钢筋混凝土楼盖设计例题

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,#,2.,楼盖结构平面布置及截面尺寸确定,确定主梁跨度为,6.6m,，次梁跨度为,6.3m,，主梁每跨内布置两根次梁，板的跨度为,2.2m,。,3.,楼盖结构的平面布置图如图,1-2,所示。,7,柱,350350,主梁,次梁,板,6300,6300,6300,6300,6300,22003,19800,31500,22003,22003,图,1,4.,板的计算,(,按考虑塑性内力重分布计算）,板厚度按不验算挠度条件应不小于高跨比条件要求板的厚度,hl/402200/40=55mm,，工业房屋楼面板最小厚度为,80mm,，故取板厚,=80mm,。,次梁截面高度应满足,h=l/18l/12=(6300/186300/12)=350525;,并且，,hl/25=252mm,，故取,h=450mm,，截面宽度,b=h/3h/2=150250mm,，,取,b=200mm,。,主梁：根据经验，多跨连续主梁的截面高度,h=(l/8l/14)=471.43825mm,；,hl/15=6600/15=440mm,，故取,h=700mm,。截面宽度,b=h/3h/2=233.33350mm,，故取,b=300mm,。,3.,板的设计,(,按考虑塑性内力重分布设计,),图,2,由可变荷载效应控制的组合,（对标准大于,4kN/m,2,的工业房屋楼面结构的活荷载分项系数,由永久荷载效应控制的组合,(2),计算简图,取,1m,板宽作为计算单元，板的实际结构如图,3,所示由图可知：次梁截面宽度为,b=200mm,，现浇板在墙上的支承长度,a=120mm,，则可以按塑性内力重分布计算，板的计算跨度为：,边跨按以下两项中较小值确定：,板为多跨连续板，对于跨数超过五跨的等截面连续板，其各跨受荷载相同，,且跨差不超过,10%,时，均可以按五跨等跨度计算。计算简图如下：,图,3,板的计算跨度,2020,2000,2000,2000,2020,图,4:,板的计算简图,(3).,弯矩计算,弯矩设计值因为边跨与中间跨的计算跨差,(20202000)/2000=1%10%,，,可按等跨连续板计算内力。,4,）配筋计算,该楼盖处于室内正常环境一级类别，板保护层厚度取,=15,，板厚,80mm,截面位置,1,B,2(,0.8M,),C(,0.8M,),弯矩设计值,（,kN.m,）,4.56,-4.56,3.08(,2.46,),-3.51(,2.81,),0.106,0.106,0.072(,0.057,),0.082(,0.066,),0.112,0.112,0.075(,0.059,),0.086(,0.068,),296,296,19,7(,156,),(1970.8,=,158,),227,(,180,),(2270.8,=,182,),选配钢筋,6/8120,6/8120,6120,6120,327,327,236,236,选配钢筋,6/8130,6/8130,6130,6130,302,302,218,218,(5),板的配筋图绘制,分布筋选用,6250,。,嵌入墙内的板面附加钢筋选用,8200,。,取,300mm,。,垂直于主梁的板面附加钢筋选用,8200,。,取,550mm,。,板角构造钢筋,:,选用,8200,双向配置板四角的上部。,取,550mm,。,板的配筋图如图,1-5,所示。,5.,次梁计算（按考虑塑性内力重分计算）,（,1,）荷载计算,（,2,）计算简图,设主梁截面尺寸为,:,6300,6300,6300,6150,6000,6000,6000,6150,图,4,边跨（一端与主梁整体连接，另一端搁置在墙上）,计算简图如图,4,所示。,（,3,）内力计算,因为边跨与中间跨的计算跨差,(61506000)/6000=2.5%10%,，,可按等跨连续梁计算内力。