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[1]

【篇名】型钢混凝土梁受扭性能的试验研究及理论分析

【作者】张根俞          【学位类型】博士      【授予单位】东南大学,

【导师】梁书亭,朱筱俊   【年份】2009.

【摘要】本文采用试验研究和理论分析相结合的方法对型钢混凝土的受扭性能展开研究，此外，对型钢混凝土的受弯性能进行了进一步的探讨。全文所做的工作和相关研究成果如下：
　　 1、通过2根钢筋混凝土对比梁，6根H形型钢混凝土梁在单调扭矩作用下的纯扭受力性能试验研究，以不同型钢种类及钢筋配筋方式为研究参数，对比钢筋混凝土梁受扭性能，揭示H型型钢混凝土梁在纯扭受力情况下的破坏形态、工作机理及裂缝的发展和分布情况；分析混凝土与H型钢截面的应力与应变分布特征；获得H形型钢混凝土梁纯扭受力状态下的强度、刚度、扭矩一扭率曲线，从而确定其开裂扭矩、极限抗扭承载力及变形性能；
　　 2、通过7根箱形型钢混凝土梁的在单调扭矩作用下的纯扭受力性能试验研究，以不同型钢种类、箱形型钢内部是否浇筑混凝土、钢筋配筋方式为研究参数，对比H形型钢混凝土粱的受扭性能，揭示箱形型钢混凝土梁在单调扭矩作用下的破坏特征、工作机理及裂缝的发展和分布情况，获得其抗扭刚度、强度、扭矩一扭率曲线等特性，来分析箱形型钢混凝土梁的工作性能和受力特点；
　　 3、在试验研究基础上，提出了H形型钥混凝土梁的开裂扭矩计算公式，分析结果表明，钢筋和型钢对H形型钢混凝土梁的开裂扭矩的提高作用可以忽略不计，按素混凝土构件计算开裂扭矩能达到满意的精度；在分析了作为薄壁杆件H型钢自由扭矩与约束扭矩基础上，提出了H形型钢混凝土梁的极限扭矩计算公式，分析表明，忽略H型钢的翘曲扭矩值，采用叠加法计算能获得满意的精度；
　　 4、针对箱形型钢混凝土梁的受扭特点，本文认为虽然箱形型铜在试件弹性阶段应变值很小，但由于其抗扭刚度很大，因此，箱形型钢在试件弹性阶段就开始发挥作用，使得试件的开裂扭矩有一定的提高，利用扭转角相等假定，基于刚度比原则，提出了箱形型钢混凝土梁的开裂扭矩计算公式。在分析了作为薄壁杆件的箱形型钥扭矩值基础上，认为箱形型钢部分承担的扭矩值可按塑性自由扭矩值计算，根据叠加法，提出了箱形型钢混凝土梁的极限扭矩计算公式；此外，将箱形型钢“弥散”到整个截面，并将有效壁厚范围内的型钢等效为纵筋与箍筋，在此提出了箱形型钢混凝土梁的极限扭矩计算公式；两个极限扭矩计算公式与试验值均一致；
　　 5、根据变角软化桁架模型，忽略混凝土的抗拉作用，从有效壁厚角度对软化空间桁架模型的诸多方程进行求解，获得了极限状态分析的一系列方程，编制了型钢混凝土受扭极限状态的分析程序，为验证程序的可行性，首先对已有的钢筋混凝土纯扭试验数据进行计算，根据计算结果对公式进行修改后应用于型钢混凝土梁受扭极限状态分析中，计算结果与试验结果基本吻合；
　　 6、将型钢混凝土梁受扭的全过程分为开裂前及开裂后两个阶段，在开裂前的阶段采用弹性分析方法，开裂后依据桁架模型推导了一系列适用于型钢混凝土梁受扭分析的关系式，并提出了型钢混凝土梁受扭性能全过程分析的简化算法，编制程序进行计算，对计算结果和试验结果进行了对比分析，表明方法合理，精度也满足要求；
　　 7、将型钢混凝土梁的受扭过程分成理想化的三个阶段，即开裂前的弹性阶段、开裂后至构件屈服阶段以及构件屈服后至极限状态阶段。在考虑诸多因素的基础上，分别推导了H形、箱形型钢混凝土梁对应于上述三个阶段的抗扭刚度计算公式。上述抗扭刚度计算结果与实测结果均表明，试件抗扭刚度值离散性很大；
　　 8、通过1根H形型钢混凝土梁，2根箱形型钢混凝土梁的纯弯受力性能试验研究，对比H形型钢混凝土梁的受弯性能，以不同型钢种类、箱形型钢内部是否浇筑混凝土为研究参数，重点分析了箱形型钢混凝土梁的抗弯性能，分析表明箱形型钢混凝土梁与H形型钢混凝土梁的受弯性能基本一致；
　　 9、根据型钢混凝土受弯破坏的特点，对约束混凝土计算理论进行修改后应用于型钢混凝土粱正截面抗弯承载力的计算中，将钢筋与型钢对核心混凝土的有效约束作用转化为混凝土的“额外强度”参与混凝土的抗弯承载力计算，提出了考虑约束效应的型钢混凝土梁抗弯承载力计算方法，与试验结果比较表明，该方法的切实可行；
　　 1O、以扭弯比为研究参数，通过3根H形型钢混凝土梁，3根箱形型钢混凝土粱的复合弯扭受力性能试验研究表明，当扭弯比较大时，扭矩起控制作用，试件将发生扭型破坏，当扭弯比较小时，弯矩起控制作用，试件将发生弯型破坏。提出了H形、箱形型钢混凝土梁的扭形破坏与弯形破坏的界限，分析了两种型钢混凝土在不同破坏形态下的破坏特征，分析表明，适当弯矩作用下，试件的扭矩值有一定程度的提高；
　　 11、在已有研究成果基础上，提出了两种型钢混凝土在大扭弯比下、小扭弯比作用下的两段式弯扭相关方程。分析后又进行改进，提出了三阶段弯扭相关方程。本文还给出了型钢混凝土梁在弯剪扭复合作用下的相关方程。

