鋼結(jié)構(gòu)課程設(shè)計(jì)報(bào)告梯形鋼屋架計(jì)算書(shū)

11－、設(shè)計(jì)資料1、某工廠車間，采用梯形鋼屋架無(wú)檁屋蓋方案，廠房跨度取27m,長(zhǎng)度為102m,柱距6m。采用1.5mX6m預(yù)應(yīng)力鋼筋混凝土大型屋面板，保溫層、找平層及防水層自重標(biāo)準(zhǔn)值為1.3kN/m2。屋面活荷載標(biāo)準(zhǔn)值為0.5kN/m2,雪荷載標(biāo)準(zhǔn)值0.5kN/m2,積灰荷載標(biāo)準(zhǔn)值為0.6kN/m2,軸線處屋架端高為1.90m,屋面坡度為i=1/12,屋架鉸接支承在鋼筋混凝土柱上，上柱截面400mmX400mm混凝土標(biāo)號(hào)為C25。鋼材采用Q235B級(jí)，焊條采用E43型。2、屋架計(jì)算跨度：Lo=27m-2X0.15m=26.7m3、跨中及端部高度：端部高度：h‘=1900mm（端部軸線處），h=1915mm（端部計(jì)算處）。屋架中間高度h=3025mm。二、結(jié)構(gòu)形式與布置屋架形式及幾何尺寸如圖一所示:2、荷載組合設(shè)計(jì)桁架時(shí),應(yīng)考慮以下三種組合：①全跨永久荷載+全跨可變荷載（按永久荷載為主控制的組合）：全跨節(jié)點(diǎn)荷

載設(shè)計(jì)值：F=（1.35X3.12+1.4X0.7X0.5+1.4X0.9X0.6）X1.5X6=49.122kN圖三桁架計(jì)算簡(jiǎn)圖本設(shè)計(jì)采用程序計(jì)算結(jié)構(gòu)在單位節(jié)點(diǎn)力作用下各桿件的力系數(shù),見(jiàn)表一。力系數(shù)（F=1）第二種組合第三種組合計(jì)算桿件桿件名稱全跨①左半跨②右半跨③第一種組合FX①F1X①+F2X②F1X①+F2X③F3X①+F4X②F3X①+F4X③力（KN）tAB上 000000000二BC,CD弦 -10.82-8.15-2.67-531.50-551.36-456.42-227.16-109.78-551.36DE,EF-17.85-12.87-4.98-87683-89963-76294-36243-19342-89963

FG，GH-21.55-14.66-6.89-105858-107090-93629-41875-25232-107090HJ-22.72-14.23-8.49-1116.05-1107.80-1008.36-415.23-292.28-1116.05IJ，JK-23.2-14.72-8.48-1139.63-1134.49-1026.38-428.05-294.39-1139.63下弦ab5.994.591.4294.24306.59251.32127.4359.10306.59bc14.7710.893.88725.53748.57627.12305.05154.89748.57cd19.9914.035.96981.951000.85861.04397.67224.811000.85de22.3414.647.71097.391100.50980.27422.16273.511100.50ef21.8612.049.821073.811037.26998.80364.14316.581073.81斜腹桿aB-11.23-8.6-2.63-551.64-574.70-471.27-238.79-110.91-574.7Bb8.996.622.37441.61455.48381.85185.4994.46455.48bD-7.71-5.37-2.34-378.73-385.31-332.81-152.50-87.59-385.31Dc5.853.742.11287.36286.56258.32108.5473.63287.36cF-4.59-2.52-2.07-225.47-217.66-209.86-76.29-66.65-225.47Fd3.11.211.89152.28138.48150.2640.9855.55152.28dH-1.92-0.07-1.85-94.31-74.00-104.83-10.83-48.96-104.83He0.67-1.021.6932.917.7354.68-18.5939.4654.68-18.59eg1.183.22-2.0457.96100.529.3974.71-37.96100.52-37.96gK1.913.95-2.0493.82140.8437.0693.89-34.41140.84-34.41gI0.670.67032.9137.0125.4017.613.2637.01豎桿Aa-0.5-0.50-24.56-27.62-18.95-13.14-2.43-27.62CbEc-1-10-49.12-55.23-37.91-26.28-4.86-55.23Gd-1-10-49.12-55.23-37.91-26.28-4.86-55.23Jg-1-10-49.12-55.23-37.91-26.28-4.86-55.23Ie-1.5-1.50-73.68-82.85-56.86-39.42-7.29-82.85Kf000000000四、桿件截面設(shè)計(jì)1、上弦桿：整個(gè)上弦桿采用相等截面，按最大設(shè)計(jì)力IJ、JK計(jì)算，根據(jù)表得：N=-1139.63KN，屋架平面計(jì)算長(zhǎng)度為節(jié)間軸線長(zhǎng)度，即： =1355mm,本屋架ox為無(wú)檁體系，認(rèn)為大型屋面板只起剛性系桿作用，不起支撐作用，根據(jù)支撐布置和力變化情況，取屋架平面外計(jì)算長(zhǎng)度 為支撐點(diǎn)間的距離，即：oy=3=4065mm。根據(jù)屋架平面外上弦桿的計(jì)算長(zhǎng)度，上弦截面宜選用兩個(gè)不oyox等肢角鋼，且短肢相并，如圖四所示：圖四上弦桿

