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短线预制悬拼连续梁施工误差实桥试验及安装线形分析
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作者 刘红平 邢江 +3 位作者 陈浩 程高 周浩 刘江 《中国公路学报》 EI CAS CSCD 北大核心 2024年第8期170-178,共9页
短线法节段预制悬拼连续梁安装线形偏差源于节段制造尺寸、质量、安装时机、温度、接缝宽度、预应力等施工误差,设置接缝垫片来纠偏安装线形易产生接缝不密实、渗水、预应力损失、整体刚度削弱等问题,但目前尚无其他有效纠偏方式。为探... 短线法节段预制悬拼连续梁安装线形偏差源于节段制造尺寸、质量、安装时机、温度、接缝宽度、预应力等施工误差,设置接缝垫片来纠偏安装线形易产生接缝不密实、渗水、预应力损失、整体刚度削弱等问题,但目前尚无其他有效纠偏方式。为探明短线法节段梁施工偏差及其对大跨连续梁悬拼安装线形的影响规律,依托某短线法节段预制拼装大跨连续梁桥,基于三维点云数据进行节段的虚拟拼装及线形控制,开展梁段质量、温度、胶接缝宽度等实桥测试和悬拼线形监测,分析施工偏差变化特征并基于有限元模型揭示主梁安装线形受施工偏差的影响规律,提出安装线形纠偏策略与方法。实桥试验及有限元分析结果表明:短线法预制连续梁节段质量偏差介于-6%~6%,而悬臂梁边中跨总质量偏差约4.5 t,仅为单个节段质量的1/10。以连续梁最大悬臂状态恒载产生最大挠度为基准值,可得到因节段制作尺寸、温度、胶接缝宽、存梁时间、节段质量及预应力等施工误差产生的下挠值分别为259.2%、108.9%、81.8%、20.5%、9.0%和7.5%。节段制造尺寸是引起安装线形偏差的关键,间接影响节段质量、胶接缝宽度,首节段尺寸偏差对安装线形的影响最大。节段制作尺寸若不及时纠偏,可产生最大83 mm的高程偏差。提出的节段预制逆作法和安装线形“两级纠偏”方法为大跨变截面连续梁安装线形控制提供参考。 展开更多
关键词 桥梁工程 悬臂拼装 实桥试验 短线法 节段预制 施工误差 安装线形
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Design of Self-Assembling Molecules and Boundary Value Problem for Flows on a Space of <i>n</i>-Simplices
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作者 Naoto Morikawa 《Applied Mathematics》 2019年第11期907-946,共40页
Self-assembling molecules are ubiquitous in nature, among which are proteins, nucleic acids (DNA and RNA), peptides and lipids. Recognizing the ability of biomolecules to self-assemble into various 3D shapes at the na... Self-assembling molecules are ubiquitous in nature, among which are proteins, nucleic acids (DNA and RNA), peptides and lipids. Recognizing the ability of biomolecules to self-assemble into various 3D shapes at the nanoscale, researchers are mimicking the self-assembly strategy for engineering of complex nanostructures. However, the general principles underlying the design of self-assembled molecules have not yet been identified. The question is “How to obtain a well-defined shape with desired properties by folding a chain of subunits (such as amino acids and nucleic acids)”, where properties are determined by the precise spatial arrangement of the subunits on the surface. In this paper, we consider the question from the viewpoint of the discrete differential geometry of n-simplices. Self-assembling molecules are then represented as a union of trajectories of 3-simplices (i.e., tetrahedrons), and the question is rephrased as a “boundary value problem” for flows on a space of tetrahedrons. Also considered is a characterization of two types of surface flows of n-simplices. It is a rough classification of surface flows, but may be essential in characterizing important properties of biomolecules such as allosteric regulation. The author believes this paper not only provides a new perspective for the engineering of self-assembling molecules, but also promotes further collaboration between mathematics and other disciplines in life science. 展开更多
关键词 Differential geometry SELF-assembling Molecule Discrete Mathematics Boundary Value Problem FLOWS of n-Simplices
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小半径桥梁预制悬拼施工中的线形纠偏措施 被引量:1
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作者 祁向宇 《交通科技》 2017年第3期85-87,共3页
小半径曲线桥采用短线匹配法预制节段梁,现场悬拼施工,线形控制难度大,精度要求高。桥梁在小半径的曲线线形及大纵坡影响下,需要对曲线内外侧的标高进行控制,防止梁体偏转。悬拼施工中可采取垫环氧树脂垫片和控制临时预应力张拉的方式... 小半径曲线桥采用短线匹配法预制节段梁,现场悬拼施工,线形控制难度大,精度要求高。桥梁在小半径的曲线线形及大纵坡影响下,需要对曲线内外侧的标高进行控制,防止梁体偏转。悬拼施工中可采取垫环氧树脂垫片和控制临时预应力张拉的方式调整梁体的线形;悬拼施工完成后可采用千斤顶提拉的方法,对合龙段两侧的高差及扭转进行调整。 展开更多
关键词 小半径 预制 悬拼 线形
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基于midas的悬臂拼装桥梁安装线形的计算 被引量:6
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作者 李冠军 王卫锋 《科学技术与工程》 北大核心 2012年第34期9425-9427,共3页
以广东省某斜拉桥为依托,用有限元分析软件midas建立了基于零初始位移法和基于切线初始位移法的两个模型,研究了悬臂拼装桥梁主梁安装线形的计算方法。为同类型桥梁安装线形的计算提供了参考。
关键词 悬臂拼装 安装线形 钢箱梁
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