预应力度对预应力混凝土框架结构抗震性能影响研究

发布时间：2018-07-03 14:39

本文选题：预应力混凝土框架 + 预应力度　；参考：《工程力学》2017年02期

【摘要】：依据我国规范设计4榀不同预应力度、抗震等级为二级的预应力混凝土框架结构,基于Open Sees分析软件,采用纤维梁、柱单元对其进行数值建模,对一榀单层单跨预应力混凝土框架的低周反复加载试验进行数值模拟,滞回曲线和骨架曲线与试验结果吻合良好,验证了该数值建模方法的实用性;在此基础上,对4榀预应力混凝土框架进行了静力弹塑性分析;最后,对按我国规范设计的抗震等级为二级的PC框架结构,在裂缝控制等级为二级时,预应力梁中非预应力筋用量的确定方法及其适用性进行了理论分析。结果表明:按我国现规范设计的预应力混凝土梁中非预应力筋用量偏多,在大震下预应力混凝土框架结构难以实现"强柱弱梁"的破坏模式,底层柱底塑性铰出现过早;适当提高梁端截面的预应力度值,能够在一定程度上改善结构的屈服机制,增大结构的整体位移延性,提高结构的抗震能力。因此,建议在进行相关规范修订时,适当减少非预应力筋配筋、提高框架梁的预应力度限值,如按04规程设计的二级预应力混凝土框架结构,其预应力度限值可提高至0.8。
[Abstract]:According to the code of our country, four prestressed concrete frame structures with different degree of prestress and grade of earthquake resistance are designed. Based on OpenSees analysis software, fiber beam and column element are used to model them numerically. The numerical simulation of a single-story single-span prestressed concrete frame subjected to low-cycle repeated loading shows that the hysteretic curve and skeleton curve agree well with the experimental results, which verify the practicability of the numerical modeling method. The static elastic-plastic analysis of four prestressed concrete frames is carried out. Finally, when the crack control grade is grade two, the PC frame structure with the grade of aseismic design according to the code of our country is designed. The method of determining the amount of non-prestressed tendons and its applicability are analyzed theoretically. The results show that the amount of non-prestressed tendons of prestressed concrete beams designed according to the present code of our country is on the high side, the failure mode of "strong column and weak beam" is difficult to be realized in prestressed concrete frame structure under strong earthquake, and the plastic hinge at bottom of bottom column appears prematurely. To a certain extent, the yield mechanism of the structure can be improved, the whole displacement ductility of the structure can be increased and the aseismic capacity of the structure can be improved by increasing the prestress degree of the beam end section. Therefore, it is suggested to reduce the reinforcement of non-prestressed tendons and increase the limit value of prestressing force of frame beam, if the pre-stressed concrete frame structure is designed according to 04 code, the pre-stressed degree limit value can be increased to 0.8.
【作者单位】：华中科技大学土木工程与力学学院;
【基金】：国家自然科学基金项目(51278218)
【分类号】：TU378.4;TU352.11

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