鄂尔多斯市纬三路西桥空腹式刚架拱结构设计

鄂尔多斯市纬三路西桥采用预应力混凝土空腹式刚架拱结构。该结构受力特点介于拱和连续刚架之间,能充分发挥2种体系的优势,受力合理,结构新颖,简洁流畅,刚劲和律动溶为一体。重点介绍了其上、下部结构设计特点,包括箱梁构造特点、内力分析、预应力体系及钢束布设、箱梁施工工艺等。     

Stress arch bunch and its formation mechanism in blocky stratified rock masses

Stress arch is a common phenomenon occurring in continuous materials and has also been proved to have great influences on the self-stabilization of soils or rock masses after excavation.In this paper,based on UDEC simulation,stress redistribution after excavation is investigated for a kind of special discontinuous material,i.e.blocky stratified rock mass.A layered stress arch system is observed with each stress arch lying over another.This special phenomenon is defined herein as "stress arch bunch".Effects of dip angle of bedding plane,lateral pressure and joint offset on this stress arch bunch are studied.Its formation mechanism is also discussed based on voussoir beam theory.     

陶瓷焊补技术在玻璃窑炉热态维修中最新研究进展

运用360°回旋自感应陶瓷焊补枪对玻璃窑炉小炉侧墙及平碹采用锆质陶瓷焊补料维修，并对维修前后做了对比分析。     

海域深水区混凝土底板钢吊箱围堰施工技术

以广深沿江高速公路深圳段项目为依托,详细介绍了工程特点,分析了围堰的施工方案;对钢吊箱围堰结构进行了优化设计,包括钢吊箱壁板、混凝土底板、腰梁及悬吊系统、拼装平台,并进行了结构验算。另外,深入探讨了钢吊箱围堰拼装及下放,包括钢吊箱围堰拼装,悬吊下放与导向安装,钢吊箱围堰的定位系统,以及钢吊箱封堵及封底混凝土施工。结合工程实例,对海域深水区承台围堰施工技术进行了创新,较好地完成了施工任务。     

应用超声三血管气管切面诊断胎儿主动脉弓异常

目的　研究超声三血管气管切面对于胎儿主动脉弓异常的诊断价值。方法　回顾性分析2010年5月至2014年5月北京协和医院诊断的17例胎儿主动脉弓异常的产前超声图像资料，并与产后超声及病理结果进行对照，分析不同类型主动脉弓异常的产前超声特征，重点关注三血管气管切面的表现。结果　17例主动脉弓异常在三血管气管切面均有阳性表现。其中主动脉弓缩窄3例，表现为主动脉弓细小；主动脉弓离断7例，表现为主动脉变细，不能连接至降主动脉；右位主动脉弓合并迷走左锁骨下动脉5例，可见环绕气管的“U”形血管环；右位主动脉弓合并镜像分支2例，可见主动脉弓位于气管右侧，动脉导管不汇入降主动脉。结论　三血管气管切面是提示胎儿主动脉弓异常敏感且有效的切面，中孕超声筛查时应重视该切面，早期发现异常并给予适当的遗传咨询。     

双曲拱桥主拱圈病害分析及其加固方法的研究

针对双曲拱桥主拱圈的常见病害,从力学的角度分析了主拱圈病害的成因,结合双曲拱桥的构造特点,以及某实桥加固后主要力学参数结果,提出了主拱圈的加固改造方法,对同类桥梁的加固具有借鉴作用。     

钢筋混凝土箱形拱桥施工控制仿真分析

以某实桥工程为研究对象,采用有限元程序建立全桥空间计算模型,对钢筋混凝土箱形拱桥的施工全过程进行了受力分析,通过对整个施工过程内力、应力和挠度的分析,研究其施工设计分环分段的合理性,为此类桥型设计提供理论参考。     

Network level bridges maintenance planning using Multi-Attribute Utility Theory

Bridge infrastructure managers are facing multiple challenges to improve the availability and serviceability of ageing infrastructure, while the maintenance planning is constrained by budget restrictions. Many research efforts are ongoing, for the last few decades, ranging from development of bridge management system, decision support tools, optimisation models, life cycle cost analysis, etc. Since transport infrastructures are deeply embedded in society, they are not only subject to technical requirements, but are required to meet the requirements of societal and economic developments. Therefore, bridge maintenance planning should accommodate multiple performance goals which need to be quantified by various performance indicators. In this paper, an application of Multi-Attribute Utility Theory (MAUT) for bridge maintenance planning is illustrated with a case study of bridges from the Netherlands road network. MAUT seeks to optimise multiple objectives by suggesting a trade-off among them and finally assigns a ranking to the considered bridges. Moreover, utility functions of MAUT appropriately account for the involved uncertainty and risk attitude of infrastructure managers. The main contribution of this study is in presenting a proof-of-concept on how MAUT provides a systematic approach to improve the decision-making of maintenance planning by making use of available data, accommodating multiple performance goals, their uncertainty, and preferences of infrastructure managers.     

低热水泥混凝土在特高拱坝中应用的可行性分析

针对低热水泥混凝土早期强度低,在大坝主体中应用较少,低热水泥混凝土能否应用于高拱坝工程仍存疑虑的情况,以白鹤滩工程为例,采用室内试验资料对比和有限元仿真结果对比相结合的方法,对白鹤滩拱坝拟采用的中热水泥混凝土和低热水泥混凝土的材料特性和温度应力仿真结果进行了对比分析。结果表明,从材料特性的角度来看,低热水泥与中热水泥混凝土各有优劣,低热水泥混凝土早龄期强度低不利于防裂,但低热水泥的绝热温升低、早期发热慢、弹模小、徐变大这些因素均有利降低整体应力水平,后期强度高则有利于提高后期安全系数,降低开裂风险。此外,有限元计算结果表明,在相同的温控措施和边界条件下,低热水泥混凝土最高温度比中热水泥混凝土低2～3℃,低热水泥混凝土冷却全过程的安全系数均要大于中热水泥混凝土,且在2. 0以上。研究成果进一步证实了低热水泥混凝土比中热水泥混凝土具有更好的抗裂特性,可以应用于特高拱坝,也为白鹤滩拱坝全坝采用低热水泥混凝土提供了重要支撑。     

某连续刚构桥大体积0号块简易托架法施工技术

山区连续刚构桥大体积0号块由于受自身高墩、大跨度及地形、地势条件的限制,现场采用简易托架给施工带来了很大的方便。主要介绍了牛腿托架施工方案,并介绍了托架安装技术。牛腿托架安装完成后进行了预压,并通过Midas civil计算软件进行托架受力验算。在预压过程中对梁段变形进行了监测,监测结果表明托架满足施工要求。