攀枝花学院毕业设计 7 内力组合及内力调整
7 内力组合及内力调整
7.1内力组合
各种荷载情况下的框架内力求得后,根据最不利又是可能的原则进行内力组合。当考虑结构塑性内力重分布的有利影响时,应在内力组合之前对竖向荷载作用下的内力进行增幅。分别考虑恒荷载和活荷载由可变荷载效应控制的组合和由永久荷载效应控制的组合,并比较两种组合的内力,取最不利者。由于构件控制截面的内力值应取自支座边缘处,为此,进行组合前,应先计算各控制截面处的(支座边缘处的)内力值。
1)、在恒载和活载作用下,跨间Mmax可以近似取跨中的M代替,在重力荷载代表值和水平地震作用下,跨内最大弯矩Mmax采用解析法计算:先确定跨内最大弯矩Mmax的位置,再计算该位置处的Mmax。当传到梁上的荷载为均布线荷载或可近似等效为均布线荷载时,按公式7-1计算。计算方式见图7-1、7-2括号内数值,字母C、D仅代表公式推导,不代表本设计实际节点标号字母。
M?M右11Mmax?ql2?左 且满足Mmax?ql2 (7-1)
1682式中:q——作用在梁上的恒荷载或活荷载的均布线荷载标准值;
M左、M右——恒载和活载作用下梁左、右端弯矩标准值;
l——梁的计算跨度。
2)、在重力荷载代表值和地震作用组合时,左震时取梁的隔离体受力图,见图7-1所示, 调幅前后剪力值变化,见图7-2。
图7-1 框架梁内力组合图
攀枝花学院毕业设计 7 内力组合及内力调整
图7-2 调幅前后剪力值变化
图中:MGC、MGD——重力荷载作用下梁端的弯矩; MEC、MCD——水平地震作用下梁端的弯矩
RC、RD——竖向荷载与地震荷载共同作用下梁端支座反力。
ql1左端梁支座反力:RC=??MGD?MGC?MEC?MED?;
2ld由M?0,可求得跨间Mmax的位置为:X1?RC/q ; dx将X1代入任一截面x处的弯矩表达式,可得跨间最大弯矩为: 弯矩最大点位置距左端的距离为X1,X1=RE/q;?0?X1?1?; 最大组合弯矩值:Mmax?qX12/2?MGE?MEF;
当X1?0或X1?1时,表示最大弯矩发生在支座处,取X1=0或X1=l,最大弯矩组合设计值的计算式为:Mmax?RCX1?qX12/2?MGE?MEF; 右震作用时,上式中的MGE、MEF应该反号。
柱上端控制截面在上层的梁底,柱下端控制截面在下层的梁顶。按轴线计算简图算得的柱端内力值,宜换算到控制截面处的值。为了简化计算,也可以采用轴线处内力值,这样算得的钢筋用量比需要的钢筋用量略微多一点。
根据《高层建筑混凝土结构技术规程》(JGJ3-2010)第3.5.3条规定:A级高度高层建筑的楼层抗侧力结构的层间受剪承载力不宜小于其相邻上一层受剪承载力的80%,不应小于其相邻上一层受剪承载力的65%;B级高度高层建筑的楼层抗侧力结构的层间受剪承载力不应小于其相邻上一层受剪承载力的75%。
7.1.1 框架梁控制截面的内力组合
1、不考虑地震作用组合下的梁端弯矩设计值的组合。 ①、基本组合:
M?1.2SGk?1.4SQk;M?1.35SGk?1.4?0.7?SQk;
②、风荷载作用下的不利组合(不考虑活载):
M?1.2SGk?1.4SWk(左);M?1.2SGk?1.4SWk(右);
攀枝花学院毕业设计 7 内力组合及内力调整
③、风荷载作用下的有利组合(不考虑活载):
M?1.0SGk?1.4SWk(左);M?1.0SGk?1.4SWk(右);
④、风荷载作用下的不利组合(考虑活载):
M?1.2SGk?0.9?1.4SQk?1.4SWk(左)?;M?1.2SGk?0.9?1.4SQk?1.4SWk(右)?;
⑤、风荷载作用下的有利组合(考虑活载):
M?1.0SGk?0.9?1.4SQk?1.4SWk(左)?;M?1.0SGk?0.9?1.4SQk?1.4SWk(右)?; 2、考虑地震作用组合下的梁端弯矩设计值的组合。
;M?1.2?SGk?0.5SQk??1.3SEk; M?1.2?SGk?0.5SQk??1.3SEk(左)(右);M?1.0?SGk?0.5SQk??1.3SEk。 M?1.0?SGk?0.5SQk??1.3SEk(左)(右)3、不考虑地震作用组合下的梁端剪力设计值的组合。 ①、基本组合:
V?1.2VGk?1.4VQk;V?1.35VGk?1.4?0.7?VQk;
②、风荷载作用下的不利组合(不考虑活载):
V?1.2VGk?1.4VWk(左);V?1.2VGk?1.4VWk(右);
③、风荷载作用下的有利组合(不考虑活载):
V?1.0VGk?1.4VWk(左);V?1.0VGk?1.4VWk(右);
④、风荷载作用下的不利组合(考虑活载):
V?1.2VGk?0.9?1.4VQk?1.4VWk(左)?;V?1.2VGk?0.9?1.4VQk?1.4VWk(右)?; ⑤、风荷载作用下的有利组合(考虑活载):
V?1.0VGk?0.9?1.4VQk?1.4VWk(左)?;V?1.0VGk?0.9?1.4VQk?1.4VWk(右)?;
4、考虑地震作用组合下的梁端弯矩设计值的组合。
;V?1.2?VGk?0.5VQk??1.3SEk; V?1.2?VGk?0.5VQk??1.3VEk(左)(右);V?1.0?VGk?0.5VQk??1.3VEk。 V?1.0?VGk?0.5VQk??1.3VEk(左)(右)内力未做调整前,横向框架梁的内力组合表,见表7-1~ 7-6。
攀枝花学院毕业设计 7 内力组合及内力调整
表7-1内力调整前横向框架梁的内力组合表(6层)