[2]

刘继明.钢筋混凝土复合受力构件受扭行为和设计方法的研究[D].导师：董毓利.:西安建筑科技大学,2004

摘要: 普通混凝土及高强混凝土随着高层建筑的发展得到广泛的应用，有必要对普通混凝土和高强混凝土承受弯压剪扭复合受力构件的结构性能做进一步研究。本文通过35根试件的试验研究和理论分析，对复合受力的混凝土框架柱的受扭行为和抗震性能进行了研究。具体为以下几个方面的内容。 通过9根承受双向偏压、弯、剪构件在反复扭矩作用下的试验研究，以轴压比和相对偏心距为主要研究参数，揭示钢筋混凝土构件中双向偏压剪反复扭矩作用下的破坏特征、开裂扭矩、刚度、强度、延性等特性和耗能性能，从而确定其开裂承载能力和极限承载能力及变形性能。 通过14根承受单向压、弯、剪，单调扭矩复合作用的高强钢筋混凝土构件和9根高强混凝土、3根高性能混凝土框架柱在双向压弯剪反复扭矩复合作用的模型试验研究，首次研究了高强混凝土框架柱在翘曲截面上的受力行为，探讨了高强混凝土框架柱抗扭性能的受力机理。以轴压比和相对偏心距为主要研究参数，揭示高强钢筋混凝土构件在单向、双向偏压剪单调、反复扭矩作用下的破坏特征、开裂扭矩、刚度、强度、延性等特性，分析了影响高强混凝土框架柱抗扭承载力的因素。 研究了承受双向压弯剪扭复合受力的普通和高强混凝土框架柱的抗震性能。在9根普通混凝土、12根高强钢筋混凝土框架柱在双向压弯剪反复扭矩复合作用的模型试验研究的基础上，对普通和高强混凝土框架柱的抗震特性和滞回特性进行了分析，研究了各影响因素对钢筋混凝土复合受扭构件抗震性能的影响。 本文对钢筋混凝土构件抗震性能进行了评论，对钢筋混凝土双向压弯剪构件在反复扭矩作用下的滞回特性及滞回模型存在的问题进行了分析，同时也分析了抗震性能中较为关键的两部分抗震性能--延性性能和耗能性能，讨论了各种影响因素对延性和耗能的影响，给出了双向压弯剪及反复扭矩作用下恢复力模型中各种滞回环的建立的方法，建立了钢筋混凝土复合受扭构件的恢复力模型 本文采用有限元非线性分析方法对弯压剪扭复合受力下的钢筋混凝土结构的非线性性能进行分析研究。在建立钢筋混凝土的有限元模型时，混凝土采用的单元为八节点六面体等参单元，钢筋单元分为两种情况，纵向钢筋采用分离式钢筋单元，箍筋采用埋藏式钢筋单元，即箍筋作为附着在混凝土等参数单元内或单元上的“膜单元”。混凝土本构关系和破坏准则采用混凝土边界面模型。该模型是一种功能较强的模型，可以用于混凝土三向受力的情况，采用损伤概念来反映混凝 摘要 土连续性刚度退化现象和非线性性能，把材料参数与混凝土一些物理现象组合在一起，使得这种 模型应用于混凝土三向受力时与实验结果的一致性和计算上的困难得以解决。可以模拟混凝土受 力后的各种特性，如混凝土的非线性应力一应变关系，循环荷载作用下的刚度退化现象，剪力引 起的混凝土的压缩和膨胀现象和超过强度极限的应变软化现象等，且这种模型的最大优点是表达 形式简单，模型参数比较容易确定，便于应用。基于混凝土在压、弯、剪、扭复合受力作用下的 情况，需要对这种结构在各种荷载情况下的内力变形状况和破坏性状进行较为精确的分析，本文 采用边界面模型对混凝土复合受力性能进行非线性分析，能有效、精确地分析复合受力构件在各 种荷载作用下全过程的受力行为，为理论分析提供各方面的验证。 本文将斜压场理论中的斜压杆表达成在平面内承受剪应力和正应力的钢筋混凝土薄膜元，借 助析架模型，满足二维应力平衡条件、莫尔应变协调条件和混凝土的双轴软化本构关系，揭示钢 筋混凝土复合受力构件在受力一变形全过程中受力行为和工作性能，为研究复合受扭构件的变形行 为打下了坚实的基础。应用这种方法，本文首次对高强钢筋混凝土压弯剪扭复合受力构件进行了 非线性全过程分析，对考虑软化的混凝土本构关系进行了修正，对混凝土斜压场进行了简化，经 分析计算与试验结果对比符合较好，说明薄膜元理论对钢筋混凝土复合受扭构件受力行为的全过 程分析是一种有效的方法。 本文将单向加载、反复加载、单向受扭、反复受扭、普通混凝土、高强混凝土构件用基于空 间析架模型的统一理论来描述，得出了反映复合受扭受力行为的强度相关关系，该统一理论能较 好地描述复合受扭构件各方面的受力性能，包容性较强，在该理论的基础上，...

