预应力施工技术在道路桥梁施工中的运用

近年来,我国道路桥梁工程施工规模与数量快速增长,对桥梁施工质量和使用性能提出了更高要求。预应力施工技术作为一种先进的施工方法,可以显著提高桥梁承载能力和使用寿命,因此在道路桥梁工程中得到了广泛应用。本文以预应力施工技术的应用范围和施工工艺为切入点,分析了其在受弯构件、加固施工和连续梁桥等领域的运用,提出了设计优化、材料控制、工序把控等质量控制措施,旨在为道路桥梁工程的高质量施工提供技术支持。

冬季道路桥梁施工中混凝土浇筑施工技术研究

本文对冬季道路桥梁施工中的混凝土浇筑施工技术进行了分析,阐述了冬季道路桥梁施工中的混凝土浇筑施工的技术要点,并对冬季道路桥梁施工中的混凝土浇筑施工的关键环节进行了说明,介绍了如何控制冬季道路桥梁施工中的混凝土浇筑施工质量的方法,最后总结了冬季道路桥梁施工中的混凝土浇筑施工技术的重点和要点,旨在提高冬季道路桥梁施工中的混凝土浇筑施工水平,保证施工质量。

加强道路与桥梁施工技术保障施工质量探究

国家经济的发展及综合国力的提升,使得道路与桥梁施工的重要作用得以体现,要想提高施工质量与效果,实现我国道路运输 行业的健康、持续发展,就要立足现状,从中找出施工中的安全隐患及质量问题,合理制定和规划施工方案。此外,在施工过程中,还要 顺应时代发展新趋势,改变以往的施工技术手段,引入先进的施工理念和操作技术,不仅能够切实保障施工技术的合理性及安全性,还能 够加快施工进程,提高施工质量。因此,本文对加强道路与桥梁施工技术保障施工质量进行探究。

混凝土施工技术在道路桥梁工程施工中的应用标准

随着城市化进程加快和交通设施建设的不断完善,道路桥梁工程的建设已经成为在城市基础设施建设中的重要组成部分。因此,本文以混凝土施工技术在道桥工程施工应用标准为研究对象,首先介绍了混凝土施工技术的要点,其次对施工过程中存在的问题进行分析,最后探究了技术应用标准,以期对于相关人员的工作提供一定的参考价值。

基于T-Swarm理论的城市道路作业区交通流建模与仿真系统研究

1研究背景及研究意义我国正处于城市化进程快速推进的阶段,大量的人口和车辆不断涌入城市,给现有城市交通系统带来了巨大的冲击,严重加剧了原本就十分突出的城市道路供需矛盾。为了缓减城市交通拥堵,很多城市正在通过大范围的道路施工来增加交通的容量,大型的交通项目,比如地铁、轻轨、高架、以及最近兴起的有轨电车等项目纷纷上马,新一轮的城市道路改建、扩建和新建正愈演愈烈。新一轮的城市道路改建、扩建和新建正愈演愈烈。而且,由于我国正处于城市化进程高速推进的阶段,

Spatiotemporal Patterns of Road Network and Road Development Pri-ority in Three Parallel Rivers Region in Yunnan,China:An Evaluation Based on Modified Kernel Distance Estimate

Road network is a critical component of public infrastructure,and the supporting system of social and economic development.Based on a modified kernel density estimate(KDE)algorithm,this study evaluated the road service capacity provided by a road network composed of multi-level roads(i.e.national,provincial,county and rural roads),by taking account of the differences of effect extent and intensity for roads of different levels.Summarized at town scale,the population burden and the annual rural economic income of unit road service capacity were used as the surrogates of social and economic demands for road service.This method was applied to the road network of the Three Parallel River Region,the northwestern Yunnan Province,China to evaluate the development of road network in this region.In results,the total road length of this region in 2005 was 3.70×104km,and the length ratio between national,provincial,county and rural roads was 1∶2∶8∶47.From 1989 to 2005,the regional road service capacity increased by 13.1%,of which the contributions from the national,provincial,county and rural roads were 11.1%,19.4%,22.6%,and 67.8%,respectively,revealing the effect of′All Village Accessible′policy of road development in the mountainous regions in the last decade.The spatial patterns of population burden and economic requirement of unit road service suggested that the areas farther away from the national and provincial roads have higher road development priority(RDP).Based on the modified KDE model and the framework of RDP evaluation,this study provided a useful approach for developing an optimal plan of road development at regional scale.

