電大土木混凝土結(jié)構(gòu)課程已知：車間倉庫的樓面梁格布置如圖17所示，軸線尺寸為30m×19.8m,樓面面層為20mm厚水泥砂漿抹面，梁板的天花抹灰為15mm厚混合砂漿，樓面活荷載選用7.0kN/m2,混凝土采用C20，梁中受力鋼筋采用HRB335,其它鋼筋一律采用HPB235，板厚80mm，次梁截面為b×h=200mm×450mm，主梁截面為b×h=300mm×700mm，柱截面為b×h=400mm×400mm。樓板周邊支承在磚墻上，試設(shè)計(jì)此樓蓋。一、板的計(jì)算（按考慮塑性內(nèi)力重分布的方法計(jì)算）1、荷載計(jì)算20mm厚水泥砂漿面層20×0.02=0.400kN/m280mm厚現(xiàn)澆鋼筋混凝土板25×0.08=2.000kN/m215mm厚石灰砂漿抹底17×0.015=0.225kN/m2恒載標(biāo)準(zhǔn)值:=0.4+2.0+0.225=2.6559.420kN/m2活載標(biāo)準(zhǔn)值:=7.000kN/m2經(jīng)試算,永久荷載效應(yīng)控制的組合為最不利組合,因此取荷載設(shè)計(jì)值=1.35×2.655+1.0×1.3×7.000=12.684kN/m22、計(jì)算簡(jiǎn)圖

取1m寬板帶作為計(jì)算單元,各跨的計(jì)算跨度為:中間跨:==2200-200=mm邊跨:=2200－100－120+1200/2=2040mm?。?020mm平均跨度:=(2020+)/2=mm3、內(nèi)力計(jì)算:因跨度差:(2020-)/=1%<10%故可按等跨連續(xù)板計(jì)算內(nèi)力各截面的彎距計(jì)算見表5截面邊跨中第一內(nèi)支座中間跨度中間支座彎距系數(shù)+1/11-1/11+1/16-1/16

(kN·m)1/11×12.7×2.022＝4.71-1/11×12.7×2.022＝－4.711/16×12.7×2.02＝3.18-1/16×12.7×2.02＝－3.18板彎距計(jì)算表54、截面強(qiáng)度計(jì)算=210N/mm2,=9.6N/mm2,=1.0,=80－20=60mm正截面強(qiáng)度計(jì)算見表6正截面強(qiáng)度計(jì)算表6截面邊跨中B支座中間跨中中間支座在平面圖上的位置①～②⑤～⑥②～⑤①～②⑤～⑥②～⑤M(kN·m)4.71－4.713.180.8×3.18－3.18-0.8×3.180.1360.1360.0920.0730.0920.0730.9270.9270.9520.9620.9520.962(mm2)403.25403.25265.11209.55265.11209.55選用鋼筋φ8@125φ8@125φ6/8@125φ6@125φ6/8@125φ6@125實(shí)際配筋面積402402314226314226根據(jù)計(jì)算結(jié)果及板的構(gòu)造要求,畫出配筋圖如圖20所示二、次梁的計(jì)算（按考慮塑性內(nèi)力重分布的方法計(jì)算）1、荷載計(jì)算板傳來的恒載：2.655×2.2=5.841kN/m次梁自重：25×0.2×(0.45－0.08)=1.850kN/m次梁粉刷抹灰：17×0.015×10.45－0.087×2=0.189kN/m恒載標(biāo)準(zhǔn)值:=5.841+1.850+0.189=7.880kN/m活載標(biāo)準(zhǔn)值:=7.000×2.2=15.400kN/m經(jīng)試算,永久荷載效應(yīng)控制的組合為最不利組合,因此取荷載設(shè)計(jì)值=1.35×7.880+1.0×1.3×15.400=30.7kN/m22、計(jì)算簡(jiǎn)圖各跨的計(jì)算跨度為:中間跨:=n=6000－300=5700mm邊跨:=6000－150－120+250/2=5855mm1.025=5873.25mm,取小值5855mm平均跨度:=(5855+5700)/2=5777.5mm跨度差:(58511-5700)/5700=2.7%<10%次梁的計(jì)算簡(jiǎn)圖見圖21。3、內(nèi)力計(jì)算:見表7、表8次梁的彎距計(jì)算表7截面邊跨中第一內(nèi)支座中間跨度中間支座彎矩系數(shù)+1/11-1/11+1/16-1/16

