J-2计算书.docx
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：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.000/1.25=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=0.500-0.040=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*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)=(640.000+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)=292.982kPaPkmin_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ex=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=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=393.694-801.900/6.750=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=YB=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(0.803,0.803)=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*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,Mdy>O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=0.850mPj2=(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.
