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公路桥梁养护中存在资金不足、技术落后、监管不力等问题,影响公路桥梁的安全性。分析公路桥梁养护现状及问题,探讨公路桥梁养护精细化管理的意义与作用,提出建立完善公路桥梁档案信息管理系统、制订科学公路桥梁养护计划、加强公路桥梁预防性维护和检测、提升公路桥梁养护人员的专业素质,以及引入先进公路桥梁检测技术和设备等应用路径。在落实公路桥梁养护精细化管理后,将显著提高公路桥梁的养护效率和质量。 相似文献
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随着人民生活水平的提升,现代桥梁在满足通行功能的同时应更注重创新发展。为此,从桥梁与建筑、桥梁与艺术和桥梁与绿化三个方面阐述桥梁创新设计的主要手法,并以三明凤岗大桥和厦门石亭路天桥为例,探究桥梁创新设计的具体思路,以期为现代桥梁的创新设计提供借鉴。 相似文献
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为确保桥梁的正常运行和安全性,检测与监测桥梁结构和健康状况至关重要。探讨新时期桥梁检测与监测技术研究的意义,阐述数字化技术的优势和特点,论述桥梁工程的常见病害类型及桥梁工程检测技术的应用,通过研究桥梁检测与监测技术及数字化发展方向的对策,对当前桥梁检测和监测技术进行总结和分析,并提出数字化技术在桥梁检测和监测中的应用前景,旨在为未来桥梁建设和维护提供参考。 相似文献
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桥梁作为大型的土木建筑,其结构十分复杂。为了消除桥梁的质量和安全隐患,需要利用无人机对其进行辅助检测,基于此,首先概述传统桥梁检测方式,其次探讨无人机桥梁检测特征,分析无人机在桥梁检测中的优劣势及无人机桥梁检测硬件设备要求,最后针对桥梁检测技术发展进行展望,以此与相关技术人员探讨。 相似文献
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随着国内桥梁建筑事业的发展,对桥梁的设计要求也越来越高。关于体外预应力混凝土桥梁设计分析研究也倍受重视。通过分析发现,桥梁的体外预应力混凝土结构大部分集中在桥梁的固定块和转向块的连接处。相对于传统的体内预应力混凝土桥梁结构,体外预应力结构具有更大的优势,不仅能够减轻质量、便于施工,而且还有利于桥梁的维护,延长桥梁的使用寿命。本文通过对体外预应力混凝土桥梁的研究,阐述了体外预应力混凝土桥梁实验设计内容,并介绍了体外预应力混凝土桥梁设计方法,在桥梁建设中具有一定的理论意义。 相似文献
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近年来随着公路运输业的发展,公路运输成为货运主要方式之一.同时道路交通事故、桥梁塌陷事件也屡见不鲜,货运车辆超载是导致桥梁质量降低、寿命周期缩短的主要原因之一,同时,桥梁建设过程中赶工期、方法不当、管理不严、降低材料标准等因素都会降低桥梁的质量,因此为确保桥梁安全使用需要对其做承载力鉴定.桥梁荷载试验是目前测定桥梁实际可具备承载力的主要方法,分为静载试验和动载试验.静载试验可以分析桥梁在实际运营中的承载能力和状态,为桥梁检测提供依据;桥梁的目前寿命质量和运营荷载等级评定可根据动载试验结果确定. 相似文献
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本文以具体桥梁工程为例,分析该桥梁超载超限车辆的运行及缺乏必要的养护,部分结构出现一定程度的风化现象和外部损伤后,通过静载鉴定试验对桥梁结构静力荷载情况进行检测,并通过动载试验测定和评价桥梁结构动力荷载情况以及桥梁构件损伤程度及实际承载能力。试验结果表明,桥梁结构应力应变、挠度、结构冲击系数等均符合设计技术要求和相关规范,桥梁结构动力性能良好,故仅需加强日常监测和桥梁管制并进行部分风化和外部损伤结构的加固养护处理。 相似文献
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P. W. Bonsall 《Transportation》1991,18(1):83-106
Current trends in requirements for parking related information and in the availability of data are reviewed. Important influences include the increased need for data to assist in the efficient operation and management of parking stock and to assess the impact of parking on the local network and economy. New sources of data are described, particular attention being given to the availability of data as a byproduct of parking management systems and computerised enforcement systems. The use and performance of audio, video and data loggers in parking surveys is discussed as is the role of computers in questionnaire surveys. New methods of analysis involving spreadsheets, graphics and analysis software, links with databases and simulation models are outlined. 相似文献
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Traveler delay costs and value of time with trip chains, flexible activity scheduling and information 总被引:1,自引:0,他引:1
Erik Jenelius Lars-Göran MattssonDavid Levinson 《Transportation Research Part B: Methodological》2011,45(5):789-807
The delay costs of traffic disruptions and congestion and the value of travel time reliability are typically evaluated using single trip scheduling models, which treat the trip in isolation of previous and subsequent trips and activities. In practice, however, when activity scheduling to some extent is flexible, the impact of delay on one trip will depend on the actual and predicted travel time on itself as well as other trips, which is important to consider for long-lasting disturbances and when assessing the value of travel information. In this paper we extend the single trip approach into a two trips chain and activity scheduling model. Preferences are represented as marginal activity utility functions that take scheduling flexibility into account. We analytically derive trip timing optimality conditions, the value of travel time and schedule adjustments in response to travel time increases. We show how the single trip models are special cases of the present model and can be generalized to a setting with trip chains and flexible scheduling. We investigate numerically how the delay cost depends on the delay duration and its distribution on different trips during the day, the accuracy of delay prediction and travel information, and the scheduling flexibility of work hours. The extension of the model framework to more complex schedules is discussed. 相似文献
