大直径高强钢绞线预应力混凝土梁受力性能

Mechanical Performances of Prestressed Concrete Beams with Large-diameter High-strength Steel Strands

为探讨大直径高强钢绞线预应力混凝土梁的受力性能,进行了6根以直径17.8mm的1860级钢绞线作为预应力钢筋和HRB400级钢筋作为非预应力钢筋的后张预应力混凝土梁在竖向荷载作用下的受力性能试验。对预应力混凝土梁中钢绞线和非预应力钢筋应力、混凝土应变以及短期最大裂缝宽度和跨中挠度等试验数据进行分析。结果表明:采用大直径高强钢绞线作为预应力钢筋的预应力混凝土梁工作性能良好,大直径高强钢绞线预应力混凝土梁受弯破坏形式和挠曲模式与普通预应力混凝土梁基本相同;试验梁跨中控制截面符合平截面假定,极限承载力可按照现行规范的正截面抗弯理论计算,按照现行规范计算的试验梁裂缝宽度和挠度与实测值吻合较好。

In order to explore the mechanical performance of prestressed concrete beam with largediameter high-strength steel strand,the stress performance tests of six post-tensioning prestressed concrete beams under vertical loads were conducted.The prestressed concrete beams were made of 1860 grade steel strand with 17.8 mm diameter as prestressed reinforcement and HRB400 grade steel bars as non-prestressed tendons.The test data about pre-stressed concrete beam,such as the stress of steel strand and non-pre-stressed reinforcement,concrete strain,maximum crack width in short term,mid-span deflection and so forth were analyzed.The results show that the work performance of prestressed concrete beam with large-diameter high-strength steel strands as prestressed reinforcement is well.The flexural failure form and flexural mode of prestressed concrete beam with large-diameter high-strength steel strand is almost same with ordinary pre-stressed concrete beam.The mid-span control section of test beam meets the plane cross-section assumption,and the ultimate bearing capacity can be calculated according to the specification of normal section bending theory.The calculated crack width and deflection of test beam according to current specification agree well with the measured value.