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1、J-2阶梯基础计算项目名称日期设计者校对者一、设计依据建筑地基基础设计规范(GB50007-2011)混凝土结构设计规范(GB50010-2010)二、示意图三、计算信息构件编号:J-2计算类型:验算截面尺寸1 .几何参数台阶数n=lhc=100Omrnal=850mma2=850mmfcb=14.3Nmfcc=14.3Nm矩形柱宽bc=750mm矩形柱高基础高度hl=500mm一阶长度bl=875m11b2=875mm一阶宽度2 .材料信息基础混凝土等级:C30ft_b=l.43Nm柱混凝土等级:C30ft_c=1.43N/m钢筋级别:HRB400fy=360Nm3 .计算信息结构重要性系数
2、:o=l.00基础埋深:dh=4.400m纵筋合力点至近边距离:as=40mm基础及其上覆土的平均容重:Y=20.OOOkN/最小配筋率:Pmin=0.150%4 .作用在基础顶部荷载基本组合值F=800.OOOkNMx=418.290kN*mMy=O.000kN*mVx=105.OOOkNVy=O.OOOkNks=l.25Fk=Fks=800.000/1.25=640.OOOkNMxk=Mxks=418.290/1.25=334.632kN*mMyk=Myks=O.000/1.25=0.000kN*mVxk=Vxks=105.000/1.25=84.OOOkNVyk=Vyks=O.000/1
3、.25=0.OOOkN5 .修正后的地基承载力特征值fa=300.200kPa四、计算参数1 .基础总长Bx=bl+b2+bc=0.875+0.875+0.750=2.500m2 .基础总宽By=al+a2+hc=0.850+0.850+1.000=2.700mAl=al+hc2=0.850+1.000/2=1.350mA2=a2+hc2=0.850+1.000/2=1.350mBl=bl+bc2=0.875+0.750/2=1.250mB2=b2+bc2=0.875+0.750/2=1.250m3 .基础总高H=hl=O.500=0.500m4 .底板配筋计算高度ho=hl-as=0.500
4、-0.040=0.460m5 .基础底面积A=Bx*By=2.500*2.700=6.7506 .Gk=*Bx*By*dh=20.000*2.500*2.700*4.400=594.OOOkNG=l.35*Gk=l.35*594.000=801.900kN五、计算作用在基础底部弯矩值Mdxk=Mxk-Vyk*H=334.632-0.000*0.500=334.632kN*mMdyk=Myk+Vxk*H=O.000+84.000*0.500=42.000kN*mMdx=M-Vy*H=418.290-0.000*0.500=418.290kN*mMdy=My+Vx*H=O.000+105.000*
5、0.500=52.500kN*m六、验算地基承载力1 .验算轴心荷载作用下地基承载力pk=(Fk+Gk)A=(640.000+594.000)/6.750=182.815kPa【5.2.1-2因Yo*pk=l.00*182.815=182.815kPafa=300.200kPa轴心荷载作用下地基承载力满足要求2 .验算偏心荷载作用下的地基承载力exk=Mdyk(Fk+Gk)=42.000/(640.000+594.000)=0.034m因ICXklBx6=0.417mX方向小偏心,由公式【5.2.2-2】和【5.2.2-3】推导Pkmax_x=(Fk+Gk)/A+6*Mdyk(B*By)=(6
6、40.000+594.000)/6.750+6*42.0001/50*2.700)=197.748kPaPkmin_x=(Fk+Gk)A-6*Mdykl(B*By)=(640.000+594.000)/6.750-6*42.0001/50*2.700)=167.88IkPaCyk=MdXk/(Fk+Gk)=334.632/(640.000+594.000)=0.271m因eykIBy6=0.450my方向小偏心Pkmax_y=(Fk+Gk)/A+6*Mdxk/(B*Bx)=(640.000+594.000)/6.750+6*1334.6321(2.70*2.500)=292.982kPaPkm
7、in_y=(Fk+Gk)A-6*Mdxk/(B*Bx)=(640.000+594.000)/6.750-6*1334.6321/70*2.500)=72.648kPa3 .确定基础底面反力设计值Pkmax=(Pkmax-pk)+(Pkmaxy-pk)+pk=(197.748-182.815)+(292.982-182.815)+182.815=307.915kPao*Pkmax=l.00*307.915=307.915kPal.2*fa=l.2*300.200=360.240kPa偏心荷载作用下地基承载力满足要求七、基础冲切验算1 .计算基础底面反力设计值1.1 计算X方向基础底面反力设计值e
