表层嵌入预应力碳纤维筋混凝土梁抗弯试验研究

EXPERIMENTAL RESEARCH ON FLEXURAL BEHAVIOR OF REINFORCED CONCRETE BEAMS STRENGTHENED WITH NEAR SURFACE MOUNTED PRESTRESSED CFRP TENDONS

为了充分发挥碳纤维增强塑料(CFRP)筋的高强性能,更有效提高加固梁的力学性能,通过在混凝土梁受弯区表层开20 mm×20 mm的槽后,对直径为7 mm的CFRP筋施加不同水平的预应力并嵌入开好的槽中,并用专用结构胶填充槽道,待结构胶固化后进行加固梁的抗弯试验。通过对9根表层嵌入预应力CFRP筋加固梁和1根未加固梁的抗弯加载试验,初步研究了加固梁的刚度、特征荷载、延性及梁的裂缝发展与破坏模式。研究表明,预应力CFRP筋的高强性能得到充分发挥,加固梁的刚度显著提高,开裂荷载最大提高了303.17%,极限承载能力最大提高237.92%,延性基本能满足抗震要求,破坏模式表现为3种形式。

In order to make full use of the high-strength performance of CFRP tendons, the different prestress was applied to 7 mm diameter CFRP tendons put on to 20 mm x 20 mm grooves opened on the concrete surface of the tensile region of concrete beams. Flexural behavior of nine RC beams strengthened with prestressed near surface mounted CFRP tendons applied different levels of prestress and that of one unstrengthened RC beam were studied. In these tests, stiffness, characteristic load, crack development and ductility of test specimens were carried out. Experimental results show that the high-strength performance of CFRP is fully used, the stiffness of strengthened beams is risen notably, the maximal crack load is increased by 303.17% , the maximal ultimate load is increased by 237.92% , the ductility of beams can approximately meet the requirements of anti-earthquake design, and failure has three expressional forms.