(2)?s?1?1?2?s2?1?1?2?0.208?0.882
2M25?106(3)As???384mm2
?sfyh00.882?360?205??minbh=0.2%?240?240?115mm2(不少筋)
5、抗剪承载力计算
?t?1.51.5??1.143?1 VWt40?103?4.608?1061?0.51?0.5?Tbh06?106?240?205故取?t?1
由V?(1.5??t)0.7ftbh0?1.25fyvAsvh0得 sAsvV?(1.5??t)0.7ftbh040?103?(1.5?1)?0.7?1.27?240?205???0.236 s1.25fyvh01.25?300?2056、抗扭承载力的计算
bcor?240?25?2?190mm,hcor?240?25?2?190mm
(1)抗扭箍筋的计算 假定??1.1
由T?0.35?tftWt+1.2?AcorAst1fyvs得
Ast1T?0.35?tftWt6?106?0.35?1?1.27?4.608?106???0.290 s1.2?fyvAcor1.21.1?300?190?190(2)抗扭纵筋的计算
??
fyAstl?cor/fyvAst1s?fyAstlsfyvAst1?cor得
91
Astl??fyvucorAst1fy?s?1.1?300?190?4?190?0.290?202mm2
360验算抗扭纵筋配筋率
?tl?0.6Astl202Tft??0.35%??tl,min?0.6?bh240?240Vbfy6?101.27??0.17@?103?2403606
满足要求 7、配筋(选筋) (1)纵筋
将布置于梁下部的受弯纵筋与受扭纵筋合并考虑。 ①梁截面上部的纵筋面积为:
Astl?101mm2 2 选用2 8(As?101(注:选用2 10钢筋较为合理) mm2)
②梁截面下部纵筋面积为:
Astl?As?101?384?485mm2 2 选用2 18(As?509mm2)
(2)箍筋
A*sv1AsvAst10.236????0.290?0.408 s2ss2①箍筋直径及间距的确定
2选用?8箍筋(Asv1?50.3mm),双肢箍,n?2
A*sv150.3??123mm 图5-2 题5-2配筋图 则s?0.4080.408取s?120mm 92 即所配箍筋为?8@120 ②验算抗扭箍的配筋率 f2A*sv12?50.31.27?sv???0.35%??sv,min?0.28t?0.28?0.12% bs240?120满足要求 配筋图如图5-2所示。 fyv30093