[3]

【篇名】新型外包钢—混凝土组合梁受扭性能试验研究

【作者】倪勇         【学位类型】硕士   【授予单位】东南大学,

【导师】秦卫红       【年份】2007.

【摘要】新型外包钢-混凝土组合梁是以较厚钢板做底板，较薄的冷弯薄壁型钢做侧板，二者通过焊缝连接形成u形截面，然后在里面浇注混凝土，作为T形截面组合梁的肋部，翼缘为楼板，钢与混凝土通过可靠连接共同受力的组合构件。本文针对此新型外包钢-混凝土组合梁的受扭性能进行了试验和理论研究，全文所做的工作和相关研究成果如下： (1)通过5根新型外包钢一混凝土组合梁的静力试验研究(2根纯扭、3根弯剪扭)，分析了该类构件的破坏形态、扭矩-扭率曲线、弯矩-挠度曲线、荷载-应变曲线、混凝土应变分布、钢筋应变分布及钢板应变分布等，初步了解了组合梁受扭时的性能和特点。 (2)纯扭作用下，采用塑性理论计算出了组合梁中T形截面混凝土梁的开裂扭矩，利用扭转角相等，计算出钢梁的贡献扭矩，从而得到新型组合梁的开裂扭矩。根据变角空间桁架理论，得到钢筋混凝土梁纯扭极限扭矩计算公式，利用组合梁中混凝土梁和钢梁破坏前扭转角相同，计算出钢梁的贡献扭矩，得到新型外包钢-混凝土组合梁的极限扭矩。计算了纯扭试验梁的开裂扭矩和极限扭矩，并与试验结果进行了比较，计算结果与试验结果吻合较好。 (3)将组合梁的抗扭刚度按开裂前弹性阶段、开裂后至组合梁屈服时和屈服后到极限状态时三个阶段来分析，组合梁纯扭刚度采用混凝土梁和钢梁刚度叠加的方法计算。考虑混凝土梁与U形截面钢梁的组合作用使钢梁贡献扭转刚度提高，本文提出了组合系数的计算方法，并借助有限元计算结果，拟合出组合系数的近似计算公式。将组合梁纯扭刚度的计算结果与试验结果进行了对比，计算结果有较高的精度。考虑弯矩和剪力作用对组合梁扭转刚度的影响，通过比较，本文得出在弯矩和剪力作用下组合梁刚度的建议计算公式。根据所提公式计算组合梁的扭转刚度，作出三折线和二折线图形，经与试验曲线对比，说明计算结果有较高的精度，验证了理论公式的合理性。 (4)由试验知，新型外包钢一混凝土组合梁在弯剪扭复合作用下，当扭弯比较大时，扭矩起控制作用，组合梁将发生扭型破坏，当扭弯比较小时，弯矩起控制作用，组合梁将发生弯型破坏。本文推导了组合梁在大扭弯比下的弯扭承载力相关公式。参考相关文献，得出小扭弯比作用下的组合梁弯扭承载力相关公式。对组合梁在弯扭作用下的弯扭承载力相关曲线进行分析，并结合有限元计算结果及试验数据提出本文组合梁的弯扭相关曲线方程。参考相关文献，本文得出组合梁在弯剪扭复合作用下的相关方程。 (5)利用有限元软件ANSYS，对试验组合梁进行了非线性有限元分析，并与试验结果进行对比，验证了这种方法的可行性，并在此基础上，对组合梁进行了参数分析。

[4]

梁书亭;朱筱俊;张根俞;箱形型钢混凝土梁开裂扭矩与极限扭矩计算分析[J].建筑结构,2011,(01):23-25. 

