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为研究方中空夹层钢管混凝土的横向局压性能,利用ABAQUS软件建立了非线性有限元分析模型,同时以压杆与试件外边长比和空心率为参数,进行了6个试件的试验研究,分析比较了试件破坏形态、荷载 位移曲线、荷载 应变曲线和承载力模拟结果与试验结果的差异及其产生的原因。结果表明:横向局压荷载作用下方中空夹层钢管混凝土具有较好的力学性能;有限元模拟得到的方中空夹层钢管混凝土横向局压性能总体上与试验结果吻合良好。 相似文献
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为研究大空心率圆锥形中空夹层钢管混凝土压弯构件的滞回性能,对10个圆锥形中空夹层钢管混凝土压弯试件(8个往复加载和2个单调加载试件)进行试验研究。考察空心率(0.6和0.8)和轴压比(0、0.2、0.4和0.6)对试件的破坏模态、P-Δ关系曲线和滞回性能的影响,并建立数值模型对单调加载的压弯试件的受力机理进行分析,最后讨论了圆锥形中空夹层钢管混凝土压弯构件侧向承载力简化计算方法。研究结果表明,两种空心率试件的破坏形态基本一致,表现为试件下部不同程度的局部破坏;往复压弯试件的P-Δ曲线较为饱满,表现出较好的滞回性能。空心率从0.6增加到0.8对试件的侧向承载力和延性影响较小,两种空心率下的峰值荷载平均相差约3%。随着轴压比增加,试件的极限荷载降低,延性逐渐变差。往复加载试件的强度退化不明显,空心率为0.8的试件刚度退化更显著。试件的平均位移延性系数为3.56,平均黏滞阻尼系数为0.322,表现出较好的耗能能力。当空心率为从0.6增加到0.8,试件的黏滞阻尼系数平均提高15%。 相似文献
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《Thin》2015
Thirty-one tests under low velocity drop weight impact were carried out to examine the residual failure modes and the time history of the impact forces, global deformations and strains of concrete filled double steel tubular (CFDST) members in this paper. The parameters varied in the testing program include the column type (straight and tapered), the boundary conditions (simply supported and fixed), the axial load level and the impact energy. The results showed that all CFDST members behaved in a ductile manner and the residual deformation consisted of local deformation at the impact section, as well as the overall bending deformation. Compared to hollow double steel tubes, the CFDST members under the same applied impact energy demonstrate superior impact behavior in terms of higher energy absorbed, smaller global deformation and local deformation due to the interaction of the sandwich concrete and double skin steel tubes. The influence of key parameters on the dynamic resistance ability of CFDST is discussed. 相似文献
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将圆锥形中空夹层钢管混凝土用于风电塔筒或输电塔架时,为满足在塔筒内设置设备等需求而将该类构件空心部分加大。为研究该类构件的偏压受力性能,进行了12个大空心率下的圆锥形中空夹层钢管混凝土偏心受压构件的试验研究,主要试验参数为荷载偏心率和长细比。利用ABAQUS软件建立有限元分析模型,对圆锥形中空夹层钢管混凝土偏心受压构件的典型破坏模态和荷载-变形关系曲线进行模拟,所得计算结果与试验结果基本吻合。通过典型算例分析了受力过程中钢管和混凝土各自所承担的荷载和纵向应力分布情况,同时分析了内、外钢管与混凝土之间相互作用力的变化情况。结果表明:偏心率和长细比对圆锥形中空夹层钢管混凝土偏心受压构件承载力及刚度有显著影响;该类构件力学行为与等截面圆中空夹层钢管混凝土偏心受压构件类似,锥度的存在使破坏位置从等截面柱的中部上移到锥形柱的3/4柱高处(柱顶处),因此在设计大空心率圆锥形中空夹层钢管混凝土偏压(压弯)构件时应考虑柱头处加强。同时,对该类构件压弯承载力计算方法给出了建议。 相似文献
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为研究全再生混凝土柱内配钢管后的轴压力学性能,设计5个内置钢管全再生混凝土组合柱试件和3个对比试件进行试验,分析体积配箍率和钢管面积比对试件承载力、延性和损伤性能的影响规律以及内配钢管后的组合效应。研究表明:钢管混凝土柱达到峰值荷载时刻滞后于中空钢筋混凝土柱,即在管外混凝土达到极限状态后,核心钢管混凝土逐渐发挥作用;随着体积配箍率的增加,组合柱的承载力和延性整体呈增长趋势,累积损伤增长变慢;提高钢管面积比,组合柱承载力降低,延性增强,提前进入损伤状态,但后期损伤发展缓慢;CECS 188:2005的计算结果与试验结果吻合良好,该规程可用于内置钢管全再生混凝土组合柱轴压承载力设计。 相似文献
