粘贴不同FRP布加固预制空心板的试验研究和计算分析

Experimental study and computational analysis on PC hollow-core slabs strengthened with different FRP strips

预应力混凝土空心板老化损伤或使用荷载增加均可能导致其受弯承载力不能满足要求，影响结构的正常安全使用。本文共进行了10块粘贴不同FRP布加固预制空心板的对比试验研究，其中3块为对比试件（CS1～CS3），2块为粘贴不同宽度GFRP布加固试件（S1、S11），3块为粘贴不同宽度和厚度CFRP布加固试件（S2、S3、S10），2块为粘贴不同层数BFRP布加固试件（S12、S13）。研究结果表明，粘贴不同类型FRP布加固预制空心板的极限荷载明显提高21％～119％，平均提高67％；极限位移显著增加60％～135％，平均提高100％。加固试件跨中截面应变随荷载增加仍基本符合平截面假定。随着FRP布宽度和厚度增加，相同荷载作用下加固试件受拉边缘中心FRP布的拉应变有所降低。粘贴FRP布加固预制空心板的理论计算和有限元分析结果均与试验值吻合较好，满足工程精度要求。根据所提出的设计公式，可进行粘贴FRP布加固预制空心板的设计，且易于施工。

Accumulative damage or increase of loadings will influence the moment-resistant abilities of or even the serviceability of PC hollow-core slabs. In order to study the influence of damage on PC slabs, ten PC hollow-core slabs were tested, including three unstrengthened reference slabs （ CS1 - CS3 ）, two slabs strengthened with GFRP strips （ S1, S11 ）, three slabs strengthened with CFRP strips （S2, S3, S10）, and two slabs strengthened with BFRP strips （S12, S13）. The test results showed that the ultimate strength of the PC hollow-core slabs strengthened with different FRP strips increased between 21% and 119% with an average of 67% , while the ultimate mid-span displacement increased between 60% and 135% with an average of 100%. The strain distributions along the height of the strengthened slabs at middle-span correspond with the plane-section hypothesis. The tensile strain of the center of the FRP strip decreased with the thick and the width of the FRP strips increased. The results of theoretical calculation and finite element （FE） analysis results agree well with the test results. The research results can provide reference for design of PC hollow-core slabs strengthened with FRP.