摘要：依据7根箱形型钢混凝土梁的受扭性能的试验结果,在变形协调基础上建立了开裂扭矩计算公式,采用等效钢筋法建立了符合我国规范计算公式形式的极限扭矩计算公式。与试验结果对比表明,建议的公式满足精度要求,可为箱形型钢混凝土梁的设计提供理论依据。

[5]

蔡建林.钢—混凝土组合梁纯扭及复合受扭性能及其损伤研究[D].导师：石启印.:江苏大学,2009

摘要: 本文所提出的新型外包钢-混凝土组合梁是针对普通钢-混凝土组合梁的一些缺陷加以改进而形成的钢-混凝土组合梁,该组合梁具有结构受力合理、施工工序优化、防火性能改善、综合经济指标提高等优点。工程中的钢-混凝土组合梁处于受扭状态是不少的,且大多处于复合受力状态,国内外对组合梁受扭情况研究较少。因此,对此新型组合梁的抗扭性能进行研究有着重要的现实意义和广阔的工程应用前景。 本文是在对此新型组合梁抗弯性能研究的基础上,对其抗扭性能进行了系统的试验研究及理论分析。具体进行了以下几个方面的工作: 1.完成了2根外包钢-混凝土T形截面组合梁的纯扭试验和3根外包钢-混凝土T形截面组合梁的弯剪扭试验,得到了组合梁的扭矩-扭率、荷载-挠度、截面应变等关系曲线。研究了此新型外包钢-混凝土T形截面组合梁在纯扭及弯剪扭作用下的破坏形态,工作机理及裂缝发展和分布情况。 2.在试验分析的基础上,对纯扭和复合受扭作用下该外包钢-混凝土T形截面组合梁的受力性能进行了理论分析。通过对组合梁受扭性能的弹塑性理论分析,提出了组合梁纯扭及复合受扭作用下开裂扭矩的计算公式;采用变角空间桁架模型,提出了组合梁在纯扭及复合受扭作用下的极限扭矩计算公式。对组合梁的抗扭刚度进行了研究,推导了组合梁开裂前阶段、从开裂到极限破坏阶段和极限破坏阶段的抗扭刚度计算公式;对组合梁弯剪扭复合作用下的相关性进行了研究,分别推导了组合梁在大、小弯扭比以及弯剪扭复合作用下的相关方程。研究了弯剪扭作用下直线组合梁连接件的设计方法,在合理假设的基础上,把受弯扭的直梁等效为受扭的圆弧曲梁,经过理论推导,提出了复合受扭组合梁中剪力连接件的实用设计方法。 3.对组合梁结构的断裂形态进行了分析,研究了其受力过程中混凝土损伤-断裂机理及其交织性,在试验的基础上,根据损伤力学的概念并借助于ANSYS软件,分析了外包钢-混凝土T形截面组合梁这一新型结构形式从加载到破坏全过程中混凝土损伤的力学行为,与混凝土损伤模型的计算结果进行了对比,两者吻合较好。 4.根据试验研究、理论分析,文章最后提出了外包钢-混凝土T形截面组合梁的研究结论与展望。

[6]

丁海军;梁书亭;朱筱俊;箱形型钢混凝土纯扭构件的非线性有限元分析[J].工业建筑,2010,(S1):367-371+390. 

摘要：基于6根箱形型钢混凝土构件纯扭试验结果,利用非线性有限元软件ABAQUS建立模型,对其受力全过程进行数值模拟,考虑型钢和混凝土之间的相互作用。对混凝土、钢筋和型钢的应力随荷载变化的规律进行分析。有限元计算结果表明:ABAQUS对纯扭构件混凝土裂缝发展情况能较好地模拟;由于箱形型钢的抗扭刚度较大,混凝土开裂时型钢截面内剪力流形成的扭矩不能忽略;模拟得到构件的开裂扭矩、极限扭矩以及扭矩-扭率关系曲线与试验结果吻合较好,验证了所建模型分析型钢混凝土梁受扭全过程分析方法的可行性。

[7]

胡少伟;聂建国;熊辉;钢-混凝土组合梁的受扭试验与分析[J].建筑结构学报,2006,(04):103-109. 