Traffic Calming in Quebec： Speed Humps and Speed Cushions

Speed management is an essential tool in ensuring the improved safety of users of urban roads, particularly vulnerable users. It relies on several measures： awareness campaigns, speed control, as well as the development and operation of the road infrastructure. Municipalities in Quebec are increasingly resorting to the development of traffic calming measures, and are facing numerous questions concerning their installation and their effectiveness. To respond to this need, the ministere des Transports du Quebec （Quebec Department of Transport） has begun publishing a series of fact sheets on a variety of traffic calming measures, including speed humps and speed cushions, raised crosswalks and intersections, neckdowns, centre islands and chicanes. A general fact sheet introduces all of the measures and notably outlines the procedure for pre-implementation analysis. Each fact sheet dedicated to an individual measure outlines the implementation context, advantages and disadvantages, geometric characteristics, effectiveness at reducing speed, and maintenance requirements, including winter maintenance. Two fact sheets are already published： the general fact sheet and the fact sheet on speed humps and speed cushions. The fact sheets as well as examples of measures implemented in municipalities are available on the minist6re＇s web site under Partenaires-Municipalites-Securite routiere.

Infrastructure-based localisation of automated coal mining equipment

A novel radar-based system for longwall coal mine machine localisation is described. The system, based on a radar-ranging sensor and designed to localise mining equipment with respect to the mine tunnel gate road infrastructure, is developed and trialled in an underground coal mine. The challenges of reliable sensing in the mine environment are considered, and the use of a radar sensor for localisation is justified. The difficulties of achieving reliable positioning using only the radar sensor are examined. Several probabilistic data processing techniques are explored in order to estimate two key localisation parameters from a single radar signal, namely along-track position and across-track position, with respect to the gate road structures. For the case of across-track position, a conventional Kalman filter approach is sufficient to achieve a reliable estimate. However for along-track position estimation, specific infrastructure elements on the gate road rib-wall must be identified by a tracking algorithm. Due to complexities associated with this data processing problem, a novel visual analytics approach was explored in a 3D interactive display to facilitate identification of significant features for use in a classifier algorithm. Based on the classifier output, identified elements are used as location waypoints to provide a robust and accurate mining equipment localisation estimate.

Health Impact Assessment of Air Pollution in Some Regions in Albania

Air is the ocean we breathe. Air supplies us with oxygen which is essential for our bodies to live. 99.9% air is nitrogen, oxygen, water vapor and inert gases. Human activities can release substances into the air, some of which can cause problems for humans, plants and animals. There are several main types of pollution and well-known effects of pollution which are commonly discussed. These include smog, acid rain, the greenhouse effect, and ＂holes＂ in the ozone layer. Each of these problems has serious implications for our health and well-being as well as for the whole environment. The age and health condition are more important also at the response opposite the pollution of air. During the last decade in our country such as result of freely population movement, development and growth of their industrial activities, growth of vehicle number, collapse of roadway infrastructure etc., an increase of air quality pollution is evident. In this study, we exhibited the causers, such as increasing of number of the old cars, which is an important factor of the air pollution and, at the same time, we exhibited the pollution indicators of the air quality, such as PM I 0, total dust, dust levels outdoors and indoors, which are in the high levels. These factors indicated on human health. We have observed the health indicators, especially lung diseases such as bronchial asthma with higher percentage, chronic bronchitis and lung cancer. There was consistency in the finding that relates the acute increases in urban air pollution and the short-term health effects or patients suffering from chronic obstructive pulmonary diseases.

