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针对新兴的中小跨径公路桥梁全预制一体化架设施工工艺,依托宁波舟山港主通道项目东海农场大桥,定量对比分析了现浇施工、预制安装施工和预制一体化安装施工等施工方案的环境、社会成本及总成本.分析表明,预制一体化安装的总成本、直接成本及环境成本居中,现浇施工方案总成本最低,反映出预制一体化架设工艺的经济适用性.基于依托工程及类似工程,提出的T梁桥预制一体化安装的专项定额,可以作为类似新建工程方案比选和已建工程评价的依据. 相似文献
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为改善公路预制拼装桥墩试件施工中存在的问题,结合公路预制桥墩大比例缩尺试验模型,分析了预制拼装桥墩的特点,探讨了试验中试件施工要点和问题的解决方法,阐述了施工准备、各节段的安装、钢筋布置、预应力筋张拉等过程,给出了试验模型的加载方案,为学者对公路预制拼装桥墩进一步的试验研究提供参考。 相似文献
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为解决装配式桥梁预制立柱施工质量问题,以某装配式桥梁工程为例,探讨桥梁预制立柱吊装要点与安装质量控制要点,阐述该工程基本资料,分析立足吊装安装流程,而后从桥梁预制立足吊装施工与安装质量控制方面系统性论述工作要点,以期为类似工程提供参考。 相似文献
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针对西气东输靖边压气站的扩建施工,介绍了施工图的分解,管道的预制与安装,以及在顸制中出现的问题及解决方法.通过采用预制化工艺,确保了扩建工程的质量和施工进度. 相似文献
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文章以红水河大桥预制桥面板安装工程为例,介绍了预制桥面板的安装方法,并针对其安装方案的选择,分析了该桥预制桥面板安装的关键技术,为今后类似桥梁预制桥面板安装提供参考。 相似文献
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钢筋骨架及预应力管道准确定位是预制箱梁施工过程中的关键控制环节之一,影响预制箱梁服役过程的受力状态。文章根据箱梁的配筋及预应力管道坐标定位特点和要求,研制了预制箱梁底腹板钢筋及预应力管道的定位架,提高了预制箱梁钢筋间距及波纹管坐标安装的精度,实现了箱梁底腹板钢筋绑扎成型的流水线施工,在保障施工质量、提高施工效率和节约施工成本方面均取得了良好的效果。 相似文献
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管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一(各因素的分值范围都是0~100分),为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。 相似文献
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通过使用连续介质快速拉格朗日差分法(Fast Lagrangian Analysis of Continua,简写FLAC)对粉土路基于粘土路基的稳定性进行分析。并对路基高度、地基种类及边坡形式等对路基稳定性产生影响的因素进行分析研究,得出以下规律:路基边坡安全系数随路基高度增大而减小,但此变化存在一临界高度,在此临界高度附近,安全系数以不同的速度减小。如将粉土地基表层30 cm的压实度由85%提高到90%,安全系数将有很大的提高;但由90%提高到93%,则安全系数变化不大。对于10~20 m高度的路基,边坡形式(即一坡式与台阶式)对路基的稳定性影响很小,后者比前者对应的安全系数稍大。 相似文献
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According to the intra-vehicle interaction, a traffic flow can generally be divided into three homogeneous states (1) that of free driving, (2) that of bunched driving, and (3) that of standing. The parameter describing the state of free driving is the desired speed, for the state of bunching it is the intra-vehicle gaps (time headway) within the convoy and the mean speed of the convoy, and for the state of standing it is the maximum jam density. These are the most essential parameters which do not depend on the actual traffic situation.This paper introduces a new model which considers the Fundamental Diagram (equilibrium speed–flow–density relationship) as a function of the homogeneous states. All traffic situations in reality can be considered as combinations of the homogeneous states and therefore can be described by the essential parameters mentioned above. The non-congested (fluid) traffic is a combination (superposition) of the states of free driving and bunched driving, the congested (jam, stop, and go) traffic is a combination of the states of bunched driving (go) and standing (stop). The contribution of the traffic states within the differently congested traffic situations can then be easily obtained from the queuing and probability theory. As a result, Fundamental Diagram in all equilibrium traffic situations is derived as simple functions of the essential parameters.According to the new model the capacity of freeways and rural highways can be determined by measuring the essential parameters. This is much easier than measuring the capacity directly.Furthermore, the probabilities of the various traffic states can be obtained from the new model. This leads to new possibilities in real-time controlling and telematics.The new model is verified by comprehensive measurements carried out on freeways and rural highways in Germany. 相似文献
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道路危险货物运输安全现状分析及对策研究 总被引:1,自引:0,他引:1
道路运输是危险货物运输的重要环节,也是与安全关系最大的环节,危险货物运输安全事故大多发生在道路运输这一环节上。从当前我国危险品运输安全现状着手,着力分析了影响我国危险品运输安全的因素,并针对这些因素提出相关对策,包括提高从业人员队伍素质、提高行业准入门槛、建立危险货物运输相关管理部门协调机制等。 相似文献
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J. S. Dodgson 《Transportation》1994,21(4):355-370
The European aviation industry is undergoing a process of liberalisation. One of the important lessons of American deregulation was that the industry is not perfectly contestable. One implication of this is that actual competition on a route is important in order to be able to secure the benefits of deregulation or liberalisation. Another is that effective competition policy is important in order to prevent anti-competitive mergers or predatory behaviour. This paper reviews the merger investigations in European aviation which have accompanied the search by carriers to secure the benefits of market power, and considers the extent of route competition within the European Community and its relationship to the different route licensing policies of different national governments. The paper considers the extent of present competition on the busiest routes, and stresses the importance of cabotage rights in opening up the European market to effective competition. 相似文献