摘要：为了研究钢-混凝土组合梁的抗扭性能,完成了4根不同配箍率的组合梁纯扭试验,借助结构分析软件,采用三维8结点实体单元的有限元模型,对组合梁纯扭试件在弹性阶段的变形、截面应力分布情况进行了分析。试验和分析结果表明:受扭承载力主要由混凝土翼板提供,翼板的截面尺寸是影响极限承载力的主要因素,其中翼板厚度对组合梁受扭承载力的影响更为显著;而配箍率对组合梁受扭承载力的影响并不大。其它条件相同时,当配箍率为0.54%左右时,组合梁受扭承载力将达到最大。提出了组合梁弹性抗扭刚度计算公式和开裂扭矩计算公式;本文采用变角空间桁架模型,并结合已有的试验成果,提出了可供设计参考的极限承载力计算公式。公式计算结果与试验值吻合良好。

[8]门进杰;史庆轩;刘继明;李家富;高强混凝土复合受扭构件钢筋应变及极限扭矩的试验研究[J].西安建筑科技大学学报(自然科学版),2007,(02):193-198. 

摘要：针对我国目前高强混凝土在实际工程中应用广泛,而国内外对高强度混凝土复合受扭构件的研究较少,对其钢筋应变和极限扭矩等力学问题进行了研究.以轴压比、相对偏心距、偏心角和配筋强度比为参数,对14根高强钢筋混凝土压弯剪构件在单调扭矩作用下的性能进行了试验研究,探讨了纵筋和箍筋在扭矩作用下的应变规律及其影响因素,分析了各参数对构件极限扭矩的影响.试验发现,复合受扭构件的纵筋应变和箍筋应变,在扭矩作用下分别表现为4种不同的变化状态;在一定范围内,试件的极限扭矩随轴压比的增大而增大,随偏心距的增大而减小,随配筋强度比的增大而增大,但当配筋强度比增大到一定值后,极限扭矩呈不变的趋势.

[9]

高云.新型外包钢—砼组合梁受扭性能的试验研究和非线性有限元分析[D].导师：石启印.:江苏大学,2008

摘要:本文以5根新型组合梁构件的受扭试验和有限元分析为基础,研究了该新型组合梁的混凝土翼板配箍率、弯扭比对组合梁抗扭承载力、变形以及破坏形态的影响。 (1)由试验可以得到:混凝土翼板配箍率对组合梁的抗扭承载力和扭转变形影响较小;弯扭比对组合梁的抗扭承载力和变形影响较大,随着弯扭比的增大,组合梁的最终破坏模式由扭型破坏逐渐转变为弯型破坏。组合梁发生扭型破坏时,混凝土翼板上的裂缝分布与普通混凝土梁破坏时相似,组合梁的抗扭承载力随着弯扭比的增大而增大,整个组合梁主要表现为扭转变形。组合梁发生弯型破坏时,相对于扭型破坏,混凝土翼板上的斜裂缝显著减少,组合梁的极限扭矩随着弯扭比的增大反而减小,组合梁的变形主要表现为弯曲变形。 (2)建立在试验基础上,进一步利用有限元分析得到:组合梁的界限弯扭比为2。当弯扭比小于2时,组合梁发生扭型破坏,不同弯扭比作用下的的抗扭刚度相差很小。当弯扭比为2时,组合梁前期抗扭刚度与纯扭作用下的抗扭刚度相差很小。当弯扭比为4时,组合梁开裂前的抗扭刚度与纯扭作用下的抗扭刚度相差不大,开裂后的抗扭刚度要明显大于纯扭以及弯扭比小于等于2时组合梁的抗扭刚度。 (3)依据试验以及有限元分析的结果,本文提出了新型组合梁在纯扭和复合受扭作用下发生扭型破坏时的抗扭刚度理论计算公式以及新型组合梁在弯剪扭作用下的弯剪扭强度相关方程。 基于本文研究工作,可望为新型外包钢—混凝土T形截面组合梁的工程设计提供参考。

[10]

谭晓演.型钢混凝土构件抗扭分析与研究[D].导师：何益斌.:湖南大学,2008

摘要:本文首先介绍了混凝土纯扭构件的破坏机理和计算方法。利用大型通用有限元软件ANSYS对8根H型型钢混凝土和含矩形钢管中空型钢混凝土纯扭构件进行了数值模拟并与已有试验进行了对比,分析结果表明通过选择合理有限元模型可以较好的预测型钢混凝土构件在纯扭作用下的受力性能。通过ANSYS后处理得到了型钢混凝土纯扭构件在各典型荷载步下混凝土、钢筋、型钢的应力和应变的分布规律以及裂缝的形成和发展过程并进行了分析,同时考虑了H型钢截面尺寸对构件抗扭性能的影响。此外还对不同扭弯比作用下的型钢混凝土构件进行了数值分析,结果表明扭矩存在会影响构件抗弯承载力,扭矩与弯矩之间存在相关性。对纯扭作用下具有相同截面尺寸和配筋的钢筋混凝土,H型型钢混凝土和含矩形钢管中空型钢混凝土构件进行了有限元分析,比较了三种截面形式构件的抗扭性能和受力机理,分析表明含矩形钢管中空型钢混凝土构件的抗扭性能最好。 在薄壁构件与钢筋混凝土构件受扭计算理论的基础上,结合已有的试验结论与前述有限元分析结果,提出了H型型钢混凝土与含矩形钢管中空型钢混凝土构件在纯扭作用下开裂扭矩和极限扭矩的简化计算方法并与试验结果进行了比较。

