,.第5章受壓構件的截面承載力5.1已知某多層四跨現(xiàn)澆框架結構的第二層內柱，軸心壓力設計值N1100kN，精品文檔放心下載樓層高H6m，混凝土強度等級為C20，采用Ⅱ級鋼筋（HRB335鋼筋）。謝謝閱讀柱截面尺寸為350mm350mm，求所需縱筋面積。精品文檔放心下載解：根據(jù)《混凝土結構設計規(guī)范》規(guī)定：1.25H1.2567.5m0則：l0750021.43，查表6－1得：0.714b350由N0.9fAfAcys1N111001033501786mm2AfA9.6350sf0.9c3000.90.714y選取425A1964mm2sA19641.6%0.6%，可以sA350350min截面每一側配筋率：19640.50.8%0.2%，可以350350min5.2已知圓形截面現(xiàn)澆鋼筋混凝土柱，直徑不超過350mm，承受軸心壓力設計謝謝閱讀值N1900kN，計算長度l4m，混凝土強度等級為C25，柱中縱筋采用精品文檔放心下載0HRB400鋼筋，箍筋用Ⅰ級鋼筋。試設計該柱截面。感謝閱讀解：柱子直徑取為350mm（1）先按普通縱筋和箍筋柱計算4m0,.l0400011.43，查表得：0.931d350A1d13.1435096162.5mm222由N0.9fAfAcysA1N1190000011.996162.53120mm2fAsf0.9c3600.90.931y3120As3.2%A96162.5選取822A3041mm2s（2）按采用螺旋箍筋柱計算，假定3%得：AA2885mm2s選取625A2945mm2s混凝土的保護層取30mm，則：dd30235060290mmcorA1d266018.5mm2cor4corfA2fAfAN0.9ccoryssoys混凝土強度等級為C25，1.0ANfAfA2f0.9ssoccorysy190000029450.911.966018.53602360368mm2其中：AdAcorss1ssos取螺旋箍筋直徑d10mm，則A 78.5mm2精品文檔放心下載ss1,.dcorAss13.1429078.5194mm感謝閱讀A368sso取s50mm，以滿足不小于40mm，并不大于80mm及0.2d的要求。cor所以：柱中縱筋選取625，A2945mm2s箍筋采用螺旋箍筋，s50mm，d10mmdA3.1429078.51429.6mm2驗算：Acorss1ssos500.25A0.252945736.25mm2，可以感謝閱讀sso s2fAfAN0.9fAccoryssoys36029450.911.966018.521.03601429.62587.6kNN0.9fAfA0.9360cys1.51876.1kN2814.2kN2587.6kN謝謝閱讀所以該柱的軸心受壓承載力設計值為2587.6kN1900kN，故滿足要求。精品文檔放心下載5.3已知柱的軸向力設計值N800kN，彎矩M160kNm；截面尺寸感謝閱讀b300mm，h500mm，aa45mm；混凝土強度等級為C30，采用ssHRB400級鋼筋；計算長度l3.5m。求鋼筋截面面積A及A。0ss解：eM1601030.2m200mm0N800103e20mm，hha455mma0seee20020220mmi0a0.5fcA0.514.33005001.341,精品文檔放心下載N8001031取 11,.l03.5715，取21.0h0.511l21350021400e/h01220111.07h125001400i0455e1.07220235.4mm0.3h136.5mmi0可以按大偏心受壓計算：eeihas235.450045440.4mm22NexfAhafbxh2，取0.5181c0ys0sbA'Nefbh210.51c0bbSf'ha'y0s800103440.41.014.330045520.51810.50.518精品文檔放心下載 3604554577mm2'bh0.002300500300mm2精品文檔放心下載min取A'300mm2sNfbxfAfA謝謝閱讀1cysySfbhNf'A'A1cb0yssfy1.014.33000.518455800103300360謝謝閱讀886mm2受拉鋼筋選用225，A982mm2；受壓鋼筋選用216，A402mm2。ssxNfAfA800103360402360982ysys235mmfb1.014.3300cx2350.5170.518h455b0故假定為大偏心受壓是正確的。垂直于彎矩作用平面的驗算：,.l03.511.67，查表得0.955b0.3NfAfAf0.9Aucysys0.90.95514.3300500360402360982精品文檔放心下載2271864N800103N滿足要求。5.4已知柱的軸向力設計值N550kN，彎矩M450kNm；截面尺寸感謝閱讀300mm，h600mm，aa45mm；混凝土強度等級為C35，采用Ⅲ感謝閱讀級鋼筋；計算長度l7.2m。求鋼筋截面面積A及A。0ss解：M450103mmme0N5501030.818818e20mm，hha555mma0eee 81820838mm謝謝閱讀i 0 a0.5fcA0.516.73006002.731，取1.01N5501031l7.21215，取1.000.6h21l2172002101838111.068121400555i0e1.068838895mm0.3h166.5mmi0可以按大偏心受壓計算：eha895600451150mmei22NexfAhafbxh，取0.5181c02ys0sb,.ANefbh210.51c0bbsfhay0s55010311501.016.730055520.51810.50.518精品文檔放心下載 36055545263mm2 bh0.2%300600360mm2謝謝閱讀minA360mm2sNfbxfAfA感謝閱讀1 c y s y SAfbhNfA1cb0yssfy1.016.73000.5185555501033602833mm2360謝謝閱讀受拉鋼筋選用232+228，A2841mm2；s受壓鋼筋選用216，A402mm2。sxNfAfA5501033604023602841ysys237.5mmfb1.016.7360cx237.50.4280.518h555b0故假定為大偏心受壓是正確的。垂直于彎矩作用平面的驗算：l07.224，查表得0.65b0.3NfAfAfA0.9ucysys0.90.6516.73006003604023602841感謝閱讀2441485.8N550103N滿足要求。5.5已知荷載作用下柱的軸向力設計值N3170kN，彎矩M83.6kNm；截面謝謝閱讀尺寸b400mm，h600mm，aa45mm；混凝土強度等級為C35，采謝謝閱讀,.用Ⅲ級鋼筋；計算長度l6.0m。求鋼筋截面面積A及A。0ss解：eM83.61030.0264m26.4mm0N3170103e20mm，hha555mma0eee26.42046.4mmi0a10.5fA16.74006000.632cl06.01015，取1.0h0.6211l21600020.63211.5440146.41400e/hh126001400555i0e1.54446.471.4mm0.3h166.5mmi0初步判定為小偏心受壓。0.8，0.5181bbh0.002400600480mm2精品文檔放心下載min1fsy1e

