框架结构截面设计例题课件.pptx

1、平平 面面 图（图（kN）框架设计的过程（考虑抗震作用时）设计延性框架 强柱弱梁 强剪弱弯1.体系确定、梁柱布置和梁柱尺寸的确定2.荷载（恒、活、风、地震作用）计算3.内力计算（分层法 D值法）4.截面设计（梁、柱子）配筋和构造要求（1）内力调整（2）内力组合（3）梁的截面设计强剪弱弯的调整梁正截面设计 斜截面设计 构造要求（4）柱子的截面设计强柱弱梁的调整 强剪弱弯的调整正截面设计 斜截面设计 构造要求（轴压比 体积配箍率）（5）结点的设计层1059.112116.1277.920101.12493.204109.0449103.527157.7167.527134.028126.50114

2、1.5558102.789156.8887.514134.028126.514141.5427102.789156.8887.514134.028126.514141.5426102.789156.8887.514134.028126.514141.5425100.746155.8447.653134.028126.375141.6814117.189153.9185.101134.028128.927139.1293126.225152.8473.697134.028130.331137.7252125.208152.4063.777134.028130.251137.8051117.954

3、150.4624.515134.028129.513138.543ABM)(mkN BAM)(mkN lMMBAABql21lMMqlVBAABA21lMMqlVBAABB21左AB跨梁调幅后的梁端弯矩和剪力CB跨梁调幅后的梁端弯矩和剪力 层1050.72410.6388.90841.51350.42132.605954.16221.6007.23654.81062.04647.574854.64821.6727.32854.81062.13847.482754.64821.6727.32854.81062.13847.482654.64821.6727.32854.81062.13847.4

4、82555.26021.7717.44254.81062.25247.368450.53523.6885.96654.81060.77648.844348.06924.7685.17854.81059.98849.632248.33024.8945.20854.81060.01849.602150.67022.6806.22054.81061.03048.590ABM)(mkN BAM)(mkN lMMBAABql21lMMqlVBAABA21lMMqlVBAABB21左重力荷载代表值作用下的弯矩调幅梁端弯矩调幅系数为0.9 第三层、第二层梁边截面及第二层、第三层、第四层柱边截面的内力 重力荷

5、载代表值作用下第三层梁边截面的内力计算如下：0.5126.225 130.33193.64222ABAABbMMVkN m边0.6152.847 137.725111.53022BABBAbMMVkN m左边0.648.06959.98830.07322BCBBCbMMVkN m右边0.424.76849.63214.84222CBCCBbMMVkN m边0.5130.331 37.23121.02422AAbVVqkN边0.6137.72537.23126.55622BBbVVqkN左左边0.659.98824.3652.6822BBbVVqkN右右边0.449.63224.3644.762

6、2CCbVVqkN边同理可求得第二层梁边截面的内力（计算过程略）。第二层、第三层、第四层B柱边截面的弯矩可根据比例求得，柱边截面的剪力和轴力取与轴线处相同。355.23BMkN m上356.83BMkN m下37.353VkN反弯点高度为 56.831.52137.353m31.521 0.7/256.8343.7531.521BMkN m下边33 1.521 0.7/255.2342.163 1.521BMkN m上边同理可求出第二层、第四层B柱边截面的弯矩 2.2.水平地震作用标准值作用下水平地震作用标准值作用下水平地震作用标准值作用下梁边截面弯矩及柱边截面弯矩同样可根据比例求得（计算过程

7、略），梁边截面剪力、柱边截面剪力和轴力均与轴线处截面同。内力的正负号作如下规定：梁弯矩：使梁的下部纤维受拉为正，反之为负；梁剪力：使梁产生顺时针方向转动为正，反之为负；柱弯矩：使柱产生逆时针方向转动为正，反之为负；柱轴力：压力为正，拉力为负；柱剪力：使柱产生顺时针方向转动为正，反之为负。第二层、第三层梁端控制截面的内力及第二层、第三层、第四层B柱端控制截面的内力。层截面重力荷载代表值作用效应水平地震作用标准值作用效应（左震）三93.642121.024162.27349.064111.530126.556164.00249.06430.07352.68091.77743.96914.84244

8、.76084.09843.969二92.645120.944158.46048.679111.065126.636165.25748.67930.32552.71092.18544.81814.97444.73087.08644.818ABL 左ABL 右BCL 左BCL 右ABL 左ABL 右BCL 左BCL 右()M kN m()V kN()M kN m()V kN层截面重力荷载代表值作用效应水平地震作用标准值作用效应（左震）四上56.3622512.73844.320114.8131.24492.590下45.5742539.73844.32098.1441.24492.590三上42.

