预应力钢管混凝土关键性参数对轴压性能的影响研究
发布时间：2019-05-06 18:08
【摘要】：本文将液压法施加预应力与钢管混凝土技术联系在一起,形成预应力钢管混凝土。预应力钢管混凝土在具有普通钢管混凝土特点的基础上,利用预先施加的应力增加受荷前钢管对核心混凝土的约束作用,这可以改善普通钢管混凝土中外包钢管对核心混凝土约束不足的问题,也可以改善自应力钢管混凝土无法主动施加预应力的问题。本文依托于江苏省高校自然科学研究项目《液压预应力钢管混凝土柱轴压性能试验研究与数值模拟》(15KJB560001),主要研究内容如下:(1)开展了3根普通钢管混凝土柱的变形试验,试验结果发现:在混凝土灌注后的前4天,钢管混凝土柱产生膨胀变形,之后由于水化收缩等使钢管混凝土柱产生收缩现象,最终的横向应变约为-108με,纵向应变约为-46με;(2)为了补偿核心混凝土的收缩,完成了6个不同膨胀剂掺量的钢管混凝土柱的变形及力学性能试验。试验结果表明:补偿收缩的最优膨胀剂掺量为12%。膨胀剂掺量为12%时试件在28天内均产生膨胀变形;与其他试件相比,膨胀剂掺量为12%时试件弹性阶段的刚度及极限承载力均为最大值;(3)进行了4根液压预应力钢管混凝土的预应力长期损失试验,试验结果表明:膨胀剂掺量为12%的预应力钢管混凝土在28天的预应力损失控制在20%以内,而未掺膨胀剂试件的预应力损失约为45%,表明掺膨胀剂可有效降低预应力损失,建议膨胀剂掺量为12%;(4)进一步开展了6根液压预应力钢管混凝土柱的轴压试验,主要参数为膨胀剂掺量(0、12%)和预应力值(0MPa、2.5MPa、5MPa、7.5MPa)。试验结果表明:施加预应力后,钢管混凝土柱弹性阶段的刚度及弹性阶段的最大轴力提升明显,且预应力值越大提升效果越明显;与非预应力钢管混凝土柱相比,预应力试件弹性阶段的最大轴力最高可达极限承载力的95.6%,弹性阶段的刚度最高可增大612%;与未掺膨胀剂的预应力试件相比,膨胀剂掺量为12%的预应力试件弹性阶段的最大轴力可提高16%左右,弹性阶段的刚度可增大94%左右;预应力试件的极限承载力变化不大;(5)使用ABAQUS软件建立了液压预应力钢管混凝土柱的轴压模型,模拟了液压法施加预应力及试件轴压的全过程,软件分析结果与试验结果吻合良好。
[Abstract]:In this paper, the prestressing force of hydraulic method and the technology of concrete filled steel tube (CFST) are combined to form the prestressed concrete filled steel tube. Based on the characteristics of concrete filled steel tube (CFST), the prestressed concrete filled steel tube (CFST) increases the restraint effect of CFST on the core concrete before loading by using the stress applied in advance. This can improve the problem that the concrete filled steel tube has insufficient restraint to the core concrete, and it can also improve the problem that the self-stressed concrete-filled steel tube can not exert the prestressing force on its own initiative. This paper is based on the "Experimental study and numerical Simulation of Axial compressive behavior of hydraulic Prestressed concrete filled Steel Tubular columns" (15KJB560001), which is based on the Natural Science Research Project of Jiangsu University. The main research contents are as follows: (1) the deformation tests of three concrete filled steel tube columns were carried out. The results showed that the expansion deformation of concrete filled steel tube columns occurred in the first 4 days after concrete pouring. The ultimate transverse strain is-108 渭 蔚 and the longitudinal strain is-46 渭 蔚 due to the shrinkage of concrete-filled steel tube columns caused by hydration and shrinkage. (2) in order to compensate the shrinkage of core concrete, the deformation and mechanical properties of six concrete filled steel tubular columns with different content of expansive agent were tested. The experimental results show that the optimal content of expansion agent for compensating shrinkage is 12%. When the content of expansive agent is 12%, the expansion deformation occurs in 28 days, compared with other specimens, the stiffness and ultimate bearing capacity of the specimen in elastic stage are maximum when the content of expansive agent is 12%. (3) the long-term prestress loss test of 4 hydraulic prestressed concrete filled steel tubes is carried out. The results show that the prestressing loss of concrete filled steel tube with 12% dilatant content is less than 20% in 28 days, and the prestress loss of concrete filled steel tube is less than 20% in 28 days. The loss of prestressing force is about 45%, which indicates that the loss of prestress can be effectively reduced by adding expansive agent, and it is suggested that the content of dilatant is 12%. (4) the axial compression tests of 6 hydraulic prestressed concrete filled steel tube columns were carried out. The main parameters were the content of expansive agent (0, 12%) and the pre-stress value (0 MPA, 2.5 MPA, 5 MPA, 7.5 MPA). The experimental results show that the stiffness and the maximum axial force of the concrete-filled steel tube columns in the elastic stage are obviously increased after prestressing, and the bigger the prestress value is, the more obvious the effect is. Compared with non-prestressed concrete-filled steel tube columns, the maximum axial force of prestressed specimens in elastic stage is up to 95.6% of the ultimate bearing capacity, and the maximum stiffness in elastic stage can be increased by 612%. Compared with the pre-stressed specimen without expansive agent, the maximum axial force of the prestressed specimen with 12% expansive agent can be increased by 16% and the stiffness of the elastic stage can be increased by about 94%, and the ultimate bearing capacity of the prestressed specimen does not change much, and the maximum axial force of the prestressed specimen with 12% content can be increased by 16% and 94% respectively. (5) the axial compression model of hydraulic prestressed concrete filled steel tube column is established by using ABAQUS software, and the whole process of applying prestressing force and axial compression of specimen by hydraulic pressure method is simulated. The software analysis results are in good agreement with the experimental results.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9