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Athanasios A. Pallis Thomas K. Vitsounis Peter W. De Langen Theo E. Notteboom 《运输评论》2013,33(4):445-471
This paper presents a taxonomy and analysis of the content of published research in port economics, policy and management (port studies). The recent increase of these publications suggests a growing interest in the study of ports. However, the research characteristics and directions of this research field are unidentified. This paper provides a systematic analysis of port studies published during the period 1997–2008. A comprehensive cross-citation and analysis of the themes, approaches and findings of all 395 relevant journal papers identifies the extent to which the research field is maturing, and the leading papers. This paper also presents an extensive analysis of the content, based on the classification of all port studies into seven research themes. For each theme, research topics, widely used research questions, concepts and research methods and the most important research findings are discussed. Finally, we identify emerging research challenges and research questions that still need to be answered. 相似文献
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In recent years, railway tunnels in karst areas have frequently suffered flooding after high-intensity rainfall, which seriously affects the safety of tunnel operation and the order of transportation, and even interrupts the traffic. Based on the water hazard case in the Yuanbaoshan Tunnel on the Zhijin-Bijie Railway Line, this paper explores the causes of lining damage in terms of geology, rainfall, and the design and construction of water hazard sections, and puts forward the treatment technology for tunnel water hazards with the core concept of "making full use of existing structures and employing open drainage methods in key sections". Besides, this paper simulates and analyzes the formation of hazards and the treatment effect through numerical simulation. The results show that the subjective causes for the damage in tunnel linings include an insufficient understanding of the water-bearing formations at the geological investigation stage, the underestimation of water hazard risks posed by high-intensity rainfall during construction, and the unimproved waterproof and drainage system in the design alteration, while the objective reasons include the development of karst near the tunnel section that passes through the stratum, the strong connectivity of water conduits, and the high-intensity rainfall in a certain period of time on the tunnel site. As for the simulation results, they show that the increase of external water pressure caused by the sudden rise in groundwater level after rainstorm significantly increases the internal force of linings, and eventually leads to a much lower safety factor of sidewall linings and large scale damage, which is in consistency with the characteristics of the actual on-site damage. After on-site emergency treatment, the tunnel structure has become stable and even encountering unprecedentedly heavy rainfall twice, the tunnel has still remained in a good condition. Since then, no water hazards and other disasters have occurred, which proves that the treatment plan is valid. © 2022, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献
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David Bauner 《Transportation Research Part A: Policy and Practice》2011,45(5):375-388
