带加劲肋方钢管混凝土柱的静力特性

方钢管内填混凝土柱(CFSTs)在现代建筑中的使用越来越广泛,与钢柱和混凝土柱相比,其材料性能和功效均有所提高。然而,尽管方钢管混凝土柱的屈曲特性优于中空钢管,由于局部屈曲,其外包钢管截面的高厚比仍受到限制。针对外包钢管带加劲肋的方钢管混凝土柱,提出了一些新的加劲肋形式。为评估这些加劲肋对方钢管混凝土柱力学性能的影响,并与传统加劲肋进行比较,该文对4个带不同加劲肋的方钢管混凝土柱和1个无加劲肋方钢管混凝土柱进行了试验。试验研究了材料的抗力、延性和失效模式等力学性能,为了对试样的综合性能进行预测和总结,也从理论上对这些力学性能进行了研究。为了解各参数对力学性能的影响,该文进行了数值模拟和大量的参数研究,相关学者的试验数据验证了数值分析结果的准确性。基于试验结果和以往的研究,提出了截面强度的设计建议。     

螺旋加劲薄壁方钢管混凝土叠合构件轴压性能及参数影响研究

薄壁钢管混凝土经济性能优势明显,但受到局部屈曲的影响,变形能力发生严重退化.本文基于螺旋加劲肋新型约束形式,提出了螺旋加劲薄壁方钢管混凝土叠合构件,通过试验研究发现:设置螺旋加劲肋可以较好约束薄壁钢管,增强构件局部抗屈曲能力,承载力和变形能力得到提高.在试验的基础上,对该叠合柱进行数值分析,研究了钢管宽厚比、加劲肋宽厚...     

加劲薄壁中空钢管混凝土短柱的强度和延性研究

一般以为内部焊接的纵向加劲肋能够提高薄壁中空钢管混凝土柱的结构性能。对36个试件进行试验,其中包括30个带加劲肋和6个不带加劲肋的短柱,以研究不同方法对于这种加劲组合短柱延性性能的改善。这些方法包括：增加加劲肋的高度、在管钢每个面上增加加劲肋的数量、采用锯齿状加劲肋、在加劲肋上焊接滚边或锚条,在混凝土中添加钢纤维。试验发现,在混凝土中添加钢纤维是提高构件延性承载力的最有效方法,同时建筑成本和施工难度也不会明显增加。     

带肋方钢管高强混凝土柱轴压性能试验研究

为研究加肋方钢管高强混凝土组合柱的轴压力学性能,以加劲肋刚度为变化参数,进行了7个带肋方钢管高强混凝土短柱试件轴压试验研究,对比分析了试件破坏特征、屈曲模态及应力应变规律。结果表明:设置加劲肋有效延缓了管壁屈曲,改变了管壁屈曲模态以及应力路径,加劲肋刚度对组合柱承载力影响不显著;随着加劲肋刚度增大,钢管环向与纵向应力比增大,钢管对核心混凝土约束作用增大,组合柱纵向刚度增大,钢管纵向屈服应力减小,钢管屈服发生在组合柱达到峰值荷载之后。     

带肋薄壁方钢管混凝土轴压短柱设计探讨

薄壁方钢管混凝土能取得较好的经济效果,适宜在结构中用作柱构件。但薄壁钢管在荷载较大时易发生局部屈曲,且降低对混凝土的约束。研究表明,在钢管纵向设置加劲肋可有效延缓管壁局部屈曲,改善构件工作性能。针对该新型方钢管混凝土轴压短柱,探讨子板件最大宽厚比及加劲肋的最小刚度确定方法。最后利用国内外常用的钢管混凝土设计规范对已有充分加劲的试验构件进行承载力计算,通过分析比较确定这些规范计算公式的适用性,供工程实践参考。     

钢筋加劲T形截面钢管混凝土柱抗震性能试验研究

制作4根钢筋加劲的T形截面钢管混凝土柱、1根非加劲T形截面钢管混凝土柱和1根T形截面钢筋混凝土柱试件,对其进行低周往复水平荷载作用下的滞回性能试验,研究其破坏模式和滞回性能,分析钢筋加劲肋的作用机理以及钢管对混凝土的约束作用。结果表明：相比T形截面钢筋混凝土柱,T形截面钢管混凝土柱破坏程度有明显减轻,刚度、承载力以及耗能性能均有明显提高;钢筋加劲肋能有效限制钢板局部屈曲和阴角处钢管与混凝土脱离,保证钢管和混凝土共同工作,对拉钢筋加劲肋相对锯齿形钢筋加劲肋的效果更加显著;含钢率较高的钢管混凝土柱承载力更高,耗能能力更好;轴压比从0.2增加到0.4时,钢筋加劲的T形截面钢管混凝土柱的承载力增大,延性降低。     

