80米烟囱计算

一、设计资料烟囱高Ｈ＝80ｍ烟囱顶部内直径Ｄ０＝4.5ｍ基本风压值（兴城）ｗ０＝0.45ｋＮ／ｍ２抗震设防烈度６度建筑场地土类别Ⅱ类烟气最高温度Ｔｇ＝150℃夏季极端最高温Ｔａ＝40℃冬季极端最低温Ｔａ＝-30℃二、材料选择及计算指标１筒壁采用强度等级Ｃ３０混凝土，ＨＲＢ３３５（２０ＭｎＳｉ）钢筋（１）混凝土计算指标：ｆｃｋ＝20.1Ｎ／ｍｍ２ｆｃ＝14.3Ｎ／ｍｍ２ｆｔｋ＝2.01Ｎ／ｍｍ２ｆｔ＝1.43Ｎ／ｍｍ２Ｅｃ＝3.0E+04Ｎ／ｍｍ２线性膨胀系数ａｃ＝1.0E-05℃重力密度＝25ｋＮ／ｍ3（2）钢筋计算指标ｆyｋ＝335Ｎ／ｍｍ２ｆy＝300Ｎ／ｍｍ２Ｅs＝2.0E+05Ｎ／ｍｍ２2隔热层矿渣棉重力密度＝2ｋＮ／ｍ3硅藻土砖砌体重力密度=6ｋＮ／ｍ33内衬粘土质耐火砖重力密度=19ｋＮ／ｍ3三、设计依据1《烟囱设计规范》GB50051；2《混凝土结构设计规范》GB50010；3《建筑抗震设计规范》GB50011；4《建筑结构荷载规范》GB50009四、烟囱形式截面号标高筒壁外半径筒壁坡度筒壁厚度矿渣棉厚度802.610.020.160.11702.810.020.160.12603.010.020.180.13503.210.020.20.14403.410.020.220.1筒身截面尺寸单筒式钢筋混凝土烟囱的计算5303.610.020.240.156203.810.020.260.157104.010.020.280.15804.360.0350.30.15五、筒身自重计算1筒壁体积V=2πrth=2π（C5+C6-0.16）/2*0.16*10=28.44m3自重G=28.44X252矿渣棉隔热层外半径及壁厚：截面1处r1=2.81-0.16t=0.1m截面2处r2=3.01-0.18t=0.1m体积V=2π（r1+r2-t）/2*t*10=16.89立方米自重G=16.89X23硅藻土隔热层外半径及壁厚：截面1处r1=2.65-0.1t=0.116m截面2处r2=2.83-0.1t=0.116m体积V=2π（r1+r2-t）/2*t*10=18.81立方米自重G=18.81X64耐火砖内衬外半径及壁厚：截面1处r1=2.55-0.116t=0.113m截面2处r2=2.73-0.116t=0.113m体积V=2π（r1+r2-t）/2*t*10=17.51立方米自重G=17.51X195每节底部重量筒身体积及自重标高（m）混凝土矿渣棉硅藻土耐火砖17026.4315.7017.4316.1626028.4416.8918.8117.51截面号体积（m3）35034.1418.0220.1218.7944040.3219.1521.4320.0753046.9720.2822.5620.7462054.1131.8947.3142.7471061.7233.5849.9845.348071.1335.9853.7649.02六、风荷载及风弯矩计算1风荷载系数：各系数取值及计算公式按《建筑结构荷载规范》。（１）风振系数βz=(1+ευφz)/μz式中ε脉动增大系数。烟囱自振周期T1按《建筑结构荷载规范》GB50009-2001附录Ｅ．１．２－２进行计算高度不超过150m的钢筋混凝土烟囱T1=０．４１＋０．１Ｘ１０－２Ｈ２／ｄT1=1.35s式中H为烟囱高度H=80m烟囱1/2高度处的外径d=6.82m据ｗ０T12=０．４５Ｘ１．３８Ｘ1.３５２=1.13　　查表7.4.3（《建筑结构荷载规范》GB50009-2001）得　ε＝式中υ－脉动影响系数，υ＝υ１θυθＢ；υ１－等截面高耸结构脉动影响系数，查表７．４．４－１；θυ－修正系数，为质量沿高度按连续规律变化时，脉动影响系数修正系数，按迎风面顶部宽度ＢＨ和底部宽度Ｂ０的比值，查表７．４．４－２；θＢ－构筑物迎风面在Ｚ高度处的宽度ＢＺ与底部宽度Ｂ０的比值；φz－振型系数，依据Ｚ／Ｈ及ＢＨ／Ｂ０查附表Ｆ表Ｆ．１．