In the beginning of the 1970s, the economies of USA and Japan were growing fast and environmental pollution was increasing to alarming levels. As passenger car emissions were found to be significant and rapidly increasing, their reduction was specially targeted. Following a bill passed by US Congress in 1968, requirements were set in 1970 for the vehicle manufacturers to reduce the emissions of carbon monoxide (CO) and hydrocarbons (HC) with 90% by 1975, and nitrogen oxides (NOx) with 90% by 1976. These requirements were soon adapted to the Japanese regulatory framework, and were known in both countries as the “Muskie Act” or “Muskie Law” after the senator who developed the original bill.The new requirements spurred tremendous research and development efforts. Car manufacturers and research institutions in USA, Japan and Europe investigated and developed alternative solutions, including gas turbine and steam engine vehicles. California, the USA state with the most severe air quality problems and the only state at the time allowed to establish more strict requirements than federal regulation, established requirements implying the use of oxidation catalysts in 1975 and three-way catalysts (TWC’s) in 1977. Japan as a nation adopted similar requirements 1976 and 1978. Export of cars from Japan to USA increased rapidly. The rest of USA adopted emission standards similar to California’s only in 1981, timing USA vehicle sales rebound after the energy crisis and grave economic downturn. Strict requirements were thus established only after more than a decade of civic and legal processes between federal authorities, the car manufacturers and NGO’s.The history of vehicle development is one of cooperation and competition. This paper argues that the international cooperation on different levels of society (government, industry and science) together with commercial competition between the two countries was strong, continuous and instrumental in enabling the development of technology, appropriate regulation and infrastructural changes and thus created a market for cleaner cars and effectively reduced emissions from the growing vehicle fleet. In other words, the introduction of TWCs was reinforced by the simultaneous development of mitigating technology in two car producing countries competing for market space. 相似文献
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隧道施工废水对水环境的影响分析及应对措施 总被引:4,自引:0,他引:4
文章根据不同隧道施工废水的来源、水量及水质的特性,分别从理化、生态、景观等方面详细分析了隧道施工废水对水环境的影响,确定了主要污染物质为油类和悬浮物(SS),其对水环境的物理化学性质方面的影响较大;并提出了加强施工机械车辆管理以减少排污量、在隧道进出口处设置沉淀池、必要时采取隔油沉淀气浮处理等相应对策。 相似文献
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Yu-Chiun Chiou Chieh-Hua Wen Shih-Hsun Tsai Wei-Ying Wang 《Transportation Research Part A: Policy and Practice》2009,43(7):665-684
Devising effective management strategies to relieve dependency on private vehicles, i.e. cars and motorcycles, depends on the ability to accurately and carefully examine the effects of corresponding strategies. Disaggregate choice models regarding the ownership, type and usage of cars and motorcycles are required to achieve this. Consequently, this study proposes integrated car and motorcycle models based on a large-scale questionnaire survey of Taiwanese owners of cars and motorcycles, respectively. Incorporating gas mileage and emission coefficients for different types of cars and motorcycles into the proposed models can enable the estimation and comparison of reductions in energy consumption and emissions under various management strategies. To demonstrate the applicability of the proposed integrated models, scenarios involving 10% and 30% increases in gas prices are analyzed and compared. The results indicate that gas price elasticities of cars and motorcycles are low, ranging from 0.47 to 0.50 for cars and 0.11 for motorcycles. Additionally, a high ratio of discouraged car users shifting to use of motorcycles neutralizes the effects of increased gas price in reducing energy consumption and emissions. Pollution of CO and HC even slightly increased because motorcycles are much more polluting in terms of CO and HC. At last, the reductions of energy consumption and emissions under 10% and 30% increase (or decrease) in other manipulating variables are also estimated and compared. The countermeasures for reducing ownership and usage of cars and motorcycles are then recommended accordingly. 相似文献