bf?('l03,b?sn,b?12hf)minl0330003' ;
其中:
??1000mm b?sn?300?8400?300?8400mm;
h'f/h0?120/(600?35)?0.21?0.1,不需考虑b?12h'f; 所以,b'f?1000mm
截面简图如下:h0?h?as?400?35?365mm
图4.6 八层中跨梁跨中截面
??1fcbfhf(h0?hf/2)?1.0?14.3?1000?120?(365?120/2)?523.38kN?m?18.3kN?m'''属于第Ⅰ类T形截面。
?s?M'f20?1fcbh?18.3?10621.0?14.3?1000?365?0.0096
??1?1?2?s?1?1?2?0.0096?0.0096??b?0.518 (满足)
As???1fcbfh0fy'?0.0096?1.0?14.3?1000?365360?140mm
2跨中截面实配正钢筋:220 As?628mm2
支座截面实配正钢筋:220 沿梁底通长延伸 (满足)
?min?(0.25,55ft/fy)max?0.25%
??Asbh0Asbh0?628300?365628300?365?0.57%??min
(满足)
????0.57%?2.5%??max
② 支座处负筋配置
设计内力:M??34.32kN?m
h0?h?as?400?35?365mm
已知支座负弯矩作用下,受压钢筋为220(As?628mm2)
?s?M?fyAs(h0?a)'''?1fcbh20?34.32?10?360?628?(365?35)1.0?14.3?300?3652?0h0'62??0.07
??1?1?2?s??0.068?0.19? (As'无法屈服)
所以,近似令x?2a'配筋:
As?Mfy(h0?a)'s?34.32?106360?(365?35)?288.8mm
2实配:220 As?628mm2
其中,以上两根钢筋通长,于跨中处充当负筋(架立筋)
?min?(0.3,65ft/fy)max?0.3%
??Asbh0?628300?365?100%?0.57%?0.3%??min
??max ?2.5% (满足) AsAs'?628628?1?0.3 (满足)
验算纵筋间距:2d?2as?s?50?70?25?145mm?b?300mm(满足)
③ 箍筋配置 剪力Vmax?43.63kN
根据《高规》6.2.6 验算受剪截面
Vc?0.2?cfcbh0?0.2?1.0?14.3?300?365?313.17kN?43.63kN
截面满足要求!
根据《高规》6.3.2 配置箍筋:加密区——?8@100(梁两端各600mm) 非加密区——?8@150
Vu1?0.42ftbh0?1.25fyvAsvsh0101100?365
?0.42?1.43?300?365?1.25?210??173.13kN?43.63kN (满足)
二级抗震等级: ?sv?0.28t?fyvf1.430.?28?2100. 0017实际?svmin?Asvsb?101300?150?0.0022?0.0017,满足要求。
因此,在全框架范围内:加密区?8@100,非加密区?8@150。