梯形钢屋架

单层厂房钢屋盖设计计算书一、设计计算资料梯形屋架跨度27m，屋架间距6m，厂房长度84m。屋架支撑于钢筋混凝土柱子上，节点采用焊接方式连接。钢筋混凝土柱高12m，其混凝土强度等级为C30。钢材为Q235-B，焊条E43型。厂房内有中级工作制桥式吊车，起重量Q≤300kN。屋面均布活荷载（不与雪荷载同时考虑）为：轻型屋面取0.3kN/㎡,但计算负荷面积不超过60㎡时，取0.5kN/㎡；重型屋面取0.5kN/㎡。屋面材料为长尺压型钢板，屋面坡度i8/1，H型钢檩条的水平间距为3.375m。基本风压为0.75kN/㎡，基本雪压为0kN/㎡。二、屋架几何尺寸的确定屋架的计算跨度mmLl26700300270003000，端部高度取mmH19900跨中高度为mm3680H,36788227000190020取mmLiHH。跨中起拱高度为60mm（L/500）。梯形钢屋架形式和几何尺寸如图1所示。三、屋盖支撑布置根据厂房长度（84m60m）、跨度及荷载情况，设置三道上、下弦横向水平支撑。因柱网采用封闭结合，厂房两端的横向水平支撑设在第一柱间，该水平支撑的规格与中间柱间支撑的规格有所不同。在所有柱间的上弦平面有檩条代替刚性与柔性系杆，以保证安装时上弦杆的稳定，在各柱间下弦平面的跨中及端部设置了柔、刚性系杆，以传递山墙风荷载。在设置横向水平支撑的柱间，于屋架跨中和两端各设一道垂直支撑。梯形钢屋架支撑布置如图2、图3、图4所示。其中SC#为上弦支撑、XC#为下弦支撑、CC#为垂直支撑、GG#为刚性系杆、RG#为柔性系杆、GWJ#为屋架。四、荷载计算1、永久荷载（水平投影面）压型钢板151.086515.0kN/㎡檩条（0.5kN/m）0.148kN/㎡屋架及支撑自重0.01L=0.27kN/㎡合计0.569kN/㎡2、可变荷载（水平投影面）因屋架受荷水平投影面积不超过60㎡，故屋面均布活荷载为0.50kN/㎡，无雪荷载。故取屋面均布活荷载为可变荷载。3、风荷载风压高度变化系数为1.056，屋面迎风面的体型系数为-0.6，背风面为-0.5，所以负风压标准值（垂直于屋面）为：迎风面：475.075.0056.16.00.11wkN/㎡背风面：396.075.0056.15.00.12wkN/㎡对轻型钢屋架，当风荷载较大时，风吸力可能大于屋面永久荷载，此时屋架弦杆和腹杆中的内力均可能变号，必须考虑风荷载组合。但此处风荷载小于永久荷载，故不考虑风荷载的影响。五、屋架杆件内力计算与组合由永久荷载控制的荷载组合值为：258.150.04.17.0569.035.1kN/㎡由可变荷载控制的荷载组合值为：383.150.04.1569.02.1kN/㎡故可变荷载效应起控制作用。1、荷载组合考虑以下二种荷载组合（1）全跨永久荷载+全跨可变荷载（2）全跨永久荷载+半跨可变荷载（3）全跨屋架、支撑及天窗架自重+半跨屋面板重+半跨屋面活荷载因在施工中能保证屋面板对称布置，所以不考虑第三种荷载组合。2、节点荷载（1）永久荷载：827.136375.3569.02.11FkN（2）可变荷载：175.146375.350.04.12FkN3、内力系数计算因屋架结构对称，由结点法解得F＝1作用于左半跨时的屋架各杆件的内力系数，如图5所示。计算过程如下由0aM，0225.30.16.60.1975.90.135.135.07.26'aR得0.1'aR；由0y，040.1'aaRR得0.3aR。结点a0x，得0abN；0y，得0.3aaARN。结点A0x，得AbABAbABNNNN858.00851.0992.00y，得05.2525.0124.0AbABNN由以上两式求得398.3,960.3ABAbNN结点b0x，得370.30851.0bcbAbcNNN0y，得079.20525.0bBbAbBNNN结点B0x，得0398.3992.0815.0992.0BcBCNN0y，得0500.1579.0124.0BcBCNN由以上两式求得581.1,698.4BcBCNN结点c0x，得659.40370.3815.0cdcBcdNNN0y，得915.00579.0cCcBcCNNN结点C0x，得0698.4992.0767.0992.0CdCDNN0y，得0498.0642.0124.0CdCDNN由以上两式求得114.0,610.4CdCDNN结点d0x，得577.40659.4707.0dedCdeNNN0y，得079.00642.0dDdCdDNNN结点D0x，得0610.4992.0720.0992.0DeDENN0y，得0507.0694.0124.0DeDENN由以上两式求得377.1,610.3DeDENN结点E0x，得610.30610.3992.0992.0''EDEDNN0y，得395.005.0610.3124.02EeEeNN结点e0y，得808.00395.0377.1694.0694.0''eDeDNN0x，得004.30586.3808.0720.0''ededNN结点D’0x，得024.30582.0581.3992.0''''CDCDNN0y，得611.00448.0375.0561.0''''dDdDNN结点d’0y，得952.00642.0''''''CdDdCdNNN0x，得334.20004.3767.0''''''cdCdcdNNN结点C’0x，得448.20730.0000.3992.0''''BCBCNN0y，得705.00611.0375.0304.0''''cCcCNN结点c’0y，得218.10579.0''''''BcCcBcNNN0x，得341.10815.0''''''''bcdcBcbcNNNN结点B’0x，得447.10992.0428.2992.0''''BCABNN0y，得829.00304.0705.0179.0''''bBbBNN结点b’0y，得579.10525.0''''''AbBbAbNNN0x，得00851.0''''''''abcbAbabNNNN结点A’0y，得0.10829.0171.0''''aAaANN0x，得0851.0992.0''''bABANN结点a’0x，得0'''AaaNR0y，得0''baN4、屋架杆件内力计算前面已求得杆件的内力系数，所以只需将杆件内力系数分别乘以各种荷载组合下节点荷载即得各种荷载组合下的杆件内力。