9、1602888.08737.353117.4073.851102.090下43.7532915.08737.353117.4073.851102.090二上43.7113263.55942.84393.7487.712110.290下54.8283290.55942.843159.9197.712110.290)(mkNM)(kNN)(kNV)(mkNM)(kNN)(kNV考虑重力荷载效应与水平地震作用效应组合时，重力荷载的荷载分项系数为1.2（当重力荷载效应起有利作用时取荷载分项系数为1.0），水平地震作用分项系数为1.3，即荷载效应组合设计值为 。另外，水平地震作用可以向左（左震）或向右（

10、右震）。1.2(1.0)1.3GEEhkSSS层截面（左震）（右震）三112.37093.642210.955210.955323.325117.313133.836111.530213.203213.203347.039101.67336.08830.073119.310119.310155.39889.23717.81014.842109.327109.327127.13794.485二111.17492.645205.998205.998317.172113.353133.278111.065214.834214.834348.112103.76936.39030.325119.8411

11、19.841156.23189.51617.96914.974113.212113.212131.18198.238ABL 右左ABL左BCL右BCLABL 右左ABL左BCL右BCLGEM2.1GEM0.1EhkM3.1EhkM3.1maxMmaxM第三层梁端剪力组合因为建筑高度为31.2m，大于30m，设防烈度为7度，根据抗震规范确定框架的抗震等级为二级。故框架梁梁端截面组合的剪力设计值应按下式调整（强剪弱弯强剪弱弯）：。1.2lrbbbGbnMMVVl截面323.325101.6736.65148.548225.239117.313347.0396.65148.548232.341155

12、.39894.4854.0058.464133.42989.237127.1374.0058.464123.376左ABL右ABL左BCL右BCL)(mkNMlb)(mkNMrb)(mlnnGbqlV21GbnrblbbVlMMV2.1 第三层梁跨中弯矩组合 由于水平地震作用有左震和右震两种可能，故梁的跨中弯矩组合要考虑两种可能的情况。以组合 的跨中弯矩为例。ABL左震时，梁端组合弯矩及梁上荷载：剪力等于0的位置，跨中弯矩最大1117.313347.03944.676 6.6578.7226.65ARkN跨中弯矩最大值截面距A端距离为：跨中弯矩最大值为：78.721.76244.676xm2m

13、ax178.72 1.762 117.31344.676 1.762186.6662ABMkN m右震时，梁端组合弯矩及梁上荷载如图b所示：1323.325 101.67344.676 6.65212.45726.65ARkN跨中弯矩最大值截面距A端距离为：212.4574.75644.676xm跨中弯矩最大值为：2max1212.457 4.756 323.32544.676 4.756181.8452ABMkN m 比较左震、右震两种情况可知，跨中最大正弯矩组合值为:max186.666ABMkN m同理可求得 的跨中最大正弯矩组合值为：BCLmax94.485BCMkN m 第三层B柱内

14、力组合 ccbMM()/tbvcccnVMMH因框架抗震等级为二级，故柱组合弯矩设计值应根据（强柱弱梁）调整后求得，柱组合剪力设计值应根据（强剪弱弯）调整后求得。层截面内力（左震）（右震）组合四上M67.63456.362149.257149.257216.891205.61981.62392.895N3015.2862512.7381.6171.6173013.6692511.1213016.9032514.355下M54.68945.574127.587127.587182.276173.16172.89882.013N3047.6862539.7381.6171.6173046.0692

15、538.1213049.3032541.355V53.18444.320120.367120.367173.551164.68767.18376.047三上M50.59242.160152.629152.629203.221194.789102.037110.469N3465.7042888.0875.0065.0063470.7102893.0933460.6982883.081下M52.50443.753152.629152.629205.133196.382100.125108.876N3498.1042915.0875.0065.0063503.1102920.0933493.0982

16、910.081V44.82437.353132.717132.717177.541170.07087.89395.364GES2.1GES0.1EhkS3.1EhkS3.1二上M52.45343.711121.872121.872174.325165.58369.41978.161N3916.2713263.55910.02610.0263926.2973273.5853906.2453253.533下M65.79454.828207.895207.895273.689262.723142.101153.067N3948.6713290.55910.02610.0263958.6973300.

