梁弯矩配筋的简化计算方法B

梁弯矩配筋的简化计算方法民用建筑所王晓星前言随着计算机的开展，大型结构的计算越来越程序化，简便化，但机算结果的正确性和适用性的判定仍然需要手算来完成，。我们一些结构设计师尤其是新参加工作的设计师在结构计算中也过分依赖于计算机，手算能力比拟薄弱，特别是在现场效劳中对结构问题的处理时，往往时间紧，又要保证结构的平安和经济，加强自己的手算能力和经验的积累对每个结构设计师都是必不可缺的。本文提出了混凝土结构设计中最常用的梁弯矩配筋的简化计算方法，愿与大家共同商讨。简化计算方法梁弯矩配筋可先计算出矩形梁的截面系数A，按此系数查得配筋系数的第一行,第二行对应的就是配筋系数值，HRB335配筋系数表见附表1，HRB400配筋系数表见附表2。配筋系数表有如下的特点：截面系数浮动范围非常大，而配筋系数却很小，多数只是0.001位的变化，而且各混凝土强度等级的截面系数范围均同。所以如果我们能记忆几个固定的数值，采用内插法进行计算，就可以脱离配筋系数表，快速而又准确地得出配筋结果。截面系数配筋量式中：为梁的弯矩设计值为梁的宽度为梁的有效高度为配筋面积公式中括号内为单位不参预计算，对于T形梁和板只需取前几个系数即可。配筋系数表第二行的第一个数为最小配筋率，最后一行为受压区高度为0.55。当精度要求不高时，对于T形梁和板采用Ⅰ级筋时可直接取配筋系数为0.050;Ⅱ级筋可取配筋系数为0.035。精确计算的公式在此不再细述，可参见混凝土结构教科书或钢筋混凝土结构计算手册。计算例如1：某梁所承受弯矩设计值为145,取梁高为500,梁宽为250,混凝土强度等级C30;HRB335钢筋;试计算配筋.C30混凝土；HRB335截面系数A650100020003000400050005500配筋系数0.03410.0350.0360.0380.0400.0430.045简化计算：取配筋系数为0.0375精确计算：受压区高度相对受压区高度纵向受拉钢筋2：某板跨中弯矩设计值为6.5,板厚取为100,混凝土强度等级C25;HRB335钢筋;试计算配筋.简化计算：精确计算(取1m宽为单元)：受压区高度相对受压区高度纵向受拉钢筋总结由上述两例比照可知，计算误差均在允许范围内即小于5%。梁的弯矩配筋在结构设计中是最常用又重要的一局部，我们只要掌握简化计算方法就可以得到事半功倍的效果。参考文献：1．混凝土结构设计标准(GB50010-2002)中国建筑工业出版社2．简明钢筋混凝土结构计算手册国振喜主编机械工业出版社3．混凝土结构构造手册中国有色工程设计研究总院主编中国建筑工业出版社4．高层建筑结构概念设计郁彦著铁道工业出版社C20HRB335fy=300A581871131717142068238426672919314533463526368738200.03440.0350.0360.0370.0380.0390.0400.0410.0420.0430.0440.0450.0460.200.3050.4740.6340.7860.9301.0671.1971.3211.4391.5521.6591.752C25HRB335fy=300A5851079163221252564295633063618389741484371457147400.03420.0350.0360.0370.0380.0390.0400.0410.0420.0430.0440.0450.0460.200.3780.5880.7860.9741.1531.3221.4831.6371.7831.9232.0572.178C30HRB335fy=300A6301297196225533081355239724348468449845253549257000.03410.0350.0360.0370.0380.0390.0400.0410.0420.0430.0440.0450.0460.2150.4540.7060.9451.1701.3851.5891.7831.9672.1432.3112.4722.62C35HRB335fy=300A6901515239129813598414846395078547058206134641466600.03410.0350.0360.0370.0380.0390.0400.0410.0420.0430.0440.0450.0460.2350.5300.8251.1031.3671.6181.8562.0812.2972.5032.6992.8863.062附表1续附表1C40HRB335fy=300A7531732262034104115474353065807625566577015733676100.0340.0350.0360.0370.0380.0390.0400.0410.0420.0430.0440.0450.0460.2560.6060.9431.2621.5641.8502.1222.3812.6282.8633.0873.3013.497C45HRB335fy=300A7941913289437684546524158616415691173547750810484500.0340.0350.0360.0370.0380.0390.0400.0410.0420.0430.0440.0450.0460.270.6701.0421.3941.7272.0442.3442.6302.9033.1623.4103.6473.884C50HRB335fy=300A8362095316941254977573764177024756680518485887292100.0340.0350.0360.0370.0380.0390.0400.0410.0420.0430.0440.0450.0460.2840.7331.1411.5261.8912.2382.5672.8803.1783.4623.7333.9934.234C60HRB335fy=300A90224943772491059256830763983619007958510101105100.03390.0350.0360.0370.0380.0390.0400.0410.0420.0430.0440.04520.3060.8731.3581.8172.2512.6643.0563.4283.7834.1214.4444.753附表2C25HRB400fy=360A6989611632221727263170355838984194445445810.02860.0290.0300.0310.0320.0330.0340.0350.0360.0370.0380.20.2790.4900.6870.8721.0461.2101.3641.5101.6481.719C30HRB400fy=360A70211541962266432763810427646845040535254800.02850.0290.0300.0310.0320.0330.0340.0350.0360.0370.0380.2000.3350.5880.8261.0481.2571.4541.6391.8141.9802.053C35HRB400fy=360A70413482291311138254449499454705886625064140.02840.0290.0300.0310.0320.0330.0340.0350.0360.0370.0380.2000.3910.6870.9641.2241.4681.6981.9142.1192.3122.405C40HRB400fy=360A75515422620355843755088571162566732714873300.02840.0290.0300.0310.0320.0330.0340.0350.0360.0370.0380.2140.4470.7861.1031.401.6791.9422.1902.4242.6452.748续附表2C45HRB400fy=360A79417032894393048335621630969117436789781040.02830.0290.0300.0310.0320.0330.0340.0350.0360.0370.0380.2250.4940.8681.2181.5471.8552.1452.4192.6772.9223.04C50HRB400fy=360A83318653169430352926154690875668142864588720.02850.0290.0300.0310.0320.0330.0340.0350.0360.0370.0380.2360.5410.9511.3341.6932.0312.3492.6482.9313.1993.327C55HRB400fy=360A86720433471471357956740756582868917946897170.02830.0290.0300.0310.0320.0330.0340.0350.0360.0370.0380.2450.5921.0411.4611.855