85m主跨预应力混凝土连续刚构桥设计

简要对预应力混凝土连续刚构桥桥型和结构尺寸的选择、设计以及结构受力分析进行了介绍.大桥采用主跨为85 m的预应力混凝土连续刚构桥,主梁采用单箱单室变截面箱型梁,配置三项预应力体系,下部结构采用矩形薄壁空心墩,钻孔桩基础.通过对该桥进行结构分析,桥梁各部分均满足规范要求,具有较好的安全性能.总结该桥的设计要点,为其他同类桥梁设计提供参考.     

单薄壁空心矩形墩连续刚构桥非线性稳定研究

以一典型单薄壁空心矩形墩连续刚构桥——王家坝大桥施工监控项目为依托,以稳定理论为基础,利用ANSYS软件建立单薄壁空心矩形墩最高墩裸墩施工阶段模型、最大悬臂施工阶段模型和成桥阶段模型,并采用不同类型单元进行模拟,分析对比各施工阶段下的稳定特征值和非线性极限荷载,总结非线性对连续刚构桥稳定的影响规律,可为施工与设计提供参考。     

V形墩连续刚构桥0号块空间有限元分析

以某座V形墩连续刚构桥为工程背景,建立V形墩连续刚构桥0号块的ANSYS有限元模型,对拆除支架后V形墩0号块在自重工况下的变形和应力进行分析,同时对V形墩的夹角和厚度在自重工况下的影响进行了研究。研究表明V形墩的下内隅、0号块主梁的跨中截面下缘、箱梁翼板根部截面上缘以及V形墩与主梁的夹角位置可能出现较高拉应力;V形墩的夹角对V形墩0号块的受力影响较为显著,在V形墩夹角较大的情况下,主梁与V形墩之间的夹角建议采用圆弧形,避免应力集中造成节点位置混凝土开裂。     

轻轨高架短线节段法桥梁整体受力性能分析

以澳门轻轨C370标段项目为背景,开展了一联5×60m混凝土节段预制等高度变截面连续箱梁桥有限元计算,以研究该类箱梁在正常使用阶段和施工状态下的结构行为,不同工况组合下梁体应力状况与预应力变化等结构静力性能。研究结果表明：在承载能力极限状态,梁体内力满足规定,整体性较好;体内外预应力增量随跨中弯矩基本呈线性变化,静力增量及预应力损失值相对较小;在施工阶段,梁体下缘压应力储备充足,满足运梁安全性要求。     

某混合梁斜拉桥钢混接合段整体有限元分析研究

在大跨度的桥梁中,单一的混凝土梁或者钢梁都会在边跨墩顶产生负反力,并会引起塔顶和主跨产生过大的偏移位移及挠度。为了充分发挥混凝土材料的压重作用和钢材跨越能力大的优势,便产生了混合梁结构,混合梁即在中孔大跨全部或部分采用钢主梁,两侧采用预应力混凝土主梁。主要采用有限元分析的方法对某混合斜拉桥钢混接合段的受力特性进行分析,真实反映其结构的复杂应力分布情况,并提出改进和完善的钢混接合构造措施。     

架桥机作用下的承台和盖梁应力状态研究

在桥梁工业化、预制标准化施工中,架桥机是主要施工机械.常见的架桥机主要用于上部结构的整体吊装或拼装,预制桥墩则使用汽车吊或龙门吊进行拼装.中建八局依托绍兴市越东路智慧快速路工程研发了一种可以同时吊运桥墩和预制梁的新型架桥机,这种墩梁一体架桥机的支腿会立在承台和盖梁上,产生的压力、拉力均较大.国内外在架桥机施工方面的研究集中在架桥机和桥梁整体承载力,缺乏对支腿作用区的应力状态研究.为填补这一研究空白,文章提取5个最不利工况,采用拉压杆模型分析法和有限元软件Midas FEA,模拟桥墩受力状态.分析结果表明理论方法和软件方法均准确可行,集中力作用区的混凝土受压、钢筋应力均满足现行混凝土桥梁规范要求,而混凝土拉应力或裂缝超限.依据分析结果,文章建议在承台和盖梁的集中力作用区配置钢筋网片、螺旋筋抵抗拉应力.     

顶推施工桥梁顶升模拟试验分析研究

本文以三跨预应力混凝土连续槽型梁顶推施工为工程背景,在顶推前对槽型梁进行顶升模拟试验,用以检验顶推过程中导梁与混凝土连接处、槽型梁关键截面的受力是否安全。首先通过Midas/Civil有限元软件建立桥梁模型,对顶推进行全过程施工仿真计算,确定桥梁顶推过程中最不利工况,在此基础上通过顶升加载模拟最不利工况下的梁体受力,通过试验过程中的变形、应力监测,将实测值与理论计算值对比分析,结果表明前导梁、槽型梁具有足够的刚度、强度安全储备,且结构基本处于弹性工作状态,整个顶升试验的顺利实施可为类似顶推桥梁施工提供实践参考。     

芝川河特大桥施工关键技术

介绍芝川河特大桥桩基、承台、高60m空心薄壁墩、重180t的50m预应力混凝土T梁预制及架设等施工关键技术，对类似工程具有一定的借鉴作用。     

薄壁高墩刚构桥的动力特性分析

以一座薄壁高墩刚构桥为研究对象,根据其墩高及薄壁的特点,运用通用有限元软件ANSYS对其建立三维有限元动力计算模型,对该桥最大悬臂施工阶段和成桥阶段的动力特性进行计算分析,获得了大桥的自振频率和振型,为该类桥梁的抗风、抗震设计研究提供了分析的基础.     

