公路桥梁支座常见病害浅析

桥梁支座在整个桥梁结构中对桥梁上部结构的受力、位移、转角起着十分重要的作用,其性能的好坏直接影响到桥梁的整体稳定性、耐久性和行车安全.文章对公路桥梁支座常见病害进行了分析,并提出了针对性的处置措施.     

基于公路桥梁下部结构环保设计方法探究

文章分析了桥梁建设对环境保护的影响,体现在生态系统、地质地形、水文与大气、社会环境等方面,指出了桥梁下部结构设计的重要性,提出了考虑环境保护的桥梁下部结构设计方法,包括了桥台、基础和桥墩的设计内容,促进了环保设计理念在桥梁建设中的落实。     

关于体外预应力混凝土桥梁设计分析

随着国内桥梁建筑事业的发展,对桥梁的设计要求也越来越高。关于体外预应力混凝土桥梁设计分析研究也倍受重视。通过分析发现,桥梁的体外预应力混凝土结构大部分集中在桥梁的固定块和转向块的连接处。相对于传统的体内预应力混凝土桥梁结构,体外预应力结构具有更大的优势,不仅能够减轻质量、便于施工,而且还有利于桥梁的维护,延长桥梁的使用寿命。本文通过对体外预应力混凝土桥梁的研究,阐述了体外预应力混凝土桥梁实验设计内容,并介绍了体外预应力混凝土桥梁设计方法,在桥梁建设中具有一定的理论意义。     

基于BIM的桥梁施工监控云平台应用研究

文章以BIM、云平台、物联网等先进技术为基础,建立桥梁施工监控云平台,解决了制定桥梁BIM实施标准和工程分解结构编码、基于TEKLA的桥梁快速建模、桥梁模型碰撞检测和轻量化处理、桥梁施工进度控制可视化等关键技术应用等问题,实现了桥梁施工进度控制可视化以及以物联网为基础的桥梁健康监测。     

生命大过天

文章介绍了广西壮族自治区公路管理局开展专项行动,治理以桥梁为重点的交通基础设施安全隐患的情况,针对在役桥梁、在建桥梁和农村公路桥梁存在的安全隐患提出了相应的治理措施。     

基于现代公路桥梁结构耐久性技术分析

我国公路桥梁不仅在数量上还是在规模上都取了巨大成就,随着港珠澳大桥、北盘江大桥等特大桥梁的建设取得成功后,高墩柱桥梁,跨江跨河桥梁等具有技术挑战的桥梁对我国桥梁建设者已经不是问题了。随着公路桥梁建设的快速发展,人们更加越来越重视高速公路的耐久性、行车舒适性等使用性能了,反观我国桥梁投入使用后的病害调查统计,设计中的结构耐久性技术问题已成为现代公路桥梁的核心问题。本文将结合工程实践调查与试验研究就现代公路桥梁的结构耐久性技术做出分析。希望对桥梁耐久性技术现象及其他桥梁病害处理提供应用研究参考。     

干线公路重点桥梁的监控管理

结合公路桥梁养护管理实际,提出了重点监控桥梁养护管理理念,探讨了监控管理原则、监控程序以及实施要求,进一步加强桥梁养护管理,提升管理水平,保障桥梁运营安全。     

桥梁与环境的协调性美学设计

文章以桥址环境、桥梁的造型和材质、桥梁美学的一般处理方法为切入点,详细阐述了桥梁与环境相互协调的重要性以及桥梁美学设计的要点。     

桥梁施工安全控制技术与安全管理措施

文章分析了导致桥梁事故的主要原因,从基坑开挖、挖孔桩施工、桥梁架设、防坠落等四个方面,提出了桥梁施工安全控制要点,并探讨了公路桥梁施工、山地桥梁施工、海上桥梁施工相应的安全管理策略,以期达到提高工程施工的安全性,减少安全事故的目的。     

高速公路桥梁段的道路养护与管理问题研究

高速公路桥梁段的道路养护与管理工作对该路段的运行情况有着重要的影响。文章从桥梁检查过程、桥梁技术状况评定、桥梁维修加固质量评定等方面,分析了高速公路桥梁段的道路养护与管理工作中存在的问题,并提出了相应的解决措施,为桥梁养护管理工作提供参考。     

The Impact of Container Type Diversification on Regional British Port Development Strategies

Abstract

Despite a concentration of container traffic in the southeast of the UK over the last few decades, regional ports are attempting new development strategies to capture or retain specific traffic segments. These include intra-European short-sea traffic and a potentially increasing feeder market. These trends are reflected in the movement of different container types, which result in a number of planning challenges related to changing infrastructural and operational requirements. This paper uses highly disaggregated data on container type movements to address three issues that can inform these planning challenges. First, the imbalance of trade resulting in empty container repositioning; second, the requirement for gauge-cleared rail routes to cater for the increasing proportion of high-cube containers; and third, the specialisation of European short-sea traffic at secondary UK ports. The results reveal the disproportionate repositioning of empty containers at Scottish ports and the importance of 45?ft, high-cube and pallet-wide containers at regional ports, highlighting their focus on intra-European short-sea traffic and raising difficulties relating to their lower quality of landside infrastructure (particularly rail) in comparison to the large south-eastern ports. The potential repercussions on hinterland infrastructure development raise questions about both public and private sector responses to regional port development.     

Survey of R&D in PRT systems

A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996.     