本文编号：2470383
[Abstract]:In this paper, the prestressing force of hydraulic method and the technology of concrete filled steel tube (CFST) are combined to form the prestressed concrete filled steel tube. Based on the characteristics of concrete filled steel tube (CFST), the prestressed concrete filled steel tube (CFST) increases the restraint effect of CFST on the core concrete before loading by using the stress applied in advance. This can improve the problem that the concrete filled steel tube has insufficient restraint to the core concrete, and it can also improve the problem that the self-stressed concrete-filled steel tube can not exert the prestressing force on its own initiative. This paper is based on the "Experimental study and numerical Simulation of Axial compressive behavior of hydraulic Prestressed concrete filled Steel Tubular columns" (15KJB560001), which is based on the Natural Science Research Project of Jiangsu University. The main research contents are as follows: (1) the deformation tests of three concrete filled steel tube columns were carried out. The results showed that the expansion deformation of concrete filled steel tube columns occurred in the first 4 days after concrete pouring. The ultimate transverse strain is-108 渭 蔚 and the longitudinal strain is-46 渭 蔚 due to the shrinkage of concrete-filled steel tube columns caused by hydration and shrinkage. (2) in order to compensate the shrinkage of core concrete, the deformation and mechanical properties of six concrete filled steel tubular columns with different content of expansive agent were tested. The experimental results show that the optimal content of expansion agent for compensating shrinkage is 12%. When the content of expansive agent is 12%, the expansion deformation occurs in 28 days, compared with other specimens, the stiffness and ultimate bearing capacity of the specimen in elastic stage are maximum when the content of expansive agent is 12%. (3) the long-term prestress loss test of 4 hydraulic prestressed concrete filled steel tubes is carried out. The results show that the prestressing loss of concrete filled steel tube with 12% dilatant content is less than 20% in 28 days, and the prestress loss of concrete filled steel tube is less than 20% in 28 days. The loss of prestressing force is about 45%, which indicates that the loss of prestress can be effectively reduced by adding expansive agent, and it is suggested that the content of dilatant is 12%. (4) the axial compression tests of 6 hydraulic prestressed concrete filled steel tube columns were carried out. The main parameters were the content of expansive agent (0, 12%) and the pre-stress value (0 MPA, 2.5 MPA, 5 MPA, 7.5 MPA). The experimental results show that the stiffness and the maximum axial force of the concrete-filled steel tube columns in the elastic stage are obviously increased after prestressing, and the bigger the prestress value is, the more obvious the effect is. Compared with non-prestressed concrete-filled steel tube columns, the maximum axial force of prestressed specimens in elastic stage is up to 95.6% of the ultimate bearing capacity, and the maximum stiffness in elastic stage can be increased by 612%. Compared with the pre-stressed specimen without expansive agent, the maximum axial force of the prestressed specimen with 12% expansive agent can be increased by 16% and the stiffness of the elastic stage can be increased by about 94%, and the ultimate bearing capacity of the prestressed specimen does not change much, and the maximum axial force of the prestressed specimen with 12% content can be increased by 16% and 94% respectively. (5) the axial compression model of hydraulic prestressed concrete filled steel tube column is established by using ABAQUS software, and the whole process of applying prestressing force and axial compression of specimen by hydraulic pressure method is simulated. The software analysis results are in good agreement with the experimental results.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9
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