18梯形屋架计算书

1、课程设计任务书课程名称:实践时间:名:号:指导教师:年月日钢结构课程设计任务书、题目某厂房总长度72m跨度为18m屋盖体系为无楝屋盖。纵向柱距6m1 .结构形式：钢筋混凝土柱，梯形钢屋架。柱的混凝土强度等级为C30,屋面坡度i=L/10;L为屋架跨度。地区计算温度高于-20°C,无侵蚀性介质，屋架下弦标高为18m2 .屋架形式及荷载：屋架形式、几何尺寸及内力系数（节点荷载P=1.0作用Q345钢，焊条为下杆件的内力）如附图所示。屋架采用的钢材、焊条为:E50型。1507.51507_5rl571507c1507.51507c(a)18米跨屋架1,01-01-01.0L0LO8.993

2、+7.962Cl029.279/+9.279(b)18米跨屋架全跨单位荷载几何尺寸作用下各杆件的内力值1.01.01.0ifF1.00.5in?-4.55-3.967-5.325(c)18米跨屋架半跨单位荷载作用下各杆件的内力值、设计内容1.屋架形式、尺寸、材料选择及支撑布置根据车间长度、屋架跨度和荷载情况，设置上、下弦横向水平支撑、垂直XXXDO1111IBR7I1111、天/1-1、2-2剖面图2.荷载计算三毡四油防水层水泥砂浆找平层保温层预应力混凝土屋面板屋架及支撑自重恒荷载总和0.4kN/m2_20.4kN/m20.45kN/m21.4kN/m-一一一一一一20.12+0.011L=0

3、.318kN/m2.968kN/m2活荷载0.7kN/m积灰荷载0.7kN/m可变荷载总和1.4kN/m屋面坡度不大，对荷载影响小，未予以考虑。风荷载对屋面为吸力，重屋面可不考虑。3 .荷载组合1 .全跨永久荷载+全跨可变荷载可变荷载效应控制的组合：F=(1.2X2.968+1.4X0.7+1.4X0.9X0.7)X1.5X6=52.59kN永久荷载效应控制的组合：F'=(1.35X2.968+1.4X0.7X0.7+1.4X0.9X0.7)X1.5X6=54.43kN故F=54.43KN2 .全跨永久荷载+半跨可变荷载全跨永久荷载设计值：F1=1.35义2.968X1.5X6=36.

4、06kN半跨可变荷载设计值：F2=(1.4X0.7+1.4X0.9X0.7)X1.5X6=16.76kN屋架杆件内力组合表杆件名称杆件编号单位内力作用时的内力系数组合1组合2计算内里全KAA左半跨B右半跨CFXAF1XA+F2XCF1XA+F2XB上弦AB0.000.000.000.000.000.000.00BGCD-6.221-4.317-1.85-338.61-281.77-323.12-338.12DEEF-8.993-5.636-3.357-489.49-417.15-345.23-489.49FG-9.102-4.551-4.551-495.42-443.18-443.18-495

5、.42下弦ac3.4702.5370.933188.87155.51182.17188.87ce7.9625.3252.637433.37365.14410.20433.37eg9.2795.3123.967505.06441.64463.07505.06斜腹杆aB-6.502-1.754-1.748-353.90-291.39-291.49-353.90Bc4.7393.1581.581257.94217.53243.96257.94cD-3.382-1.862-1.520-184.08-161.80-167.54-184.08De1.8840.5401.344102.3298.4789.9

6、9102.32eF-0.6900.615-1.305-37.47-49.69-17.51-49.69Fg-0.462-1.6321.170-25.090.99-45.98-45.98竖杆Aa-0.5-0.50.00-27.16-20.16-28.54-28.54Cc-1.0-0.10.00-54.43-40.31-57.07-57.07Ee-1.0-0.10.00-54.43-40.31-57.07-57.07Gg0.8120.4060.40644.2039.5439.5444.204 .截面选择按腹杆最大内力N=-353.9kN查表选用中间节点板厚度t=10mm,荷载支座节点板厚度t=12m

7、m。1 .上弦整个上弦不改变截面，按最大内里计算：假定人=60对于双角T形钢，当绕x.y轴失稳时属于类b截面，由附表查得x=0.735,需要的截面几何量：A=N/巾minf=4954.2/(0.735义310)=21.74cm2ix=lox/人=150.75/90=2.51cmiy=loy/人=300/90=5.0cm由附表选用2L80X10,A=30.26cm2,ix=2.42cm,iy=3.74cm入x=lox/ix=150.75/2.26=62.290入y=loy/iy=300/3.54=80.21入=150双角T钢型截面绕对称轴(y)轴应按弯扭屈曲计算长细比入yzb/t=8.0<