腹桿最大力N=-574.7KN,查表可知，中間節(jié)點(diǎn)板厚度取12mm,支座節(jié)點(diǎn)板厚度取14mm。設(shè)九=60，根據(jù)《規(guī)》由雙邊角鋼組成的T行和十字形截面均屬于b類，查Q235鋼軸心受力穩(wěn)定系數(shù)表，①=0.807，N1139.63義1。3則需要截面積：A=一= =6568.3mm2好0.807義215l 135.5cm l 406.5需要回轉(zhuǎn)半徑i=等= =2.26cm，i=等= =6.78cmx入60 y入60根據(jù)A、i、i查角鋼規(guī)格表，初選用2L180X110X12,肢背間距a=12mm,xy該截面特性如下：A=67.42cm2,i=3.10cm,i=8.75cm。b/1=180/12=15

xy 1按所選角鋼進(jìn)行驗(yàn)算：l1355九=lox=135,5=43.71＜［九］=150xi3.10x:b/1=180/12=15＞0.561/b=0.56x4065/180=12.651 oy1bl2t2 180 40652x122九=3.7—(1+7——)=3.7x x(1+ )"t 52,7b4 12 52.7x18041-7.89<[l]=150截面在x和y平面皆屬b類，由于系數(shù)表得①=0.819,則有:yN1139630o= = :①A0.819x6740y所需截面合適。九＞X，只需求出中yzx y206.45<215N/mm2查軸心受壓桿穩(wěn)定2、下弦桿:整個(gè)下弦桿采用同一截面，按最大設(shè)計(jì)值計(jì)算，根據(jù)表得桿de力最大N=1100.50KN。計(jì)算長(zhǎng)度又有：=2700mm, =26700/2=13350mm。選用需要截面面積A=N=11饗9=5118.60mm2=51.19cm2,f215選用2L160x100x12,采用短肢相并，如圖五所示：圖五下弦桿圖五下弦桿i=28.2mm,i=78.2mm。xy該截面特性如下：i=28.2mm,i=78.2mm。xy長(zhǎng)細(xì)比計(jì)算：入=lox=-300-=106.38<Ed=350xi2.82x,l 1335 「I…九=_°y= =170.72<lkJ=350yi 7.82yN1100500o= = =183.08MPa<215MPaA6011滿足要求。3、端斜桿aB：已知桿件軸力N=-574.70kN,l=l=2390mm。