Instandsetzung einer “müden” Straßenbrücke mit orthotroper Fahrbahn

Repair of a “tired” road bridge with orthotropic deck. The proneness to fatigue of steel bridges with an orthotropic deck appears in many damages because of the increasing traffic of heavy vehicles. On the example of an aggrieved highway‐bridge the specific weak points and the executed damage analysis will be shown. The gained knowledge leaded to the development of different alternatives of repair and to the presented repair concept. To improve the global characteristics of the structure additional supports will be built, for the local strengthening a reinforced concrete slab will be built as composite structure with the existing steel deck.     

长大双洞公路隧道联络通道间距设置研究

为了更有效且经济地对双洞单向公路隧道联络通道的设置间距进行确定,本研究首先结合PHOENICS计算软件建立了某特长双洞单向公路隧道的计算模型,并对隧道内的火灾烟雾场及温度场进行了模拟研究;进而以修正的Crane模型及FED死亡模型为基础,以“高温-CO”叠加伤害为原则,通过微元积分的手段对火灾温度及CO浓度进行了进一步的修正,从而推导出了人员逃生过程中的生命损失值模型;再以荷兰学者在Benelux隧道内所进行的火灾人员疏散实验研究为基础,结合蒙特卡洛法给出了逃生人员的疏散时间及疏散速度的分布情况,最终将以上所得研究结果进行联立,得出了“联络通道间距—人员死亡概率”关系曲线。研究表明:双洞单向公路隧道发生火灾时,其通风风速超过临界风速时才会有利于下游温度及CO浓度的控制,否则通风将会对下游人员的逃生形成负作用。当环境风速为0 m/s且逃生距离为200 m时,人员逃生失败概率为1.008 65%;当环境风速为2.0 m/s且逃生距离为400 m时,人员逃生失败概率最大,其大小为3.319 91%。最终结合风险评价等级得出了长大双洞隧道联络通道间距应小于320 m为宜。     

A Computational Methodology for Assessing the Time‐Dependent Structural Performance of Electric Road Infrastructures

An infrastructure adapted to dynamic wireless recharging of electric vehicles is often referred to generically as Electric Road (“e‐road”). E‐roads are deemed to become essential components of future grid environments and smart city strategies. Several technologies already exist that propose different ways to integrate dynamic inductive charging systems within the infrastructure. One e‐road solution uses a very thin rail with box‐section made of fibre‐reinforced polymer, inside which an electric current flows producing a magnetic field. In spite of the great interest and research generated by recharging technologies, the structural problems of e‐roads, including vibrations and structural integrity in the short and/or long period, have received relatively little attention to date. This article presents a novel computational methodology for assessing the time‐dependent structural performance of e‐roads, including a recursive strategy for the estimation of the lifetime of surface layers. The article also reports some numerical findings about e‐roads that will drive further numerical analyses and experimental studies on this novel type of infrastructure. Finally, numerical simulations have been conducted to compare an e‐road with a traditional road (“t‐road”), in terms of static, dynamic and fatigue behavior.     

Hydrogen energy stations: along the roadside to the hydrogen economy

Hydrogen has become more than an international topic of discussion within government and among industry. With the public announcements from the European Union and American governments and an Executive Order from the Governor of California, hydrogen has become a “paradigm change” targeted toward changing decades of economic and societal behaviours. The public demand for clean and green energy as well as being “independent” or not located in political or societal conflict areas, has become paramount. The key issues are the commitment of governments through public policies along with corporations. Above all, secondly, the advancement of hydrogen is regional as it depends upon infrastructure and fuel resources. Hence, the hydrogen economy, to which the hydrogen highway is the main component, will be regional and creative. New jobs, businesses and opportunities are already emerging. And finally, the costs for the hydrogen economy are critical. The debate as to hydrogen being 5 years away from being commercial and available in the marketplace versus needing more research and development contradicts the historical development and deployment of any new technology be it bio-science, flat panel displays, computers or mobile phones. The market drivers are government regulations and standards soon thereafter matched by market forces and mass production. Hydrogen is no different. What this paper does is describes is how the hydrogen highway is the backbone to the hydrogen economy by becoming, with the next five years, both regional and commercial through supplying stationary power to communities. Soon thereafter, within five to ten years, these same hydrogen stations will be serving hundreds and then thousands of hydrogen fuel powered vehicles. Hydrogen is the fuel for distributed energy generation and hence positively impacts the future of public and private power generators. The paradigm has already changed.     