Modular route bus design – A method of meeting transport operation and vehicle manufacturing requirements

This research examines the problem of route bus specification and vehicle manufacturability. In order for bus operators to provide transport services, a range of vehicle configurations must be available from bus manufacturers, generating variety which has a negative impact on the manufacturing process. Larger part inventories, uncontrolled labour tasks and more troublesome maintenance are known impacts of this variety. This research identifies the functional necessities in route bus interior design and reduces the problems in bus manufacture and operation caused by specification diversity by proposing a modularised system of bus design. In particular, it makes recommendations as to how bus configuration should be carried out, ensuring an optimum mix of operational and manufacturing needs:

• 1.Determine user needs before the bus specification process.
• 2.Designs to be developed by the manufacturer in response to user needs.
• 3.This design should be standardised where possible, as suggested by the user needs.
• 4.Where user needs dictate product variations, apply a mass customisation approach to accommodate these needs.

The recommendations are communicated in design proposals for a modular bus interior, demonstrated by four cases designed to meet the present status quo of bus interior design and predictions for the future of the field.     

Productive efficiency and ownership of urban bus services

The established ownership mix of urban bus operations in Australia provides a unique opportunity to investigate the productivity differences between public and private bus service supply. Using duality theory in economics which links economic indices of factor productivity to the cost structure of a firm, we develop empirical measures of total and partial productivity of inputs, and adjust the differences for the effects of ownership status and operating environment. The evidence supports the notion that private supply of public passenger transport in general has performed more efficiently in the past than public supply, although the differences in productivity need not continue in the future.     

Optimization of bus stop locations for improving transit accessibility

A mathematical model is developed in this paper to improve the accessibility of a bus service. To formulate the optimization model, a segment of a bus route is given, on which a number of demand entry points are distributed realistically. The objective total cost function (i.e. the sum of supplier and user costs) is minimized by optimizing the number and locations of stops, subject to non‐additive users' value of time. A numerical example is designed to demonstrate the effectiveness of the method thus developed to optimize the bus stop location problem. The sensitivity of the total cost to various parameters (e.g. value of users' time, access speed, and demand density) and the effect of the parameters on the optimal stop locations are analyzed and discussed.     

Determinants of modal choice in freight transport

In the next few years, exciting developments in the field of freight transport are likely to occur. The Channel Tunnel will be perceived as giving railways much greater distance of operation, compared to the current train ferry to/from Great Britain. The further development of swap-body technology will allow easier modal transfer and the creation, in 1992, of a single market in Europe will transform the pattern of trade. All of these are likely to have significant impacts on modal choice, and hence modal split, in freight transport. Reappraisal by many firms of the modes of transport used is likely but will it result in a net transfer of freight from road to rail and, if so, to what extent? To answer such questions, an accurate and reliable method of predicting modal split is required. Research in the past has concentrated on the development of modal split models based on generalised costs. These fail to explain adequately the prevalence of road freight in the UK. From surveys of freight managers within industry, it is clear that models to date rely too heavily on the economic cost factor and too little on behavioural factors (Jeffs 1985). This paper derives from a recent study of freight transport modal choice from the standpoint of the transport decision-maker within the firm. It attempts to shed light on the actual parameters which should be incorporated into a modal split model. Many variables appear to exert an influence on modal choice decision-making process. However, it is possible to categorise them into six main groups, namely: customer-requirements; product-characteristics; company structure/organisation; government interventions; available transport facilities; and perceptions of the decision-maker him/herself. It is the interactions and inter-relationships between these which ultimately determine freight modal split. This study has shown that the relationship between the outcome of the transport decision process and the values of particular determinants of modal split is not straight-forward, due to the complexity and variety of interactions involved. Perhaps one of the main reasons for researchers' failure hitherto to develop a successful modal-split model has been the preoccupation with techniques that rely on the development of common metric (e.g. generalised cost), which has led to the exclusion of some important explanatory variables along quite different dimensions. Another important issue concerns the appropriate level of aggregation. In order not to reduce the explanatory power of the key variables, it is important to work at a disaggregate level, although this does make substantial demands on data. The use of factor analysis enables both the aggregation of information without loss of behavioural reality and the specification of variables in terms of a common metric. In conclusion, freight transport has usually been examined within too narrow a framework. It must be placed firmly within the context of the total industrial process. The demand for freight transport is directly influenced by the level, composition and geographical distribution of production and consumption activities. Freight flows are complex and so it is highly unlikely that a universal mode-choice model can ever be developed. Future research should, therefore, be directed towards developing partial models in response to specific needs of those involved in decision-taking in the freight sector.     

管道风险分析指数评分法中分值调整初探

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。     

Governing autonomous vehicles: emerging responses for safety,liability, privacy,cybersecurity, and industry risks

ABSTRACT

The benefits of autonomous vehicles (AVs) are widely acknowledged, but there are concerns about the extent of these benefits and AV risks and unintended consequences. In this article, we first examine AVs and different categories of the technological risks associated with them. We then explore strategies that can be adopted to address these risks, and explore emerging responses by governments for addressing AV risks. Our analyses reveal that, thus far, governments have in most instances avoided stringent measures in order to promote AV developments and the majority of responses are non-binding and focus on creating councils or working groups to better explore AV implications. The US has been active in introducing legislations to address issues related to privacy and cybersecurity. The UK and Germany, in particular, have enacted laws to address liability issues; other countries mostly acknowledge these issues, but have yet to implement specific strategies. To address privacy and cybersecurity risks strategies ranging from introduction or amendment of non-AV specific legislation to creating working groups have been adopted. Much less attention has been paid to issues such as environmental and employment risks, although a few governments have begun programmes to retrain workers who might be negatively affected.