复合加劲方钢管混凝土柱的承载力与制作方案分析

为了克服方钢管混凝土柱中,方钢管对混凝土的约束比圆钢管相对较差的弱点,提出采用复合加劲方钢管混凝土柱。在用钢量相近的前提下,通过加劲肋提高管壁的屈曲强度,增强对混凝土的约束,从而提高承载能力。由于管壁内施工空间狭窄,加劲肋与管壁的满焊连接比较困难。提出填塞点焊的方法,分析了方钢管混凝土的屈曲变形模式,给出了焊点的具体间距和数量。     

带肋薄壁方钢管混凝土轴压短柱受力性能试验研究

为研究带肋薄壁方钢管混凝土轴压短柱的受力性能,以钢管宽厚比、加劲肋宽度和加劲肋个数为参数,对26个薄壁方钢管混凝土短柱进行了试验研究。研究结果表明:对于无肋试件,在达到承载力以前管壁已经发生鼓曲,且试件宽厚比越大,鼓曲越早发生,鼓曲部位的钢管截面越早退出工作,没有发挥出钢管混凝土的优势。设置加劲肋后薄壁方钢管混凝土短柱的受力性能得到明显改善,钢管壁的局部鼓曲得以延缓,材料强度得到了充分利用,试件承载力提高。当试件宽厚比为60、80时,加劲肋宽度对试件承载力影响最明显,加劲肋宽度越大,承载力越高,增加加劲肋个数对试件承载力影响不大;而当试件宽厚比为100时,设置单个加劲肋已不能满足对管壁局部屈曲的抗弯刚度要求,必须增加加劲肋的个数以增加约束钢管变形的支撑点,减小管壁局部屈曲的波长,提高试件局部屈曲的临界荷载。同时利用ABAQUS有限元计算软件对薄壁带肋方钢管混凝土轴压短柱的受力全过程进行了模拟,并将试验结果与有限元模拟结果进行了对比,两者吻合良好,为下一步分析奠定基础。     

Experimental research on mechanical behavior of concrete-filled thin-walled stiffened square steel tubular short column under axial load

为研究带肋薄壁方钢管混凝土轴压短柱的受力性能,以钢管宽厚比、加劲肋宽度和加劲肋个数为参数,对26个薄壁方钢管混凝土短柱进行了试验研究。研究结果表明：对于无肋试件,在达到承载力以前管壁已经发生鼓曲,且试件宽厚比越大,鼓曲越早发生,鼓曲部位的钢管截面越早退出工作,没有发挥出钢管混凝土的优势。设置加劲肋后薄壁方钢管混凝土短柱的受力性能得到明显改善,钢管壁的局部鼓曲得以延缓,材料强度得到了充分利用,试件承载力提高。当试件宽厚比为60、80时,加劲肋宽度对试件承载力影响最明显,加劲肋宽度越大,承载力越高,增加加劲肋个数对试件承载力影响不大;而当试件宽厚比为100时,设置单个加劲肋已不能满足对管壁局部屈曲的抗弯刚度要求,必须增加加劲肋的个数以增加约束钢管变形的支撑点,减小管壁局部屈曲的波长,提高试件局部屈曲的临界荷载。同时利用ABAQUS有限元计算软件对薄壁带肋方钢管混凝土轴压短柱的受力全过程进行了模拟,并将试验结果与有限元模拟结果进行了对比,两者吻合良好,为下一步分析奠定基础。     

直肋和开孔肋对方钢管混凝土短柱轴压性能影响研究

设置加劲肋可以明显改善方钢管混凝土试件的屈曲性能,提高方钢管混凝土短柱中钢管的约束性能。通过对普通钢管混凝土、设直肋和开孔肋的钢管混凝土试件进行研究,并结合有限元对加劲肋的增强作用机理进行分析。研究结果表明:试件加劲后承载力都得到了有效提高,并且由于加劲肋的存在钢管鼓曲形态由单波型鼓曲变为双波型鼓曲;带肋试件侧边中部混凝土中的应力增大,混凝土受压破坏部位范围更大。从试件性能角度来看,加劲后钢管可以为核心混凝土提供更可靠的约束,其中:直肋试件承载力更高、开孔肋试件延性更大。     