Real‐Time Estimation of Pollution Emissions and Dispersion from Highway Traffic

Traffic‐related air pollution is a serious problem with significant health impacts in both urban and suburban environments. Despite an increased realization of the negative impacts of air pollution, assessing individuals' exposure to traffic‐related air pollution remains a challenge. Obtaining high‐resolution estimates are difficult due to the spatial and temporal variability of emissions, the dependence on local atmospheric conditions, and the lack of monitoring infrastructure. This presents a significant hurdle to identifying pollution concentration hot spots and understanding the emission sources responsible for these hot spots, which in turn makes it difficult to reduce the uncertainty of health risk estimates for communities and to develop policies that mitigate these risks. We present a novel air pollution estimation method that models the highway traffic state, highway traffic‐induced air pollution emissions, and pollution dispersion, and describe a prototype implementation for the San Francisco Bay Area. Our model is based on the availability of real‐time traffic estimates on highways, which we obtain using a traffic dynamics model and an estimation algorithm that augments real‐time data from both fixed sensors and probe vehicles. These traffic estimates combined with local weather conditions are used as inputs to an emission model that estimates pollutant levels for multiple gases and particulates in real‐time. Finally, a dispersion model is used to assess the spread of these pollutants away from the highway source. Maps generated using the output of the dispersion model allow users to easily analyze the evolution of individual pollutants over time, and provides transportation engineers and public health officials with valuable information that can be used to minimize health risks.     

Traffic safety: problems and solutions

The author discusses the three main elements of the highway safety problem—human, vehicle and roadway—with special attention to recent accident information, subsequent research activities, and remedial programs. Both accident occurrence and preventative countermeasures are considered within the framework of a three‐phase sequence; precrash, crash, and postcrash phases. Methods for identifying and controlling problem drivers (especially intoxicated drivers), improved “packaging” systems for vehicle occupants, and increasing the crash‐worthy qualities of motor vehicles are summarized. The Experimental Safety Vehicle Program is cited as an example of the type of international cooperation that should be expanded with participation by all nations.     

一种定量评价地铁交通社会与环境效益的模型

通过“有无对比法”和“地上地下对比法”,构造了地铁交通社会效益和环境效益计算指标体系,提出了地铁交通社会、环境效益货币化计算模型。案例应用结果表明:①地铁交通对城市经济发展促进作用明显;②地铁沿线房地产升值效益占据地铁交通社会和环境效益总量的绝对比例,达98%;③地铁沿线房地产升值效益、减少空气污染、减少噪声污染等溢出效益可以通过税收等手段进行内部化;④该模型计算结果可以作为地铁交通建设及沿线公共地下空间开发融资和决策的依据。     

Conceptualising Regeneration in the New Deal for Communities

This paper aims to unpack the term “regeneration”, using a discourse analysis approach to examine the ways in which local actors involved in a New Deal for Communities partnership in Newcastle upon Tyne formulate their understandings of regeneration. The paper finds that “regeneration” is a term that has been taken up and used by local actors who have not considered its meaning in any substantive depth, and argues that this is the result of both the powerful policy discourse surrounding regeneration, and the lack of dialogue locally about the nature of the problems to be addressed. The paper concludes by arguing for regeneration partnerships to be given the time and support to discuss local issues in order to facilitate partnership working and develop an appropriate agenda for regeneration.     

Generative methods in urban design: a progress assessment

The year 2007 marked the 20‐year anniversary of A New Theory of Urban Design (1987), a slender volume by Christopher Alexander and colleagues that serves as a notable milepost within the half‐century old “design methods movement” in which Alexander himself played a seminal role. The “generative” design method of A New Theory focused less upon the specification of a final form through schematic planning, and more on the stepwise process by which a form might emerge from the evolutionary actions of a group of collaborators. In so doing, it challenged the notion of “design” as a progressive expression of schematic intentions, and argued for a conception of design as a stepwise, non‐linear evolution in response to a series of contextual urban factors. In the 20 years since, significant progress has been made to develop the insights of generativity in urban design, as in other fields. Some of Alexander’s ideas have been incorporated – notably by practitioners of The New Urbanism – and some have been challenged and dismissed, including, notably, by Alexander himself. The author assesses progress since this milepost volume – substantial, he argues – as well as setbacks and shortcomings, and significant opportunities still remaining.     

