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水平荷载计算7.1风荷载标准值风压标准值计算公式为;0wwzsz式中,基本风压200.45/wkNm;z——风压高度变化系数,建设地点位于济南市,所以地面粗造度为C类,s——风荷载体型系数,由《荷载规范》查得:迎风面为0.8,背风面为0.5;z——风振系数,因结构高度为H=19.6m30m可取0.1zB——计算单元迎风面的宽度,取为4.2m。房屋高度的分布荷载标准值Awpzsw0计算各层点的受风面积时取上层一半和下层一半之和。顶层取女儿墙高度和下层一半之和,底层计算高度从基础顶开始取。顶层A=(1+3.6/2)X4.2=11.76M2中间层A=3.6x4.2=15.12m2底层A=206.79.3215.526.3m4.2=18.38m2各层楼面处风荷载标准值的计算见下表层次zzsZ(m)20(/)wkNmA(2m)KNPw50.741.01.319.550.4511.765.0940.741.01.315.950.4515.126.5530.741.01.312.350.4515.126.5520.741.01.38.750.4515.126.5510.741.01.35.150.4518.387.96风荷载计算简图如下:风荷载计算简图风荷载沿房屋高度分布图7.2框架梁柱线刚度计算取4轴框架作为计算框架,考虑到楼板对梁的作用,边框架梁I=1.5I0中框架梁I=2.0I0(I0为不考虑楼板作用的梁截面惯性矩),梁柱均采用C30混凝土CE=3.07102/mKNAC,DF跨梁选用L3:b=250mm,h=700mmI0=1/12bh3=1/120.25.0.73=7.1410-3m4i=EI/L=1.5EI0/L=1.57.1410-3E/7.8=1.3710-3E(m3)CD跨梁选用L2:b=250mm,h=400mmI0=1/12bh3=1/120.250.43=1.3410-3m4i=EI/L=2EI0/L=21.3410-3E/7.8=0.8910-3E(m3)上部各层柱:i=0.9xEI/L=0.9xE/3.61/120.50.53=1.30510-3E(m3)(0.9折减)底层柱:i=EI/L=E/(4.2+0.45+0.5)1/120.50.53=1.0110-3E(m3)注:计算线刚度时根据地质资料,确定基础顶离室外地面为500mm,室内外高差为450mm,则底层高度为4.2+0.45+0.5=5.15m各梁柱构件的线刚度经计算如下图:7.3柱的抗侧刚度D值柱的侧移刚度D值可根据公式进行计算:212hiαDcc式中:cα——框架柱侧移刚度修正系数,根据不同的情况按表3-4计算,其中K表示梁、柱线刚度比。ci——柱的线刚度;h——框架柱的计算跨度;按照上述公式5-4,可计算出各柱的侧移刚度,将计算单元范围内所有柱的D值相加,即为该层框架的总侧移刚度iD。柱侧移刚度修正系数cα楼层类别边柱中柱cα一般层ciiiK24212342ciiiiKiKKc2底层固端ciiK2ciiiK21KKc25.0根据梁、柱线刚度比K的不同,柱可分为中框架梁边柱、中框架梁中柱、边框架梁边柱、边框架梁中柱以及楼梯间柱。一般层中柱:102.11080.10260.530.660.530.610K(1.37+0.89+1.37+0.89/2x1.31)102.11080.10260.530.660.530.610K1.725柱侧移刚度修正系数:355.0102.12102.12KKc1.725/2+1.725=0.463修正后柱侧移刚度:mmNhiαDcc/511203000108.1012355.01221020.463X12X1.31X1010/36002=5616N/mm框架柱侧移刚度D值楼层中柱iDmmN/KcαiD1mmN/2~6层1.7250.4635616112321层2.240.64644388877楼层边柱iDmmN/KcαiD1mmN/2~6层1.0460.343416083201层1.360.554380676127.4风荷载作用下的水平位移验算框架在风荷载的作用下的会产生一定的位移,通过风荷载的作用下可以对框架进行侧移的初步估算,水平荷载作用下的层间侧移可按公式计算。jjijVuD式中jV——第j层的总剪力;ijD——第j层所有柱的抗侧刚度之和;ju——第j层的层间位移。第一层的层间侧移值求出以后,可以计算各楼板标高处的侧移值的顶点侧移值,各层楼板标高处的侧移值是该层以下各层层间位移之和。顶点侧移是所有层层间侧移之和。j层侧移:1jjjjuu;顶点侧移:1njjuu。依据框架层间侧移刚度计算各层相对侧移和绝对侧移,计算过程见下表风荷载作用下的框架层间剪力及侧移计算层次计算高度mmkNFikNVimkNDimDViiimjijh536005.095.09195520.000260.000260.000000074360011.6411.64195520.000590.000850.000000243360018.1918.19195520.000930.001780.000000492360024.7424.74195520.001270.003050.000000841515032.732.7165000.001980.005030.000002注:按上述方法求得的框架结构侧向水平位移只是由梁、柱弯曲变形所产生的变形量,而未考虑梁、柱的轴向变形和截面剪切变形所产生的结构侧移。但对一般的多层框架结构,按上式计算的框架侧移已能满足工程设计的精度要求。风荷载作用下框架的侧移验算:层间侧移最大值:1/14081/550(满足要求)。7.5水平荷载内力计算7.5.1风荷载标准值作用下的内力计算风荷载作用下框架内力计算仍采用一榀框架计算:其反弯点高度剪力分配仍按前述方式,取同一榀框架计算。