腐蚀钢绞线预应力混凝土梁的受弯性能试验研究

为研究腐蚀钢绞线预应力混凝土梁的受弯性能退化特征,制作了5根先张预应力混凝土梁试件和5根钢管抽芯成孔后张预应力混凝土梁试件,并对每组中的4根梁进行了为期13个月的掺盐加速腐蚀(腐蚀率0.94%~2.87%),然后对10根梁进行了3分点静载试验。试验及分析结果表明:腐蚀钢绞线预应力混凝土梁正截面会发生两种典型的受弯破坏方式,一种是传统的适筋破坏(力筋强化→混凝土压碎),因腐蚀尚未影响到预应力钢筋强化到混凝土压碎的完整过程,因而不会导致梁的极限承载力和变形能力降低;另一种是压碎前腐蚀钢绞线钢丝率先被拉断(断丝破坏),这种破坏会导致梁的极限承载力和变形能力发生不同程度的降低;在腐蚀率不大(小于2.87%)的情况下,腐蚀对钢绞线预应力混凝土梁的开裂弯矩、初始强化弯矩、极限弯矩以及初始强化挠度的影响都不显著,但会导致断丝破坏梁的极限挠度(断丝时)明显减小;在极限荷载之后,梁仍可以维持较高的承载能力继续承载并发展残余变形。

Experimental study on bending property of prestressed concrete beams with corroded steel strands

In order to study the deterioration of bending property of prestressed concrete beams under the condition of steel strands corrosion,5 pre-tensioned prestressed concrete beams and 5 post-tensioned prestressed concrete beams with knockout core pores were fabricated.Of which,4 beams of each group were mixed with salt to be corroded for 13 months(corrosion rates are from 0.94% to 2.87%).Then,all the 10 beams were subjected to loads at the 3 divided points.The experimental results and analysis indicate that,the...