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浅谈预应力混凝土连续梁悬臂浇筑的三角挂篮设计 总被引:1,自引:0,他引:1
该文通过结合工程实例,阐述了三角挂篮的设计,通过对挂篮组件的检算降低挂篮重量,达到节约钢材、满足工况、降低施工难度的要求。 相似文献
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该文对混凝土斜拉桥前支点挂篮三种止推方式进行了分析比较,认为选用不同的止推形式对主梁局部受力影响较大。对于止推力较大的情况,采用锚固在横梁、底板和腹板角点处的连接拉杆止推方式较为合理可行。 相似文献
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郑州市中心区铁路跨线桥为(106+248+106)m双塔单索面跨线斜拉桥,其上部结构跨越货运铁路、客运铁路、站场专用线等多条铁路。针对该桥结构特点和施工难点,将跨线桥主梁分为A、B、C区:A区位于斜拉桥的两端,远离铁路限界,采用支架法现浇;C区为主跨中央139m范围,位于铁路专用线上方,采用挂篮悬浇施工;B区为桥塔两侧的对称区段,直接跨越铁路运营线,通过比选,2号塔B区主梁采用挂篮悬浇方案,3号塔B区主梁采用转体方案。施工中在铁路上方设置铁路防护屏蔽网,采用宽幅全封闭挂篮技术解决了铁路上方施工净空有限的难题,将转体分次进行,压缩单次"天窗点"时间,减少了施工对既有铁路运营的干扰和影响。 相似文献
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悬臂浇筑施工技术是当前大型桥梁施工的重要技术选择,通过有效的技术控制手段能够对桥梁工程质量提供有效的保障。该文主要从工程施工宏观和细观两个层面对于悬臂浇筑桥梁施工技术展开了讨论,根据施工的四个步骤0#块段施工、挂篮施工、边跨施工,以及合龙段施工逐一展开分析。该文更加注重对细节内容的分析和把握,对于具体的工程施工具有一定的参考价值。 相似文献
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该文通过有限元软件对A15公路浦东运河大桥箱梁挂篮悬浇的结构进行了验算,对施工过程中的安全提出了部分优化方案,从而有效控制了横梁受力和结构变形。 相似文献
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This paper reports the results of a 1998 survey carried out among a small sample of people who had called the TravInfo Travel Advisory Telephone System (TATS) in April 1997 looking for current information about traffic conditions in the San Francisco Bay Area. The survey employed a series of tradeoff questions designed to identify the specific attributes of the information that the respondents felt to be most important, and to estimate the relative values that these users had for various possible information improvements. Despite the small size of the sample, it proved feasible to investigate how the implicit valuations placed on each attribute of the service (update frequency, extent of road coverage, and level of customization) varied among different user segments. For the most part, respondents appeared to value basic enhancements – those that establish an initial quality differential above the baseline set by free broadcast traffic information – more than they value further subsequent improvements. Overall, more frequent information updates are the highest priority among the range of possible enhancements explored in the survey, followed by an extension of coverage to include major arterials in addition to freeways. However, the evidence suggests relatively little value in door-to-door coverage – that is, coverage of streets beyond the freeway and major arterial networks. This research produced some estimates of the average monetary values ("willingness to pay") that the sample of current users attached to information improvements of various kinds. While these values varied among subgroups in ways that fit a priori expectations, it is not clear whether they provide an unbiased picture of the users' absolute levels of willingness to pay, such that they could be used reliably to inform (for example) information pricing decisions. The value of this research lies more clearly in the light it sheds on the relative structure of user preferences, and on the variations in preferences between information attributes and market segments. Overall, the authors conclude that the prospects for self-sustaining ATIS services are unclear. In response to a direct question, a majority of users (perhaps influenced by a strategic bias) indicated that they were unwilling to pay for ATIS services; some of these same people, however, indicated later that they might indeed be willing to buy a particular enhanced ATIS package, in direct competition with free broadcast services. 相似文献
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