Study on influence of ground settlement in bored metro tunnel

At present the bored construction method is one of the main construction methods of metro and tunnel construction in China. The empirical estimated formulas of tunnel ground surface settlement using the bored construction method were obtained, combining the mechanical stimulant calculated result of tunnel model of different embedded depth, different cross section and different construction method and the actual measurement data of Beijing metro construction. According to the regressed analysis of calculated data, the calculated equations of ground surface settlement value and settlement range of tunnel section under the condition of different embedded depth, different cross section and different construction method were gained. Among them there are some empirical formulas can apply to the construction design of metro tunnel directly.

Key Techniques for the Construction of High-Speed Railway Large-Section Loess Tunnels

The successful completion of the Zhengzhou-Xi＇an high-speed railway project has greatly improved the construction level of China＇s large-section loess tunnels, and has resulted in significant progress being made in both design theory and construction technology. This paper systematically summarizes the tech- nical characteristics and main problems of the large-section loess tunnels on China＇s high-speed railway, including classification of the surrounding rock, design of the supporting structure, surface settlement and cracking control, and safe and rapid construction methods. On this basis, the key construction tech- niques of loess tunnels with large sections for high-speed railway are expounded from the aspects of design and construction. The research results show that the classification of loess strata surrounding large tunnels should be based on the geological age of the loess, and be determined by combining the plastic index and the water content. In addition, the influence of the buried depth should be considered. During tunnel excavation disturbance, if the tensile stress exceeds the soil tensile or shear strength, the surface part of the sliding trend plane can be damaged, and visible cracks can form. The pressure of the surrounding rock of a large-section loess tunnel should be calculated according to the buried depth, using the corresponding formula. A three-bench seven-step excavation method of construction was used as the core technology system to ensure the safe and rapid construction of a large-section loess tunnel, following a field test to optimize the construction parameters and determine the engineering measures to stabilize the tunnel face. The conclusions and methods presented here are of great significance in revealing the strata and supporting mechanics of large-section loess tunnels, and in optimizing the supporting structure design and the technical parameters for construction.

Advanced Methods of Evaluating Benefits from Improved Flood Immunity in Queensland

The regular occurrence and the high costs of flooding to both road agencies and communities is a strong impetus to investigate the methodologies applied to evaluating flood immunity road projects. Very little literature exists on methods of evaluating the benefits of improving flood immunity through better road infrastructure. This paper attempts to address some of the numerous issues hindering the accurate evaluation of flood immunity road projects. The methodologies presented in this paper are designed to evaluate benefits that are not normally included or not fully considered in evaluations; such benefits include reduced flood related road accidents, costs of not travelling during the closure period and additional costs from unanticipated flood events. A key focus of the paper is the consideration of the evaluation of improved flood immunity from a network perspective rather than the typical approach of evaluating flood immunity projects in isolation to each other. The application of the proposed methodologies is demonstrated with a hypothetical example of a typical rural network subjected to regular flooding. The results of the analysis, conducted using the proposed methodologies, reveals that the currently applied methodologies account for less than half the likely value of benefits of a package of projects that will prevent the complete isolation of communities during serious flood events.

Comparison of Crack Width and Space between SCC and Conventional Concrete Beams

Concrete is a material which is in wide use in engineering especially in construction engineering and road infrastructure facilities. Development trends for high rise constructions, modern skyscrapers indicate that building such constructions with normal concretes and low consistency is impossible, therefore there is a need for concrete with high processes because of great amount of reinforcement in cross-section of concrete elements. Solution for such construction is self-compacting concrete because of its ability to fill good formworks without compaction and vibration. Considering this fact, researches for cracks, mechanical characteristics of concrete and deformations have been conducted worldwide. In this paper, we conducted an experimental research to determine the cracks on beams of self-compacting concrete and compared it with conventional concrete. The experimentally-obtained results will be presented for both types of concrete for： module of elasticity, compression strength, crack with and cracks spacing for duration failure testing time t = 400 days.

