500MPa钢筋预应力混凝土梁疲劳受力性能试验研究

进行了3根采用HRB500级钢筋作为非预应力筋、钢绞线作为预应力筋的预应力混凝土梁的疲劳受力性能试验。对预应力混凝土梁在疲劳荷载作用下的500MPa级钢筋应力、钢绞线应力、混凝土应变以及疲劳荷载下裂缝和刚度变化的特点进行了较详细分析,并对250万次疲劳作用后的试验梁剩余静载承载力和受力特点进行了分析。试验研究结果表明,采用500MPa级钢筋作为非预应力筋的预应力混凝土梁在疲劳荷载作用下的受力性能良好,500MPa级钢筋的抗拉强度能够充分发挥,试验梁的剩余静载承载力较高,钢绞线和非预应力钢筋都能达到屈服强度,表现出较好的延性。为我国混凝土结构设计规范进一步修订时在预应力结构中采用500MPa级钢筋作为非预应力筋提供了参考依据。

Experimental study on fatigue behavior of prestressed concrete beams using 500MPa steel bars as nonprestressed reinforcement

Based on the fatigue test results of 3 prestressed concrete beams using the HRB500 steel bars as nonprestressed reinforcement,the stress of nonprestressed reinforcement and prestressed strand and the strain of concrete are discussed;the rigidity and cracking of the prestressed beams under cyclic loading are analyzed,and the flexural behavior of the prestressed concrete beams after 2.5 million times cyclic loading are also discussed and analyzed.The results show that the fatigue behavior of the prestressed concrete beams using the 500MPa steel bars as nonprestressed reinforcement under cyclic loading is satisfied.It is also found that the flexural bearing capacity of the beams after 2.5 million times cyclic loading is still higher,and both the 500MPa nonprestressed reinforcements and the prestressed strands can reach their yielding strength at the ultimate state.This may be regarded as a reference for future revision of the Chinese Design Code to use the 500MPa steel bars in prestressed concrete beams.