调整前横向框架梁的内力组合表恒载活载左风载右风载左震右震控制截不利内 层 次面力不考虑地震的组合1.0恒+1.4风(有1.2恒+0.9(1.4活+1.4风)(不利)利)左风右风左风右风-13.7258.8549.78-56.16-42.6351.4560.21-54.21-48.8750.3048.84-50.3050.74-38.5251.7740.56-49.08-60.0146.3951.69-49.15-66.9542.7626.24-42.7647.50-39.77113.3489.47-96.02-83.45101.2099.95-96.72-93.3993.7676.36-97.6298.42-62.10106.9781.18-89.64-99.0996.6492.29-92.16-109.6786.9856.02-90.8495.50考虑地震的组合不利内力控制力SGK-26.1255.3145.17-52.62-51.3248.9255.95-51.68-57.9146.5337.54-46.5349.12SQK-15.5534.7524.70-23.56-23.5631.9223.00-25.73-25.4327.4116.78-30.4730.171.2恒+1.4风1.35恒1.2恒(不利)+1.4*0.SWK(左)SWK(右)SEK(左)SEK(右)+1.4活7活左风右风8.862.533.29-2.536.211.813.04-1.816.462.698.07-2.691.163.753.75-8.86-2.53-3.292.53-6.21-1.81-3.041.81-6.46-2.69-8.072.69-1.1678.0621.4740.86-21.4786.7714.4640.86-14.4686.7724.2878.06-24.285.61-78.06-21.47-40.8621.47-86.77-14.46-40.8614.46-86.77-24.28-78.0624.28-5.61-53.11115.0288.78-96.13-94.57103.3999.34-98.04-105.0994.2168.54-98.49101.18-50.50108.7285.19-94.13-92.3797.3298.07-94.98-103.1089.6867.12-92.6895.88-18.9469.9158.81-66.69-52.8961.2471.40-64.55-60.4559.6056.35-59.6060.57-43.7562.8349.60-59.60-70.2856.1762.88-59.48-78.5452.0733.75-52.0757.321.0恒+0.9(1.41.2重力载+1.3地1.0重力载+1.3活+1.4风)(有震最大正M最大负M非地震地震控地震利)及相应V及相应V控制力制力左风右风左震右震左震右震-34.55102.2880.44-85.49-73.1891.4288.76-86.38-81.8184.4668.85-88.3188.60-56.8895.9172.15-79.12-88.8386.8681.10-81.82-98.0977.6848.51-81.5385.6760.80115.13122.14-105.1937.0896.65134.06-96.2528.05103.85156.59-105.6884.34-142.1559.3115.91-49.37-188.5259.0627.82-58.66-197.5540.72-46.36-42.5569.7567.58100.60110.64-92.3149.7083.68120.57-83.3442.1891.80147.41-93.3371.50-135.3744.774.40-36.49-175.9046.0814.33-45.75-183.4328.67-55.55-30.2056.9167.58115.13122.14-36.4949.70103.39134.06-45.7542.18103.85156.59-30.20101.18-142.1544.774.40-105.19-188.5246.0814.33-98.04-197.5528.67-55.55-105.6847.50-62.10115.0289.47-96.13-99.09103.3999.95-98.04-109.6794.2176.36-98.49101.18-142.15115.13122.14-105.19-188.5296.65134.06-96.25-197.55103.85156.59-105.6884.34AB左B右 六 层C左C右DMVMVMVMVMVMVMAB跨 间MBC141.7864.53MCD141.7864.53-3.7510.74-10.74260.48254.64175.39164.89147.03136.53256.17246.72227.81218.36222.82194.89188.01160.08260.48136.53260.48222.82-3.7510.74-10.74260.48254.64175.39164.89147.03136.53256.17246.72227.81218.36222.82194.89188.01160.08260.48136.53260.48222.82注:1、表中M以下部受拉为正,V以顺时针为正; 2、承载力抗震调整系数?RE弯矩取0.75,对剪力取0.85;
3、重力载=恒载+0.5活载;4、弯矩单位为kN.m ,剪力单位为kN 。
攀枝花学院毕业设计 7 内力组合及内力调整
表7-2 内力调整前横向框架梁的内力组合表(5层)
