预应力碳纤维布加固钢筋混凝土箱形简支梁的试验研究

Experimental Study on Simple Supported RC Box Beam Strengthened with Prestressed CFRP Sheets

传统外部粘贴碳纤维增强复合材料加固技术无法充分发挥碳纤维材料性能,加固效果有限。对2根采用外部粘贴预应力碳纤维布加固的已开裂箱形梁进行了受弯模型试验,并研究了预应力碳纤维布加固对已开裂箱梁抗弯刚度及延性的影响。研究表明,对于受损较为严重的梁,采用预应力碳纤维布加固,碳纤维布对裂缝的扩张有一定的限制作用,对刚度较完好梁,加固后其刚度有所提高,能起到加固的效果,但其延性性能有所退化。在正常体位加固梁时,应该考虑碳纤维布的粘贴质量,对理论计算的刚度值进行适当折减。

Traditional external bonded CFRP composite strengthening technique cannot make full use of the material property of carbon fiber, and its strengthening effeet is limited. A flexural model experiment on two eracked box beams strengthened with external bonded prestressed CFRP sheets was condueted and the influence of the strengthening on the flexural rigidness and the ductility of the cracked box beams was investigated. The result shows that （1） strengthening with prestressed CFRP sheets can prevent the propagation of the cracks in the seriously damaged beam; （2） the strengthening can increase the flexural rigidness and slightly decrease the duetility capability of the slightly damaged beam ; （3） when strengthening beam in normal position, the value of theoretieal caleulated flexural rigidness of the strengthened beam should be considered by a reduction according to the bonding quality between CFRP sheets and the conerete.