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本文介绍了炳草岗金沙江大桥斜拉桥部分主塔下横梁、中横梁、上横梁、外伸梁现浇施工用支架的设计与施工,分别从地形情况、拆卸方便、结构计算以及结构优化进行了详细阐述,对施工用各种临时支架设计具有一定的参考价值。 相似文献
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文章利用Midas Civil软件建立计算模型,对扣件式钢管脚手架的立杆自由长度、纵横立面剪刀撑、水平剪刀撑在支架体系中的作用进行分析,同时分析了地基不均匀沉降对支架体系的影响,提出了扣件式钢管脚手架的设计与施工要点。 相似文献
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文中研究受采空沉陷区地表移动影响下埋地管道的变形特征,建立煤矿区采动沉陷油气管道的有限元仿真计算模型,对管线方向与工作面推进方向不同夹角开采的影响进行研究,分析了管道的力学行为及变形演化规律,结果表明:夹角为90°工况下管道受地下煤层开采的影响最小,为采空区管道的设计、建设提供参考。 相似文献
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索道的线路支架是索道重要的受力构件,在长期的承重载荷和交变应力作用下,会发生变形或断裂,严重威胁索道的安全运行。本分析了支架产生疲劳的各种原因,并提出了减缓支架产生疲劳破坏的安全技术措施。 相似文献
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Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD). An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip. It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links. 相似文献
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《Transportation Research Part A: General》1991,25(6):407-418
The main deficiency of most current modeling approaches to transportation can be identified as neglect of the integration of existing geographical knowledge in regard to the ex ante transport/land use modeling approaches, with its focus on territorial dynamics and theory development. This paper addresses this aspect of the problem by introducing a theoretical and methodological framework for the analysis of the interrelationship between land uses. The analysis attempts to determine to what extent the functional land use in a city can be considered an ordered pattern. The order sought does not rely on purely spatial configurations, but on the correlation of transportation and land use. The first section of this paper focuses on theoretical considerations. It stresses the fact that conventional approaches do not apply in the present context. It then suggests an alternative based on areas of influence and measured in terms of level of attractance of land uses. The second describes a procedure based on this alternative following the remarkable contribution of Hanjoul, Beguin and Thill. An application of this procedure to the analysis of Shanghai is then examined. Finally, an evaluation of the strategies for optimizing the interrelationship between land uses is presented. The paper concludes with a possible research agenda. 相似文献
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明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。 相似文献
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介绍了城市轨道交通工程中杂散电流不同的监测系统的构成,分析了集中式、分散式和智能型等监测系统的配置和功能,以及智能型实时在线监测系统的重要意义,为轨道交通工程杂散电流监测系统的选择与应用提供参考。 相似文献
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《Transportation Research Part A: General》1982,16(5-6):363-370
The paper considers the possibility of quantitative analysis of behaviour, with particular reference to travel behaviour, from a methodological standpoint. The chief conclusion is that the nature of the subject implies that disaggregate statistical analysis is the most useful technique. The relationship of this methodology to theoretical issues is discussed, concluding that general theoretical issues are not susceptible to empirical resolution. The theoretical framework essential to analysis or forecasting of behaviour must therefore be established a priori The paper concludes with a discussion of the practical problems and achievements of disaggregate analysis. 相似文献
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天然气自动计量系统有多种组态软件,由于软件的不相通性,造成了计量系统数据采集的通用性差、数据传输与入库的时效性差、数据利用的可靠性低.结合各组态软件的实际情况,从设计上充分利用Oracle大数据处理能力以及Partition(分区表)的特性,实现历史数据的存储,应用WebService与COM+数据访问组件提供多层数据访问架构,采用OPC与DDE工业数据交换协议,实现了各站场计量数据的实时上传,为连续数据采集和实时监控提供了可能,节约了改造成本. 相似文献
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This paper estimates the efficiencies and productivity changes of 12 international airports in the Asia-Pacific region based on data from 1998 to 2006. We apply stochastic frontier analysis (SFA) to compute efficiency estimates and use the Malmquist productivity index (MPI) to analyze productivity changes. We use the SFA model with a translog-type production function after testing the statistical hypotheses. According to the results of the SFA hypothesis tests, airports have experienced a technological regression; the deviations from the efficiency frontier are caused more by technical inefficiency than random noise. However, the inefficiency was found to decrease. The MPI reveals a declining trend resulting more from technological change than from efficiency change, with a decrease in inefficiency. Taken together, both the hypothesis tests and the MPI not only provide consistent conclusions, but also suggest that airports should concentrate on technological progress. 相似文献