17、5853938.6453280.533V51.41242.843143.377143.377194.789186.22091.965100.534层截面内力（左震）（右震）组合GES2.1GES0.1EhkS3.1EhkS3.1经“强柱弱梁”调整后的第三层B柱的最不利内力层截面内力组合项值组合项值组合项值三上M275.901177.071275.901N3470.7102883.0813470.710下M284.108181.583284.108N3503.1102910.0813503.110V292.179187.124292.179maxNMminNMmaxMN及相应的 及相应的 及相应

18、的 LAB截面尺寸为250mm700mm，LBC截面尺寸为250mm500mm，柱截面尺寸为600mm600mm，混凝土强度等级为C30，纵向受力钢筋采用HRB400级钢 筋，箍筋采用HPB235级钢筋。正截面受弯承载力计算 LAB 跨中最大正弯矩：186.666MkN m622100.75 186.666 100.0891.0 14.3 250 665REscMf bh11 211 2 0.0890.0930.518sb 2101.0 14.3 250 665 0.093614.16360csyf bhAmmf1minmax614.161.430.351%(0.25%,0.550.550.2

19、18%)0.25%250 700360styAfbhf满足要求。选配3 18（）钢筋。2763sAmm层计算公式支座左截面跨中截面支座右截面支座左截面跨中截面支座右截面三323.325186.666347.039155.39894.485127.1370.1530.0890.1650.1510.0920.1230.1670.350.0930.5180.1810.350.1650.350.0970.5180.1320.351102.84614.161195.29761.92447.92609.540.6300.3510.6830.6100.3580.4880.250.250.250.250.25

20、0.25实选钢筋201820201820实配钢筋面积12567631256942509628)(mkNM201bhfMcREss211)(201mmfbhfAycs(%)1bhAs(%)minABLBCLLAB的最大剪力为:232.341VkN00.20.2 1 14.3 250 665475475N475.475kN0.85 232.341197.49kNccREf bhV 00.420.42 1.43 250 66599850N99.85kN0.85 232.3 41197.49kNtREf bhV321000.42197.49 10998500.559mm/mm1.251.25 210

21、665svREtyvnAVf bhsf h箍筋选8双肢箍，1250.31800.5590.559svnAsmm4bh2 81001.5bh梁端加密区要求箍筋直径不小于8mm；加密区箍筋间距取（加密区范围取（，500mm）的较大值，8d，100mm）的 较小值，即（175mm,160mm,100mm）即（1050mm,500mm）的较大值，取1050mm。非加密区箍筋选 ，配箍率验算如下：2 81501,min2 50.31.430.268%0.280.191%250 150210svsvsvnAbsLBC的剪力最大值为:133.429VkN00.20.2 1 14.3 250 46533247

22、5N332.475kN0.85 133.429 113.415kNccREf bhV 00.420.42 1.43 250 46569820N69.82kN0.85 133.4 29113.415kNtREf bhV321000.42113.415 10698200.357mm/mm1.251.25 210465svREtyvnAVf bhsf h箍筋选8双肢箍，1250.32820.3570.357svnAsmm梁端加密区要求箍筋直径不小于8mm；加密区箍筋间距取（hb/4，8d，100mm）的小值，即（125mm,160mm,100mm）的较小值，取s=100mm。故加密区箍筋选28100

23、。加密区范围取（1.5hb，500mm）的较大值，即（750mm,500mm）的较大值，取750mm。非加密区箍筋选28100，配箍率验算如下：1,min2 50.31.430.268%0.280.191%250 150210svsvsvnAbs满足要求。1.轴压比验算max3503.11NkN35031100.680.814.3 600600ccNf A2.正截面受弯承载力计算四组最不利内力，即：284.1083503.11MkN mNkN第一组 第二组 275.9013470.71MkN mNkN第三组 第四组 181.5832910.081MkN mNkN177.0712883.081M

24、kN mNkN采用对称配筋时，101.0 14.3 600 560 0.51824888862488.89bcbNf bhNkN第一组、第二组:REbNN为小偏心受压；第三组、第四组 REbNN为大偏心受压 现取第一组和第四组最不利内力进行配筋计算。因水平地震作用产生的弯矩设计值小于总弯矩设计值的75 152.62974.4%152.62952.504故柱的计算长度取为 01.251.25 33.75lHm 第一组 284.1083503.11MkN mNkN603284.108 1081.13503.11 10MemmN30600 3020aehmm081.1 20 101.1iaeeemm

