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根据有关文献资料,从结构可靠度理论研究的历史、现状、桥梁结构可靠度理论研究现状及应用简例、工程结构可靠度发展趋势等方面对可靠度理论在桥梁结构中的应用进行了综述. 相似文献
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从汶川大地震后桥梁结构的破坏情况,对桥梁震害的起因、破坏形式、抗震设防标准和桥梁抗震措施几个方面进行深入的研究和探讨,以期在桥梁设计时充分考虑结构抗震要求,提高桥梁抗震能力,力争做到大震时结构不倒塌,尽量减小对道路交通的影响. 相似文献
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文章阐述了桥梁在施工过程中产生裂缝问题的危害,从桥体结构、桥体载荷、外部温湿度影响以及原始的设计等方面,分析了桥梁产生裂缝的诸多因素,并提出了严把桥梁设计关口、严选桥梁施工材料、加强施工过程管理以及加强混凝土结构养护等预防桥梁施工过程中产生裂缝的措施。 相似文献
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混凝土桥梁结构缺陷分析及预防 总被引:1,自引:0,他引:1
混凝土桥梁结构的缺陷种类繁多,对结构的危害巨大.从设计、施工、使用等方面分析了混凝土桥梁结构产生缺陷的原因,指出了预防缺陷的措施. 相似文献
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This paper reports the most extensive meta-analysis of values of time yet conducted, covering 3109 monetary valuations assembled from 389 European studies conducted between 1963 and 2011. It aims to explain how valuations vary across studies, including over time and between countries. In addition to the customary coverage of in-vehicle time in review studies, this paper covers valuations of walk time, wait time, service headway, parking space search time, departure time switching, time in congested traffic, schedule delay early and late, mean lateness and the standard deviation of travel time. Valuations are found to vary with type of time, GDP, distance, journey purpose, mode, the monetary numeraire and a number of factors related to estimation. Model output values of time compare favourably with earnings data, replicate well official recommended values obtained from major national studies, and are transferable across countries. These implied monetary values serve as very useful benchmarks against which new evidence can be assessed and the meta-model provides parameters and values for countries and contexts where there is no other such evidence. 相似文献
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以古拱桥与现代新拱桥迭合而成的复式拱桥的加固与保护设计为例,通过现场病害调查、合理计算模型的探讨找出病害所在及病害产生的原因,提出了桥梁加固与保护所采取的方法。 相似文献
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Speed dispersion is essential for transportation research but inaccessible to certain sensors that simply record density, mean speed, and/or flow. An alternative is to relate speed dispersion with these available parameters. This paper is compiled from nearly a quarter million observations on an urban freeway and a resulting data-set with two speed dispersion measures and the three fundamental parameters. Data are examined individually by lane and aggregately by direction. The first dispersion measure, coefficient of variation of speed, is found to be exponential with density, negative exponential with mean speed, and two-phase linear to flow. These empirical relationships are proven to be general for a variety of coefficient ranges under the above function forms. The second measure, standard deviation of speed, does not present any simple relationships to the fundamental parameters, and its maximum occurs at around a half to two-thirds of the free flow speed. Speed dispersion may be significantly different by lane. 相似文献
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市场经济所带来的多元化择业观念,使毕业生集体主义观念和社会责任感观念淡化,从而在就业选择上趋向于功利化、自我化。文章针对当前交通职业技术学院学生职业价值观的这一变化,分析学生现实型职业价值观与传统型职业价值观之旬的冲突,提出了交通职业技术学校在职业价值观教育方面应采取的措施。 相似文献
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道路交通事故分析及预防对策 总被引:1,自引:0,他引:1
道路交通事故的预防是一个系统工程,通过对全国和新疆道路交通安全现状与道路交通事故原因的对比分析,分别从影响道路交通安全的人、车、路及环境四个方面提出了降低和预防道路交通事故的发生,确保行车安全的相应措施和建议。 相似文献
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Jonathan E. D. Richmond 《运输评论》2013,33(3):357-390
Abstract The role of a metaphor of centrally controlled air conditioning in governing Singaporean transport planning is examined, and its consequences evaluated. A modern transportation system has been put in place to link a hierarchy of central places. Tight government control has made change possible. A reliance on technical expertise at the expense of public involvement has, however, failed to develop public transport to effectively serve a range of dispersed‐destination travel needs. Regulatory approaches, furthermore, have discouraged service innovation. Policies making car purchase expensive have restricted car ownership. Effective change would be facilitated by involving a highly educated public more in decision‐making. 相似文献