【提要】  对体外预应力混凝土梁的使用性能进行研究，探讨其刚度和裂缝的计算方法。考虑到体外索对构件刚度和控制裂缝的贡献较相同数量的有粘结筋小的特点，参照相关文献，提出体外索等效折减系数为020，从而实现体外预应力与有粘结预应力混凝土梁刚度和裂缝计算公式的统一。试验结果表明，运用该方法计算体外预应力混凝土梁的刚度和裂缝与试验结果吻合良好。
【关键词】  体外预应力  混凝土梁  刚度  挠度  裂缝
Calculation Study on Stiffness and Crack of Externally Prestressed Concrete Beam/Xiong Xueyu1,2，Wang Shousheng3（1 Prestressed Institute，TongjiUniversity,Shanghai 200092,China；2 Key Laboratory of Advanced Civil Engineering Materials,Tongji University,Shanghai 200092,China；3 Shanghai Municipal Engineering Design Institute,Shanghai 200092,China）
Abstract:The working performance of externally prestressed concrete beam is studied, and
the calculation methods of stiffness and crack are summarized and analyzed.  Therecommended value of the equivalent reduced coefficient of external tendon is 020, considering its contributions to stiffness and restraint to crack,which is smaller than that of bonded ones, and the results show good coincidence.
Keywords:external prestressing;  concrete beam;  stiffness;  deflection;   crack
1)同济大学预应力研究所，上海，200092；2)先进土木工程材料教育部重点实验室（同济大
学），上海，200092；3)上海市政工程设计研究总院，200092。
*《建筑结构体外预应力加固技术规程》和上海市《预应力混凝土结构设计规程》（修订）研究项目，上海市建设技术发展基金（B05043）资助项目。