25、03750 6006.255lh，故要考虑偏心距增大系数影响 130.50.5 14.3 600 6000.9180.8 3503.11 10cREf AN015lh，取 21.0220120111()16.250.918 1.01.142101.114001400560ilehh 6001.142 101.140375.45622iheeamm1021010100.43()()REbcbREccbNf bhNef bhf bhha 3320.8 3503.11 100.518 1.0 14.3 600 5600.5180.8 3503.11 10375.4560.43 1.0 14.3 60

26、0 5601.0 14.3 600 560(0.80.518)(56040)0.5952100(10.5)()REcssyNef bhAAfha320.8 3503.11 10375.456 1.0 14.3 600 5600.595(1 0.5 0.595)360(56040)0按构造配筋。第四组 177.0712883.081MkN mNkN603177.071 1061.42883.081 10MemmN30600 3020aehmm061.42081.4iaeeemm03750 6006.255lh，故要考虑偏心距增大系数影响 130.50.5 14.3 600 6001.121.00

27、.8 2883.081 10cREf AN，取 11.0015lh，取 21.0220120111()16.251.0 1.01.1981.414001400560ilehh mmaheei866.3564026004.8119.12310.82883.081 10268.821.014.3600REcNxmmf b0240290.08bammxhmm100(0.5)0.8 2883081 356.866 14.3 600 268.82(560 0.5 268.82)()360(56040)REcssyNef bx hxAAf ha0按构造配筋。最小总配筋率为 min0.8%，故 220.4%

28、0.004 6001440ssAAbhmm实选各 4 22,21520ssAAmm的受拉和受压钢筋 037506.258600lb1.00.9()0.9 1.0(14.3 600 600 360 2 1520)56181605618.16ucysNf Af ANkNa 0.8 3503.112802.5uRENNkN满足要求。最大剪力设计值为 max292.179VkN，相应的轴力设计值为 3503.11NkN023002.0522560nHh0.30.3 14.3 600 60015444001544.43503.11cf ANkNNkN1544.4NkN取 01031.05(0.056)1

29、1.050.85 292.179 101.43 600 5600.056 15444002.05 10300 360REtsvyvVf bhNnAsf h按构造配置箍筋。采用复合箍筋，由于轴压比 0.680.7c，故取 0.15v，柱箍筋加密区的体积配箍率为：14.30.151.02%210cvvyvff采用 箍筋 4 1011 122 21 24 78.5(530530)116530 530 1.02%ssvn A ln A lsmml l柱端加密区要求箍筋直径不小于8mm；加密区箍筋间距取（8d，100mm）的小值，即（176mm,100mm）的较小值，取s=100mm；故加密区箍筋选41

30、0100。加密区范围取（hc，Hn/6，500mm）的较大值，（600mm,2300/6=383mm,500mm）的较大值，取600mm。非加密区箍筋选 4 10150478.5 53020.79%0.6%0.5 1.02%0.51%530 530 150v满足要求。1.节点核芯区剪力设计值 00(1)jbbbjbcbMhaVhaHh左震时，347.03989.237436.276bMkN m右震时，101.673 155.398257.071bMkN m故计算Vj，取 436.276bMkN mHc取节点上、下柱反弯点之间的距离，即：182.276203.221230070023002895

31、182.276216.891203.221205.113cHmmhb、hbo均取节点两侧梁的平均值，即 600bhmm0565bhmm61.2436.276 1056535(1)759676759.68565352895600jVNkN2.剪压比验算 12503002bcbmmbmm故bj按下列两式的小值采用，即：min0.52500.5600550550600bcjcbhmmbmmbmm600jhmm因节点四侧各梁截面宽度均小于柱截面宽度的1/2，故取 1.0j11(0.30)0.3 1.0 14.3 550 60016655291665.53759.680.85jcjjjREf b hNkNVkN满足要求。22511.1210.50.5 14.3 6002574cccNkNf b hkN故取 2511.121NkN取节点处箍筋同柱端加密区箍筋，即 4 10100031(1.10.05)1550565 35(1.1 1.0 1.43 550 600 0.05 1.0 2511.121 10210 4 78.5)1157.30.85600100jbjtjjjyvsvjREcbhaf b hNf AbskN jV满足要求。三层框架梁及三层B柱配筋