CFRP用于火灾后钢筋混凝土梁抗弯加固的试验研究及有限元分析

Experimental Investigation and FEM Analysis on the Flexural Strengthening for RC Beams Strengthened with CFRP after Fire Damage

笔者结合对结构火灾损伤的分析 ,采用有限元分析软件ANSYS对火灾后CFRP加固钢筋混凝土梁荷载与应变、挠度的关系进行了数值分析 ,并与试验结果进行了比较 ,吻合良好。加固后的混凝土梁在钢筋屈服后 ,仍然有一定的荷载容量。这种荷载承受能力可一直持续到结构破坏 ,这主要是碳纤维布在后期发挥的作用 ,用碳纤维布加固受火后的混凝土梁 ,能明显地提高梁的极限承载力 ,在钢筋屈服后对梁的刚度有较大幅度的提高。在挠度的计算中 ,在钢筋屈服后 ,有限元模型由于混凝土的裂缝快速发展 ,刚度下降很大 ,所以挠度在相同荷载下 ,稍大于试验值。这与笔者提出的扰度简化计算公式的计算结果与试验数据十分吻合。用ANSYS对CFRP加固梁进行分析能够达到比较精确的理论分析结果。

According to the analysis of the structural damage from fire, using a finite element software ANSYS (Analysis System), the relationship of load-displacement and the relationship of load-stress of RC beams strengthened with CFRP (Carbon Fiber Reinforced Plastics) after fire damage were discussed. The results of numerical calculation coped well with the experimental results. RC beams strengthened with CFRP still had a lot of loading capacity and could increase the ultimate strength and the stiffness of the beams after the steel has yielded. The decrease of stiffness due to the fast development of cracks after the steel has yielded caused that the displacement value of numerical calculation was a little larger than the experimental results. The results of simplified design formula showed great coincidence with the experimental results. Relatively accurate theoretical results of RC beams strengthened with CFRP through ANSYS could be obtained.