Joint development at transit stations in the United States

Joint development, as the term is generally used in connection with transit systems in the United States, is real estate development that is closely linked to public transportation services and station facilities, and takes advantage of the market and locational advantages provided by them. Research conducted by LEK Associates for the Urban Mass Transportation Administration (UMTA) suggests that, in addition to helping shape urban growth and land development, joint development is also a surprisingly effective means of increasing transit system ridership and farebox revenues, as well as a source of increasingly significant revenues from the sale or lease of air rights.The completion of nine joint development projects in as many different cities, started under the former Urban Initiatives Program, for example, net additional annual ridership might reach 12000000 one-way trips. Net additional annual farebox revenues might reach over $9000000. This added revenue would be sufficient to repay the $62 million combined UMTA/transit operator investment in the nine projects, exclusive of the costs of the basic transit system improvements around which the projects are planned, in less than six years.Among transit authority-administered joint development programs examined in a separate study, the Washington Metropolitan Area Transit Authority (WMATA) has had the most success in generating significant value capture income. For example, the cumulative revenue realized by WMATA from just six joint development projects in the Washington, DC region, through September 1983 exceeded $ 6.9 million. Projections through fiscal year 1986 indicate cumulative revenues approximating $ 28 million will be received from developer leases.     

Urban transportation modeling: The discussion continues

This article is a response to John Polak's article, entitled, A Comment on Supernak's Critique of Transport Modeling, published elsewhere in this issue of TRANSPORTATION. It offers necessary clarifications to the issues discussed in an earlier article in this journal (Supernak, 1983). It also responds to the philosophical issues discussed in Polak's article, such as the nature of transport phenomena, and the role, form and methodology of transport modeling.     

Regional impacts of new transport infrastructure: a multisectoral potentials approach

This is the second of two background papers sponsored for the Symposium by the Administrative Commission for the north of the Netherlands. Its purpose is to provide an indication of the effects of the proposed high speed rail line between Amsterdam, Groningen and Hamburg on employment in the corridor. The authors first review the techniques of forecasting these effects discussed in the literature. The potentials approach is adopted for their analysis, the mathematics and underlying assumptions of which are presented. Finally, this model is run to provide an estimate of the impact on regional employment of three variants of the proposed rail line.     

The design of bus route systems — An interactive location-allocation approach

An interactive modelling approach is developed to solve the practical problem of bus route network design. Possible bus routes are identified with facilities which can be located. Zones or pairs of zones in the urban area are identified with customers who will be allocated to the established facilities. It is shown that the classical Set Covering Problem is useful under the assumption of fixed demand; the Simple Plant Location Problem is effective under the assumption of demand which is sensitive to the level of bus service provided.     

人类仿真技术在铁路系统中的应用

摘要：对应用于铁路人机工程学的人类仿真方法进行了总结,即一种仿真器是采用虚拟现实技术来模拟环境,例如驾驶仿真器、乘坐舒适度仿真器、铁路车站仿真器等。另一类仿真器则采用计算机仿真技术来评价列车司机工作时承受的精神负担、列车碰撞引起的旅客运动方式及损伤等。     

接触网鸟害防治措施研究

分析了接触网鸟害的特点,总结了接触网上易发生鸟害的位置,对不同位置接触网鸟害防治措施进行了比较,从设计、施工、运营等多角度出发提出了接触网鸟害综合防治的建议。     

跨繁忙航道超宽钢箱梁梁上运梁及分块安装方案研究

巴拿马四桥为巴拿马国内第一座公轨合建混合梁斜拉桥,桥面宽51m,中跨钢箱梁标准节段长13m,为典型超宽超重结构。桥位处通航要求高,施工期间不得占用航道,既有道路拥挤。针对这些问题,提出了一种创新的施工方案:边跨混凝土梁段采用挂篮对称悬浇施工,待混凝土梁和结合段施工完成后再架设钢箱梁;钢箱梁采用纵向分段、横向分块,通过索塔侧向提梁上桥面;梁上运梁至悬臂端桥面吊机处,尾部提梁前移并空中旋转90°,调整好姿态后再横向移梁进行匹配对位,对称张拉相应位置斜拉索。为了验证该施工方案的可行性,采用Midas civil建立了全桥有限元模型,对整个施工阶段进行了模拟计算,结果表明该方法存在横向偏载效应,但整个施工阶段结构安全可靠,可为今后同类桥梁架设提供参考。     

