一、 Spreader bar selection (refer to drawing T3510-Lifting Sketch-3)a、平衡梁选择（参见图T3510-吊装草图-3）The spreader bar uses the steel pipe ofφ219×8, material=20#, length=3.8m, mechanics specialty is F=5300mm2,rotating radius isr=74.48 mm 平衡梁选用φ219×8的钢管,材质20#,长3.8米,其力学特性为截面积F=5300mm2，回转半径r=74.48 mmSpreader bar pulling isP2= P1cos19.5=Q/2 =120.68/2t P2=64.19t=629062N P2----------吊装梁所受正压力平衡梁受力为P2= P1cos19.5=Q/2 =120.68/2t P2=64.19t=629062NSpreader bar slightness ratio: λ=μl/r=3800/74.48=51.02平衡梁细长比: λ=μl/r=3800/74.48=51.02From above u-----length factor. Two ends hinge u=1 L----Supporting girder length L=3.8m上式中u-----长度系数、两端铰支 u=1L-----支撑梁长 L=3.8m 折减系数Φ=1.018-0.0023*51.02=0.9Reduction coefficientΦ=1.018-0.0023*51.02=0.9Spreader bar stress[σ]= P2/(ΦF)= 629062/ (0.9×5300)=131N/mm2平衡梁应力为[σ]= P2/(ΦF)= 629062/(0.9×5300)=131N/mm2Bend limit of steel tube isσs=245.15N/mm2 Take safety factor n=1.8钢管的屈服极限为:σs=245.15N/mm2取安全系数n=1.8[δ] = δs /n =245.15/1.8 = 136.19N/mm2＞σb、两端夹板钢板计算钢板所受应力δ=P2/A =629062N/102050 mm2=6.16N/ mm2δ-----钢板所受压应力N/ mm2P2----吊装梁所受正压力NA------受压面积mm2钢板δ=20 Q235 的屈服极限为:σs=225N/mm2取安全系数n=1.8[δ] = δs /n =225/1.8 = 125N/mm2＞δ,钢板满足要求.C、对夹螺栓的计算F1=G/2+f=G/2sin70F1-----钢丝绳受力64.19T=629062Nf--------钢丝绳受摩擦力f=F2*ζ+n*N*ζ*2N--------螺栓对钢丝绳的压力(t)ζ-------钢丝绳在钢板上摩擦系数ζ=0.2n--------螺栓数量选4套G/2sin70-G/2=G/2ctg70*0.2+4*N*0.2*2N=2.3T选用M20的螺栓，4套；查表得M20的螺栓旋紧螺母时螺栓对钢板的压力大小为2.5T。
满足使用要求此时螺栓的扭矩值为60N.M二、 Spreader bar selection (refer to drawing T3510-Lifting Sketch-3)a、平衡梁选择（参见图T3310-吊装草图-3）The spreader bar uses the steel pipe ofφ219×8, material=20#, length=3.8m, mechanics specialty is F=5300mm2,rotating radius isr=74.48 mm 平衡梁选用φ219×8的钢管,材质20#,长2.7米,其力学特性为截面积F=5300mm2，回转半径r=74.48 mmSpreader bar pulling isP2= P1cos30=Q/2 =80.1/2t P2=46.03t=451094N P2----------吊装梁所受正压力平衡梁受力为P2= P1cos30=Q/2 =80.1/2t P2=46.03t=451094NSpreader bar slightness ratio: λ=μl/r=2700/74.48=36.25平衡梁细长比: λ=μl/r=2700/74.48=36.25From above u-----length factor. Two ends hinge u=1 L----Supporting girder length L=2.7m上式中u-----长度系数、两端铰支 u=1L-----支撑梁长 L=3.8m 折减系数Φ=1.018-0.0023*36.25=0.93Reduction coefficientΦ=1.018-0.0023*36.25=0.93Spreader bar stress[σ]= P2/(ΦF)= 451094/ (0.93×5300)=91.51N/mm2平衡梁应力为[σ]= P2/(ΦF)= 451094/ (0.93×5300)=91.51N/mm2Bend limit of steel tube isσs=245.15N/mm2 Take safety factor n=1.8钢管的屈服极限为:σs=245.15N/mm2取安全系数n=1.8[δ] = δs /n =245.15/1.8 = 136.19N/mm2＞σb、两端夹板钢板计算钢板所受应力δ=P2/A =451094N/102050 mm2=4.42N/ mm2δ-----钢板所受压应力N/ mm2P2----吊装梁所受正压力NA------受压面积mm2钢板δ=20 Q235 的屈服极限为:σs=225N/mm2取安全系数n=1.8[δ] = δs /n =225/1.8 = 125N/mm2＞δ,钢板满足要求.C、对夹螺栓的计算F1=G/2+f=G/2sin70F1-----钢丝绳受力46.03t =451094Nf--------钢丝绳受摩擦力f=F2*ζ+n*N*ζ*2N--------螺栓对钢丝绳的压力(t)ζ-------钢丝绳在钢板上摩擦系数ζ=0.2n--------螺栓数量选4套G/2sin60-G/2=G/2ctg60*0.2+4*N*0.2*2N=1.2T选用M20的螺栓，4套；查表得M20的螺栓旋紧螺母时螺栓对钢板的压力大小为2.5T。
满足使用要求此时螺栓的扭矩值为30N.M。