梁彎矩配筋的簡化計算方法B

梁彎矩配筋的簡化計算方法民用建筑所王曉星前言隨著計算機(jī)的開展，大型結(jié)構(gòu)的計算越來越程序化，簡便化，但機(jī)算結(jié)果的正確性和適用性的判定仍然需要手算來完成，。我們一些結(jié)構(gòu)設(shè)計師尤其是新參加工作的設(shè)計師在結(jié)構(gòu)計算中也過分依賴于計算機(jī)，手算能力比擬薄弱，特別是在現(xiàn)場效勞中對結(jié)構(gòu)問題的處理時，往往時間緊，又要保證結(jié)構(gòu)的平安和經(jīng)濟(jì)，加強(qiáng)自己的手算能力和經(jīng)驗的積累對每個結(jié)構(gòu)設(shè)計師都是必不可缺的。本文提出了混凝土結(jié)構(gòu)設(shè)計中最常用的梁彎矩配筋的簡化計算方法，愿與大家共同商討。簡化計算方法梁彎矩配筋可先計算出矩形梁的截面系數(shù)A，按此系數(shù)查得配筋系數(shù)的第一行,第二行對應(yīng)的就是配筋系數(shù)值，HRB335配筋系數(shù)表見附表1，HRB400配筋系數(shù)表見附表2。配筋系數(shù)表有如下的特點：截面系數(shù)浮動范圍非常大，而配筋系數(shù)卻很小，多數(shù)只是0.001位的變化，而且各混凝土強(qiáng)度等級的截面系數(shù)范圍均同。所以如果我們能記憶幾個固定的數(shù)值，采用內(nèi)插法進(jìn)行計算，就可以脫離配筋系數(shù)表，快速而又準(zhǔn)確地得出配筋結(jié)果。截面系數(shù)配筋量式中：為梁的彎矩設(shè)計值為梁的寬度為梁的有效高度為配筋面積公式中括號內(nèi)為單位不參預(yù)計算，對于T形梁和板只需取前幾個系數(shù)即可。配筋系數(shù)表第二行的第一個數(shù)為最小配筋率，最后一行為受壓區(qū)高度為0.55。當(dāng)精度要求不高時，對于T形梁和板采用Ⅰ級筋時可直接取配筋系數(shù)為0.050;Ⅱ級筋可取配筋系數(shù)為0.035。精確計算的公式在此不再細(xì)述，可參見混凝土結(jié)構(gòu)教科書或鋼筋混凝土結(jié)構(gòu)計算手冊。計算例如1：某梁所承受彎矩設(shè)計值為145,取梁高為500,梁寬為250,混凝土強(qiáng)度等級C30;HRB335鋼筋;試計算配筋.C30混凝土；HRB335截面系數(shù)A650100020003000400050005500配筋系數(shù)0.03410.0350.0360.0380.0400.0430.045簡化計算：取配筋系數(shù)為0.0375精確計算：受壓區(qū)高度相對受壓區(qū)高度縱向受拉鋼筋2：某板跨中彎矩設(shè)計值為6.5,板厚取為100,混凝土強(qiáng)度等級C25;HRB335鋼筋;試計算配筋.簡化計算：精確計算(取1m寬為單元)：受壓區(qū)高度相對受壓區(qū)高度縱向受拉鋼筋總結(jié)由上述兩例比照可知，計算誤差均在允許范圍內(nèi)即小于5%。梁的彎矩配筋在結(jié)構(gòu)設(shè)計中是最常用又重要的一局部，我們只要掌握簡化計算方法就可以得到事半功倍的效果。參考文獻(xiàn)：1．混凝土結(jié)構(gòu)設(shè)計標(biāo)準(zhǔn)(GB50010-2002)中國建筑工業(yè)出版社2．簡明鋼筋混凝土結(jié)構(gòu)計算手冊國振喜主編機(jī)械工業(yè)出版社3．混凝土結(jié)構(gòu)構(gòu)造手冊中國有色工程設(shè)計研究總院主編中國建筑工業(yè)出版社4．高層建筑結(jié)構(gòu)概念設(shè)計郁彥著鐵道工業(yè)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續(xù)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續(xù)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