Experimental behaviour of concrete-filled stiffened thin-walled steel tubular columns

An experimental study on the structural behaviour of concrete-filled stiffened thin-walled steel tubular columns is presented in this paper. The stiffening was achieved by welding longitudinal stiffeners on the inner surfaces of the steel tubes. Companion tests were also undertaken on 12 unstiffened concrete-filled steel tubular (CFST) columns, with or without steel fibres in the infill concrete. The test results showed that the local buckling of the tubes was effectively delayed by the stiffeners. The plate buckling initially occurred when the maximum load had almost reached for stiffened specimens, thus they had higher serviceability benefits compared to those of unstiffened ones. Some of the existing design codes were used to predict the load-carrying capacities of the tested composite columns.     

带肋方钢管混凝土轴压短柱试验研究及有限元分析

以方钢管宽厚比和加劲肋高厚比为主要变化参数,进行了14个带肋方钢管混凝土轴压短柱试验研究;同时采用有限元软件ABAQUS对带肋方钢管混凝土轴压短柱的荷载-变形关系进行了计算,计算结果与试验结果吻合良好。同时从应力-应变关系、核心混凝土和钢管的纵向应力分布及其相互作用等方面对比分析了无肋、单肋和双肋方钢管混凝土轴压短柱的受力性能。分析结果表明：设置加劲肋不仅提高了核心混凝土的纵向应力,而且明显减小了钢管管壁的拉应力区范围,改善了管壁的稳定性;带肋试件的约束作用主要集中在钢管角部和加劲肋处,随着每边加劲肋数量的增加,角部约束力明显增大。图13表1参11     

Experimental behaviour of stiffened concrete-filled thin-walled hollow steel structural (HSS) stub columns

Test results on concrete-filled steel tubular stub columns with inner or outer welded longitudinal stiffeners under axial compression are presented in this paper. The research was mainly focused on square hollow section (SHS) columns; two rectangular hollow section (RHS) columns were also tested. A longitudinal stiffener was provided on each side of the stiffened SHS column, while only two stiffeners were welded to the longer sides of the stiffened RHS column. The main experimental parameters considered were the height-to-thickness ratio and stiffener rigidity. In addition, empty tubes with or without stiffeners, as well as unstiffened concrete-filled steel tubes were also tested for comparison. Requirements for stiffener rigidity are developed by modifying a formula presented in the literature. Existing theoretical model and design codes were used to predict the load versus axial strain relationships and load-carrying capacities of the adequately stiffened composite sections respectively; reasonable results were achieved.     

薄壁方钢管混凝土短柱承载性能非线性有限元分析

采用ANSYS软件,对薄壁方钢管混凝土短柱的承栽性能进行非线性有限元分析.考虑轴压作用下带肋与不带肋两种截面形式的薄壁方钢管混凝土短柱力学性能,并得出其破坏模态,计算结果与试验结果吻合较好.针对该类构件,探讨加劲肋和钢管强度对其承载力的影响.结果表明,设置加劲肋能有效提高薄壁方钢管混凝土短柱的轴压承载力,与不带肋短拄相...     

Experimental investigation on concrete-filled stainless steel stiffened tubular stub columns

This paper presents an experimental investigation on concrete-filled normal-strength stainless steel stiffened tubular stub columns using the austenitic stainless steel grade EN 1.4301 (304). The stiffened stainless steel tubes were fabricated by welding four lipped angles or two lipped channels at the lips. Therefore, the stiffeners were formed at the mid-depth of the sections. In total, five hollow columns and ten concrete-filled columns were tested. The longitudinal stiffener of the column plate was formed to avoid shrinkage of the concrete and to behave as a continuous connector between the concrete core and the stainless steel tube. The behavior of the columns was investigated using two different nominal concrete cubic strengths of 30 and 60 MPa. A series of tests was performed to investigate the effects of cross-section shape and concrete strength on the behavior and strength of concrete-filled stainless steel stiffened tubular stub columns. The measured average overall depth-to-width ratios (aspect ratio) varied from 1.0 to 1.8. The depth-to-plate thickness ratio of the tube sections varied from 60 to 90. Different lengths of columns were selected to fix the length-to-depth ratio to a constant value of 3. The concrete-filled stiffened stainless steel tubular columns were subjected to uniform axial compression over the concrete core and the stainless steel tube to force the entire section to undergo the same deformations by blocking action. The column strengths, load–axial strain relationships and failure modes of the columns are presented. Several comparisons were made to evaluate the test results. The results of the experimental study showed that the design rules, as specified in the European specifications and the ASCE, are highly conservative for square and rectangular cold-formed concrete-filled normal-strength stainless steel stiffened stub columns.     