Kathodischer Korrosionsschutz von Stahl in Beton: Instandsetzung des Parkhauses “Am Gericht” in Frankfurt am Main

Cathodic Protection of Steel in Concrete Rehabilitation of the Multi Storey Car Park “Am Gericht” in ”Frankfurt am Main” Within the last decades, the rehabilitation reinforced concrete structures that are affected by chloride‐induced corrosion have become more and more important. In such cases, cathodic protection as an electrochemical rehabilitation method often is a reliable and cost effective procedure. The rehabilitation of the multi‐storey car park “Am Gericht” in Frankfurt am Main shows exemplarily the realization of this technique. The theory of cathodic protection will be explained as well as special details that have to be considered in practice. The data of early de‐polarization measurements show the actual conditions of the cp‐system and the protected object, respectively.     

Reflections on the history of indoor air science,focusing on the last 50 years

The scientific articles and Indoor Air conference publications of the indoor air sciences (IAS) during the last 50 years are summarized. In total 7524 presentations, from 79 countries, have been made at Indoor Air conferences held between 1978 (49 presentations) and 2014 (1049 presentations). In the Web of Science, 26 992 articles on indoor air research (with the word “indoor” as a search term) have been found (as of 1 Jan 2016) of which 70% were published during the last 10 years. The modern scientific history started in the 1970s with a question: “did indoor air pose a threat to health as did outdoor air?” Soon it was recognized that indoor air is more important, from a health point of view, than outdoor air. Topics of concern were first radon, environmental tobacco smoke, and lung cancer, followed by volatile organic compounds, formaldehyde and sick building syndrome, house dust‐mites, asthma and allergies, Legionnaires disease, and other airborne infections. Later emerged dampness/mold‐associated allergies and today's concern with “modern exposures‐modern diseases.” Ventilation, thermal comfort, indoor air chemistry, semi‐volatile organic compounds, building simulation by computational fluid dynamics, and fine particulate matter are common topics today. From their beginning in Denmark and Sweden, then in the USA, the indoor air sciences now show increasing activity in East and Southeast Asia.     

Developing a risk assessment model for PPP projects in China — A fuzzy synthetic evaluation approach

Earlier research works on PPP showed that an objective, reliable, and practical risk assessment model for PPP projects is essential to the successful implementation of PPP projects. However, actual empirical research studies in this research area are rather limited. This paper reports the second stage of a funded research study, which aims to develop a fuzzy synthetic evaluation model for assessing the risk level of a particular critical risk group (CRG) and the overall risk level associated with PPP projects in China. At the first research stage, thirty-four risk factors were identified through a comprehensive literature review and 3 new risk factors were proposed during a two-round Delphi questionnaire survey. The most critical 17 risk factors were selected through the calculation of normalized values. The correlation of these 17 critical risk factors (CRFs) was further analyzed via factor analysis and 6 CRGs were formulated, namely: (1) Macroeconomic Risk; (2) Construction and Operation Risk; (3) Government Maturity Risk; (4) Market Environment Risk; (5) Economic Viability Risk; and (6) Government Intervention. On the basis of the research works conducted at the first research stage, the weightings for each of the 17 critical risk factors (CRFs) and 6 CRGs were determined through the two-round Delphi questionnaire survey. A set of knowledge-based fuzzy inference rules was then established to set up the membership function for the 17 CRFs and 6 CRGs. The empirical research findings showed that the overall risk level of PPP highway projects is between “moderate risk” and “high risk”. Hence it could be construed that investment in PPP highway projects in China may be considered as risky. In fact, the Delphi survey respondents perceived that “Government Intervention” is the most CRG; with “Government Maturity Risk” being the second; “Economic Viability Risk” the third; “Market Environment Risk” the fourth; “Construction and Operation Risk” the fifth; and “Macroeconomic Risk” the last. These findings revealed that government intervention and corruption may be the major hurdles to the success of PPP highway projects in China. These may be caused by inadequate law and supervision system and poor public decision-making process. Although the fuzzy synthetic evaluation model was primarily developed for PPP projects in general, the research method could be replicated in a specific type of PPP project, such as water treatment projects and hospital projects, to produce similar models for inter-type comparisons. By doing so, it provides an opportunity for practitioners to assess the risk level of different types of PPP projects based on objective evidence rather than subjective judgment. The most CRG for different types of PPP projects could be identified and both precautionary and remedial actions could be taken as soon as possible. Such an extension would provide a deeper understanding of managing different types of PPP projects.     