因?yàn)閘=l，故采用不等肢oxoy oxoy角鋼，長(zhǎng)肢相并，使i'i,選用角鋼2L125義80義10，如圖六所示：xy圖六端斜桿則其截面特性如下：A=3942mm2，i=39.8mm，i=33.9mmxyl2390 l2390對(duì)該截面驗(yàn)算如下：入=-ox= =60.05,入=-oy= =70.50xi39.8 yi33.9xy又因?yàn)椋篵21t=80/10=8<0.48x2390/80=14.34=79.33<lx]=150.L1.09b4) =79.33<lx]=150所以：取入=入1+ 2-=70.50x1+ 戶y 1212 I 23902x102)0y因?yàn)椋壕牛綳，只需求中，查軸心受壓桿穩(wěn)定系數(shù)表得①=0.692，于是有:yzx y yz=210.68N/mm2<f=210.68N/mm2<f=215N/mm2①S0.692x3942所需截面合適。4、腹桿eg-gK：此桿在g節(jié)點(diǎn)處不斷開(kāi)，采用通長(zhǎng)桿件。最大拉力：N=140.84kN,N=100.52kN；gK eg最大壓力：N=34.41kN,N=37.96kN；gK eg再分式桁架中的斜腹桿，在桁架平面的計(jì)算長(zhǎng)度取節(jié)間中心間距：=2027mm在桁架平面外的計(jì)算長(zhǎng)度：N 34.41l=l(0.75+0.25t)=4055x(0.75+0.25x )=3960mmoy1 N 37.961選用2L100x10,如圖七所示。圖七腹桿eg-gK查角鋼規(guī)格表得：A=3852mm2, ‘?=30.5mm,x對(duì)此截面驗(yàn)算如下：i=46.0mm。ylx2027”“R] =66.46<圖七腹桿eg-gK查角鋼規(guī)格表得：A=3852mm2, ‘?=30.5mm,x對(duì)此截面驗(yàn)算如下：i=46.0mm。ylx2027”“R] =66.46<vk]=15030.51oy3960=86.09<ll]=15046.0又因?yàn)?b/1=100/10=10<0.581/b=0.58x3960/100=22.97

oy所以取:入=X1+

yzy0.475b4)=86.09x1+I0.475x1004)39602x102)=88.70<ll]=150因?yàn)椋壕虐酥恍枨笾衴z壓應(yīng)力：O,yz查表得①=0.630,于是有:379600謳―0.630x3852y二156MPa<215MPa，滿足要求。拉應(yīng)力：o=—=140840=36.56MPa<215MPa，滿足要求。A38525.豎桿Ie：該桿件N=-82.85KN,l=0.8l=0.80xx2801=2241mm,l=l=2801mmoy由于桿件力較小，按九=［九］=150選擇，需要的回轉(zhuǎn)半徑為:,l2241 1/八i= = =14.9mmx[X] 150l2801,i=-^-=一y [X] 150=18.67mm查型鋼表，選用2L63X8，如圖八所示:圖八中豎桿A=A=1902mm2i=19.0mm ,x其截面特性為：i=31.0mmy對(duì)此截面驗(yàn)算如下:九二-ex