桩基非对称局部冲刷条件下土体应力变化解析解

传统桩基局部冲刷坑模型主要采用对称形态的坑体来分析,然而实际问题中局部冲刷坑体常为非对称,这使得桩基处于更不利的状态。评价桩基承载力的关键之一是合理计算冲刷坑造成的土体应力状态变化。而对于桩周形成非对称冲刷坑时土体应力变化,目前仍然没有较为完善和严格的理论分析方法。针对该问题,根据已有试验得到的非对称局部冲刷坑形态,提出非对称冲刷坑内土体应力计算的平面应变简化模型;并基于弗拉曼解在半无限空间中的应用,将冲刷坑以上土体看做荷载并引起土体内应力重分布,得到非对称冲刷坑下土体应力分布计算的平面应变解析解。通过有限元中的"生死单元法"模拟非对称局部冲刷坑的形成过程,并将有限元得到的冲刷坑内土体应力结果与解析解计算结果进行对比,验证解析解的正确性。随后基于该方法考虑桩尺寸的影响,得到非对称局部冲刷坑形成后桩周土体的垂直及水平有效应力计算方法,并与有限元计算结果进行了对比。结果表明：在考虑桩尺寸时,解析解计算结果略保守。在此基础之上,对非对称冲刷坑参数的敏感性进行分析,指出桩上、下游侧冲刷深度差值对桩周土体的应力影响较大,得到了非对称冲刷坑下桩周土体的垂直有效应力及水平有效应力差的变化规律,研究结果可为工程设计提供参考。     

Research on the Influence of Vertical Deformation of Bridge on the Track RegularityEI北大核心

Research purposes: The vertical deformation of high-speed railway (HSR) bridge will cause the track irregularity, which threatens the safe and efficient operation of the HSR. Taking the 32 m simple supported beam bridge as the research object, based on the existing mapping analytical model for bridge vertical deformation and rail geometry, the influence of the track regularity of the CRTS Ⅰ slab ballastless track structure caused by the key parameters such as the bridge vertical deformation amplitude, the hanging length of the beam end and the vertical stiffness of mortar layer were studied, and the corresponding measures to control the rail deformation were proposed, to provide theoretical reference for comprehensive treatment of rail deformation of HSR bridge. Research conclusions:(1) The pier settlement, the vertical rotation of the beam end and the beam fault will cause the rail to follow the beam deformation, and "up-warping" of the rail on the vertical deformation boundary will appear. (2) The rail deformation is directly proportional to the vertical deformation amplitude of the bridge and the key to control the rail deformation is to reduce the vertical deformation of the bridge. (3) The rail deformation can be controlled by reducing the hanging length of beam and vertical stiffness of mortar layer. (4) The research results can provide a theoretical reference for controlling the vertical rail deformation of high-speed railway bridges. © 2018, Editorial Department of Journal of Railway Engineering Society. All right reserved.     

The Reinforcement Analysis of Prestressed Anchor Frame Beam in the Deep Cutting Slope under Three Dimensional Strong EarthquakeEI北大核心

Research purposes: In order to further study the reinforcement of prestressed anchor frame beam in the deep cutting slope under three dimensional strong earthquake, a model of the deep cutting slope is built through FLAC 3D simulation software, the seismic wave to the model from three directions of x,y and z is input, and the dynamic response of the slope is analyzed. Then, the prestressed anchor frame beam reinforcement measures are applied to the model, and this paper analyzes the reinforcement effect of the prestressed anchor frame beam to the deep cutting slope under three dimensional strong earthquake. Research conclusions:(1) The prestressed anchor frame beam has a good effect on restraining the horizontal displacement of the deep cutting slope. (2) Under the three dimensional strong earthquake, the prestressed anchor frame beam has a good effect on the horizontal acceleration and horizontal velocity of the deep cutting slope, which reduces the peak of horizontal acceleration and horizontal velocity. (3) Through the comparison of the response before and after the reinforcement of the prestressed anchor frame beam is given under the 9 degrees three dimensional strong earthquake, it can be concluded that the prestressed anchor frame beam can provide good reinforcement effect to the deep cutting slope. (4) This research can be used for reference to the earthquake resistance of the slope engineering. © 2018, Editorial Department of Journal of Railway Engineering Society. All right reserved.