（同济大学预应力研究所  上海 200092； 先进土木工程材料教育部重点实验室（同济大学）  上海 200092）
【提要】  阐述了预应力次轴力的本质，分析了影响次轴力的因素。公式推导与算例分析说明，将约束引起的预应力次轴力考虑为预应力损失进行设计时，会使有粘结预应力结构的设计偏于不安全，而在无粘结预应力结构设计中则偏于保守。因此，设计预应力框架结构时，应将侧向约束考虑为作用在截面重心的次轴力，而不是预应力损失。
【关键词】  预应力结构  次轴力  承载能力极限状态  使用极限状态
Study on Lateral Restraint in Prestressed Structure/Xiong Xueyu， Zhang Caihong，Wu Xueshu(Prestressed Institute，Tongji University, Shanghai  200092,China; Key Laboratory of Advanced Civil Engineering Materials，Tongji University, Shanghai  200092, China）
Abstract:The essence of secondary axial force and influential factor is presented. Throug
h equation deduction and numerical example, it is proved that if secondary axial force is considered as prestress loss, the design may be unsafe for bonded PC structure while be conservative for unbonded PC structure. Thus the secondary axial force should be considered as force axially acting on sectional centroid instead of prestress loss in the design procedure.
Keywords:prestressed structure;   secondary axial force;   ultimate capacity state; ultim
ate service state