(kN·m)1/11×30.7×5.8552=95.7-1/11×30.7×5.7782=-93.21/16×30.7×5.702=62.3-1/16×30.7×5.702=-62.3次梁的剪力計(jì)算表8截面A支座B支座左B支座右c支座剪力系數(shù)0..450.550.550.55

(kN)0.45×30.7×5.73=79.160.55×30.7×5.73=96.70.55×30.7×5.70=96.30.55×30.7×5.70=96.34、正截面強(qiáng)度計(jì)算（1）次梁跨中截面按T形截面計(jì)算邊跨：=5.855/3=1.95m=0.2+1.98=2.18m取=1.95m中間跨：=5.7/3=1.90m=0.2+2.0=2.2m取=1.90m支座截面按矩形截面計(jì)算(2)判斷截面類型h0＝h－35＝450－35＝415mm，fy＝300N/mm2=1.0×9.6×1950×80×(4111-80/2)=561.6kN·m＞95.7kN·m(62.3kN·m)屬于第一類T形截面次梁正截面強(qiáng)度計(jì)算見表9次梁正截面強(qiáng)度計(jì)算表9截面邊跨中B支座中間跨中中間支座M(kN·m)95.7-93.262.3-62.3或(mm)195020019002000.02970.2820.01980.1880.9850.8300.990.895(mm2)780.4901.9505.5559.1選用鋼筋2φ16(彎)2φ16(直)2φ14(直)3φ16(彎)1φ16(彎)2φ16(直)2φ12(直)2φ16(彎)實(shí)際配筋面積(mm2)8049116036285、斜截面強(qiáng)度計(jì)算：次梁斜截面強(qiáng)度計(jì)算見表10次梁斜截面強(qiáng)度計(jì)算表10截面A支座B支座左B支座右C支座(kN)79.1696.796.396.3(kN)0.25×1.0×9.6×200×415=199.2kN>V截面滿足要求(kN)0.7×1.1×200×415=63.91kN<V按計(jì)算配箍箍筋直徑和肢數(shù)φ6雙肢

(mm2)2×28.3=56.62×28.3=56.62×28.3=56.62×28.3=56.6(mm)404.3188.1190.4190.4實(shí)配間距(mm)180180180180計(jì)算結(jié)果及次梁的構(gòu)造要求，繪次梁配筋圖,見圖22。三、主梁的計(jì)算（按彈性理論計(jì)算）1、荷載計(jì)算:次梁傳來的恒載：7.88×6.0=47.28kN/m2主梁自重：25×0.3×（0.7－0.08）×2.2=10.23kN梁側(cè)抹灰：17×0.015×（0.7－0.08）×2×2.2=0.696kN恒載標(biāo)準(zhǔn)值:=47.28+10.23+0.696=58.206kN活載標(biāo)準(zhǔn)值:=15.4×6=92.400kN恒載設(shè)計(jì)值:1.35=1.35×58.206=78.58kN活載設(shè)計(jì)值:1.3=1.3×92.40=120.1kN2、計(jì)算簡(jiǎn)圖各跨的計(jì)算跨度為:中間跨:==6600-400+400=6600mm邊跨:=6600－120－200+370/2+400/2=6665mm≤1.025+b/2=1.025×（6600－120－200）+400/2＝6637mm,取小值6637mm平均跨度:=(6637+6600)/2=6619mm跨度差:(6637-6600)/6600=0.56%<10%主梁的計(jì)算簡(jiǎn)圖見圖23。3、內(nèi)力計(jì)算:(1)彎距計(jì)算(值由附表5－1查得)邊跨:=78.58×6.637=521.5kN=120.1×6.637=797.1kN中跨:=78.58×6.6=518.6kN=120.1×6.6=792.7kN平均跨:=78.58×6.619=520.1kN=120.1×6.619=795kN主梁彎矩計(jì)算見表11。(2)剪力計(jì)算(值由附表查得)剪力計(jì)算見表12。主梁彎矩及剪力包絡(luò)圖見圖24主梁彎矩計(jì)算表11項(xiàng)次荷載簡(jiǎn)圖①恒載