The “penalty factors” method for the prediction of TBM performances in changing grounds

Tunnel construction by TBMs through hard rock is significantly affected by the geological and geotechnical conditions at tunnel level. Ground parameters such as uniaxial compressive strength, fracturing degree and abrasiveness, and factors such as water inflows and stress level may deeply affect the way a TBM will perform. In addition, different types of TBMs will behave differently in a given condition.This paper presents a method for TBM performance prediction in changing grounds, which has been developed in the framework of the European project “New Technologies for Tunnelling and Underground Works” (NeTTUN). The model starts from an optimum TBM performance in best conditions, i.e. when all ground parameters are in their “best state”. A stepwise reduction of the optimum advance rate is then performed, according to “reduction factors” that quantify the effect of degrading ground conditions on the TBM advance rate. By doing so, the “penalty factors” model is able to take into account a very wide range of ground conditions, from very good to very poor. Two types of TBMs commonly employed in rock tunnelling have been considered, i.e. Gripper and Shielded machines, each of them characterized by its own set of reduction factors.In order to consolidate the factor values and to validate the model, a TBM performance database, also developed in the framework of the project NeTTUN, has been used. The database includes a large number of tunnels excavated in different ground conditions with all standard TBM types. The comparison between the values given by the “penalty factors” model and the actual TBM performances observed during construction shows that the developed tool may provide a reliable estimation of the TBM performance based on simple ground parameters.The “penalty factors” model has also been interfaced with the DAT (“Decision Aids for Tunnelling”). The DAT software, co-developed by MIT and LMR-EPFL, is able to compute the probabilistic distributions of the tunnel construction time and – cost in function of the geology – and construction related uncertainties.The model is conceived to be used in its present form. However, the methodology can be easily adapted to match the expertize of the user, who is free to update the optimal performances, the ground parameters and/or the values of the reduction factors according to his/her own experience. The model can also be extended to other TBM types and to conventional excavation methods.     

施工单位在公路施工期间的噪声管理

从施工噪声的来源及危害出发,阐述了公路施工噪声的特点,从计划、组织、协调和现场控制等方面提出了公路施工噪声管理措施,从而处理好公路施工噪声和周边环境的矛盾。     

A 3D Evaluation Method for Rail–Highway Hump Crossings

Rail–highway grade crossing crashes may be caused by long vehicles with low clearances becoming stranded when attempting to negotiate rail–highway crossings with steeply graded profiles—hump crossings. Although design standards have been established to encourage the construction that most vehicles are able to successfully navigate, the combination of grade profile and cross‐section interacting with unique vehicle dimensions may lead to instances where vehicles may have difficulty crossing. This article describes a three‐dimensional (3D)‐based (LiDAR) methodology to identify and evaluate the severity of hump crossings. A five‐level criterion is proposed to rate the magnitude of contact. The methodology is demonstrated by modeling seven common low‐clearance vehicle types at three types of hump crossings. Field testing indicates a good correlation between the predicted degree of vehicle‐crossing conflicts and those observed in the field. Results are applicable to operations (e.g., truck routing) or for maintenance and reconstruction programs. Future research could extend the methodology to tunnel and bridge clearances, real‐time warning systems, autonomous vehicles, or even nontransportation applications.     

新疆盐渍土地区城市道路路基路面设计

本文依据《新疆盐渍土地区公路路基路面设计与施工技术规范》,以新疆鄯善县某工业园区的道路工程设计为实例,针对工程所在地为盐渍土地区的特殊性,分析了该地区公路病害发生的主要原因及危害,提出了盐渍土地区城市道路路基路面新的设计思路,采用土工布隔断层设计为道路的施工提供依据。     

基于等效车流量的高速公路交通噪声预测模型

通过对美国联邦公路管理局（FHWA）公路噪声预测模型进行深入分析,引入等效车流量和等效车速概念处理混合车流,应用统计方法建立了高速公路中交通噪声自由传播的计算模型,并据此导出高速公路交通噪声预测模型。采用实测数据对模型进行了验证,结果表明,采用本方法建立的预测模型有效可行,且计算更加简便,预测结果比较符合我国高速公路交通现状。     

城市道路施工期间交通组织规划探析

不同道路的施工,会对其周边区域的通行状况产生不同的负面影响。在道路施工期间,针对相应的交通影响范围进行科学的道路交通组织规划,显得尤为重要。宁波市通途路与江南路施工期间的交通组织规划,以OD分流为核心指导思想,具体从"面""线""点"三个层次(施工区域、施工沿线和施工道路交叉口)上进行。