混凝土梁加固后的新旧混凝土界面力学性能变化

Experimental Study on Interface Mechanical Properties of Reinforced Concrete (RC) Beams Reinforced by Concrete Layers

以破旧建筑物纤维增强复合材料加固法为例,基于界面粘附强度的理论分析,配合剥离试验来求出加固界面破坏时的界面破坏能G。通过采用有限元方法计算出不同剥离角度的GⅠ、GⅡ的比值,然后进一步利用研制的双L型梁试验,来测量加固界面剥离的临界剥离力,从而验证剥离试验的结果。研究结果显示,剥离试验中造成混凝土与纤维增强复合材料贴片界面破坏的剥离力P,随着剥离角度α的增加而越来越小。但是由理论公式所推算出来的界面破坏能G,其变化并无固定的趋势,因此G值与P和α并非为简单的线性关系。另外双L型梁试验所得到的临界剥离力,会随着施力的位置改变而变化,同时临界剥离力P也随着施力点与支承距离的增加而减少,这与有限元程序计算的结果大致类似,本文研究对衡量老旧建筑物的加固设计效果提供了重要的参考。

Based on the theoretical analysis of the interfacial adhesion strength,the disintegration energy of the interface was obtained by combining the peeling test with the fiber reinforced composite reinforcement method of the old building as an example. The ratio of GⅠand GⅡwith different peel angles was calculated by finite element method. The critical peel force of the interface was measured by using the developed double L-beam test to verify the results of the peeling test. The results show that the peeling force P caused by the interfacial damage between the concrete and the fiber reinforced composite patch in the peeling test is getting smaller and smaller as the peeling angle α increases. However,the interface failure can be deduced from the theoretical formula,and there is no fixed trend. Therefore,the G value is not a simple linear relationship with P and α. In addition,the critical stripping force obtained by the double L-beam test will change with the change of the position of the force,and the critical stripping force P decreases with the increase of the force point and the bearing distance. This is the result of the finite element program which is similar to this,which provides an important reference for measuring the effect of reinforcement design of old buildings.