,弯矩计算：,室内正常环境一级类别,(,见,2010,混凝土规范,p102,表,8.2.1),，梁保护层厚度取,=25,，,截面,计算公式,计算结果,1,B,2,C,截面位置,1,B,2,C,弯矩设计值,（,kN.m,）,101.36,-98.91,66.33,-75.81,0.025,0.328,0.016,0.206,685.90,845.69,438.98,565.18,选配钢筋,763,911,461,615,3 14,18,2 16,3 18,4 14,（,5,）次梁斜截面承载力计算,截 面,A,B,（左）,B,（右）,C,79.99,106.13,97.28,97.28,箍筋肢数直径,26,26,26,26,73.78,69.34,69.34,73.78,270,270,270,270,选配箍筋（按构造）,6150,6150,6150,6150,250,120,175,175,6305,6250,6600,6600,80,700,620,图,7,主梁计算跨度,边跨（一端与柱整体连接，另一端搁置在墙上）,计算简图如图,8,所示。,A,B,A,B,1,2,1,6600,6490,6490,图,8,：主梁计算简图,荷 载简 图,跨内最大弯矩,支座弯矩,剪 力,0.244,0.067,-0.267,-0.267,0.733,1.267,1.000,1.000,1.267,-0.733,0.289,-,-0.133,-0.133,0.866,1.134,0,0,1.134,-0.866,-,0.200,-0.133,-0.133,-0.133,0.133,1.000,1.000,0.133,0.133,0.229,0.170,-0.311,-0.089,0.689,1.311,1.222,0.778,0.089,0.089,（,3,）内力计算,表,4,等截面等跨连续梁内力系数表,A,B,A,B,1,2,1,（,3,）内力计算,因为边跨与中间跨的计算跨差,(66006490)/6600=1.7%10%,，,可按等跨连续梁计算内力。主梁按弹性理论计算，主梁自重近似化为集中荷载，,在集中荷载作用下（三跨）连续梁的弯矩、剪力系数列于表,4,。,弯矩计算：,项 次,荷载简图,G,471.69 475.69 479.69,P,818.58 825.52 832.46,1,2,3,4,5,组合项次,组合值,+,351.66,+,198.63,组合项次,组合值,+,78.80,+,-383.75,+,-78.58,主梁弯矩计算见表,5,，弯矩包络图如图,9,所示。,表,5,主梁弯矩计算表,注：表中项次,5,中的,B,支座数值为,C,支座弯矩系数和弯矩值。,图,9,主梁弯矩包络图,+,=,78.80,+,=,383.75,+,=,351.66,+,+=198.63,+=78.58,项 次,荷载简图,G,72.68,P,126.13,1,2,4,5,组合项次,组合值,+,162.50,+,-235.12,+,226.81,组合项次,组合值,+,140.17,+,-257.45,+,72.68,表,6,主梁剪力计算表,主梁剪力计算见表,6,剪力包络图如图,10,所示。,剪力包络图如图,10,所示。,+,+,+,+,+-(G+P),+,162.50,140.17,-235.12,-257.45,226.81,72.68,28.00,28.00,图,10,主梁剪力包络图,截面,计算公式,计算结果,1,B,支座,弯矩,B,2,下,2,上,截面位置,1,B,2,C,弯矩设计值,（,kN.m,）,351.66,-348.96,198.63,-78.58,0.0322,0.280,0.0175,0.0515,1523.25,1768.74,842.49,338.09,选配钢筋,1570,1884,911,461,3 14,18,2 16,5 20,6 20,（,5,）主梁斜截面承载力计算,截 面,A,B,（左）,B,（右）,162.50,257.45,226.81,箍筋肢数直径,28,28,28,173.49,169.89,169.89,选配箍筋,（按构造）,8250,8250,8250,箍筋肢数直径,28,每道弯起钢筋,1 20,（,6,）主梁吊筋计算,由次梁传给主梁的全部集中荷载：,每边需附加吊筋面积为（,),选用,2 16,，,7.,画施工图,板的配筋图、次梁的配筋图和主梁的配筋图分别见图,11,、图,12,和图,13,。,