粘贴CFRP布加固受火后预应力混凝土空心板的试验研究

Experimental research of fire-damaged PC hollow-core slab strengthened with CFRP sheets

为研究火灾后预应力混凝土空心板采用粘贴碳纤维布加固前后的力学性能和破坏形态,进行8块受火后加固的预应力混凝土空心板的静载试验研究,并考虑15,30,45和60 min 4种不同受火时间。研究结果表明:粘贴CFRP布加固受火损伤预制空心板能有效抑制其开裂并显著提高承载力,但破坏模式由加固前的弯曲破坏转变为剪切破坏;受火加固试件初始弯曲刚度小于未受火对比试件的弯曲刚度,但后期弯曲刚度明显大于未受火对比试件的弯曲刚度。

To study the mechanical properties and failure modes of fire-damaged prestressed concrete hollow-core slabs before and after being strengthened by CFRP sheets, 8 strengthening specimens exposed to fire were experimentally studied by static load tests. Among all the specimens, four different fire durations for 15, 30, 45 and 60 min were considered. The experimental results show that fire-damaged slabs strengthened with CFRP sheets inhabit cracking effectively and improve bearing capacity significantly, but their failure mode is changed into shear failure from original bending failure. And compared with control specimens of non-heated, initial bending stiffness of strengthening fire-damaged specimen is lower, but the later bending stiffness becomes much higher.