現(xiàn)澆混凝土樓蓋課程設(shè)計(jì)

板的設(shè)計(jì)取板厚h=80mm>l/40=2400/40=60mm取1m寬板帶為計(jì)算單元，按考慮塑性內(nèi)力重分布方法計(jì)算內(nèi)力。荷載計(jì)算樓面面層板自重板底抹灰恒荷載活荷載總荷載設(shè)計(jì)值計(jì)算簡圖次梁截面高h(yuǎn)=(1/8～1/12)×7200=(400～600)mm可取h=500b=(1/3～1/2)×500mm=(167～250)mm，取b=200mm，板的實(shí)際支撐情況如圖1—1a計(jì)算跨度為：中間跨l0=ln=2400mm-200mm=2200mm邊跨l0=ln+h/2=(2200mm-100mm-120mm)+80mm/2=2220≤ln+a/2=2220+120/2=2280mm由于邊跨與中間跨的跨度差（2220-2200）mm/2200mm=0.9%<10%,故可按等跨連續(xù)板計(jì)算，板的計(jì)算簡圖見圖1-1b,所示(a)(b)1-1板的計(jì)算簡圖彎矩計(jì)算：M1=1/11ql02=1/11×11.088KN/m×(2.22m)2=4.97KN·mMB=-1/11ql02=-1/11×11.088KN/m×(2.22m)2=-4.97KN·mMC=-1/14ql02=-1/14×11.088KN/m×(2.20m)2=-3.83KN·mM2=M3=1/16ql02=1/16×11.088KN/m×(2.20m)2=3.35KN·m配筋的計(jì)算板截面有效高度h0=80mm-25mm=55mm。因中間板帶的內(nèi)區(qū)格四周與梁整體連接，故M2和MC值降低20%。計(jì)算過程見表1.1，板的配筋平面圖見圖1.2表1.1板的配筋計(jì)算截面1B2,3CM/(kN·m)4.97-4.973.35(2.68)-3.83(-3.06)αs=M/(α1fcbh02)0.171-0.1710.115(0.092)-0.132(-0.106)0.189-0.1580.123(0.097)-0.124(-0.101)AS=α1ξbh0fC/fy475-397309(244)-312(-254)實(shí)配鋼筋/mm2變板帶Φ8/10@125AS=515Φ8@125AS=402Φ8@125AS=402Φ6/8@125AS=314中間板帶Φ10@160AS=491Φ8/10@160AS=403Φ6/8@160AS=246Φ8@160AS=314注：括號內(nèi)數(shù)據(jù)為中間板帶的數(shù)據(jù)。次梁的設(shè)計(jì)主梁截面高度h=(1/8～1/14)×7200㎜=(900～514)㎜.取h=750㎜.主梁寬度取250㎜，次梁的幾何尺寸及支撐情況見圖1-2（a）荷載計(jì)算板傳來的恒載次梁自重次梁粉刷恒荷載活荷載總荷載設(shè)計(jì)值計(jì)算簡圖次梁按考慮塑性內(nèi)力重分布方法計(jì)算內(nèi)力計(jì)算跨度為中間跨：l0=ln=6300㎜-250㎜=6050㎜邊跨:l0=ln+a/2=(6300㎜-250㎜/2-120㎜)+120㎜=6175㎜<1.025ln=6206㎜故邊跨取l0=6175㎜邊跨與中間跨的計(jì)算跨度相差（6175-6025）㎜/6050㎜=2.9%<10%故可取按等跨連續(xù)梁計(jì)算內(nèi)力，計(jì)算簡圖見圖1-2（b）所示(a)(b)1-2次梁的計(jì)算簡圖（3）內(nèi)力計(jì)算彎矩：M1=1/11ql02=1/11×29.47kN/m×(6.175)2=102.16kN·mMB=-1/11ql02=-1/11×29.47kN/m×(6.175)2=-102.16kN·mMC=-1/14ql02=-1/14×29.47kN/m×(6.050)2=-77.05kN·mM2=M3=1/16ql02=1/16×29.47kN/m×(6.050)2=67.42kN·m剪力：VAR=0.45qln=0.45×29.47kN/m×6.055m=80.30kNVBl=0.6qln=0.6×29.47kN/m×6.055m=107.06kNVBR=VCl=VCr=0.55qln=0.55×29.47kN/m×6.055m=98.06kN配筋的計(jì)算次梁跨中按T形截面進(jìn)行正截面受彎承載力計(jì)算，翼緣計(jì)算寬度按下面的較小值采用bf'=1/3l0=1/3×6050mm=2017mm,bf'=b+sn=200mm+2200mm=2400mm,故取bf'=2017mm。跨中及支座截面均按一排鋼筋考慮，故取h0=460mm,翼緣厚度hf'=80mm。α1fcbf'hf'(h0-hf'/2)=9.6N/mm×2017mm×80mm×(460mm-80mm/2)=650.6kN·m此值大于跨中彎矩設(shè)計(jì)值M1，M2,M3故各跨中截面均屬于第一類T形截面，支座按矩形截面計(jì)算，次梁正截面受彎承載力計(jì)算見表1.3c表1.3c次梁正截面承載力計(jì)算截面1B2,3CM/(kN·m)102.16-102.1667.42-77.05b或bf'/mm20172002017200αs=M/(α1fcbh02)0.025-0.2510.016-0.190ξ=1-√1-2αs0.0250.1<0.226<0.350.016-0.175AS=α1ξbh0fC/fy742739475515實(shí)配鋼筋/㎜2次梁斜截面受剪承載力計(jì)算見表1.3d，考慮塑性內(nèi)力重分布時(shí)，箍筋數(shù)量應(yīng)增加20%，故計(jì)算時(shí)將ASV乘以1.2。箍筋配筋率ρsv應(yīng)大于或等于0.24ft/fy=0.0013,各截面均滿足要求表1.3d次梁斜截面受剪承載力截面ArBlBr,Cl,CrV/kN80.30107.0698.060.25βcfcbh0/kN220.8>V220.8>V220.8>V0.7ftbh0/kN70.8<V70.8<V70.8<V=0.094mm=0.360mm=0.271mm實(shí)配鋼筋雙肢φ8@2