Effect of reinforcement stiffeners on square concrete-filled steel tubular columns subjected to axial compressive load

Eight stiffened square concrete-filled steel tubular (CFST) stub columns with slender sections of encasing steel and two non-stiffened counterparts were tested subjected to axial compressive load. Four types of reinforcement stiffeners and steel tensile strips were introduced to postpone local buckling of steel tubes, in which the tensile strip was first used as stiffener in CFSTs. The stiffening mechanism, failure modes of concrete and steel tubes, strength and ductility of stiffened square CFSTs were also studied during the experimental research. A numerical modeling program was developed and verified against the experimental data. The program incorporates the effect of the stiffeners on postponing local buckling of the tube and the tube confinement on concrete core. Extensive parametric analysis was also conducted to examine the influencing parameters on mechanical properties of stiffened square CFSTs.     

带肋薄壁复式钢管混凝土柱的抗震性能研究

带肋薄壁复式钢管混凝土柱具有较好的耐火性能和经济性,同时钢管混凝土构件多用于地震频发区域,因此有必要研究其抗震性能。以轴压比和内管外径为主要参数,进行了6根带肋薄壁复式钢管混凝土压弯柱的低周反复加载试验。试验结果表明：该类组合柱的滞回曲线饱满,具有良好的抗震性能,其承载能力和耗能能力明显高于带肋薄壁钢管混凝土对比柱;该类柱均为面内压弯破坏;随着轴压比的增大,试件的延性、累积耗能随之减小,后期刚度退化加剧;随着内管外径的增大,试件的承载力、延性和耗能能力提高,但内管外径对刚度退化的影响较小。建立了带肋薄壁复式钢管混凝土柱的有限元模型,并利用试验结果检验了模型的准确性。基于该模型开展参数分析,结果表明钢管屈服强度、外部混凝土强度、轴压比、径宽比、径厚比和长细比等参数对该类构件的承载力影响较显著。最后基于参数分析,建议了荷载 挠度恢复力模型。     

轴心受压双钢管混凝土短柱正截面受压承载力理论分析及试验研究

研究了由同心设置的内、外圆钢管构成的轴心受压双钢管混凝土短柱正截面受压承载力,分析了单钢管混凝土柱与双钢管混凝土柱的受力机理,并根据纤维模型法原理,采用适用于钢管混凝土受力特性的钢材与混凝土材料本构关系,给出了轴心受压双钢管混凝土短柱的荷载-位移全过程数值分析和正截面承载力计算公式。进行了5个双钢管混凝土短柱的轴心受压试验,验证理论分析的正确性。理论分析与试验研究表明:轴心受压双钢管混凝土短柱与单钢管混凝土柱的受力全过程都可以分为弹性阶段、弹塑性阶段和破坏阶段。双钢管混凝土短柱的破坏形态为腰鼓形,其外层混凝土的工作性能与单钢管中的混凝土大致相同,但内钢管中的内层混凝土受到的约束效应较大,且不是内、外钢管对它的约束效应的叠加,因此对内层混凝土约束效应的确定是计算承载力的关键。通过与相同含钢率的轴心受压单钢管混凝土短柱受力过程的对比得出:双钢管混凝土柱的承载力明显高于单钢管混凝土柱,且具有非常好的延性和整体     

方钢管混凝土框架-十字加劲薄钢板剪力墙结构水平承载力研究

为研究方钢管混凝土框架-十字加劲薄钢板剪力墙结构的抗震性能和水平承载力,进行了一榀缩尺比为1∶3的2层单跨方钢管混凝土框架-十字加劲薄钢板剪力墙结构的拟静力试验,得到了其破坏形态、荷载-位移滞回曲线、骨架曲线、特征荷载和位移等。利用有限元软件ABAQUS对其进行了非线性数值模拟,分析了方钢管混凝土框架-十字加劲薄钢板剪力墙的抗震性能、受力机理和破坏机制。基于试验和数值模拟结果,结合理论研究,提出了方钢管混凝土框架-十字加劲薄钢板剪力墙的水平承载力的计算式,并将其计算结果与试验、数值模拟结果进行对比。结果表明：方钢管混凝土框架-十字加劲薄钢板剪力墙具有较高的水平承载力、初始刚度及良好的延性和耗能能力,水平承载力计算式的计算结果与试验、数值模拟结果吻合较好。