8、0.58loy/b=21.75,故按下式计算Xyz=Xy(1+0.475b710y2t2)=81.194>Xy故由入max=Xyz=81.94,按b类查附表得巾=0.5536=n/巾A=4954.2/(0.632X30.26)=296.06N/mm2<f=310N/mm2因截面无孔眼削弱，可不验算强度。又因轧制钢翼缘和腹板，可不验算局部稳定填板每个节间放一块(满足l1范围内不少于两块)，la=75.38cm<40i=40X2.42=96.8cm2 .下弦下弦不改变截面，按最大内力计算：Nmax=505.06kN,lox=300cm,loy=900cm,连接支撑的螺栓孔中心至节

9、点板边缘的距离约为100cm(eg节间)，可不考虑螺栓孔削弱。需要的截面几何量：A=N/f=5050.6/310=16.29cm2ix=lox/入=300/350=0.86cmiy=loy/入=1500/350=2.57cm由附表选用2L75X7,A=20.26cm2,ix=2.30cm,iy=3.47cm入x=lox/ix=300/2.30=130.43<入=350入y=loy/iy=900/3.47=259.37<入=3506=N/A=249.29N/mm2<f=310N/mm2填板每个节间放一块，l1=150cm<80i=80X2.30=184cm3 .斜腹杆(1

10、)杆件aB:N=-353.90kN,lox=loy=253.0cm假设入=80,对于双角T形钢，当绕x.y轴失稳时属于类b截面，由附表查得巾x=0.574,需要的截面几何量：A=N/巾minf=3539.0/(0.574X310)=19.82cm2ix=lox/人=253.0/80=3.16cmiy=loy/人=3.16cm由附表选用2L100x6,A=23.86cm2,ix=3.10cm,iy=4.44cm入x=lox/ix=253.0/3.10=81.61<入=150入y=loy/iy=253.0/4.44=56.98双角T钢型截面绕对称轴(y)轴应按弯扭屈曲计算长细比入yzb/t=

11、16.7<0.58loy/b=14.67,故按下式计算入yz=3.9Xb(1+loy2Xt2/18.6b?/t=71.20<入x故由入max=入x=81.61,按b类查附表得巾=0.5636=N/巾A=3539.0/(0.563X23.86)=263.45N/mm2<f=310N/mm2因截面无孔眼削弱，可不验算强度。又因轧制钢翼缘和腹板，可不验算局部稳定填板放两块，la=84.30cm<40i=40X3.1=124cm(2)杆件Bc:N=257.94kN,lox=0.8l1=0.8/X261.3=209.04cm,by=261.3cm需要的截面几何量：A=N/f=25

12、79.4/310=8.32cm2ix=lox/人=209.04/350=0.60cmiy=loy/人=261.3/350=0.75cm由附表选用2L63X4,A=9.96cm2,ix=1.96m,iy=2.94cm入x=lox/ix=209.04/1.96=106.65<入=350入y=loy/iy=261.3/2.94=88.88<入=350(T=N/A=258.98N/mm2<f=310N/mm2填板放两块，l1=87.1cm<80i=80X1.96=156.8cm.(3)杆件Ee:N=-50.07kN,lox=0.8l1=0.8X259.0=207.20cm,by

13、=259.0cm。内里较小可按入选择截面，需要的截面几何量：ix=lox/入=207.20/150=1.38cmiy=loy/入=259.0/150=1.73cm由附表选用2L50x6,A=11.38cm2,ix=1.51cm,iy=2.48cmx=lox/ix=207.20/1.51=137.22<入=150入y=loy/iy=259.0/2.21=104.44<X=150双角T钢型截面绕对称轴(y)轴应按弯扭屈曲计算长细比入yzb/t=8.33<0.58loy/b=29.93,故按下式计算Xyz=Xy(1+0.475b710y2t2)=105.72<入x故由Xmax

14、=Xx=137.22,按b类查附表得巾=0.2606=N/巾A=500.7/(0.260X11.38)=166.04N/mm2<f=310N/mm2因截面无孔眼削弱，可不验算强度。又因轧制钢翼缘和腹板，可不验算局部稳定填板放四块，la=51.8cm<40i=40X1.51=55.2cm其余杆件截面选择见表，注意连接垂直支撑的中央竖杆采用十字形截面，其斜平面计算长度lo=0.9l，其他腹杆除Aa外，lox=0.8l.物价杆件截面选用表杆件名称杆1件号内里设计值(kN)计算长度(cm)所用截面截回积(cm2)计算应力(N/mm2)容许长细比入杆件端部的角钢肢背和肢尖焊缝填板数loxlo