8、x=Mdy(F+G)=52.500/(800.000+801.900)=0.033m因exBx6.0=0.417mX方向小偏心Pmaxx=(F+G)A+6*Mdy|/(B*By)=(800.000+801.900)/6.750+6*52.5001/(2.50*2.700)=255.985kPaPmin_x=(F+G)A-6*Mdy|/(B*By)=(800.000+801.900)/6.750-6*52.5001/(2.50*2.700)=218.652kPa1.2 计算y方向基础底面反力设计值ey=Mdx(F+G)=418.290/(800.000+801.900)=0.261m因eyBy6
9、=0.450y方向小偏心Pmax_y=(F+G)A+6*Mdx/(B*Bx)=(800.000+801.900)/6.750+6*1418.290/(2.70*2.500)=375.027kPaPmin_y=(F+G)/A-6*Mdx/(B*Bx)=(800.000+801.900)/6.750-6*i418.290/70*2.500)=99.6IOkPa1.3 3因Mdx0Mdy0Pmax=Pmaxx+Pmaxy-(F+G)/A=255.985+375.027-(800.000+801.900)/6.750=393.694kPa1.4 计算地基净反力极值Pjmax=Pma-GA=393.69
10、4-801.900/6.750=274.894kPaPjmax_x=Pmax_x-G/A=255.985-801.900/6.750=137.185kPaPjmax_y=Pmax_y-G/A=375.027801.900/6.750=256.227kPa2 .验算柱边冲切YH=hl=O.50011,YB=bc=O.750m,Y1.=hc=l.OOOniYBl=Bl=I.250m,YB2=B2=1.250m,Y1.l=Al=I.350m,Y1.2=A2=1.350mYHo=YH-as=0.460m2.1 1因(YH800)hp=l.02.2 X方向柱对基础的冲切验算X冲切位置斜截面上边长bt=Y
11、B=O.750mX冲切位置斜截面下边长bb=YB+2*YHo=l.670mX冲切不利位置bm=(bt+bb)2=(0.750+1.670)/2=1.210mX冲切面积Alx=max(Y1.l-Y1.2-YHo)*(YB+2*YHo)+(Y1.I-Y1./2-YHO,(Y1.2T1.2THO)*(YB+2*YHo)+(Y1.2-Y1.2-YHo=max(l.350-1.000/2-0.460)*(0.750+2*0.460)+(1.350-1.000/2-0.460,(1.350-1.000/2-0.460)*(0.750+2*0.460)+(1.350-1.000/2-0.460)=max(0
12、.803,0.803)=0.803X冲切截面上的地基净反力设计值Flx=Alx*Pjmax=0.803*274.894=220.850kNo*Flx=l.00*220.850=220.85kNo*Flx0.7*Bhp*ft_b*bm*YHo(6.5.5-1)=0.7*1.000*1.43*1210*460=557.16kNX方向柱对基础的冲切满足规范要求2.3 y方向柱对基础的冲切验算y冲切位置斜截面上边长at=Y1.=l.OOOrny冲切位置斜截面下边长ab=Y1.+2*YHo=l.920my冲切截面上的地基净反力设计值Fly=Aly*Pjmax=0.000*274.894=0.OOOkNo
13、*Fly=l.00*0.000=0.OOkNo*Fly0.7*Bhp*ft_b*am*YHo(6.5.5-1)=0.7*1.000*1.43*1460*460=672.27kNy方向柱对基础的冲切满足规范要求八、基础受剪承载力验算1.计算剪力Az=al+a2+hc=850+850+1000=2700mmBz=bl+b2+bc=875+875+750=2500mmA,=Bz*max(al,a2)=2500.0*max(850.0,850.0)=2.13m2Vs=A,*p=2.1*118.5=251.9kN基础底面短边尺寸大于柱宽加两倍基础有效高度,不需验算受剪承载力!九、柱下基础的局部受压验算因
14、为基础的混凝土强度等级大于等于柱的混凝土强度等级,所以不用验算柱下扩展基础顶面的局部受压承载力。十、基础受弯计算1 .因MdX0,MdyO此基础为双向受弯2 .计算1-1截面弯矩因exBx6=0.417mX方向小偏心a=(B-bc)2=(2.500-0.750)/2=0.875mPj1=(Bxa)*(Pmax_xPmin_x)/Bx)+Pminx-GA=(2.500-0.875)*(255.985-218.652)/2.500)+218.652-801.900/6.750=124.119kPa因eyBy/6=0.450my方向小偏心a=(By-he)/2=700-1.000)/2=0.850m
15、Pj2=(By-a)*(PmaXy-Pinin_y)/By)+Pminy-GA=(2.700-0.850)*(375.027-99.610)/2.700)+99.610-801.900/6.750=169.522kPax=1.023y=1.087MI_l=l/48*Bx*(B-bc*(2*By+hc)*(Pjl+Pjmax_x)=1/48*1.023*(2.500-0.750*(2*2.700+1.000)*(124.119+137.185)=109.15kN*mMII_l=l/48*y*(By-hc*(2*Bx+bc)*(Pj2+Pjmax_y)=1/48*1.087*(2.700-1.000*(2*2.500+0.750)*(169.522+256.227)=160.