直接基于位移的预应力混凝土框架结构抗震设计方法

DIRECT DISPLACEMENT-BASED SEISMIC DESIGN FOR PRESTRESSED CONCRETE FRAME STRUCTURES

  • 摘要: 通过对传统直接基于位移的抗震设计方法中等效单自由度体系的等效刚度计算方法的改进,减少了影响等效刚度计算结果准确性的不确定因素,并将其应用于直接基于位移的预应力混凝土框架结构的抗震设计,提高了设计方法的有效性。该文根据是否考虑裂缝控制和强柱弱梁要求,采用上述设计方法设计了四种不同配筋的预应力混凝土框架,其静力弹塑性分析结果表明性能点结构位移均满足性态目标的要求,设计方法是有效的。同时,预应力框架结构的裂缝控制、预应力度、柱的配筋方式、强柱弱梁及其他抗震构造要求等将造成在设计需求地震作用下框架结构的承载力严重超强,并导致性能点的位移不同程度小于目标位移。

     

    Abstract: Through an improvement on calculation of the equivalent stiffness for an equivalent single- degree-of-freedom system in the traditional direct displacement-based seismic design (DDBD) method, the uncertainties which impact the accuracy of the equivalent stiffness are reduced. Also the validity of DDBD method is advanced, when it is applied in the seismic design of prestressed concrete frame (PCF) structures. According to the crack control and strong column weak beam requirements, four different PCF structures were designed using the above method. The pushover analysis results show that the structural displacements on performance points are satisfied and the design method is effective, but the crack control, the degree of prestressing, reinforcements of columns, strong column weak beam and other details of seismic design requirements could cause the bearing capacity of frame structures to be excessively high under design earthquakes. At the same time, it could cause the displacement corresponding to the performance points less than the target displacement too.

     

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