基于B3模型的钢筋混凝土梁徐变研究

发布时间：2018-03-03 18:19

本文选题：徐变　切入点：B3模型　出处：《北京交通大学》2008年硕士论文　论文类型：学位论文

【摘要】： 徐变是混凝土材料重要的长期性能,当钢筋混凝土梁在长期荷载作用下,徐变将使其挠度增加,并产生钢筋与混凝土之间的应力重分布,影响了结构的适用性,以及安全性和耐久性。由于徐变对钢筋混凝土梁力学性能的影响机理复杂,目前,这一问题还没有得到合理地解决。本文将基于固结理论的混凝土徐变B3模型运用到钢筋混凝土梁的计算中,结合钢筋混凝土梁的受力特点,建立了符合混凝土徐变微观机理的钢筋混凝土梁的徐变计算模型,进而提出了钢筋混凝土梁的长期挠度计算模型。模型考虑了钢筋与混凝土之间的应力重分布,以及受压区混凝土高度随时间的不断变化。通过计算结果与试验数据相对比分析,可以看出基于B3模型的钢筋混凝土徐变计算模型的结果与试验结果吻合良好,同时该模型较ACI、CEB-FIP等模型更加合理、准确。本文分析了配筋率(ρ)对钢筋混凝土梁长期徐变变形的影响,得到钢筋混凝土梁长期变形随配筋率增大而较小的结论。此外,由于B3模型中考虑了混凝土配合比对徐变的影响,运用此新建模型,本文分析了混凝土的水灰比(w/c)、骨料水泥比(a/c)、作用荷载等因素对钢筋混凝土梁长期徐变变形的影响,并初步得到其规律:钢筋混凝土梁的徐变随混凝土水灰比的增长及作用荷载增大而提高,随骨料水泥比的升高而有所降低。
[Abstract]:Creep is an important long-term performance of concrete material. When reinforced concrete beam is subjected to long-term load, creep will increase its deflection and produce stress redistribution between reinforcement and concrete, which affects the applicability of the structure. The influence of creep on the mechanical properties of reinforced concrete beams is complicated, so this problem has not been solved reasonably. In this paper, the concrete creep B3 model based on consolidation theory is applied to the calculation of reinforced concrete beam, and the creep calculation model of reinforced concrete beam is established, which accords with the microscopic mechanism of concrete creep, combined with the stress characteristics of reinforced concrete beam. Furthermore, a long-term deflection calculation model of reinforced concrete beams is proposed. The stress redistribution between reinforcement and concrete and the continuous variation of concrete height in compression zone are considered in the model. The calculated results are compared with the experimental data, and the calculated results are compared with the experimental data. It can be seen that the calculated results of RC creep model based on B3 model are in good agreement with the experimental results, and the model is more reasonable and accurate than the ACIN CEB-FIP model. In this paper, the effect of reinforcement ratio (蟻) on the long-term creep deformation of reinforced concrete beams is analyzed. It is concluded that the long-term deformation of reinforced concrete beams decreases with the reinforcement ratio increasing. In addition, the effect of concrete mix ratio on creep is considered in the B3 model. Based on the new model, the effects of water cement ratio (w / c), aggregate / cement ratio (a / c), and load on the creep deformation of reinforced concrete beams are analyzed in this paper. The creep of reinforced concrete beams increases with the increase of concrete water-cement ratio and the action load, and decreases with the increase of aggregate cement ratio.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：TU375.1

【引证文献】