xix2241 R] 1 =115.2<仄]=150,九=-°y=19.4 yiy280130.492.1<E<]=150名稱桿件編號(hào)力（KN）計(jì)算長(zhǎng)度（cm）截面規(guī)格截面面積（cm2）容許長(zhǎng)細(xì)比［九］計(jì)算應(yīng)力N/mm2因?yàn)?b/t=63/8=7.875<0.581oy/b=10兀10y上弦IJJK-1139.63135.50406.502L180X110X1267.42150.00206.45下弦de1100.50270.001335.002L160X100X1260.10350.00183.08腹桿Aa-27.62191.50191.502L63X819.02150.0094.10aB-574.70239.00239.002L125X80X1039.42150.00210.68Bb455.48239.00298.752L100X1038.52350.00118.25Cb-55.23212.70265.882L63X819.02150.0059.630.58x2801/63=25.787所以：0 0C0.475b4)入=X1+ W yI 1212oy因?yàn)榫?gt;x，只需求中，只需求中，查表得①=0.463,于是有：xxN82850o= = =94.IMPa<215MPa①A0.463x1902x其余各桿件截面選擇過(guò)程不一一列出，計(jì)算結(jié)果見(jiàn)表二：架桿件截面選擇表 表二bD-385.31261.50326.882L100X1038.52150.00153.89Dc287.36261.50326.882L100X1038.52350.0074.60Ec-55.23235.20294.002L63X819.02150.0069.64cF-225.47280.90351.132L100X1038.52150.0096.43Fd152.28280.90351.132L63X819.02350.0080.06Gd-55.23257.60322.002L63X819.02150.0079.99dH-104.83300.80376.002L63X819.02150.00196.14He54.68-18.59300.80376.002L63X819.02150.00102.31Ie-82.85280.10350.132L63X819.02150.00137.41eg100.52-37.96202.70253.382L100X1038.52150.0033.80gk140.84-34.41202.70253.382L100X1038.52150.0047.36、節(jié)Kf0.00302.50302.502L63X819.02200.000.00占八、、gI37.01186.60233.252L63X819.02350.0019.46設(shè)Jg-55.23140.00175.002L63X819.02150.0039.89計(jì)用E43焊條時(shí)，角焊縫的抗拉、抗壓和抗剪強(qiáng)度設(shè)計(jì)值fw=160N/mm2。f1、下弦節(jié)點(diǎn)“b”：設(shè)“Bb”桿的肢背和肢尖焊縫=8mm和6mm，各桿件力由表1查得，f則所需的焊縫長(zhǎng)度為：'KNO. 0.7x455.48x103肢背：/= 1 +2h= +2x8=193.92mm，取l—210mm；W2x0.7hfwf 2x0.7x8x160 wf1f〃KN? 0.3x455.48x103肢尖：l= 2 b2h= F2x6=113.67mm，取l—130mm；W 2x0.7hfwf 2x0.7x6x160 wf2f設(shè)“Db”桿的肢背與肢尖焊縫分別為8mm和6mm,則所需的焊縫長(zhǎng)度為：'KN2 0.7x385.31x103肢背:l= 1 +2h= +2x8=166.51mm,取l—180mm；W2x0.7hfwf2x0.7x8x160 wf1f肢尖：l〃=K2N +2h=0.33-+2x6=98.01mm，取l,=110mm;W 2x0.7hfwf2x0.7x6x160 wf2f豎桿“Cb”，因其力很小，焊縫尺寸可按構(gòu)造縫確定，取焊腳尺寸h=5mm。根據(jù)上面求得的焊縫長(zhǎng)度，并考慮桿件之間應(yīng)有的間隙及制作和裝配等誤差，按比例繪出接點(diǎn)詳圖，從而確定節(jié)點(diǎn)板尺寸為390mmX500mm。下弦桿與節(jié)點(diǎn)板連接的焊縫長(zhǎng)度為500mm, =6mm。焊縫所受的力在左右兩下弦桿的力差△N=748.57-306.59=441.98KN,受力較大的肢背處的焊縫應(yīng)力為：KANT= 1 f2x0.7hl

fw

焊縫強(qiáng)度滿足要求。0.7x441.98x103、2x0.7x5x(500-2x6)=99.57N/mm2<160mm2節(jié)點(diǎn)板尺寸：根據(jù)以上求得的焊縫長(zhǎng)度，并考慮桿件之間應(yīng)有的間隙和制作裝配等誤差，按比列作出構(gòu)造詳圖，從而定出節(jié)點(diǎn)尺寸。如圖九所示圖九節(jié)點(diǎn)板b尺寸2、上弦節(jié)點(diǎn)“B”：斜桿Bb與節(jié)點(diǎn)板連接焊縫計(jì)算，與下弦節(jié)點(diǎn)b中Bb桿計(jì)算相同。斜桿aB與節(jié)點(diǎn)板連接焊縫計(jì)算。設(shè)“aB”桿肢背與與肢尖的焊縫分別為10mm和8mm。又N=574.70KN，則所需焊縫長(zhǎng)度為：KN―i—200mm；W2x0.7hfwf1f+2h