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本文进行了9个矩形钢管混凝土和3个空心矩形钢管的横向局部承压试验。试验的主要参数为局部承压面积和管内混凝土填充长度。试验结果表明,矩形钢管混凝土横向局部承压强度提高系数高于素混凝土局部承压强度提高系数,钢管参与了局部承压,管内混凝土的填充长度也是影响横向局部承压强度的主要因素。在分析横向局部承压机理的基础上,构造了考虑钢管参与工作和混凝土长度影响的局部承压强度计算公式,与J.A.Packer和本文的试验结果相比,均吻合较好,为我国正在编制的《矩形钢管混凝土结构技术规程》中桁架X型受压节点承载力计算提供了参考依据。 相似文献
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《Thin》2014
This paper presents a finite element analysis (FEA) of circular concrete filled steel tubular (CFST) members under local bearing forces applied either perpendicularly to the member or at an angle of 45°. The established FEA modeling was verified by the experimental results that have been published in an international journal. The FEA modeling was then used to perform analysis on the typical failure modes and full-range load-deformation relations of CFST subjected to local bearing forces. Finally, simplified formulae for calculating the strength of CFST under local bearing forces was presented. Practical guidance was also given to avoid premature local buckling of brace member and premature fracture of chord member. 相似文献
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利用ABAQUS有限元软件分别建立考虑外钢管施工初应力和同时考虑钢管与型钢施工初应力的内配十字形型钢圆钢管混凝土轴压短柱数值模型,并对建模方法进行验证。计算施工初应力存在时内配型钢钢管混凝土轴压短柱的荷载-位移全过程曲线及其各部件的承载力分配曲线,并分析混凝土与钢管、混凝土与型钢的接触应力及应力发展状态。最后对初应力系数、构件长细比、钢管和型钢的含钢率、钢管和型钢的屈服强度以及混凝土的抗压强度等因素进行了参数分析。结果表明:考虑外钢管施工初应力对内配型钢钢管混凝土轴压构件力学性能的影响规律与其对钢管混凝土轴压构件力学性能的影响规律基本一致; 外钢管和型钢施工初应力的同时存在使混凝土与钢管、型钢的相互作用时间延迟,减弱钢管对混凝土的套箍作用和混凝土对型钢的局部约束,使组合构件提前进入弹塑性阶段并扩大此阶段的范围,导致组合柱极限承载力随着初应力值的增大逐渐减小; 构件长细比对轴压短柱的承载力影响系数有显著影响。 相似文献
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为了研究圆锥形中空夹层钢管混凝土轴压短柱的受力机理,通过有限元软件ABAQUS建立了该类构件的力学模型,并与已有试验数据进行对比,验证了模型的合理性。分析了典型构件的受力全过程荷载-应变关系曲线、钢管与混凝土之间的相互作用力、破坏模态和荷载分配; 同时分析了空心率、锥度、钢管径厚比和混凝土强度等参数对相互作用力的影响。结果表明:典型构件荷载-应变关系曲线可分为弹性段、弹塑性段、下降段和稳定段4个阶段; 构件破坏是由外钢管向外鼓曲所导致的,破坏截面约在0.8H(H为构件高度)柱高处; 锥度和空心率的改变对构件破坏截面位置影响较大,随着锥度和空心率的增大,破坏截面位置逐渐向柱顶靠近; 影响外钢管与混凝土之间相互作用力的主要因素有空心率、锥度、外钢管径厚比、外钢管屈服强度和混凝土强度; 影响内钢管与混凝土之间相互作用力的主要因素有空心率、锥度和外钢管屈服强度; 内钢管径厚比与内钢管屈服强度对混凝土与内、外钢管之间的相互作用力影响较小,可不作为主要参数进行分析。 相似文献
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An investigation into the fire performance of self-consolidating concrete (SCC) filled double skin tubular columns (CFDST) during the standard fire test is reported. Six full size SCC filled CFDST columns were designed for the fire tests. Detail failure modes of overall specimens and each component in the columns as well as temperatures, deformation and fire endurance were presented. Fire performance of the CFDST columns were studied through analysis of the limiting temperature of the outer tube, composite action between steel and concrete and effect of a number of parameters on the fire endurance. It showed that the limiting temperature in the CFDST columns is significantly higher than that in concrete filled steel tubular (CFST) columns or critical temperature in steel structural components. Strong evidence was found to prove the existence of composite action between steel and concrete in the CFDST columns during fire exposure. Effect of a number of parameters on the fire endurance of the composite columns was identified. Investigation into the fire performance of the columns also reveals possible solutions to improve the fire resistance of CFDST members. 