预应力混凝土梁施工阶段数值模拟

采用有限元分析软件ANSYS对先张法预应力混凝土简支梁施工阶段进行数值模拟分析。结果表明,ANSYS有限元分析计算值与理论值吻合较好,为预应力混凝土结构的分析提供了较好的途径和方法。教学实践表明:有限元数值模拟分析补充、丰富了教学内容,对常规教学方式提供一种思路。     

Design and research of gymnasium structure in Zhejiang University

INTRODUCTION The gymnasium project located in the newcampus of Zhejiang University is a symbol building(Fig.1). The requirements on the functions and theesthetics make it distinguished from a traditionalgymnasium. It is a two-story building with the firstfloor used for field competition and the second floorfor students’ basketball training. The heavy live loadsacting on the second floor and the requirement of 35m unobstructed space challenge the creativity of thestructural enginee…     

连续刚构桥零号块施工技术

结合某铁路特大桥的工程施工实践,介绍了连续刚构桥零号块托架的搭设方法,底模、侧模、端模的设计,钢筋的绑扎,地板、腹板、中隔板及顶板的混凝土的灌注与养护等施工技术;阐述了连续梁的施工控制管理及分析系统,希望为今后的桥梁零号块施工提供参考。     

浅谈预应力混凝土的特点及施工工艺

从我国预应力混凝土发展的角度,以某学校餐厅兼礼堂预应力框架梁为例,浅谈预应力混凝土的特性,介绍其材料选用、土建施工工艺及张拉施工工艺等,并对其今后发展进行了分析。.     

Optimum design of large span concrete filled steel tubular arch bridge based on static,stability and modal analysis

A three-dimensional finite element model was established for a large span concrete filled steel tubular (CFST) arch bridge which is currently under construction. The arch rib, the spandrel columns, the prestressed concrete box-beam, the cast-in-situ concrete plate of bridge deck, the steel box-beam and the crossbeams connecting the two pieces of arch ribs, were modeled by three-dimensional Timoshenko beam elements (3DTBE). The suspenders were modeled by three-dimensional cable elements (3DCE). Both geometric nonlinearity and prestress effect could be included in each kind of element. At the same time a second finite element model with the same geometric and material properties excepted for the sectional dimension of arch rib was set up. Static dynamic analyses were performed to determine the corresponding characteristics of the structure. The results showed that the arch rib's axial rigidity could be determined by static analysis. The stability and vibration of this system could be separated into in-plane modes, out-of-plane modes and coupled modes. The in-plane stability and dynamic characteristics are determined by the arch rib's vertical stiffness and that of out-of-plane is determined by the crossbeams' stiffness and arch rib's lateral stiffness mainly. The in-plane stiffness is much greater than that of out-of-plane for this kind of bridge . The effect of geometric nonlinearity and prestress effect on bridge behavior is insignificant.     

预应力混凝土连续箱梁有限元损伤分析(英文)

为了确定预应力混凝土箱粱的极限承载能力,进行了预应力混凝土连续箱梁的破坏性试验,提出一种有限元损伤分析方法模拟箱梁结构行为.基于实体退化壳单元对箱梁进行模拟,并考虑了结构材料的非线性效应.由于预应力混凝土箱梁中通常存在大量曲线预应力钢筋,提出一种组合单元,并用该单元模拟箱梁中的预应力钢筋,该方法可使结构分析时单元数量大大降低.试验结果和理论分析对比表明:提出的方法能够有效地用于预应力混凝土连续箱梁的破坏性试验计算分析中;研究的旧桥依然存在较大的极限承载能力.     

Seismic Analysis for Rigid-Framed Prestressed Reinforced Concrete Bridge in Tianjin Light Railway

The seismic analysis of a rigid-framed prestressed concrete bridge in Tianjin Light Railway is performed. A 3-D dynamic finite element model of the bridge is established considering the weakening effect caused by the soft soil foundation. After the dynamic characteristics are calculated in terms of natural frequencies and modes, the seismic analysis is carried out using the modal response spectrum method and the time-history method, respectively. Based on the calculated results, the reasonable design values are finally suggested as the basis of the seismic design of the bridge, and meanwhile the problems encountered were also analyzed.Finally, some conclusions are drawn as ：1 ) Despite the superiority of rigid-framed prestressed concrete bridge,the upper and lower ends of the piers of the bridge are proved to be the crucial parts of the bridge, which are easily destroyed under designed earthquake excitations and should be carefully analyzed and designed; 2) The soft soil foundation can possibly result in rather weakening of the lateral rigidity of the rigid-framed bridge, and should be paid considerable attention; 3) The modal response spectrum method, combined with time-history method, is suggested for the seismic analysis in engineering design of the rigid-framed prestressed concrete bridge.