Soil Depletion

Soils are under threat around the world. Erosion, pollution, salinization and acidification degrade soils irreversibly. Evidently, the rate of soil degradation greatly exceeds the rate of soil formation. In some countries, soil lost is almost 100 times faster than the rate of its formation. Therefore, soil needs to be considered as a nonrenewable resource. Incessant construction activities along with unsustainable mining operations and energy-related undertakings in recent years have accelerated the degradation of soil in Turkey. Highway travellers can witness the mindless plunder all over the land. As one travels smoothly on newly constructed highways, looming along the roads are piles of leftover destruction： heaps of broken asphalt from previous roads; newly excavated topsoil dumped into adjacent streams; eroded hillsides. In the age of global climate change, these so-called development efforts sound incomprehensible since such anthropogenic activities exacerbate the change. Clearly, climate change increases the erosion rates and reduces the soil quality. This fact alone requires each country to adopt and implement sound conservation practices to protect their soils, and hence, social stability and security. The most effective way to conserve soil is to establish and maintain ground cover vegetation. Avoiding unnecessary soil sealing also conserves soil.

Digital Dividend： The Path Towards Business and Marketing Development

Wireless radio spectrum is an important resource that allows for increased business development, throtigh the provision of services using wireless networking infrastructures. Since radio spectrum is limited, an optimal utilization of it is required, by adopting advanced spectrum management methods. The current transition from analogue to digital terrestrial television may act as a unique opportunity, in order to reallocate this valuable spectrum resource. After the transition, a part of the traditional analogue television spectrum bands will be completely released, allowing for the use of this spectrum by sophisticated wireless systems. Furthermore, digital terrestrial television interleaves spectrum bands in order to avoid possible interference between adjacent channels used by broadcasting stations, thus leaving spectrum holes exploited by novel wireless networks, namely unlicensed secondary systems. In this context, this article investigates business and marketing development issues, arising by utilizing released and interleaved television spectrum bands

A systematic review of the effect of various interventions on reducing fatigue and sleepiness while driving

Purpose： To identify and appraise the published studies assessing interventions accounting for reducing fatigue and sleepiness while driving. Methods： This systematic review searched the following electronic databases： Medline, Science direct, Scopus, EMBASE, PsyclNFO, Transport Database, Cochrane, BIOSIS, ISI Web of Knowledge, specialist road injuries journals and the Australian Transport and Road Index database. Additional searches included websites of relevant organizations, reference lists of included studies, and issues of major injury journals published within the past 15 years. Studies were included if they investigated interventions/exposures accounting for reducing fatigue and sleepiness as the outcome, measured any potential interventions for mitigation of sleepiness and were written in English. Meta-analysis was not attempted because of the heterogeneity of the included studies. Results： Of 63 studies identified, 18 met the inclusion criteria. Based on results of our review, many interventions in the world have been used to reduce drowsiness while driving such as behavioral （talking to passengers, face washing, listening to the radio, no alcohol use, limiting the driving behavior at the time of 12 p.m. - 6 a.m. etc）, educational interventions and also changes in the environment （such as rumble strips, chevrons, variable message signs, etc）. Meta-analysis on the effect of all these in- terventions was impossible due to the high heterogeneity in methodology, effect size and interventions reported in the assessed studies. Conclusion： Results of present review showed various interventions in different parts of the world have been used to decrease drowsy driving. Although these interventions can be used in countries with high incidence of road traffic accidents, precise effect of each intervention is still unknown. Further studies are required for comparison of the efficiency of each intervention and localization of each intervention ac- cording to the traffic pattems of each country.

Strategic Ideas of Greenway Construction in Ecological Zhejiang Province

This article grasps the implication of ecology based on thetheory ofgreenway. With the purposeofmaking Zhejiang Provincebecomeanecological province,itpointsoutthattheproblems exist in the greenway construction and makes it clear that the greenway construction is very important. Furthermore, in combination with the linear green open spaces, such as greening passages, touristareas, and administration facilitiesin Zhejiang Province, this article putsforward the strategic ideas of the greenways construction and the strategies, measures to apply the greenways construction.