相似文献
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为研究方钢管螺旋筋复合约束混凝土轴压短柱破坏机理,完成了12个试件的轴心受压试验。观察了试件外观破坏情况、核心混凝土破坏形态及螺旋筋失效模式,并分析了受力过程中螺旋筋、纵筋、方钢管的应力发展和内力分配情况。试验结果表明:方钢管、螺旋筋、纵筋及核心混凝土四者能协同工作,各种材料强度均能充分发挥;螺旋筋在弹性受力阶段发挥的作用较小,不能延缓方钢管发生局部鼓曲,而主要在弹塑性及流塑阶段发挥约束作用,能显著提高轴压短柱的承载力和变形能力;方钢管和螺旋筋对核心混凝土形成双重约束机制,当方钢管发生鼓曲后螺旋筋能有效补充对核心混凝土的约束作用,进而改善了方钢管对核心混凝土约束不均匀的特性。 相似文献
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A series of new unified design formulas for calculating the temperature field and fire resistance under axial compressive loading of a circular solid or hollow concrete filled double steel tubular (CFDST) short and slender columns exposed to fire are presented in this paper. The results of the experiments are firstly derived from exploring the fundamental behavior of the CFSDT slender columns under the ISO 834 standard fire and temperature distributions. Failure modes and axial deformation versus time curves are also obtained and discussed. It was realized that a solid or slender CFDST column has different temperature fields, stronger limiting temperature and better fire resistance, as compared to columns filled with plain concrete. Also, the load ratio and steel ratio have no evident difference between the results of the solid and hollow CFDST columns. A three-dimensional finite element analysis (FEA) model is developed to calculate the temperature field of CFDST columns. After calibration of the FE model, the influences of important parameters on the temperature field of the composite columns are investigated and a unified formula for calculating average temperatures of the columns’ cross-section is obtained. Combining the average temperature with the “Unified theory” under axial compression, a simplified design method is put forward, which provides a unified formulation for both the plain CFST and CFDST columns relating to the axial bearing capacity at room and elevated temperature. The proposed formulas are calibrated through comparisons with fire tests on the columns, and it was found that the method produces safe results on average. 相似文献
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为了探索配筋对薄壁钢管高强度混凝土柱轴心受力性能的改善机理,进行了18根试件的轴心受压试验。试验中设计了2种混凝土保护层厚度的配筋钢管混凝土及对应的钢筋混凝土、钢管混凝土和素混凝土等6组试件,以弹性阶段、屈服阶段、强化阶段和破坏阶段的荷载与位移或荷载与应变关系、承载力、套箍系数为评价参数,研究了此类构件的基本力学特性,并发现:核心混凝土内配置钢筋后采用薄壁钢管是可行的;要提高钢管混凝土的工作性能,配置钢筋的效果明显优于增加钢管壁厚的效果。最终提出了适合此类构件的承载力计算公式。 相似文献