外文翻譯---預(yù)應(yīng)力碳纖維布加固鋼筋混凝土梁抗彎性能研究-文庫吧在線文庫
【正文】 he CFRP sheets, the sectional area of the steel bar and CFRP sheets should be converted into the concrete sectional area which is located at the gravity center of the steel bar and the CFRP sheets separately. 5 Calculation of Icr The moment of inertia I cr of the converted section of cracking section for central axis is: . Calculation of 0I 0I i s calculated by the section posed of the cross section area of the concrete and the converted area of plain reinforced bars, prestressed steel strands and prestressed CFRP sheets. In which, X—the depth of pression x can be calculated by the static balancing of the tensile area, the pression area and the neutral axis. b—the width of the web of the ISection hthe depth of the web of the ISection 33 221)2 2 21)( 0 ) ( ( )( ) ( ( ) ( )1139。 13 2 3 2 3bh bh ) 39。fb—the effective width of the pressed flange of the ISection ——the effective depth of the pressed flange of the ISection b f ——the effective width of the tensile flange of the ISection h f——the effective depth of the tensile flange of the ISection s??——the ratio of the elastic modulus of the steel bar to that of the concrete p——the ratio of the elastic modulus of the prestressed steel strands to that of the concrete cf? the ratio of the elastic modulus of the CFRP sheets to that of the concrete According to equations （ 6 ） and （ 7 ） , the reinforcement of CFRP sheets changes the rigidity of the section in a very limited way. Though CFRP sheets are of high strength, they are quite thin and of small area and a small section moment inertia. Therefore they generally have a small impact on the rigidity. This is why the strengthening of CFRP sheets does little in changing the rigidity of the structure in long span bridges. 4. Conclusions The analysis above shows that: The influences of prestressed CFRP sheets on deflection mainly lie in altering the rigidity of the section and causing displacement in the members. For long span bridges, altering the thickness of CFRP sheets can not dramatically ameliorate the deflection of midspan in bridges. This can be proved by the way of FEM: though CFRP sheets are of high strength, they are quite thin and of small area and a small section moment of inertia. Therefore they generally have a small impact on the rigidity. 7 References [1] Chinese National Standards, “Concrete Structure Design SpecificationGB503672020,” Beijing： China Architecture amp。 本文以當(dāng)前廣泛使用的箱形梁橋?yàn)槟Ｐ?，推?dǎo)了使用碳纖維加固后橋梁撓度的計(jì)算方法和并且對結(jié)構(gòu)加固后的力學(xué)性能做了理論上的分析 。 0I—用碳纖維布加固混凝土后橫截面的二次轉(zhuǎn)換彎矩； cr—用碳纖維布加固混凝土后開裂截面的二次轉(zhuǎn)
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