横向约束部分预应力混凝土高耸结构延性系数研究

Study on ductility factor of high-rise tower structure of partial prestressed concrete with confined ring section

高耸结构一般采用环形截面形式,随着高度的增加,为满足正常使用要求,普遍采用较高的预应力度,由此导致延性降低,为此加强混凝土的横向约束,以提高构件的延性。根据周边均匀配筋的环形截面的受力特点和平截面假定,应用复合箍筋约束混凝土和核心钢管混凝土的应力应变关系,进行了部分预应力压弯构件延性系数计算。计算表明,普通预应力混凝土构件加入复合约束箍筋后,延性系数大幅提高,承载力提高幅度不大;加入核心钢管后,延性系数和承载力均显著提高。因此建议超高耸结构混凝土塔筒优先采用核心钢管来提高延性和承载力。

For partial prestressed concrete high-rise tower structure with ring section, in order to meet regular service, the higher prestress degree usually is applied. Therefore, it is necessary to correctly count ductility factor, strengthening transverse confinement of concrete is applied. According to the character of uniform reinforcement with ring section and assumption of strains of section keeping in plane, moreover stress-strain relationship of concrete confined by overlapping hoops and steel tubes, the formula of ductility factor for partial prestressed concrete pressure-bent member with ring section are put forwarded, which can be used as a reference for design and the related calculations. It is seen from the examples that the ductility factor increases when overlapping hoops are applied, in addition, both ductility factor and bearing capacity increase remarkably when central steel tubes are applied. For super high-rise tower structures, central steel tubes are suggested.