1、一、构件编号: 现浇钢筋混凝土板LB-1二、示意图三、依据规范 建筑结构荷载规范 GB50009-2012 混凝土结构设计规范 GB50010-2010四、计算信息 1.几何参数 计算跨度: Lx = 2700 mm; Ly = 4800 mm 板厚: h = 120 mm 2.材料信息 混凝土等级: C25 fc=11.9N/mm2 ft=1.27N/mm2 ftk=1.78N/mm2 Ec=2.80104N/mm2 钢筋种类: HRB400 fy = 360 N/mm2 Es = 2.0105 N/mm2 最小配筋率: = 0.200% 纵向受拉钢筋合力点至近边距离: as = 25mm
2、保护层厚度: c = 15mm 3.荷载信息(均布荷载) 永久荷载分项系数: G = 1.200 可变荷载分项系数: Q = 1.400 准永久值系数: q = 1.000 永久荷载标准值: gk = 8.000kN/m2 可变荷载标准值: qk = 3.500kN/m2 4.计算方法:塑性板 5.边界条件(上端/下端/左端/右端):固定/固定/固定/固定 6.设计参数 结构重要性系数: o = 1.00 塑性板 = 1.800五、计算参数: 1.计算板的跨度: Lo = 2700 mm 2.计算板的有效高度: ho = h-as=120-25=95 mm六、配筋计算(lx/ly=2700/4
3、800=0.5632.000 所以按双向板计算): 1.X向底板钢筋 1) 确定X向板底弯矩 Mx = (G*gk+Q*qk)*Lo2) = 0.0311*(1.200*8.000+1.400*3.500)*2.72 = 3.289 kN*m 2) 确定计算系数 s = o*Mx/(1*fc*b*ho*ho) = 1.00*3.289106/(1.00*11.9*1000*95*95) = 0.031 3) 计算相对受压区高度 = 1-sqrt(1-2*s) = 1-sqrt(1-2*0.031) = 0.031 4) 计算受拉钢筋面积 As = 1*fc*b*ho*/fy = 1.000*1
4、1.9*1000*95*0.031/360 = 98mm2 5) 验算最小配筋率 = As/(b*h) = 98/(1000*120) = 0.081% min = 0.200% 不满足最小配筋要求 所以取面积为As = min*b*h = 0.200%*1000*120 = 240 mm2 采取方案 8200, 实配面积251 mm2 2.Y向底板钢筋 1) 确定Y向板底弯矩 My = Mx = 0.3164*3.289 = 1.041 kN*m s = o*My/(1*fc*b*ho*ho) = 1.00*1.041 = 0.010 = 1-sqrt(1-2*s) = 1-sqrt(1-2
5、*0.010) = 0.010 As = 1*fc*b*ho*/fy = 1.000*11.9*1000*95*0.010/360 = 31mm2 = As/(b*h) = 31/(1000*120) = 0.025% 3.X向支座左边钢筋 1) 确定左边支座弯矩 Mox = Mx = 1.8*3.289 = 5.920 kN*m s = o*Mox/(1*fc*b*ho*ho) = 1.00*5.920 = 0.055 = 1-sqrt(1-2*s) = 1-sqrt(1-2*0.055) = 0.057 As = 1*fc*b*ho*/fy = 1.000*11.9*1000*95*0.0
6、57/360 = 178mm2 = As/(b*h) = 178/(1000*120) = 0.148% 所以取面积为As = min*b*h = 0.200%*1000*120 = 240mm2 4.X向支座右边钢筋 1) 确定右边支座弯矩 5.Y向上边支座钢筋 1) 确定上边支座弯矩 Moy = My = 1.8*1.041 = 1.873 kN*m s = o*Moy/(1*fc*b*ho*ho) = 1.00*1.873 = 0.017 = 1-sqrt(1-2*s) = 1-sqrt(1-2*0.017) = 0.018 As = 1*fc*b*ho*/fy = 1.000*11.9
7、*1000*95*0.018/360 = 55mm2 = As/(b*h) = 55/(1000*120) = 0.046% 6.Y向下边支座钢筋 1) 确定下边支座弯矩七、跨中挠度计算: Mk - 按荷载效应的标准组合计算的弯矩值 Mq - 按荷载效应的准永久组合计算的弯矩值 1.计算荷载效应 Mk = Mgk + Mqk = 0.0311*(8.000+3.500)*2.72 = 2.609 kN*m Mq = Mgk+q*Mqk = 0.0311*(8.000+1.0*3.500)*2.72 = 2.609 kN*m 2.计算受弯构件的短期刚度 Bs 1) 计算按荷载荷载效应的两种组合作
8、用下,构件纵向受拉钢筋应力 sk = Mk/(0.87*ho*As) 混规(7.1.4-3) = 2.609106/(0.87*95*251) = 125.741 N/mm sq = Mq/(0.87*ho*As) 混规(7.1.4-3) 2) 计算按有效受拉混凝土截面面积计算的纵向受拉钢筋配筋率 矩形截面积: Ate = 0.5*b*h = 0.5*1000*120= 60000mm2 te = As/Ate 混规(7.1.2-4) = 251/60000 = 0.418% 3) 计算裂缝间纵向受拉钢筋应变不均匀系数 k = 1.1-0.65*ftk/(te*sk) 混规(7.1.2-2)
9、= 1.1-0.65*1.78/(0.418%*125.741) = -1.100 因为不能小于最小值0.2,所以取k = 0.2 q = 1.1-0.65*ftk/(te*sq) 混规(7.1.2-2) 因为不能小于最小值0.2,所以取q = 0.2 4) 计算钢筋弹性模量与混凝土模量的比值 E E = Es/Ec = 2.0105/2.80104 = 7.143 5) 计算受压翼缘面积与腹板有效面积的比值 f 矩形截面,f=0 6) 计算纵向受拉钢筋配筋率 = As/(b*ho)= 251/(1000*95) = 0.264% 7) 计算受弯构件的短期刚度 Bs Bsk = Es*As*ho2/1.15k+0.2+6*E*/(1+ 3.5f)(混规(7.2.3-1) = 2.0105*251*952/1.15*-1.100+0.2+6*7.143*0.264%/(1+3.5*0.0) = 8.340102 kN*m2 Bsq = Es*As*ho2/1.15q+0.2+6*E*/(1+ 3.5f 3.计算受弯构件的长期刚度B 1) 确定考虑荷载长期效应组合对挠度影响增大
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