第i层第m柱所分配的剪力为:iimimVDDV,iiWV。框架柱反弯点高度比,可根据公式5-6计算,i的取值进行取值,即:=iK,3210yyyyy式中:0y——标准反弯点高度比,是在各层等高、各跨相等、各层相等、各层梁和柱线刚度都不改变的情况下求得的反弯点高度比;1y——因上、下层梁刚度比变化的修正值;2y——因上层层高变化的修正值;3y——因下层层高变化的修正值。上式中,0y、1y、2y、3y值均用线性内插法按照《混凝土结构设计》A轴框架柱反弯点位置层数/hmK0y1y2y3yy/yhm53.61.0460.350.000.000.000.3501.2643.61.0460.400.000.000.000.4001.4433.61.0460.450.000.000.000.4501.6223.61.0460.500.000.000.000.501.815.151.360.650.000.000.000.653.35C轴框架柱反弯点位置层数/hmK0y1y2y3yy/yhm53.61.7250.360.000.000.000.371.33243.61.7250.460.000.000.000.431.54833.61.7250.460.000.000.000.471.69223.61.7250.500.000.000.000.501.80015.152.240.580.000.000.000.532.73D轴框架柱反弯点位置层数/hmK0y1y2y3yy/yhm53.61.0460.360.000.000.000.371.33243.61.0460.460.000.000.000.431.54833.61.0460.460.000.000.000.471.69223.61.0460.500.000.000.000.501.80015.151.360.580.000.000.000.532.73F轴框架柱反弯点位置层数/hmK0y1y2y3yy/yhm53.61.7250.350.000.000.000.3501.2643.61.7250.400.000.000.000.4001.4433.61.7250.450.000.000.000.4501.6223.61.7250.500.000.000.000.501.815.152.240.650.000.000.000.653.351imcMVyh上;cimMVyh下中柱处的梁:1bcjbjcjbbiMMMii左下左上左右;1bcjbjcjbbiMMMii右下右上左右边柱处的梁:1cjbjcjMMM下总上梁端剪力:lMMVbbb21柱轴力:nikrblbiVVN1)(风荷载作用下A框架柱剪力和梁柱端弯矩的计算楼层kNVi/D)//(mkNimD)//(mkNDDimkNVim/yhm/上cM)//(mkN下cM)//(mkN总bM)//(mkN55.091955241600.2131.0841.262.5371.3662.573411.641955241600.2132.4791.445.3553.5706.721318.191955241600.2133.8741.627.676.27611.24224.741955241600.2135,.271.89.4869.48615.762132.71650038060.2317.553.3513.5925.2923.076风荷载作用下F框架柱剪力和梁柱端弯矩的计算楼层kNVi/D)//(mkNimD)//(mkNDDimkNVim/yhm/上cM)//(mkN下cM)//(mkN总bM)//(mkN55.091955241600.2131.0841.262.5371.3662.573411.641955241600.2132.4791.445.3553.5706.721318.191955241600.2133.8741.627.676.27611.24224.741955241600.2135,.271.89.4869.48615.762132.71650038060.2317.553.3513.5925.2923.076风荷载作用下C框架柱剪力和梁柱端弯矩的计算楼层/iVkN/(/)DkNm/(/)imDkNmimDD/imVkN/yhm/cMkNm上/cMkNm下/bMkNm左/bMkNm右55.091955256160.2871.461.3323.3111.9453.1272.129411.641955256160.2873.341.5486.8545.1707.1544.87318.191955256160.2875.221.6929.9608.83211.1817.611224.741955256160.2877.11.80012.7812.7815.20810.352132.71650044380.2698.802.7321.29624.02426.96518.355风荷载作用下D框架柱剪力和梁柱端弯矩的计算楼层/iVkN/(/)DkNm/(/)imDkNmimDD/imVkN/yhm/cMkNm上/cMkNm下/bMkNm左/bMkNm右55.091955256160.2871.461.3323.3111.9452.1293.127411.641955256160.2873.341.5486.8545.1704.877.154318.191955256160.2875.221.6929.9608.8327.61111.181224.741955256160.2877.11.80012.7812.7810.35215.2
本文标题:水平荷载计算书
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