鋼管、型鋼腳手架計算

鋼管懸挑腳手架計算KF001,,,,,,,,,

一、計算參數(shù),,,,,,,,,

,搭設(shè)高度H,,14.4,m,,,,,

,立桿橫距l(xiāng)b,,1200,mm,外伸長度a,,300,mm,

,立桿縱距l(xiāng)a,,1800,mm,,,,,

,步高h(yuǎn),,1800,mm,,,,,

,步數(shù)n,,8,步,,,,,

腳手架的鋼管選用(φ48×3.5)其計算參數(shù)為：,,,,,,,,,

,截面模量W,5080,mm3,回轉(zhuǎn)半徑i,15.8,mm,,,

,截面積A,489,mm2,截面慣性距I,121900,mm4,,,

,鋼材的彈性模量E,,206000,N/mm2,,,,,

本計算書中的規(guī)范指的是《建筑施工扣件式鋼管腳手架安全技術(shù)規(guī)范》JGJ130—2001,,,,,,,,,

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二、腳手架計算,,,,,,,,,

（一）、大橫桿的計算,,,,,,,,,

把大橫桿簡化為連續(xù)三跨梁來計算簡圖如下,,,,,,,,,

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1、荷載計算,,,,,,,,,

恒荷載計算,,,,,,,,,

,竹排片的規(guī)格為1.2m×1.5m，自重標(biāo)準(zhǔn)值為56N/m2,,,,,,,,

,竹排片自重,,56×lb÷3=,,22.4,N/m,,,

,鋼管自重,,,,38.4,N/m,,,

,,,小計：g=,,60.8,N/m,,,

活荷載計算,,,,,,,,,

,結(jié)構(gòu)腳手架,,施工均布活荷載P=,,2000,N/m2,,,

,q=P×lb÷3=,,,,800,N/m,,,

2、強度驗算,,,,,,,,,

,荷載作用下的彎矩M的計算,,,,,,,,

,M=0.1×（g×1.2+q×1.4）×la2=,,,,386.52,N·m,,,

,大橫桿強度的驗算,,σ=M/W=,76.09,N/mm2,≤,[f]=205N/mm2,,

,滿足要求,,,,,,,,

,其中:,f為Q235鋼抗拉、抗壓和抗彎強度設(shè)計值見規(guī)范表5.1.6,,,,,,,

3、撓度驗算,,,,,,,,,

,w=0.677×（g×1.2+q×1.4）×la4/（100×E×I）=,,,,,3.38,mm,≤,[w]

