扫描，分析了井水位的年变化规律、主要干扰因素和地震短期前兆异常特征，提出了如何判别水位年变叠加、峰谷相位移动和峰谷极差增减等异常是否打破年变规律的有效方法。根据这些指标，统计了观测期间乌鲁木齐监视区内发生5级以上地震时水位的相关异常参数，并对该井的地震预测效能进行了初步评价。     

Estimation of strength-reduction factors for elastoplastic systems: a new approach

A new rule is presented to estimate strength-reduction factors in single-degree-of-freedom elastoplastic oscillators, in which reduction factors depend only on displacement elastic spectra, so they are not an explicit function of structural period. It is found that the proposed rule yields good results when applied to accelerograms recorded in firm and soft soils, and for damping ratios of 2, 5 and 10 per cent of the critical. It is shown that the proposed reduction rule is more general than others previously published, and at least as accurate. © 1998 John Wiley & Sons, Ltd.     

Structural damage assessment using improved Dempster-Shafer data fusion algorithm

As an efficient tool in handling uncertain issues, Dempster-Shafer evidence theory has been increasingly used in structural health monitoring and damage detection. In applications, however, Dempster-Shafer evidence theory sometimes leads to counter-intuitive results. In this study, a new fusion algorithm of evidence theory is put forward to address various counter-intuitive problems and manage the reliability difference of the evidence. The proposed algorithm comprises the following aspects:(1) Dempster's combination rule is generalized by introducing the concept of evidence ullage. The new rule allows classical Dempster's rule and can resolve counter-intuitive problems cause by evidence conflict and evidence compatibility;(2) a reliability assessing method based on a priori and posterior knowledge is proposed. Compared with conventional reliability assessment, the proposed method can reflect the actual evidence reliabilities and can efficiently reduce decision risk. Numerical examples confirm the validity and utility of the proposed algorithm. In addition, an experimental investigation on a spatial truss structure is carried out to illustrate the identified ability of the proposed approach. The results indicate that the fusion algorithm has no strict request on the accuracy and consistency of evidence sources and can efficiently enhance diagnostic accuracy.     

On the estimation of hysteretic energy demands for SDOF systems

Based on a statistical study of the dynamic response of single degree of freedom (SDOF) systems subjected to earthquake ground motions, a rule to estimate hysteretic energy demands is proposed. Expressions for elastic–perfectly plastic, stiffness degrading and pinching SDOF systems were obtained. The proposed rule does not explicitly depend on the period of the system; instead, it depends on the elastic pseudo‐acceleration and elastic velocity spectra. It is shown that the proposed rule can be applied to compute hysteretic energy demands for systems located at different soil conditions. In addition, information about scatter and bias of the proposed rule is also presented. Copyright © 2007 John Wiley & Sons, Ltd.     

井水位的“记忆”滞后效应

观测资料表明,井水位对信息响应存在的“记忆”滞后现象,它与一般的位相滞后不同,在鲁２９井现场试验也证明了井水位对井吕空气压力变化的响应存在的“记忆”滞后现象。利用水平层状承压含水层模式,从理论上解释了井水位对井口空气压力变化响应“记忆”滞后现象,认为这种现象与水井含水层的导水系数有关,含水层导不系数越小,这种现象越明显,用一般多元回归方法无法较好地扣除井水位中“记忆”滞后影响,作给出了一种可以扣     

A modal combination rule for spatially varying seismic motions

The spatial variability of seismic ground motion is an important aspect for the earthquake resistant design of extended facilities. A modified response spectrum model, which addresses the problem of multiply supported structures subjected to imperfectly correlated seismic excitations, has already been developed (see References 1 and 2). The present paper proposes a modal combination rule for the case of non-uniform seismic input, which would be used together with the modified response spectrum model in order to compute physical responses. This rule, which accounts for modal cross-correlations, is an extension to an existing rule for the case of uniform seismic motions. It modifies the existing modal cross-correlation coefficients through a correction factor which depends on structural properties and on the characteristics of the wave propagation phenomenon. Finally, some practical considerations on the theoretical development are addressed. They aim at suggesting reasonable simplifications which render the modal combination rule more appealing for engineering purposes. The proposed practical combination rule is validated through a numerical experiment which also characterizes the effect of non-uniform seismic input on modal cross-correlation.     

地下结构地震反应分析中材料非线性的影响

基于静、动统一数值分析方法,建立了考虑土与结构接触效应和材料非线性的地下结构地震反应分析模型,并利用通用有限元软件ANSYS对某地铁地下结构地震反应进行数值模拟,探讨了地下结构的非线性地震反应规律,并分析了材料非线性对地下结构地震反应的影响。结果表明:考虑土与地下结构材料的非线性特性后,地下结构在强地震作用下发生了较大的塑性变形,应力、应变最大值位置发生明显变化,应力、应变状态发生明显改变,而对位移、速度、加速度反应的影响不大。