[11]

雷强.型钢混凝土受扭构件的非线性有限元分析[D].导师：白国良.:西安建筑科技大学,2007

摘要:本文应用有限元软件ANSYS对承受扭矩作用的型钢混凝土构件进行有限元模拟，以分析型钢混凝土受扭构件的力学性能。 有限元分析是结构分析的重要研究方向，它能够比较准确的分析许多结构构件的受力性能。本文应用ANSYS建立受扭构件的有限元模型进行非线性计算，并与已有的试验结果进行对比。对受扭构件的承载力、混凝土应力随荷载变化的情况、型钢、钢筋应力分布规律、构件裂缝的开展情况进行了计算分析。探讨了混凝土保护层厚度对内部型钢抗扭承载力的影响，结合已有的试验结果，在有限元分析的基础上，提出了型钢混凝土纯扭构件开裂扭矩、极限扭矩的计算方法。对型钢混凝土压扭构件和弯扭构件进行了有限元模拟，分析结果表明，随着轴压力的增大型钢混凝土构件抗扭承载力先增大后减小；型钢混凝土构件弯矩和扭矩之间存在着相关性。本文的分析得到的结论为型钢混凝土受扭构件的进一步研究提供基础。

[12]

数据库 Earthquake Engineering Abstracts  

题名   Analysis of composite beam-columns under lateral cyclic loading   

作者   Lee, Tai-Kuang; Pan, Austin D. E.   

来源   Journal of Structural Engineering. Vol. 127, no. 2, pp. 186-193. Feb. 2001   

文摘   This paper proposes a reliable and computationally efficient beam-column finite-element model for the analysis of composite (steel-reinforced concrete) members of fully encased sections under cyclic loading conditions that induce uniaxial bending and axial force. The member is discretized into longitudinal steel reinforcement, steel shape, and concrete fiber elements such that the section force-deformation relation is derived by integration of the stress-strain relation of the fibers. The nonlinear behavior of the element is derived from the nonlinear stress-strain relation of the steel and concrete fibers, with consideration of buckling of the longitudinal reinforcement and steel shape. The model, which is incorporated with the DRAIN-2DX program, is calibrated and compared with experimental data from cyclic and pseudodynamic tests of fully encased composite beam-columns. The accuracy and efficiency of the model are demonstrated through correlation between the experimental results and analytical simulations. The crushing strains of the concrete cover predicted by the analytical simulations were significantly higher in comparison with those suggested by theoretical stress-strain models. Based on the comparison with the empirical data, stiffness reduction is suggested for the fiber model analysis. Buckling of the longitudinal reinforcement appears to be the main cause leading to severe stiffness decay of fully encased composite beam-columns. 

[13]

CSA / ASCE Civil Engineering Abstracts  

题名   Shear Strength Prediction for Concrete Members   

作者   Rebeiz, K.S.   

来源   Journal of Structural Engineering. Vol. 125, no. 3, pp. 301-308. Mar. 1999   

文摘   This study presents alternative shear strength prediction equations for steel-reinforced concrete members without web reinforcements. It uses the techniques of dimensional analysis, interpolation function, and multiple regression analysis. More than 350 data were obtained from existing sources of reinforced concrete beam shear test results covering a wide range of beam properties and test methods. This analysis was done for both normal-strength concrete and high-strength concrete members with compressive strength up to 104 MPa (15,110 psi). The derivation of accurate cracking and ultimate shear strength prediction equations incorporated the original use of an interpolation function that takes into account the difference in behavior between the arch action of short beams and the beam action of long beams. The use of the interpolation function was instrumental in producing accurate cracking and ultimate shear strength equations as evidenced by the excellent correlation between experimental and theoretical values. 

[14]

A new ultra long-spanning, combined steel formwork and reinforcement hybrid decking system using cold-formed components

Gl?sle, Mathias1; Patrick, Mark1; Grey, Ross2 Source: Seventeenth International Specialty Conference on Cold-Formed Steel Structures: Recent Research and Developments in Cold-Formed Steel Design and Construction, p 603-616, 20##

