型钢套拱在圬工拱桥加固中的应用

圬工拱桥是早期修筑的公路中主要采用的桥型,但随着交通发展逐渐暴露出病害情况以及承载能力不足的问题。超重车辆通行会对桥梁产生疲劳应力幅度加大、损伤加剧等病害,甚至造成结构破坏事故。因此,依托实际工程,在对圬工拱桥进行超重车辆通行前的承载能力评定的基础上,采用型钢套拱的加固方案提升圬工拱桥的承载能力。通过有限元计算以及实际荷载法综合评价加固后的圬工拱桥的车辆通行安全性,验证该加固方法的实际应用性能。     

公路拱桥常见病害处治技术

文章介绍了广西公路拱桥存在的常见病害及处治方法,为类似拱桥病害处治提供经验。     

沙尾左江特大桥主桥结构设计及受力分析

沙尾左江特大桥主桥是主跨为360m的中承式钢管混凝土提篮拱桥,为世界最大跨度的公路钢管混凝土提篮拱桥。文章介绍了该桥主桥主要构件设计要点,通过有限元软件程序,对主拱结构进行静力、动力及稳定性分析。计算结果表明:主桥结构强度、刚度、稳定及动力性能均较优。     

探讨山洪灾害对公路桥梁的破坏与对策

文章结合山洪对公路拱桥、梁桥两类桥型的上构破坏形式及机理进行分析,提出相应对策,供公路设计和养护部门参考。     

新技术新工艺

<正>广西500m级钢管混凝土拱桥建造技术获得重大突破日前,依托广西壮族自治区公路桥梁工程总公司负责施工的同类型桥梁"世界第一"跨径——合江长江一桥(波司登大桥)完成的500m级钢管混凝土拱桥建造核心技术研究课题顺利通过鉴定验收,鉴定结果认定该课题研究成果创新性突出,总体达到国际先进水平。该课题由广西壮族自治区公路桥梁工程总公司、四川省交通运输厅公路规划勘察设计研究院、重庆交通大学、柳州欧维姆机械股份有限公司共同完成。该课题以530m跨径的合江长江一桥(波司登大桥)为依托进行科研攻关,解决了超大跨径钢管混凝土拱桥建造核心技术问题,确保了大桥     

大跨度钢管混凝土拱桥极限承载能力影响研究

为了保证大跨度桥梁的安全性能,以某长江公路大桥工程作为背景,对其极限承载能力进行一系列研究,明确钢管混凝土拱桥极限承载能力对各种设计参数的敏感程度,为提高后续更大跨径钢管混凝土拱桥的极限承载能力提供一定参考。     

钢管混凝土拱桥计算理论探讨

介绍钢管混凝土拱桥的发展历史,对钢管混凝土拱桥计算理论,分别从刚度取值、内力计算、应力计算与验算、变形计算与验算等方面进行阐述。     

公路旧拱桥现场检查技术

对公路原有拱桥的承载力进行科学的理论检算和评定,有必要对旧拱桥的现场检查技术进行研究,以提高现场检查技术水平和管理水平,为桥梁的综合评价、确定桥梁的继续使用条件和应采用的加固与维修技术提供了可靠的依据。     

强风荷载地区钢管混凝土拱桥设计探讨

强风荷载地区,风荷载效应对钢管混凝土拱桥的受力影响较大。文章依托某钢管混凝土拱桥工程实例,通过计算分析和方案比选,提出强风荷载地区钢管混凝土拱桥设计需要注意的主要问题,并提出相应的对策,可为类似桥梁工程的设计与计算提供参考。     

V型拱桥与普通拱桥的力学性能对比研究

文章以某跨径为420 m的柔性吊杆下承式钢箱拱桥为研究对象,通过有限元软件计算,对比分析了V型拱桥与普通拱桥在刚度、承载力、稳定性、动力性能、用钢量等方面的差异。研究结果表明,采用增加斜杆的V型拱桥较原拱桥仅增加约10%的用钢量,具有显著的抗变形能力,同时有效增强了主梁的线刚度,使得新型拱桥的整体性得到加强,刚度和承载力大幅提高。     

Analysis of factors affecting the choice of route of pedestrians

Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD).

An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip.

It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links.     

