湖北省高速公路改扩建建设需求及建设时序浅析

随着经济的快速发展及高速公路的快速建设,湖北省高速公路建设将由规模扩张向增效扩容转变,高速公路改扩建也将成为湖北省今后一段时间内的建设重点,而研判一段时间内高速公路改扩建项目的建设需求及建设时序势必也将成为相关规划编制的重要内容及关键性问题之一.论述高速公路改扩建建设需求及建设时序的判定方法和思路,分析湖北省高速公路改扩建建设需求的主要来源和建设时序判定需遵循的基本原则,以供编制相关规划参考.     

公路跨线桥全寿命周期设计方案研究

跨线桥上跨运营线路,其施工架设、养护、维修都受到下穿运营线路的影响.如何能在设计方案阶段便考虑到检测、监测、维修、拆除的安全便捷,成为跨线桥方案设计阶段需要考虑的问题.以辽宁省内一批新建跨线桥为背景,从全寿命周期角度考虑跨线桥设计方案,对各个寿命环节内需要解决的问题、得以实现的方法全面考虑,以保证跨线桥在全寿命周期内自身性能良好、对运营铁路影响小、经济效益最优.通过从运输、架设、设计细节、养护维修、阶段费用和全寿命周期费用等方面对3个方案进行对比分析,得到不同外部条件下所适用的不同的设计方案,为上跨铁路、公路桥梁快速架设、智能养护、全寿命周期成本等方面提供参考.     

Research trends and agenda on the Belt and Road (B&R) initiative with a focus on maritime transport

The ‘Silk Road Economic Belt and the 21st-Century Maritime Silk Road’ (collectively known as Belt and Road, B&R) has been initiated by the Chinese government in 2013. The B&R is increasingly becoming a focal point for socio-economic–political interests because of its likely impact on land and sea transport and maritime logistics. The aims of this study were threefold: first, to provide an overview on the B&R, focusing on its key structural elements, such as transport corridors, city clusters, dry ports, infrastructure, zoning, and area development; second, to identify the expected impacts of the B&R on trade and implications on structural changes in transportation systems, port networks, and international logistics. Finally, to discuss major research trends and setting up of research agenda which will contribute to enriching the existing literature and shaping the global trade operations and drive economic growth in the context of the B&R.     

港口对腹地城市经济增长的空间溢出效应研究

将港城关系研究视角拓展至空间维度,利用2003—2016年中国沿海港口数据和城市数据,采用空间面板模型实证检验港口对腹地城市经济增长的影响.结果表明:港口不仅产生地区内溢出,也产生空间溢出;不仅促进所在城市经济增长,对腹地城市经济增长也具有显著的空间溢出效应;2008年金融危机后,港口空间溢出效应的显著性大幅增强;分区域检验中,环渤海港口对所在城市经济增长有明显的促进作用,但港口对腹地城市的空间溢出效应有限.     

市政工程造价控制浅谈

该文通过项目各阶段对工程造价影响的分析,从立项决策阶段、项目设计阶段、项目实施各阶段出发,分析影响控制工程造价的主要因素,并根据不同阶段的特点,论述有效控制工程价的措施。     

地铁不同场段分布对其规模分配和运营成本的影响

城市轨道交通的车辆段和停车场需要占用大量的城市土地,合理分配场段规模可以优化占地面积,提高运营效率。基于一场一段情况下,总结出不同接轨方案的场段规模分配计算方法,提出场段分布位置在线路中接近对称时,场段规模大致相等的研究结论。同时,提出地铁收发车空跑距离计算模型,并对不同场段分布对运营成本的影响因素进行分析,提出降低运营期间场段收发车空跑运营成本的途径。     

中天山隧道TBM施工机械台班维护费研究

为解决再制造TBM隧道施工机械台班维护费随工作台班数变化的成本支出控制问题，为相关企业的造价管理提供理论支撑，通过对西康秦岭隧道TB880E型全断面岩石掘进机施工现场统计的维护费数据进行分析，建立维护费和TBM台班数的数学关系模型，提炼出TBM维护费随台班数的发展函数关系式，验证中考虑到TBM停滞期间发生费用和局部再制造费用对工作台班数的影响，最后以中天山隧道等项目的TBM维护费支出情况来验证理论的正确性。得出： TBM隧道施工机械台班维护费和工作台班数存在一定的函数关系； 研究思路和成果可为今后类似隧道工程在前期概算编制、成本控制等方面提供参考，为铁路行业的管理者在今后制定相关TBM隧道施工企业定额、项目精细化管理提供借鉴。     

Bicriterion shortest path problem with a general nonadditive cost

A bicriterion shortest path problem with a general nonadditive cost seeks to optimize a combination of two path costs, one of which is evaluated by a nonlinear function. This paper first identifies a number of emerging transportation applications for which such a shortest path problem might be considered a core subproblem. We propose to first approximate the general nonlinear cost function with a piecewise linear counterpart, and then solve each linear subproblem sequentially. A specialized algorithm is developed to solve the subproblems, which makes use of the efficient path set (or the convex hull) to update upper and lower bounds of the original problem. Conditions under which the solution to a subproblem must belong to the efficient path set are specified. Accordingly, we show that the optimal path must be efficient if the nonlinear cost function is concave. If the optimal path to a subproblem is not efficient, partial path enumeration, implemented using a simple K-shortest path ranking procedure, is conducted to close the gap. The proposed algorithm includes strategies aiming to expedite path enumeration by using upper bounds derived from the efficient path set. Numerical experiments are conducted to demonstrate correctness and effectiveness of the proposed algorithm.     

The causal relationship between GDP and domestic air passenger traffic in Brazil

Abstract

This paper examines the causal relationship between economic growth and domestic air passenger transport in Brazil, using Granger's causality test. Total domestic passenger-kilometres are used as a proxy for air transport demand and gross domestic product as a proxy for economic growth. The test spans the period from 1966 to 2006. The results lead to the acceptance of the hypothesis that there is a unidirectional Granger causal relationship from economic growth to domestic air transport demand in Brazil, having a high elasticity in the short term.     

Demographic indicators of the relative need for artificial reefs in Florida

Abstract

Artificial reef development involves pfonning from a number of perspectives including biological, océanographie, engineering, and social. This article reviews previous studies and identifies demographic variables that affect the use of artificial reefs by recreational anglers. An index of relative demand was created employing eight components: number of coastal county resident boat anglers, nonresident boat anglers, tourist boat anglers, nonboat anglers, number of fishing clubs, number of charter/party boats, number of registered pleasure boats, and the rate of county population growth. By comparing the magnitude of the index to the number of existing artificial reefs off of Florida's 35 coastal counties, an estimate of relative need was graphically portrayed on a state map. Indian River county on the Atlantic coast and Hernando, Hillsborough, Pasco, Citrus, Levy, Lee, and Charlotte counties on the central Gulf coast are the areas with the greatest demand relative to existing reef supply.