预应力混凝土框架结构“强柱弱梁”设计方法研究

发布时间：2018-06-30 03:25

本文选题：预应力混凝土框架 + 强柱弱梁　；参考：《华中科技大学》2016年硕士论文

【摘要】：预应力混凝土框架结构被广泛地应用于要求大空间、大跨度的建筑结构中,对其抗震性能评价仍存在不少争议,在罕遇地震时难以实现“强柱弱梁”的屈服机制。因此,本文对我国现行《预应力混凝土结构抗震设计规程》(JGJ140-2004)和《建筑抗震设计规范》(GB50011-2010)中“强柱弱梁”设计方法进行研究,给出各抗震等级预应力框架柱端弯矩调整方法及调整系数的建议取值,评估该系数对预应力框架抗震性能的影响,以期为04预应力规程的修订提供参考依据。首先,阐述预应力混凝土框架抗震性能和“强柱弱梁”机制研究现状,对影响预应力混凝土框架结构“强柱弱梁”屈服机制的因素进行分析,发现梁端实际抗震受弯承载力超强是预应力框架难以实现“强柱弱梁”的主要原因。基于此,提出以梁端实际抗震受弯承载力调整柱端弯矩的设计方法。其次,参照现行规范设计7度0.1g区三层、六层PC框架和8度0.2g区三层、六层PC框架,在OpenSees平台上建立各框架非线性模型,并验证模型的准确性。建模时保证除底层柱底外,其它柱截面纵筋不屈服,通过模型在罕遇地震下各柱截面内力确定所需纵筋面积,进而确定所需的设计弯矩,求出各层节点处柱截面设计弯矩与梁端实际抗震受弯承载力比值。为考虑地震动的不确定性,各框架分别选取35条地震动记录进行分析,对每条地震波结果进行统计分析,给出各抗震等级预应力框架柱端弯矩调整系数的建议取值。对抗震等级为三级PC框架,建议边节点和中节点处分别取1.05、1.0;对抗震等级为二级PC框架,建议边节点和中节点处分别取1.25、1.15;对抗震等级为一级PC框架,建议边节点和中节点分别处取1.3、1.2。最后,对抗震等级分别为三级和二级的PC框架分别按建议取值和规范规定系数设计框架,通过静力弹塑性分析、增量动力分析和易损性分析评估各框架抗震性能。结果表明,本文建议取值系数有助于提高PC框架抗震性能,实现“强柱弱梁”屈服机制。
[Abstract]:Prestressed concrete frame structures are widely used in buildings with large space and long span. There are still many controversies on the seismic performance evaluation of prestressed concrete frame structures. It is difficult to realize the yield mechanism of "strong columns and weak beams" in rare earthquakes. Therefore, this paper studies the design methods of "strong columns and weak beams" in the current Code for Seismic Design of Prestressed concrete structures (JGJ140-2004) and the Code for Seismic Design of buildings (GB50011-2010). In this paper, the methods of adjusting the bending moment at the end of the column and the suggested values of the adjustment coefficient are given, and the influence of the coefficient on the seismic behavior of the prestressed frame is evaluated, in order to provide a reference for the revision of the 04 prestress code. First of all, the aseismic behavior of prestressed concrete frame and the research status of "strong column and weak beam" mechanism are described, and the factors influencing the yield mechanism of "strong column and weak beam" of prestressed concrete frame structure are analyzed. It is found that the actual seismic and flexural bearing capacity at the end of the beam is very strong, which is the main reason why it is difficult for the prestressed frame to realize the "strong column and weak beam". Based on this, the design method of adjusting the bending moment of column end with the actual seismic flexural capacity of beam end is put forward. Secondly, according to the current specification, we design the three-layer frame of 7 degrees 0.1g, the frame of 6-layer PC, the three-layer frame of 8-degree 0.2g zone, and the six-layer PC frame. The nonlinear model of each frame is built on OpenSees platform and the veracity of the model is verified. When modeling, it is guaranteed that the longitudinal reinforcement of other column sections will not yield except the bottom column bottom, and the required longitudinal reinforcement area is determined by the internal force of each column section in the model under rare earthquake, and then the required design moment is determined. The ratio of the design moment of column section to the actual seismic flexural bearing capacity of beam end is obtained. In order to consider the uncertainty of ground motion, 35 seismic records are selected for each frame, and the results of each seismic wave are statistically analyzed, and the suggested values of the moment adjustment coefficient at the end of the column of each seismic grade prestressed frame are given. For the third grade PC frame, it is suggested that the edge node and the middle node should be 1.05U 1.0 respectively; for the second grade PC frame, 1.25 and 1.15 are recommended for the side node and the middle node; for the seismic grade, the first grade PC frame should be used. It is suggested that the side node and the middle node should be taken at 1.3 / 1.2 respectively. Finally, the design frame of PC frame with three and two seismic grades is designed according to the recommended values and the specified coefficients of the code, respectively. The seismic performance of each frame is evaluated by static elastic-plastic analysis, incremental dynamic analysis and vulnerability analysis. The results show that the proposed coefficient is helpful to improve the seismic performance of PC frame and realize the yield mechanism of "strong column and weak beam".
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU378.4

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