,其中:,[w]為受彎構(gòu)件允許撓度值查規(guī)范表5.1.8,,,,,,,

,[w]=la/150=,,,12,mm,,,,

,滿足要求,,,,,,,,

,荷載作用下的中間支座反力的計算,,,,,,,,

,R=1.1×（g×1.2+q×1.4）×la=,,,,2362.06,,N,,

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（二）、小橫桿的計算,,,,,,,,,

小橫桿只考慮大橫桿產(chǎn)生的集中力作用，計算簡圖如下：,,,,,,,,,

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1、強度驗算,,,,,,,,,

,計算集中力R作用下的彎距M,,,,,,,,

,集中力R到支座的距離c=lb/3=,,,400,mm,,,,

,M=R×c=,944.8,N·m,,,,,,

,小橫桿的驗算,,σ=M/W=,186.0,N/mm2,≤,[f]=205N/mm2,,

,滿足要求,,,,,,,,

2、撓度驗算,,,,,,,,,

,w=R×c×（3lb2-4c2）/（24×E×I）=,,,,5.77,mm,≤,[w],

,其中:,[w]=lb/150=,,8,mm,,,,

,滿足要求,,,,,,,,

,驗算小橫桿和立桿間扣件的抗滑承載力,,,,,,,,

,根據(jù)實際的受力情況可知R1=0.5×R=,,,,1181.0304,N,,,

,則小橫桿和立桿間的扣件受力是,,,,,,,,

,,R1+R=,3543.09,,N,≤,Rc=8000N,,

,滿足要求,,,,,,,,

,其中:,Rc為扣件抗滑承載力設(shè)計值見規(guī)范表5.1.7,,,,,,,

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（三）立桿計算,,,,,,,,,

1、荷載計算,,,,,,,,,

恒荷載計算,,,,,,,,,

,大橫桿自重,,,38.4×la×4=,,276.48,N,,

,小橫桿自重,,,38.4×（lb+a）×1=,,57.6,N,,

,扣件自重,,,15×6=,,90,N,,

,竹筏片腳手板,,,56×la×lb=,,120.96,N,,

,欄桿及擋板自重,,,140×la=,,252,N,,

,安全網(wǎng)自重,,,20×la×h=,,64.8,N,,

,,,,小計：N1=,,861.84,N,,

活荷載計算,,,,,,,,,

,,,,N2=P×la×lb=,,4320,,N,

,活荷載的層數(shù)n',,,2,,,,,

風(fēng)荷載的計算,,,,,,,,,

,計算參數(shù)：,,風(fēng)壓高度變化系數(shù)uz,,,1.025,,,

,,,腳手架風(fēng)荷載體型系數(shù)us,,,1.04,,,

,,,基本風(fēng)壓wo,,,0.4,KN/m2,,

,wk=0.7×uz×us×wo=,,,,0.30,KN/m2,,,

,立桿自重N3=38.4×H=,,,552.96,N,,,,

2、立桿內(nèi)力的計算,,,,,,,,,

有關(guān)參數(shù)的計算,,,,,,,,,

,計算長度lo=k×u×h=,,,3.22,m,,,,

,其中：,計算長度附加系數(shù)k,,,,1.155,,,

,單桿計算長度系數(shù)u查規(guī)范表5.3.3,單桿計算長度系數(shù)u查規(guī)范表5.3.3,,,,1.55,,,

,長細(xì)比λ=lo/i=,,204,≤,[λ]=,210,,,

,查規(guī)范中的附表C可得φ=,,,0.174,,,,,

2.1組合風(fēng)荷載的作用,,,,,,,,,

,立桿底端的軸力N為,,,,,,,,

,N=(n×N1/2+N3)×1.2+0.85×(n'×N2/2)×1.4=,,,,,9941.184,N,,

,風(fēng)荷載作用下的立桿段彎距值,,,,,,,,

,M=0.85×1.4×wk×la×h2/10=,,,,207.15,N·m,,,

,立桿穩(wěn)定性驗算,,,,,,,,

,N/（φ×A）+M/W=,,,157.61,N/mm2,≤,[f]=205N/mm2,,

,滿足要求,,,,,,,,

2.2不組合風(fēng)荷載的作用,,,,,,,,,

,立桿底端的軸力為,,,,,,,,

,N=(n×N1/2+N3)×1.2+(n'×N2/2)×1.4=,,,,10848.384,N,,,

,立桿穩(wěn)定性驗算,,,,,,,,

,N/（φ×A）=,,127.50,,N/mm2,≤,[f]=205N/mm2,,

,滿足要求,,,,,,,,

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（四）、連墻件的計算,,,,,,,,,

本腳手架按兩步三跨計算，連墻件采用圓鋼,,,,,,,,,

,步數(shù)n1,2,跨數(shù)n2,3,,,,,

,選用圓鋼的直徑為φ,,,10,mm,,,,

,截面積A=πr2=,,,78.5,mm2,,,,

連墻件的軸向力設(shè)計值的計算,,,,,,,,,

,Nl=Nlw+No=,,13.12,KN,,,,,

,其中：,Nlw為風(fēng)荷載產(chǎn)生的連墻件軸向力設(shè)計值,,,,,,,

,Nlw=1.4×wk×Aw=,,8.12,KN,,,,,

,其中：,Aw為每個連墻件的覆蓋面積內(nèi)腳手架外側(cè)面的迎風(fēng)面積,,,,,,,

,,,Aw=bw×hw=,,19.44,m2,,,

,,,bw=n2×la=,,5400,mm,,,

,,,hw=n1×h=,,3600,mm,,,

,,No為連墻件約束腳手架平面外變形所產(chǎn)生的軸向力,,,,,,,

,,雙排架的No,,5,KN,,,,

連墻件的強度驗算,,,,,,,,,

,σ=Nl/A=,167.2,N/mm2,≤,0.85×[f]=,,174.25,N/mm2,

,滿足要求,,,,,,,,

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（五）、懸挑架的計算,,,,,,,,,

計算簡圖,,,,,,,,,

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支撐架層高h(yuǎn)',,4.5,m,角度α=,1.310193935,弧度,,,

荷載取值：,,,,,,,,,

,腳手架傳遞給挑梁的設(shè)計值N,,,,10848.384,N,,,

1、求支座反力,,,,,,,,,

,∑MA=0,Rbx×h'=N×lb,,,Rbx=,2893,N,壓,

,∑MB=0,Rax×h'+N×lb=0,,,Rax=,-2892.9024,N,拉,

,∑Fy=0,Rby=2×N=,,21697,N,,,,

2、求各桿內(nèi)力,,,,,,,,,

,2節(jié)點,,,,,,,,

,∑Fy=0,N24×Sinα-N=0,,,N24=,11227.48056,N,壓,

,∑Fx=0,N12-N24×Cosα=0,,,N12=,2893,N,拉,

,5節(jié)點,,,,,,,,

,∑Fx=0,N45×Cosα-Rbx=0,,,N45=,11227.48056,N,壓,

,∑Fy=0,N35+N45×Sinα-Rby=0,,,N35=,10848.384,N,壓,

,3節(jié)點,,,,,,,,

,∑Fy=0,N13=N35=,10848,N,壓,,,,

,∑Fx=0,N34=,0,N,,,,,

,1節(jié)點,,,,,,,,

,∑Fy=0,N-N13+N14×Sinα=0,,,N14=,0,N,,

,∑Fx=0,Rax+N12=0,,,N12=,2893,N,拉,

,搭接立桿容許荷載[N],,,11.6,kN,,,,

滿足要求,,,,,,,,,

壓桿穩(wěn)定性驗算,,,,,,,,,

,斜桿長度l=h'/Sinα=,,,4.657,m,,,,

,計算長度lo=k×l=