杆件内力计算过程见表1。表1屋架构件内力组合表（单位：KN）杆件内力系数（F=1）单项荷载内力内力组合最不利组合活载恒载第一种第二种名称编号左半跨①右半跨②全跨③㈠左半跨F2*①㈡右半跨F2*②㈢全跨F1*③㈠+㈡+㈢㈠+㈢㈡+㈢上弦杆AB-3.398-1.447-4.875-48.167-20.511-67.407-136.085-115.574-87.918-136.085A’B’-1.447-3.398-4.875-20.511-48.167-67.407-136.085-87.918-115.574-136.085BC-4.698-2.448-7.146-66.594-34.700-98.808-200.102-165.402-133.508-200.102B’C’-2.448-4.698-7.146-34.700-66.594-98.808-200.102-133.508-165.402-200.102CD-4.610-3.024-7.814-65.347-42.865-108.044-216.256-173.391-150.909-216.256C’D’-3.024-4.610-7.814-42.865-65.347-108.044-216.256-150.909-173.391-216.256DE-3.610-3.610-7.220-51.172-51.172-99.831-202.175-151.003-151.003-202.175D’E-3.610-3.610-7.220-51.172-51.172-99.831-202.175-151.003-151.003-202.175下弦杆ab0000000000a’b’0000000000bc3.3701.3414.71147.77019.00865.139131.917112.90984.147131.917b’c’1.3413.3704.71119.00847.77065.139131.91784.147112.909131.917cd4.6592.3346.99366.04133.08496.692195.817162.733129.776195.817c’d’2.3344.6596.99333.08466.04196.692195.817129.776162.733195.817de4.5773.0047.58164.87942.582104.822212.283169.701147.404212.283d’e3.0044.5777.58142.58264.879104.822212.283147.404169.701212.283斜腹杆Ab3.9601.5795.53056.13322.38276.463154.978132.59698.845154.978A’b’1.5793.9605.53022.38256.13376.463154.97898.845132.596154.978Bc1.5811.2182.79922.41117.26538.70278.37861.11355.96778.378B’c’1.2181.5812.79917.26522.41138.70278.37855.96761.00378.378Cd-0.1140.9520.838-1.61613.94611.58723.9179.97125.53325.533C’d’0.952-0.1140.83813.946-1.61611.58723.91725.5339.97125.533De-1.3770.808-0.569-19.51911.453-7.868-15.934-27.3873.585-27.387D’e0.808-1.377-0.56911.453-19.519-7.868-15.9343.585-27.387-27.387竖杆Aa-3.000-1.000-4.000-42.525-14.175-55.308-112.008-97.833-69.483-112.008A’a’-1.000-3.000-4.000-14.175-42.525-55.308-112.008-69.483-97.833-112.008Bb-2.079-0.829-2.908-29.470-11.751-40.209-81.430-69.679-51.960-81.430B’b’-0.829-2.079-2.908-11.751-29.470-40.209-81.430-51.960-69.679-81.430Cc-0.915-0.705-1.620-12.970-9.993-22.400-45.363-35.370-32.393-45.363C’c’-0.705-0.915-1.620-9