Abstract: A new ultra long-spanning, combined steel formwork and reinforcement system designed to span up to 6 or 7 metres (20.7 or 23 feet) without propping has been under development for nearly a decade in Australia. The steel decking system includes a number of innovative features that make it adaptable to almost any type of building construction ranging from conventional, shallow one-way composite slabs in steel-frame buildings to deep two-way post-tensioned slabs in concrete-frame buildings. The hybrid system comprises a number of distinctly-different cold-formed steel components, which have efficient shapes and utilize different thicknesses, steel grades and coatings. The overall height of the main decking panel can vary from 90 to 260 mm (3.54 to 10.24 in) with an additional three intermediate sizes, despite the components being made from the same roll-forming equipment. The panel has a closed cellular section and is precambered to limit the final deflection under wet-concrete conditions. These panels can be interconnected for maximum spanning capability, or else different types of infill panels can be fitted between them to form composite slabs with a variety of cross-sectional shapes and features. Slabs of minimum overall depth or minimum weight can be constructed using the system. The cellular section can form a void in the concrete, or it can have holes pre-punched in its webs allowing it to be filled with concrete either partially or completely along its length. Prestressing cables and reinforcing bars can be fitted longitudinally and if need be transversely in the slab, even in the soffit region. Comprehensive sets of structural tests, some quite innovative, are currently being performed to thoroughly investigate the behaviour of the system for both the formwork and composite states. In particular, this involves developing a complete understanding of the complex behaviour of the main decking panel and its different cold-formed components under a variety of loading conditions that induce vertical and longitudinal shear, longitudinal and transverse bending, and torsion. The behaviour of the mechanical connection between the elements is being closely investigated experimentally, allowing the moment capacity of potentially critical cross-sections with partial shear connection to be accurately predicted and the spacing between connections optimised. (15 refs.)

[15]

CYCLIC TORSION TESTS ON REINFORCED CONCRETE BEAMS.

Venkappa, Velpula1; Pandit, Ganpat S.1 Source: Journal of structural engineering New York, N.Y., v 113, n 6, p 1329-1340, Jun 1987

Abstract: Reversed cyclic torsion tests on nine normal-weight and three light-weight reinforced reinforced concrete beams are reported, along with nonreversible cyclic torsion tests on four reinforced concrete beams and two companion static tests. The variables studied were the peak torque, the range and the frequency of loading. Basic information concerning concrete and steel strains, the angle of twist, the torsional stiffness, the cracking torque, and the ultimate torque in cyclic torsion has been reported. (4 refs.)

[16]

Effective Torsional Rigidity of Reinforced Concrete Members

Tavio1, 2; Teng, Susanto3 Source: ACI Structural Journal, v 101, n 2, p 252-260, March/April 20##

Abstract: This paper presents a simple procedure for calculating the effective torsional rigidity of reinforced concrete members. The torsional rigidity of a reinforced concrete member, such as a spandrel beam, determines the amount of rotation that the member undergoes, and that, in turn, determines the amount of end moment that will be transferred by the supported transverse member to the spandrel beam. Thus, the effective torsional rigidity is an important parameter for three-dimensional analysis of reinforced concrete structures. The method presented in this paper relates torsional rigidity to the applied torque, taking the effect of reinforcement into account. The method is applicable throughout the entire loading history from the uncracked state to the fully cracked state and even up to the ultimate limit state. Prior to cracking, the elastic and uncracked torsional rigidity of the section is used. After the formation of torsional cracking, the proposed procedure interpolates between torsional rigidities immediately after cracking and that at the ultimate limit state. The proposed procedure has been verified by comparing its predictions with test data available in the literature. Comparison between the computed and experimental torque-twist curves shows that the proposed procedure for computing effective torsional rigidity is reasonably accurate. (17 refs.)

[17]

Ultimate strength of reinforced concrete beams in combined torsion and shear

Klus, J.P. Source: American Concrete Institute -- Journal, v 65, n 3, p 210-216, Mar, 1968

Abstract: Series of rectangular reinforced concrete beams with normal percentages of longitudinal and transverse steel was tested and interaction of their torsional and flexural shear capacities was developed; effects of bending and amount of reinforcement are discussed; various interaction formulas are compared; beams were cast from single batch to avoid any variation due to concrete strength or proportions; ready-mixed concrete was designed to have compressive cylinder strength of about 2970 psi.

[18]

Reinforced, partially, and fully prestressed slender concrete columns under biaxial bending and axial load

Rodriguez-Gutierrez, J.A.; Aristizabal-Ochoa, J.D. Source: Journal of Structural Engineering, v 127, n 7, p 774-783, July 2001