１风振系数计算标高筒壁外半径（m）（m）θＢ＝ＢＺ／Ｂ０θυυ１802.610.600.891702.810.640.892603.010.690.893503.210.740.884403.410.780.875303.610.830.866203.810.870.837104.010.920.78804.361.00（２）风压高度变化系数μｚ；地面粗糙类别按Ａ类，查表７．２．１（３）风荷载体型系数μｓ＝0.62风荷载标准值ｗk＝βzμｓμｚｗ０=0.27βzμｚ截面号脉动影响系数1.50将βz、μｚ代入列表计算，如下表。3风弯矩标准值计算标高筒壁外半径节高风振系数（m）（m）（m）βz802.611.512.271702.81101.482.202603.01101.442.123503.21101.352.034403.41101.261.925303.61101.181.806203.81101.101.637104.01101.041.38804.36101.001.00七、地震作用及内力计算1水平地震作用及弯矩。（1）烟囱自振周期：T1=0.45+0.0011H2/d=1.48s（2）烟囱底部弯矩和剪力。地震影响系数按Ⅱ类场地，特征周期Tg=0.45(s),水平地震影响系数最大值αmax=0.16截面号高度变化系数μｚ12硅藻土厚度耐火砖厚度0.1160.11330.1160.1130.1160.1130.1160.1130.1160.1134筒身截面尺寸单筒式钢筋混凝土烟囱的计算0.2360.230.2360.230.2360.230.2360.2352π（C5+C6-0.16）/2*0.16*106=710.9kN7=2.65m=2.83m8=33.8kN=2.55m=2.73m=112.9kN=2.434m=2.614m=332.7kN每节下部重量混凝土矿渣棉硅藻土耐火砖（kN）660.731.4104.6307.1660.7710.933.8112.9332.71814.6自重（kN）853.536.0120.7357.03147.41007.938.3128.6381.24669.11174.440.6135.4394.06391.51352.763.8283.8812.18314.21543.067.2299.9861.511016.91778.272.0322.5931.414023.6烟囱自振周期T1按《建筑结构荷载规范》GB50009-2001附录Ｅ．１．２－２进行计算kNs2/m21.453修正系数，为质量沿高度按连续规律变化时，脉动影响系数修正系数，按迎风面顶部宽度ＢＨ和底部宽度Ｂ０的比值，查表７．４．４－２；构筑物迎风面在Ｚ高度处的宽度ＢＺ与底部宽度Ｂ０的比值；υ＝υ１θυθＢＺ／Ｈφz0.801.001.002.271.510.860.880.852.201.480.920.750.692.121.440.970.630.502.031.351.020.500.341.921.261.070.380.211.801.181.090.250.101.631.101.080.130.031.381.040.000.001.001.00振型系数风压高度变化系数μｚ风振系数βz=(1+ευφz)/μz脉动影响系数0.930.8848.94244.70.8249.51981.70.7448.522208.80.6546.103909.10.5743.156055.70.4839.248614.20.3933.9711538.80.2727.4614770.5地震影响系数按Ⅱ类场地，特征周期Tg=0.45(s),水平地震影响系数最大值αmax=0.16均布风荷载ｗk＝0.27βzμｚ（kN/m2）集中风荷载Qik=(ｗik+ｗ(i-1)k)/2(ri+ri-1)h1(kN)风弯矩Mwk=∑Qikhi(kN·m)80m70m60m50m40m30m20m10m0.00每节重量（kN）1103.71190.21367.21556.11744.32512.42771.53104.1