0.244127.2

78.2-0.267-138.90.06734.70.06734.7-0.267-138.9②活載

0.289230.4

194.5-0.133-105.7

-105.7

-105.7-0.133-105.7③活載

-35.6

-70.7-0.133-105.70.200158.50.200158.5-0.133-105.7④活載

0.229182.5

99.8-0.311-247.2

75.90.170134.8-0.089-70.8⑤活載

-23.9

-47.3-0.089-70.80.170134.8

75.9-0.311-247.2內(nèi)力組合①+②357.6272.7-244.6-71-71-244.6①+③91.67.5-244.6193.2193.2-244.6①+④309.7178-386.1110.6169.5-209.7①+⑤103.330.9-209.7169.5110.6-386.1最不利內(nèi)力組合項(xiàng)次①+③①+③①+④①+②①+②組合值(kN·m)91.67.5-386.1-71-71-386.1組合項(xiàng)次①+②①+②①+⑤①+③①+③①+④組合值(kN·m)357.6272.7-209.7193.2193.2-209.74、正截面強(qiáng)度計(jì)算(1)確定翼緣寬度主梁跨中按T形截面計(jì)算邊跨：=6.37/3=2.2123m=0.3+5.7=6.0m取=2.2123m中間跨：=6.6/3=2.2m=0.3+5.7=6.0m取=2.2m支座截面仍按矩形截面計(jì)算(2)判斷截面類型取=640mm（跨中），=610mm（支座）=1.0×9.6×2212.3×80×(640-80/2)=1019.42kN·m＞357.6kN·m(193.2kN·m)屬于第一類T形截面主梁剪力計(jì)算表12項(xiàng)次荷載簡(jiǎn)圖①恒載

0.73357.6-1.267-99.561.00078.58②活載

0.866104.0-1.134-136.200③活載

-0.133-16-0.133-161.000120.1④活載

0.68982.7-1.311-157.51.222146.8⑤活載

-0.089-10.7-0.089-10.70.77893.4(kN)組合項(xiàng)次①+③①+④①+⑤組合值41.6-257.1172(kN)組合項(xiàng)次①+②①+⑤①+④組合值161.6-110.3225.4（3）截面強(qiáng)度計(jì)算主梁正截面強(qiáng)度計(jì)算見表135、斜截面強(qiáng)度計(jì)算：主梁斜截面強(qiáng)度計(jì)算見表14表中＝G+P=78.58+120.1=198.68KN主梁正截面強(qiáng)度計(jì)算表13截面邊跨中B支座中間跨中M(kN·m)357.6-386.1193.2-71(kN)___198.68×＝39.74______(kN·m)357.6-346.36193.2-710.0410.3230.0220.0100.9790.7970.9890.995(mm2)1902.52298.11017.4371.6選用鋼筋2φ25(彎)3φ20(直)1φ18+3φ25(彎)2φ16+1φ20(直)2φ16(直)1φ18+1φ25(彎)2φ16(直)2443.61147.3402主梁斜截面強(qiáng)度計(jì)算表14截面A支座B支座左B支座右(kN)161.6257.1225.4(kN)0.25×1.0×9.6×300×610=439.2kN>V截面滿足要求(kN)0.7×1.1×300×610=140.91kN<V按計(jì)算配箍箍筋直徑和肢數(shù)φ6@200雙肢140.91×10