Abstract: An analytical model that determines the inelastic structural response, ultimate strength and failure mode of reinforced concrete, partially prestressed concrete, and prestressed concrete slender columns of any cross section under biaxial bending and axial load is presented. The effects of rotational and lateral restraints at the ends are included, but the effects of shear deformations and torsional moments along the member are neglected. The proposed method uses (1) a nonlinear stress-strain relationship for the concrete; (2) a multilinear elastic-plastic relationship for the conventional reinforcement; (3) a modified Ramberg-Osgood function for the prestressed steel; (4) Gauss's integral method for equilibrium at the sectional level to generate the moment-axial load-curvature characteristics (i.e., M-P-φ diagrams) along the member; and (5) the finite-element method to evaluate the transverse deflections and second-order moments (P-δ and P-Δ effects) along the member. The proposed method can be utilized (1) to study the effects of creep, confinement, and tension-stiffening in the concrete and relaxation in the prestressed steel on the behavior, strength, ductility, and failure mode of slender concrete columns; and (2) to analyze prismatic and nonprismatic slender concrete columns of an arbitrary cross section under different end supports and bracing conditions. The biaxial bending behavior, strength ductility and failure mode of slender concrete columns can be obtained using a minicomputer, and as expected they depend on (1) bracing and support conditions; (2) cross section and reinforcement layout along its span; (3) the stress-strain characteristics of the concrete and different reinforcements; and (4) the type and intensity of the applied loads. Three numerical examples are presented in detail to verify and show the effectiveness of the proposed method. [19]

Title 3D analysis of solid reinforced concrete beams subjected to combined load of bending, torsion and shear

Author(s) Alnuaimi, AS

Source Computational Methods and Experimental Measurements XIII 46185-194 20##

Abstract This paper presents a comparison between experimental and an in house 3-D finite element analysis results of three reinforced concrete solid beams subjected to combined loadings of bending, shear and torsion. The finite element program adopted was based on a 20 node isoparametric element. A non-linear elastic isotropic model, proposed by Kotsovos, was used to model concrete behaviour, while steel was modelled as an embedded element exhibiting elastic-perfectly plastic response. Allowance was made for shear retention and for tension stiffening in concrete after cracking. Only fixed direction, smeared cracking modelling was adopted. The beam dimensions were 300x300mm cross section, 3800mm length. Experimental results were compared with the non-linear predictions. The comparison was judged by load displacement relationship, steel strain, and load and mode of failure. Good agreement was observed between predicted ultimate and experimentally measured loads. It was concluded that the present program can confidently be used to predict the behaviour and failure load of reinforced concrete solid beams subjected to combined load of bending, torsion and shear. 

[20]

Title Reinforced concrete slabs and steel-concrete composite beams under pure torsion

Author(s) Nie, JG; Tang, L

Source 8th International Conference on Steel-Concrete Composite and Hybrid Structures, Proceedings482-492 20##

Abstract The experimental results of reinforced concrete slabs and steel-concrete composite beams subjected to pure torsion are presented. The test series consisted of four slabs and four beams, and the major variables were the aspect ratio of cross section and the torsion reinforcements. All test slabs exhibited a typical skew-bending failure mode. The rotating-angle softened truss model (RA-STM) developed by Hsu underestimated the torsion strength of the test slabs. A new assumption was presented that the centerline of the shear flow coincided with the centroidal line of the equivalent compression stress block in the concrete struts, and torsion reinforcement ratios were redefined. The RA-STM using these proposals can predict not only the torsion strength but also the post-cracking behavior of the slabs accurately. Tests of the beams showed that only concrete flange contributed towards the torsion strength of composite beam. The contribution of joist can be neglected, but it plays a vital role in restraining concrete flanges from deforming longitudinally, which enhances the resistance of concrete flange. Additionally, several design formulas were discussed. 

[21]

Reinforced concrete floor slabs with spherical void formers verification of shear and torsional resistance (Reinforced concrete floor slabs with spherical void formers verification of shear and torsional resistance)

Albert, Andrej1; Pfeffer, Karsten2; Schnell, Jürgen3 Source: Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology, v 77, n 2, p 182-184, 20##

Abstract: A test series for identifying the shear resistance of voided flat of the cobiax system is reported. In a first series of six four-point bending tests, the reinforcing steel positioning cages used in practical applications for buoyancy safety and void former fixation were not installed. Three additional tests without cages were carried out to verify the shear resistance also for cases of transverse bending acting simultaneously with the main bending moment, as is the case in flat floors. Comparing the crack patterns to the principal strains shows that the FEM model used realistically models the cracking behavior of the investigated specimens both with and without void formers. The cracking pattern produced in the FEM analysis corresponded to that anticipated for torsion and displayed good correlation with the cracking patterns observed in the test. (14 refs.)

[22]

TORSION AND BENDING IN LONGITUDINALLY REINFORCED CONCRETE BEAMS.

Martin, L.H. Source: Building Science, v 8, n 4, p 339-350, Dec 1973

Abstract: The paper shows that theoretically the failure moments of a concrete member reinforced with longitudinal steel only and subject to torsion and bending, are related by three theoretical general interaction equations derived by considering two modes of behavior. Mode 1 occurs where the compression zone is at the top of the section and failure is controlled by the strength of the concrete under the combined action of direct stress and shear stress due to torsion. Mode 2 occurs when the compression zone is at the side of the section and failure is controlled by the tensile strength of the concrete. (21 refs.)