输油管道中原油乳状液的流变性研究

原油乳状液的流变性是原油开采后在管道中输送的重要研究方面,为了更好地研究这一性质,采用电动搅拌机、偏光显微镜以及流变仪等仪器来测定不同含水率的原油乳状液在不同条件下的黏度,观测不同含水率的原油乳状液在偏光显微镜下的形态。并且分别对原油乳状液的黏度与含水率之间的关系以及与剪切速率之间的关系进行研究,初步确定了所测区块原油乳状液的转相点以及该区块原油乳状液的流变特性,为生产中的油气集输提供了理论依据。     

Preliminary results of an analysis of areas of influence in Shanghai

The main deficiency of most current modeling approaches to transportation can be identified as neglect of the integration of existing geographical knowledge in regard to the ex ante transport/land use modeling approaches, with its focus on territorial dynamics and theory development. This paper addresses this aspect of the problem by introducing a theoretical and methodological framework for the analysis of the interrelationship between land uses. The analysis attempts to determine to what extent the functional land use in a city can be considered an ordered pattern. The order sought does not rely on purely spatial configurations, but on the correlation of transportation and land use. The first section of this paper focuses on theoretical considerations. It stresses the fact that conventional approaches do not apply in the present context. It then suggests an alternative based on areas of influence and measured in terms of level of attractance of land uses. The second describes a procedure based on this alternative following the remarkable contribution of Hanjoul, Beguin and Thill. An application of this procedure to the analysis of Shanghai is then examined. Finally, an evaluation of the strategies for optimizing the interrelationship between land uses is presented. The paper concludes with a possible research agenda.     

埋地管道防腐保温层失效评价

明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。     

城市轨道交通杂散电流监测系统概述

介绍了城市轨道交通工程中杂散电流不同的监测系统的构成,分析了集中式、分散式和智能型等监测系统的配置和功能,以及智能型实时在线监测系统的重要意义,为轨道交通工程杂散电流监测系统的选择与应用提供参考。     

Applicability of disaggregate models of behaviour: A question of methodology

The paper considers the possibility of quantitative analysis of behaviour, with particular reference to travel behaviour, from a methodological standpoint. The chief conclusion is that the nature of the subject implies that disaggregate statistical analysis is the most useful technique. The relationship of this methodology to theoretical issues is discussed, concluding that general theoretical issues are not susceptible to empirical resolution. The theoretical framework essential to analysis or forecasting of behaviour must therefore be established a priori The paper concludes with a discussion of the practical problems and achievements of disaggregate analysis.     

实现多组态计量软件集中监控的可行性分析

天然气自动计量系统有多种组态软件,由于软件的不相通性,造成了计量系统数据采集的通用性差、数据传输与入库的时效性差、数据利用的可靠性低.结合各组态软件的实际情况,从设计上充分利用Oracle大数据处理能力以及Partition(分区表)的特性,实现历史数据的存储,应用WebService与COM+数据访问组件提供多层数据访问架构,采用OPC与DDE工业数据交换协议,实现了各站场计量数据的实时上传,为连续数据采集和实时监控提供了可能,节约了改造成本.     

注汽管道承压能力评估和实物试验验证

基于失效评估图技术对某注汽管道进行了承压能力评价,给出了管线在不同腐蚀壁厚情况下的极限承压能力和极限裂纹尺寸。并利用实物爆破试验验证了评价方法的安全性和有效性,通过对爆破断口进行宏观和微观分析,发现管段的开裂属于脆性开裂。     

Direct analysis of the perceived importance of attributes of reliability of travel modes in urban travel

Reliability of travel modes was found to be the most important characteristic of transportation systems in several attitudinal investigations of individual travel behavior. This paper represents the first part of a research effort aimed at gaining a better understanding of the characteristics of reliability of transportation modes in urban travel. In this research, reliability characteristics are identified; their importance relative to each other is assessed, and an insight into possible structure of an objective reliability index is discussed. The research is based on perceived values of reliability, which were identified through a large attitudinal survey conducted in the Chicago metropolitan area.     

盾构隧道管片接头抗剪力学性能研究

通过对南京长江盾构隧道环向管片接头进行的三组原型抗剪(无螺栓剪切、有螺栓逆剪和有螺栓顺剪)加载试验,分析研究了管片接头在剪力作用下的受力、变形和破坏特征,给出了管片接头混凝土接触面的静摩擦系数,得到了接头剪力主要由混凝土接触面承担、破坏形式为连接斜螺栓剪切延性破坏的结论。通过对管片结构的有限元数值模拟计算得出:接头处的剪力与轴力比小于接缝面的摩擦系数,管片不会发生相互错动,结构是稳定的。