15、y上弦FG-495.42150.75300.002L80X1028.26274.35150每节间1下弦eg505.06300.001500.02L75X720.26249.29350每节间1斜腹杆aB-353.90253.0253.02L100X623.86263.451506-1604-1202Bc257.94209.04261.302L63X49.96258.983504-1704-902cD-184.08229.12286.402L90X621.28169.281506-904-703De102.32229.12286.402L30X44.56224.363504-704-403eF-4

16、9.69249.92312.402L56X816.74130.761506-404-304Fg-45.98249.92312.402L56X816.74121.01506-404-304竖杆Aa-28.54199.0199.02L45X610.16121.081506-404-303Cc-57.07183.2229.02L45X610.16209.591506-404-303Ee-57.07207.20259.02L50X611.38166.041506-404-304Gg44.20289X0.9=260.1+36X56.7665.382006-404-3035.节点设计(1)下弦节点设计“c

17、”先算腹杆与节点板的连接焊缝：Bc杆肢背及肢尖的焊缝的焊脚尺寸取hfi=hf2=4mm,则所需的焊缝长度(考虑起灭弧缺陷)：肢背lwi=257940/(3X0.7X4X200)+2X4=161.54mm,用170mm;肢尖lw2=257940/(6X0.7X4X200)+2X4=84.77mm,用90mm.腹杆Cc和cD的杆端焊缝同理计算，其次验算下弦杆与节点板连接焊缝，内力差AN=Nce-Nac=433.37-188.87=244.5kN>75.76kN.由斜腹杆焊缝决定的节点板量得节点板长度是52.0cm,角焊缝计算长度lw=52.0-1.2=50.8cm,采用hf=6mm,肢背焊缝

18、应力为：r1=244500/(3X0.7X6X508)=38.20N/mm2<ff=200N/mm2下线节点“c”(2)上线节点“B”腹板aB,Bc的杆端焊缝计算同上。这里验算上线与节点板的连接焊缝：节点板缩进8mm肢背采用塞焊缝，承受节点荷载：Q=54.43kN,hf=t/2=5mm,lwi=lw2=48.0-1.0=47.0cm(T=54430/(2X0.7X5X470)=16.55N/mm2<0ff=1.22X200=244N/mm2肢尖焊缝承担弦杆内力差AN=NAB-NBC=338.12-0=338.12kN>74.31kN,偏心距e=8-2.5=5.5cm偏心力矩M

19、=ANe=338.12X5.5=18.60kN-m,采用hf=10mm,则对AN:r=338120/(2X0.7X10X508)=47.54N/mm2对M:(Tf=6M/(2Xhexlw2)=6X18600000/(2X0.7X10X5082)=30.89N/mm2则焊缝强度为：V(af/”)2+rf2=53.86N/mm2<ff=200N/mmF上弦节点“B”(3)屋脊节点“G”腹杆杆端焊缝计算从略。弦杆与节点板连接焊缝受力不大，按构造要求决定焊缝尺寸，可不计算。这里只进行拼接计算，拼接角钢采用与上弦杆相同截面2L80X10,除倒棱外，竖肢需切去A=t+hf+5=10+10+5=25m

20、m,按上线坡度热弯。拼接角钢与上弦连接焊缝在接头一侧的总长度(设hf=10mm)Elw=N/(0.7hf义ff)=353.87mm共四条焊缝，认为平均受力，每条焊缝实际长度：lw=353.87/4+20=108.47mm拼接角钢总长度为：l=2lw+20=236.94mm<600mm取拼接角钢长度为600mm.(5)F/2F/2(4)支座节点“a”15支座节点“a”杆端焊缝计算从略，以下给出底板等的计算底板计算支反力Rd=327.18kN,混凝土强度C30,fc=14.3N/mm2,所需底板净面积：An=327180/14.3=22879.72mm2=228.80cm2锚栓直径取d=25

21、mm,锚栓孔直径为50mm,则所需底板毛面积：A=An+Ao=228.80+2X4X5+3.14X52/4=2580.43cm2按构造要求采用地板面积为axb=28X28=784cm2>280.43cm2,垫板采用-100X100X12,孔径26mm,实际底板净面积为：An=784-2X4X5-3.14义52/4=724.4cm2底板实际应力：q=3271.8/724.4=4.52N/mm2a=，(14-0.5)2+(14-0.6)2=18.92cmb1=13.5X13.4/18.92=9.45cmb1/a1=9.45/18.92=0.50查表得0=0.056,贝U:M=Bqa2=0.056X4.52X189.22=9060.85N-mm所需底板厚度：t>V6Mmax/f