城市多媒体电子地图集内容设计

结合各种类型的城市多媒体电子地图集,试图对城市多媒体电子地图的内容的设计做粗浅的概括和探讨。     

基于角色的土地利用规划管理信息系统访问控制模型设计与实现

土地利用规划系统中敷据众多,空间数据库权限管理任务繁重。笔者提出以土地利用规划管理为业务主线,面向事务和角色管理的县级土地利用规划管理系统中基于角色的访问控制模型。实践表明,该模型减轻了系统日常维护管理负担,降低了对系统管理员的要求。     

钢筋混凝土扁梁柱节点抗震设计方法

为考虑扁梁柱节点内、外核心区的相互作用,对扁梁柱节点的内、外核心区进行了重新划分,认为内、外核心区有一个重叠的区域,给出了地震作用在扁梁柱节点内外核心区的分配方法,采用压杆模型和软化桁架模型,提出扁梁柱节点的设计方法。该方法可以考虑节点核心区钢纤维和扁梁中无粘结预应力对扁梁柱节点抗剪极限承载力的作用。该设计方法的可靠性得到四个钢筋混凝土扁梁柱节点试验数据的验证。     

基于性能的抗震设计方法在剪力墙结构中的应用

本文对基于性能的抗震设计方法中最具有代表性的直接基于位移的设计方法在剪力墙结构中的应用进行了研究。采用结构非线性分析程序探讨了墙厚、混凝土强度等级、纵筋配筋率、钢筋级别、轴压比、墙长等因素对单肢剪力墙屈服位移的影响,从而对现有的屈服曲率计算公式进行了改进。另外将按顶点荷载作用下的屈服位移计算公式求出的屈服位移与实际倒三角形荷载作用下的剪力墙屈服位移进行了比较,,从而推导出倒三角形荷载作用下的屈服位移计算公式。     

钢框架-混凝土抗侧力结构的抗震性能研究

在双重抗侧力结构体系中,地震作用主要由支撑框架或剪力墙等抗侧力结构承受,框架则主要承受竖向荷载,但是对框架的水平抗力也有具体要求。我国规范和美国规范对钢框架-剪力墙结构中框架应该承担的剪力有不同的规定,并且给出相应的抗震校核方法。此外,人们需要了解在混合结构中减少柱的数量对结构抗震性能的影响。为此,本文进行了2种钢-混凝土混合结构地震响应的有限元分析,并且考虑了柱距的变化,得到了轴压比的变化规律,对由两国抗震校核方法的计算结果进行了对比,提出了相关的设计建议。     

考虑双向水平地震作用的结构设计问题研究

分析了抗震设计中考虑双向水平地震作用的必要性,指出了研究双向地震作用的必要性,通过国内外规范相关条文的对比指出目前研究有待完善的关键问题和方向,结合近期研究成果对其中几个值得注意的问题提出建议。     

A comparative study between China and U.S. on seismic design philosophy and practice of a long span arch bridge

This paper presents the first of a series of case studies on the seismic design of long span bridges （cable-stayed bridges, suspension bridges and arch bridges） under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that （1） the selected near field ground motions cause larger responses to key components （critical sections） of the bridge （such as arch rib ends） with a maximum increase of more than twice those caused by the site specific ground motions; （2） piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and （3） large vertical components of near field ground motions may not significantly affect the bridge＇s internal forces provided that their peak acceleration spectra ordinates only appear at periods of less than 0.2s. However, they may have more influence on the longitudinal displacements of sliding bearings due to their large displacement spectra ordinates at the fundamental period of the bridge.     

Parametric study on performance of bridge retrofitted by unseating prevention devices

1 Introduction Structural retro?t techniques (Roberts, 2005), such as restrainers, concrete shear keys, steel jackets, CFRPshells, base isolators, or dampers have been widely studied and implemented in actual structures based on the experiences learned from past earthquakes. In the Chi-Chi earthquake (EERI, 2001), the damage to simply-supported PCI girder bridges provided a different view from which to examine the function of a rubber bearing system for simply- supported bridges (NCREE,…     

An evaluation of force-based design vs. direct displacement-based design of jointed precast post-tensioned wall systems

The unique features of jointed post-tensioned wall systems, which include minimum structural damage and re-centering capability when subjected to earthquake lateral loads, are the result of using unbonded post-tensioning to attach the walls to the foundation, along with employing energy dissipating shear connectors between the walls. Using acceptance criteria defined in terms of inter-story drift, residual drift, and floor acceleration, this study presents a multiplelevel performance-based seismic evaluation of two five-story unbonded post-tensioned jointed precast wall systems. The design and analysis of these two wall systems, established as the direct displacement-based and force-based solutions for a prototype building used in the PREcast Seismic Structural Systems （PRESSS） program, were performed at 60% scale so that the analysis model could be validated using the PRESSS test data. Both buildings satisfied the performance criteria at four levels of earthquake motions although the design base shear of the direct displacement-based jointed wall system was 50% of that demanded by the force-based design method. The study also investigated the feasibility of controlling the maximum transient inter-story drift in a jointed wall system by increasing the number of energy dissipating shear connectors between the walls but without significantly affecting its re-centering capability.     

低渗透储层的径向电阻率特征及含油性 ——以鄂尔多斯盆地洛河油田延长组长61为例

鄂尔多斯盆地中部洛河油田长61低渗透油层由于含油饱和度变化大、油层非均质强,再加淡水钻井液侵入,造成油层电阻率径向分布不均且变化大。通过双感应-八侧向测井与阵列感应测井响应特征对比分析,认为水层的径向电阻率均为增阻侵入,油层、油水同层的径向电阻率普遍具有减阻侵入、低阻环带、高阻环带特征或相关趋势。其中,减阻侵入有助于识别高含油饱和度、高电阻率油层和油水同层,低阻环带和高阻环带有助于识别低电阻率油水同层。另外,部分油水同层的双感应-八侧向测井径向电阻率组合具有“增阻侵入”且深感应电阻率低的特征,推测可能是受双感应-八侧向测井探测范围限制,为低阻环带靠近井眼附近遭受淡水钻井液侵入影响的结果,深感应测井反映的是侵入带电阻率而不是油水同层的电阻率,容易被误解释为水层。因此,对于双感应-八侧向测井中具有“增阻侵入”特征且深感应电阻低值的储层,其流体性质有水层、油水同层这两种可能性,需要结合深探测测井资料或油藏地质特征进一步分析,以提高油层、水层的识别率。