f0.65x574.70x103 +2x10=186.77mm，取l=2x0.7x10x160 w肢尖:KN

□ 2x0.7hfwf2f-0.35x574.70x103+2x8二128.25mm，取〃、=f2x0.7x8x160 w140mm；為了便于在上弦上擱置大型屋面板，上弦節(jié)點(diǎn)板的上邊緣可縮進(jìn)上弦肢背8mm。用槽焊縫將上弦角鋼和節(jié)點(diǎn)板連接起來(lái)。槽焊縫可按兩條焊縫計(jì)算，焊縫強(qiáng)度設(shè)計(jì)值應(yīng)乘以0.8的折減系數(shù)，計(jì)算時(shí)可略去屋架上弦坡度的影響，而假定集中荷載F與上弦垂直（節(jié)點(diǎn)荷載由槽焊縫承受，上弦兩相鄰節(jié)間的力差由角鋼肢尖焊縫承受，這時(shí)槽焊縫必然是安全的，因此可不必驗(yàn)算）。上弦桿尖焊縫受力為左右上弦桿的力差：△N=574.70-0=574.70KN。設(shè)需焊縫長(zhǎng)度為530mm，h=—x12=6mm,hf1 2'=10mm。則肢尖:f2：b.65x5747001+(49120)12x1.22；2x0.7xh'l'fw=85.98N <0.8fw=0.8x160/mm2 f2x0.7x6x(530-12)2x0.7xh''l''fwfT,ln.35x574700.2― 10x(512x1.22；2x0.7x30-20)=28.31N/mmm2故焊縫強(qiáng)度滿足要求。節(jié)點(diǎn)板尺寸如圖十所示：<0.8fw圖十節(jié)點(diǎn)板B尺寸3、屋脊節(jié)點(diǎn)“K”：弦桿一般用與上弦桿同號(hào)角鋼進(jìn)行拼接，為使拼接角鋼與弦桿之間能夠密合，并便于施焊，需將拼接角鋼進(jìn)行切肢、切棱。拼接角鋼的這部分削弱可以靠節(jié)點(diǎn)板來(lái)補(bǔ)償。拼接一側(cè)的焊縫長(zhǎng)度可按弦桿力計(jì)算。設(shè)肢尖、肢背焊縫為10mm,則所需焊縫計(jì)算長(zhǎng)度為：（一條焊縫）1139630411396304x0.7x10x160+10=264.38mm拼接角鋼總長(zhǎng)度取700>264.37X2=528.74。上弦肢尖與節(jié)點(diǎn)板的連接焊縫，應(yīng)按上弦力的15%計(jì)算。設(shè)肢尖焊縫=10mm,節(jié)點(diǎn)板長(zhǎng)度為600mm節(jié)點(diǎn)板長(zhǎng)度為600mm，則節(jié)點(diǎn)一側(cè)弦桿焊縫的計(jì)算長(zhǎng)度為l=(600/2-10—20)=270mm，則焊縫應(yīng)力為:=45.22MPa0.15=45.22MPa2x0.7x10x2706x6x0.15x1139630x802x0.7x10x2702=80.40MPa<160MPa，，o .80.4.(-f)2+T2=(——)2+45.222=79.92MPa<160MPaVPf1.22f故滿足要求。節(jié)點(diǎn)板尺寸如圖十一所示：圖十節(jié)點(diǎn)板K圖十節(jié)點(diǎn)板K尺寸4、端部支座節(jié)點(diǎn)“a"：如圖十二所示:圖十二 支座節(jié)點(diǎn)a為便于施焊，下弦角鋼水平肢的底面與支座底板的距離一般不小于下弦伸出肢的寬度，故可取為160mm。在節(jié)點(diǎn)中心線上設(shè)置加勁肋，加勁肋的高度與節(jié)點(diǎn)板的高度相同，厚度同端部節(jié)點(diǎn)板為14mm。所需底板凈面積為：（1）支座底板計(jì)算：所需底板凈面積為：支座