调整前横向框架梁的内力组合表恒载活载左风载右风载左震右震 层 次控制截不利内面力不考虑地震的组合1.0恒+1.4风(有1.2恒+0.9(1.4活+1.4风)(不利)利)左风右风左风右风3.1967.2748.05-60.76-32.4178.6344.49-59.74-20.0456.4253.03-59.9847.4368.54-48.7352.4328.75-45.92-68.8368.0526.65-49.16-57.9240.625.71-44.1839.81-22.30123.4578.93-107.44-65.65153.5366.11-167.55-64.3799.4087.63-108.1690.52-69.02110.1061.57-94.08-98.43144.0050.06-158.03-98.4685.1945.05-93.9583.67考虑地震的组合不利内力控制力SGK-22.7759.8538.40-53.34-50.6273.3435.57-54.45-38.9848.5229.37-52.0843.6262.09SQK-14.5535.6819.18-29.17-16.9048.2212.22-77.34-27.4927.0424.68-30.6027.5847.251.2恒+1.4风1.35恒1.2恒(不利)SWK(左)SWK(右)SEK(左)SEK(右)+1.4活+1.4*0.7活左风右风18.545.306.89-5.3013.013.786.37-3.7813.535.6416.90-5.642.725.834.61-18.54-5.30-6.895.30-13.01-3.78-6.373.78-13.53-5.64-16.905.64-2.72-5.83-4.61103.2728.4054.06-28.40114.8019.1254.06-19.12114.8032.13103.27-32.136.42-103.27-28.40-54.0628.40-114.80-19.12-54.0619.12-114.80-32.13-103.2732.13-6.42-47.69121.7772.93-104.85-84.40155.5259.79-173.62-85.2696.0869.80-105.3490.96-45.00115.7670.64-100.60-84.90146.2660.00-149.30-79.5692.0063.84-100.3085.92-1.3779.2455.73-71.43-42.5393.3051.60-70.63-27.8366.1258.90-70.3956.15-53.2864.4036.43-56.59-78.9682.7233.77-60.05-65.7250.3311.58-54.6048.5468.051.0恒+0.9(1.41.2重力载+1.3地1.0重力载+1.3活+1.4风)(有震最大正M最大负M非地震地震控地震利)及相应V及相应V控制力制力左风右风左震右震左震右震-17.74111.4871.25-96.77-55.52138.8658.99-156.66-56.5789.7081.76-97.7481.80-64.4698.1353.89-83.42-88.31129.3342.94-147.14-90.6775.4839.17-83.5374.9498.20130.15127.87-118.4378.36141.80120.29-136.6085.97116.22184.30-122.6377.24-170.3156.31-12.69-44.59-220.1292.08-20.26-86.89-212.5132.68-84.20-39.0960.55104.21114.61118.27-104.8590.17122.31111.96-117.9896.52103.81175.96-109.1565.76-164.3040.77-22.29-31.01-208.3172.59-28.60-68.26-201.9720.27-92.54-25.6149.06104.21130.15127.87-31.0190.17155.52120.29-49.1696.52116.22184.30-25.6190.96-170.3140.77-22.29-118.43-220.1268.05-28.60-173.62-212.5120.27-92.54-122.6339.81-69.02123.4578.93-107.44-98.43155.5266.11-173.62-98.4699.4087.63-108.1690.96-170.31130.15127.87-118.43-220.12141.80120.29-136.60-212.51116.22184.30-122.6377.24AB左B右 五 层C左C右DMVMVMVMVMVMVMABMCD跨 间MBC152.3870.4014.56-14.56281.42274.71191.02174.69160.54144.22278.91264.21248.43233.74244.02206.17206.51168.65281.42144.22281.42244.0212.37-12.37140.66130.1380.9655.64139.85128.23127.43115.82118.9486.78101.8069.63140.6655.64140.66118.94注:1、表中M以下部受拉为正,V以顺时针为正; 2、承载力抗震调整系数?RE弯矩取0.75,对剪力取0.85;
3、重力载=恒载+0.5活载;4、弯矩单位为kN.m ,剪力单位为kN 。