塔吊天然地基基础.docx
塔吊基础设计计算书1. 计算参数(1) 基本参数采用1台QTZ5613塔式起重机，塔身尺寸1.50m；现场地面标高-5.15m,基础底标高-6.35m,基础埋设深度1.20m。(2) 塔吊基础受力情况何载情况基础荷载P(kN)M(kN.m)FkFhMMz工作状态528.0030.401500.000M基础顶面所受垂直力 基础顶面所受水平力 基础顶面所受倾覆力矩 基础所受扭矩塔吊基础受力示意图比较桩基础塔吊基础的工作状态和非工作状态的受力情况塔吊基础按工作状态计算Fk=528.00kN, Fh=30.40kN, Mk=1500.00+30.40X1.20=1536.48kN.mFk，=528.00X 1.35=712.80kN, Fh，=30.40X1.35=41.04kN, M=(1500.00+30.40X 1.20)X 1.35=2074.25kN.m塔吊基础示意图2. 基础底面尺寸验算(1) 基础尺寸长(a)=5.90m,宽(b)=5.90m,高(h)=1.20m(2) 基础混凝土强度等级 C35, ft=1.57N/mm2, y 砼=25kN/m3(3) 基础底面尺寸验算Gk=abhy 砼=5.90X5.90X1.20X25=1044.30kNPk=(Fk+Gk)/A=(528.00+1044.30)/(5.90X5.90)=45.17kPa基础底面矩 W=0.1179a3=0.1179X5.903=24.21m3M /W=1536.48/24.21=63.46kPa kM"w=63.46kPa>Pk=45.17kPa,则进行偏心距计算(M +F h)/(F +G ) = (1536.48+30.40X1.20)/(30.40+1044.30)=1.46m k vk k偏心距e=1.46mV0.25X5.90=1.48m，基础底面尺寸满足要求。3. 地基承载力验算基础底面标高-6.35m、基础置于土层:全风化软质岩地基承载力特征值fak=250.00kPa、地基土Y =20.00kN/m3(1) 修正后的地基承载力特征值计算fa=fak+n bY (b-3)+n dY m(d- 0.5)=250.00+0.30X20.00X(5.90-3)+2.00X 19.50X(1.20-0.5)=294.70kPa(2) 地基承载力验算1) 当轴心荷载作用时P(Fk+Gk)/A=45.17kPa<f294.70kPa,地基承载力满足要求。2) 当偏心荷载作用时Pkmax=(Fk+Gk)/A+Mk/W=(528.00+1044.30)/34.81+1536.48/24.21=108.63kPaPkmax=108.63kPaV1.2Xf353.64kPa,地基承载力满足要求。Pkmin=(Fk+Gk)/A-Mk/W=45.17-1536.48/24.21=-18.29kPa4. 抗倾覆验算Mk=1536.43kN.m倾覆力矩M倾=Mk=1536.48kNm抗倾覆力矩 M 抗=(Fk+Gk)a/2= (528+1044.30)X5.90/2=4638.29kN.mM 抗/M 倾=4638.29/1536.48=3.02M抗/M倾=3.02> 1.60,抗倾覆满足要求。5. 受冲切承载力验算Pj=Fk'/A+M"/W=712.80/34.81+2074.25/24.21=106.14kPaAl= (1.50+2X 1.20+5.90)X(5.90-1.50)/2-1.20/2=4.90m2h1.20-0.07=1.13m, P h1+(0.9-1)X(1130-800)/(2000-800)=0.97气=1.50m,ab=1.50+2X 1.13=3.76m,am=(1.50+3.76)/2=2.63m0.7P hpftamh0=0.7X0.97X 1.57X2.63X 1130=3168.13kNFL=PjAL=106.14X4.90=520.09kNa =1, P h(800/1130)0.25=0.92,am/L=2.63/5.90=0.45(a -P,/1.4ftP hs)P hs/p h1-106.14/(1.4X1570.00X0.92)X0.92/0.97=0.90FL=520.09kN<0.7P hftamh0=3168.13kN基础抗冲切承载力=3168.13kN>F520.09kN,基础抗冲切满足要求。6. 受剪切承载力验算a/L=0.45<(a -P/1.4f P )P /P =0.90 mjl hs hs hp基础受剪切承载系数二0.90>am/L=0.45,基础受剪切满足要求。7. 基础配筋验算(1) 基础弯矩计算a=(5.90-1.50)/2=2.20m,a =1.50m,L=5.90mPjmax=Fk'/A+Mk'/W=712.80/34.81+2074.25/24.21=106.15kPaPjmin=Fk'/A-Mk'/W=712.80/34.81-2074.25/24.21=-65.20kPaPjI=Pjmax-(Pjmax+Pjmin)/La=106.15-(106.15+65.20)/5.90X2.20=42.26kPaM=1/12a2Pjmax(3L+a )+Pji (L+a )= (1/12 X 2 . 202)X106.15X(3X5.90+1.50)+42.26X(5.90+1.50)=948.16kN.m(2) 基础配筋基础采用HRB335钢筋，f =300N/mm2yAs1=M/(0.95f h0)=948.16X 106/(0.95X300X 1130)=2944mm2按照最小配筋率|3 =0.15%计算配筋As2=p bh0=0.0015X5900X 1130=10001mm2比较As1和七，按As2=10001mm2配筋，取3220188mm(钢筋间距满足要求)；基础配筋 As=32X314=10048mm2>As2=10001mm2,满足要求。8. 计算结果(1) 基础尺寸长(a)=5.90m,宽(b)=5.90m,高(h)=1.20m,基础底标高-6.35m。(2) 混凝土强度等级C35,双向底筋3220。1200
