不同纤维增强复合材料加固钢梁疲劳性能试验研究

Experimental study of the fatigue performance of steel beams strengthened with different fiber reinforced polymers

对外贴高弹模碳纤维增强复合材料(高弹模CFRP)板、高强度CFRP板、钢丝-玄武岩纤维复合板(SBFCP)和焊接钢板等加固人工受损钢梁疲劳性能进行试验研究,分析不同材料加固对钢梁疲劳性能的影响,讨论钢梁疲劳加固效果的影响因素。试验结果表明:等拉伸刚度加固条件下,纤维增强复合材料加固钢梁的疲劳寿命总体上是未加固钢梁的3.33～5.26倍,而焊接钢板加固钢梁的疲劳寿命是未加固钢梁的1.74倍;与传统焊接钢板加固相比,纤维增强复合材料可以推迟钢梁裂纹的萌生,降低裂纹的扩展速率和钢梁的残余挠度,增加构件的疲劳寿命,改善构件的破坏模式,其中高弹模CFRP板加固效果最理想,而SBFCP加固性价比最高;加固材料和界面对疲劳性能有明显的影响。

An experimental study was conducted to investigate the fatigue performance of artificially damaged steel beams strengthened with different externally bonded fiber reinforced polymers, such as high modulus carbon fiber reinforced polymer （high modulus CFRP） plate, high strength CFRP plate, steel wire-basalt fiber composite plate （SBFCP） and welded steel plate. The strengthening effects of different materials on the fatigue performance of steel beams were analyzed , and the influencing factors of the fatigue performance of steel beams were discussed. Experimental results showed that the fatigue life of steel beams strengthened with fiber reinforced polymer was 3.33 - 5.26 times that of the un-strengthened beams, while the fatigue life of steel beams strengthened with welded steel plate only 1.74 times that of the un-strengthened beams. With the equivalent tensile stiffness of strengthening materials, comparing with welded steel plates, the application of fiber reinforced polymer can substantially postpone crack initiation, reduce crack growth rate and residual deflection of steel beams, prolong fatigue life and improve failure modes. Among the tested strengthening materials, high modulus CFRP plate had the best strengthening effects, and SBFCP was proved to be a strengthening material with the best performance-price ratio. Strengthening material and the interface have considerable influences on fatigue performance.