钢管混凝土劲性骨架组合柱极限承载力计算方法研究

发布时间：2018-05-31 16:56

本文选题：钢管混凝土 + 劲性骨架　；参考：《福州大学》2013年硕士论文

【摘要】：钢-混凝土组合柱在建筑工程中得到了较广泛的应用；而在混凝土拱桥中,以钢管混凝土为劲性骨架再外包混凝土的施工方法也应用到很多桥梁中,但以往的工程中均不考虑劲性骨架的承载作用,为进一步增强混凝土拱桥的跨越能力,同时方便施工,因此出现了考虑劲性骨架承载力的钢桁腹杆-劲性骨架混凝土组合拱。由于拱以受压为主,所以这种组合拱的截面可简化为钢管混凝土劲性骨架组合柱的研究。但目前类似组合柱的承载力研究中,均以荷载-位移曲线的极值点作为承载力的判断标准,而本文则从桥梁工程的实际出发,以这种组合柱外围混凝土剥落作为承载力标志,开展了试验及有限元分析,并提出了相应的承载力计算公式,主要工作与结论包括以下几个方面：(1)以面积比(组合柱内钢管混凝土面积与整个柱截面面积之比)为主要研究参数,进行了钢管混凝土劲性骨架组合柱的轴压试验研究。试验结果表明,整个受力过程可划分为三个阶段,分别为弹性阶段、弹塑性阶段与塑性阶段,组合柱在不同面积比情况下表现出不同的受力性能与破坏模式,混凝土剥落可能发生在弹塑性阶段,也可能发生在塑性阶段,以混凝土剥落为标志的承载力与峰值荷载并不一定重合。(2)结合已有文献的试验结果进行对比发现,面积比参数对组合柱初裂荷载、剥落荷载及峰值荷载均有影响。随面积比增大,初裂荷载、剥落荷载、初裂荷载与峰值荷载的比值呈现先增大后减小的规律,剥落荷载与峰值荷载的比值呈逐渐减小的规律,且这种规律不因配筋量或偏心率的变化而改变。(3)采用通用有限元软件ABAQUS建立了钢管混凝土劲性骨架组合柱的有限元模型,并通过与试验对比,验证了所建模型的正确性并开展了有限元参数分析。分析结果表明,面积比对组合柱剥落承载力的影响规律与试验相同,影响组合柱剥落承载力的主要参数有面积比、纵筋配筋量、混凝土强度及钢管强度等,在不同的面积比区段,组合柱的承载力(剥落荷载)不能简单地等效为混凝土承载力和钢管混凝土承载力的叠加。(4)在试验研究及有限元参数分析的基础上,并结合现有组合柱承载力计算公式的对比,提出了以面积比划分区段,考虑不同程度的钢管混凝土承载力与外围混凝土承载力的组合形式的组合柱承载力计算公式。精度分析表明,公式计算值与有限元值相差在10%之内,计算公式可供实际工程应用。
[Abstract]:Steel-concrete composite columns have been widely used in construction projects, and in concrete arch bridges, the concrete filled steel tube (CFST) reinforced concrete composite columns are also used in many bridges. However, in previous projects, the bearing capacity of rigid skeleton is not considered. In order to further enhance the span capacity of concrete arch bridge and to facilitate construction, a steel truss web and concrete composite arch with stiffness skeleton bearing capacity is presented. Because the arch is mainly under compression, the section of the composite arch can be simplified to the research of steel tube concrete reinforced concrete rigid skeleton composite column. At present, however, in the study of bearing capacity of similar composite columns, the extreme point of load-displacement curve is taken as the criterion of the bearing capacity, and the concrete spalling around the composite column is taken as the bearing capacity symbol in this paper from the actual situation of bridge engineering. The test and finite element analysis are carried out, and the corresponding formulas for calculating the bearing capacity are put forward. The main work and conclusions are as follows: (1) taking the area ratio (the ratio of the concrete filled steel tube area in the composite column to the section area of the whole column) as the main research parameter, the axial compression test of the concrete filled steel tube reinforced concrete composite column is carried out. The experimental results show that the whole stress process can be divided into three stages: elastic stage, elastic-plastic stage and plastic stage. The composite columns show different mechanical properties and failure modes under different area ratios. The spalling of concrete may occur in the elastic-plastic stage or in the plastic stage. The bearing capacity marked by the spalling of concrete does not necessarily coincide with the peak load. Area ratio parameters have influence on initial crack load, peeling load and peak load of composite column. With the increase of area ratio, the ratio of initial crack load, peeling load, initial crack load to peak load increases first and then decreases, and the ratio of peeling load to peak load decreases gradually. And this rule does not change with the change of reinforcement quantity or heart rate.) the finite element model of steel tube concrete reinforced concrete composite column is established by using the general finite element software ABAQUS, and the model is compared with the test. The correctness of the model is verified and the finite element parameter analysis is carried out. The results show that the effect of area ratio on the peeling capacity of composite columns is the same as that of tests. The main parameters affecting the peeling capacity of composite columns are area ratio, reinforcement ratio of longitudinal reinforcement, strength of concrete and steel tube, etc. In different area ratio sections, the bearing capacity (peeling load) of composite columns can not be simply equivalent to the superposition of concrete bearing capacity and concrete filled steel tube bearing capacity. On the basis of experimental research and finite element parameter analysis, the bearing capacity of composite columns cannot be simply equivalent to the superposition of concrete bearing capacity and steel tube concrete bearing capacity. Based on the comparison of the existing formulas for calculating the bearing capacity of composite columns, a formula for calculating the bearing capacity of composite columns is put forward, which is divided into sections by area ratio and takes into account the combined forms of bearing capacity of concrete-filled steel tubular (CFST) and external concrete. The accuracy analysis shows that the difference between the calculated value and the finite element value is less than 10%, and the formula can be used in practical engineering.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU398.9

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