h2

ei

a30071.445

183.6mmeei

h2

a

71.430045

326.4mmxaAaNe'fbxh1c2sss0s3170103183.61.016.7x450.8360400x20.5180.8解得x461mmxfAhaNefbxh21c0ys0s,.ANefbxh0.5x1c0sfhay0s3170103326.41.016.7400461555461236055545192mm2bh480mm2min為了防止反向破壞，對A進行驗算。sNhaeehfbhh01c02A2asafhy0s31701033004526.4201.016.7400600555300感謝閱讀 36055545負數(shù)不會發(fā)生反向破壞。受拉鋼筋選用218，A509mm2；受壓鋼筋選用218，A509mm2。ss由NfbxfAA和1f1cyssssy1得x444mmh0.518555287.5mm精品文檔放心下載0所以按小偏心受壓計算是正確的。驗算垂直于彎矩作用方向的承載力：l06.015，查表得0.895b0.4NfAfAf0.9Aucysys0.90.89516.7400600360509360509精品文檔放心下載3523643.64N3170103N滿足要求。5.6已知軸向力設計值N7500kN，彎矩M1800kNm；截面尺寸b800mm，精品文檔放心下載,.1000mm，aa45mm；混凝土強度等級為C30，采用Ⅱ級鋼筋；計算精品文檔放心下載長度l6m，采用對稱配筋（AA）；求鋼筋截面面積AA。感謝閱讀0 s s s s解：NfbxfAfA感謝閱讀1 c y s y sxN7500103655.6mmxh525.25mmfb1.014.3800bb01c按小偏心受壓計算。MN180075000.24m240mm0感謝閱讀e100033mm，hha955mma300seee 24033273mm感謝閱讀i 0 a0.5fcA0.514.380010000.763感謝閱讀N75001031l06000615，取1.0h1000211l2160002012730.76311.0681400e/hh1210001400955i0e1.068273292mm0.3h286.5mmi0eeha29250045747mmi2s按簡化方法計算：0.81Nfbhb1c0Ne0.43fbh2b1c0fbha1c00.8hb075001030.55114.38009550.5575001037470.43114.38009552114.38009550.80.55955450.645xh0.645955616mm謝謝閱讀0,.AANefbh210.51c0ssfahy07500103747114.380095520.64510.50.645300955453663mm2bh1600mm2min選用825，AA3927mm2。ss5.7已知柱的軸向力設計值N3100kN，彎矩M85kNm；截面尺寸感謝閱讀400mm，h600mm，aa45mm；混凝土強度等級為C20，采用Ⅲ謝謝閱讀級鋼筋；配有A1964mm2（425），A603mm2（316），計算長度ssl06m，試復核截面是否安全。xNfAfA31001033601964360603解：ysys1.09.6400fbc680mmh按小偏心受壓計算，重新計算x。NfbxfAA感謝閱讀1cysssx0.831001031.09.6400x36019645553606030.5180.8所以x610.5mmh取xh600mm進行計算。xfafbxhAh1c02ys0seN1.09.6400600555300360196455545精品文檔放心下載3100103305.8mmeieh2a305.860024550.8mm精品文檔放心下載取1.0,.e50.8mmie

e

e

50.820

30.8mm0

i

aNe310010330.895.48kNmM85kNm感謝閱讀0經(jīng)計算1.35與假定的1.0相矛盾精品文檔放心下載重新選取1.4，則e36.3mm感謝閱讀ie

e

e

36.320

16.3mm0

i

aNe310010316.350.53kNm謝謝閱讀0經(jīng)過計算1.4，可以。因MM85kNm，故截面不安全。u5.8已知某單層工業(yè)廠房的形截面邊柱，下柱高 5.7m，柱截面控制內力謝謝閱讀N870kN，M420kNm；截面尺寸b80mm，h700mm，精品文檔放心下載b'350mm