价值工程理论在沥青混合料碳排放减排措施中的应用

沥青混合料碳排放减排措施是降低碳排放的有效手段,而对减排措施的选择将直接影响工程的质量和经济效益。本文运用价值工程理论的基本原理与方法,论述价值工程在减排措施选择中的应用方法和步骤,并结合工程实例,对减排措施方案的选择进行研究。结果表明,运用价值工程理论的方法可以择优确定沥青混合料碳排放减排措施。     

不同RAP掺量下就地热再生沥青混合料空隙率优选分析

依托福建省某高速路面预防性养护工程,采用最大理论密度线理论设计了再生沥青混合料级配,通过马歇尔试验研究了RAP料在86%、90%、94%掺量下再生沥青混合料空隙率的变化,并基于二次回归方程建立了不同RAP掺量与再生沥青混合料空隙率之间的回归方程,说明了不同RAP掺量与空隙率之间的变化趋势。研究结果表明:随着RAP料掺量增加,再生沥青混合料空隙率在逐渐降低;当再生沥青混合料空隙率控制在4%时,RAP料掺量约为89%。     

山区高速公路边坡稳定性评价方法浅析

山区高速公路边坡的稳定性对道路交通安全具有重要影响,通过对国内外很多边坡稳定性评价方法的介绍,指出了各种边坡稳定性评价方法存在的缺陷,并提出了一些建议。     

交通职业技术学院学生职业价值观问题研究

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。     

压气条件下泥膜进气值测量试验研究

在压气条件下,进气是泥膜透气失效的起始点。为测量并研究泥膜在气压下的进气压力值（进气值）,通过自制的试验装置,在不同压气条件下对3种泥膜进行进气值测量试验。试验结果表明： 1)由闭气排水与固结排水的差值可以辨别泥膜是否进气,得到泥膜进气值; 2)采用泥膜特征孔径D90/2代入推导公式可近似计算泥膜进气值; 3)泥膜在不同压气条件下进气值不同,增压速率越低,泥膜进气值越大; 4)在较快和较慢的增压速率下存在进气值变化趋于稳定的现象,最大进气值为最小值的2倍以上。     

A Pareto-improving hybrid rationing and pricing policy with multiclass network equilibria

This paper extends the work on Pareto-improving hybrid rationing and pricing policy for general road networks by considering heterogeneous users with different values of time. Mathematical programming models are proposed to find a multiclass Pareto-improving pure road space rationing scheme (MPI-PR) and multiclass hybrid rationing and pricing schemes (MHPI and MHPI-S). A numerical example with a multimodal network is provided for comparing both the efficiency and equity of the three proposed policies. We discover that MHPI-S can achieve the largest reduction in total system delay, MHPI can induce the least spatial inequity and MHPI-S is a progressive policy which is appealing to policy makers. Furthermore, numerical results reveal that different classes of users react differently to the same hybrid policies and multiclass Pareto-improving hybrid schemes yield less delay reduction when compared to their single-class counterparts.     

Formulating cargo inventory costs for liner shipping network design

This study examines how to incorporate the inventory costs of containerized cargoes into existing liner service planning models such that the designed networks could be improved while not causing extra modeling/computational burden. Two approaches are compared: (i) not considering the inventory costs at all and (ii) incorporating the inventory costs associated with onboard time and those related to transshipment by assuming a fixed connection time. The two models are compared with the ideal model capturing the exact inventory costs on a route choice problem and a capacity planning problem based on extensive randomly generated and practical numerical experiments. The results show that: first, ignoring the inventory costs in service planning models may lead to network design with much higher costs (poor network design decisions); second, in service planning models assuming weekly frequency, the inventory costs associated with onboard time could be formulated exactly, and those related to the connection time of weekly services could be approximated by assuming fixed connection time of 3.5 days for ports with 1 day’s minimum connection time and 4.5 days for ports with 2 days’ minimum connection time.     

Empirical analysis of short period traffic counts and their efficiency: the case of Indian traffic

Short period traffic counts (SPTCs) are conducted routinely to estimate the annual average daily traffic (AADT) at a particular site. This paper uses Indian traffic volume data to methodically and extensively study the effect of four aspects related to the design of SPTCs. These four aspects are: (i) for how long, (ii) on which days should SPTCs be carried out, (iii) how many times, and (iv) on which months should SPTCs be carried out? The analyses indicate that the best durations for conducting SPTCs are 3 days (starting with a Thursday) and 7 days, for total traffic and truck traffic, respectively. Further, these counts should be repeated twice a year keeping a separation of two months between the counts to obtain good estimates of AADT at minimal cost. An additional outcome of this study has been the determination of seasonal factor values for roads in developing economies, like India.     

A logit-based model for measuring the effects of transportation infrastructure on land value

Mutual interactions between transportation and land use have long been debated. Despite progress made in computational technology, the study of these interactions is not adequately developed. The most important aspect of such interactions is given by the changes in land values due to changes in transportation infrastructures. We consider the behavioural features of these interactions along with the constraints on the land and/or zoning restrictions and propose a reliable model for the first time to predict land value changes with respect to changes in transportation facilities and accessibility. The proposed model is a logit-based mathematical programming methodology where the relative price of land is predicted with respect to transportation accessibility, neighbourhood amenities, location premium, availability of land, and zoning regulations. A real-world case study is used to exhibit the applicability of the proposed methodology and demonstrate the efficacy of the algorithms and procedures.     

内河航道桥梁船撞时船体最大变形量研究

目前在桥梁船撞防护的专项设计或船撞力专题研究中,对船舶撞击力的研究和桥梁在船舶撞击作用下的响应关注较多,而对船体最大变形量的研究较少。基于ANSYSLS-DYNA软件,对4种不同载质量的内河代表船舶在3种航速、2种碰撞角度下撞击4种墩型的船撞工况进行数值模拟,提取船体最大变形量,并分析船体最大变形量与船舶载质量、撞击速度、桥墩类型及撞击角度的关联性,同时与经验公式做对比。研究结果表明,撞击速度及撞击角度是船体最大变形量的主要控制因素,桥墩类型与之关系不明显。