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1、第五章豎向荷載作用下橫向框架(KJ-3)內(nèi)力計(jì)算由于結(jié)構(gòu)基本對(duì)稱,在豎向荷載作用下的框架側(cè)移可略去不計(jì)。其內(nèi)力分析采用彎矩分配法,在豎向荷載作用下梁端可以考慮塑性內(nèi)力重分布,取彎矩調(diào)幅系數(shù)0.8,樓面的豎向荷載分別按恒載及滿跨活載計(jì)算。5.1豎向恒載作用下內(nèi)力計(jì)算5.1.1恒荷載計(jì)算:(1)計(jì)算單元:計(jì)算單元寬度為3.9m,如圖所示。直接傳給框架的樓面荷載如圖中水平陰影所示,計(jì)算單元范圍內(nèi)的樓面荷載則直接通過次梁以集中力的形式傳給橫向框架梁,作用在各結(jié)點(diǎn)上。由于縱向框架梁與柱軸線不重合,因此在框架結(jié)點(diǎn)上還
2、作用有集中力矩。15(2)荷載計(jì)算①均布荷載:在上圖中=4.125/m代表橫梁自重。②頂層:A、D柱集中力=(2.256+2.187+4.1×1.35)×3.9=38.92KNC柱集中力=(2.187+4.1×2.55)×3.9=49.30KNF1處集中力=(1+4.1×2.7)×3.9=47.10KNF2處集中力=(1+4.1×2.4)×3.9=42.28KNF3處集中力=(1+4.1×2.85)×3.9=49.47KN附加節(jié)點(diǎn)彎矩:38.92×0.18=7③1~4層:A、D柱集中力=(3.8×3.15
3、+2.187+3.9×1.35)×3.9+3.6×5.625=96.0KNC柱集中力=(3.8×3.15+2.187+3.9×2.55)×3.9+3.6×6.75=118.30KNF1處集中力=(1+3.9×2.7)×3.9=44.97KNF2處集中力=(3.8×3.15+1+3.9×2.4)×3.9=87.09KNF3處集中力=(1+3.9×2.85)×3.9=47.25KN附加節(jié)點(diǎn)彎矩:96.0×0.18=17.28即,5層邊柱附加彎矩:38.92/2×0.42+96/2×0.18=16.814層邊柱
4、附加彎矩:96/2×0.42+96/2×0.18=28.82-3層邊柱附加彎矩:96/2×1.0+96/2×0.18=56.641層邊柱附加彎矩:96×0.18=17.28155.1.2活荷載計(jì)算活荷載布置:辦公室:2.0kN/m2走廊、樓梯、衛(wèi)生間:2.5kN/m2不上人屋面:0.5kN/m2活載作用在次梁上,次梁作用在主梁上,故考慮框架時(shí),活載按集中力布置?;詈奢d作用下框架梁梁上的荷載分布如下:屋面:P1=0.5×3.9×1.35=2.63KN;F1=0.5×3.9×2.7=5.27KNF2=0.5×
5、3.9×2.4=4.68KNP2=0.5×3.9×2.55=4.97KNF3=0.5×3.9×2.85=5.56KNP3=0.5×3.9×1.35=2.63KN露面:P1=2×3.9×1.35=10.53KN;F1=2×3.9×2.7=21.06KNF2=2×3.9×1.35+2.5×3.9×1.05=20.77KNP2=2.5×3.9×1.05+2×3.9×1.5=21.94KNF3=2×3.9×2.85=22.23KNP3=2×3.9×1.35=10.53KN一層:P2=2.5×1.95×2.55+2
6、×1.95×1.5+2.5×1.95×1.05=23.4KNF3=2.5×1.95×2.85+2×1.95×2.85=25.01KNP3=2.5×1.95×1.35+2×1.95×1.35=11.85KN15活荷載滿跨布置圖(單位:)恒荷載布置圖單位(單位:)活載各層隔跨布置-①工況(單位:)活載各層隔跨布置-②工況(單位:)155.1.3恒載作用下固端彎矩計(jì)算均布荷載:=—4.125×7.52/12=-19.34=—4.125×5.72/12=-11.17=4.125×7.52/12=19.34=4.1
7、25×5.72/12=11.17集中力作用下:①=-(47.1×2.7×4.82+42.28×5.4×2.12)/7.52=-70.21=(47.1×4.8×2.72+42.28×2.1×5.42)=75.89=-49.47×3×2.72/5.72=-33.3=49.47×2.7×32/5.72=37②=-(44.97×2.7×4.82+87.09×5.4×2.12)/7.52=-91.83=(44.97×4.8×2.72+87.09×2.1×5.42)=125.73=-47.25×3×2.72/5.72
8、=-31.81=47.25×2.7×32/5.72=35.3415故豎向恒載作用下,待分配彎矩為:MA5=70.21+19.34-16.81=72.74MA4=91.83+19.34-28.8=82.37MA3=MA2=91.83+19.34-56.64=54.53MA1=91.83+19.34-17.28=93.89Mc5左=-(75.89+19.34)=-95.23Mc5右=(33.3+11.17)=44.47MC4左=M