σsq = 2.14*10^6/(0.87* 101.* 251.) = 96.837N/mm2
矩形截面,Ate=0.5*b*h=0.5*1000*120.= 60000.mm2
ρte = As / Ate (混凝土规范式 7.1.2-4)
ρte = 251./ 60000.= 0.004
当 ρte <0.01 时,取ρte = 0.01
ψ = 1.1 - 0.65* 2.01/( 0.01* 96.84) = -0.247
当 ψ<0.2 时,取ψ = 0.2
ωmax = αcr*ψ*σsq/Es*(1.9c+0.08*Deq/ρte) (混凝土规范式 7.1.2-1)
ωmax =1.9*0.200* 96.837/200000.*(1.9*20.+0.08* 8.00/0.01000) = 0.019mm,满足规范要求!
⑤、右端支座跨中裂缝:
裂缝间纵向受拉钢筋应变不均匀系数 ψ, 按下列公式计算:
ψ = 1.1 - 0.65 * ftk / (ρte * σsq) (混凝土规范式 7.1.2-2)
σsq = Mq / (0.87 * ho * As) (混凝土规范式 7.1.4-3)
σsq = 3.36*10^6/(0.87* 101.* 251.) = 152.367N/mm2
矩形截面,Ate=0.5*b*h=0.5*1000*120.= 60000.mm2
ρte = As / Ate (混凝土规范式 7.1.2-4)
ρte = 251./ 60000.= 0.004
当 ρte <0.01 时,取ρte = 0.01
ψ = 1.1 - 0.65* 2.01/( 0.01* 152.37) = 0.244
ωmax = αcr*ψ*σsq/Es*(1.9c+0.08*Deq/ρte) (混凝土规范式 7.1.2-1)
ωmax =1.9*0.244*152.367/200000.*(1.9*20.+0.08* 8.00/0.01000) = 0.036mm,满足规范要求!
一、基本资料:
1、房间编号: 9
2、边界条件(左端/下端/右端/上端):固定/固定/固定/铰支/
3、荷载:
永久荷载标准值:g = 4.80 kN/m2
可变荷载标准值:q = 2.50 kN/m2
计算跨度 Lx = 3600 mm ;计算跨度 Ly = 2250 mm
板厚 H = 120 mm; 砼强度等级:C30;钢筋强度等级:HRB400
4、计算方法:弹性算法。
5、泊松比:μ=1/5.
6、考虑活荷载不利组合。
二、计算结果:
Mx =(0.01714+0.04686/5)*(1.20* 4.80+1.40* 1.25)* 2.2^2 = 1.01kN•m
考虑活载不利布置跨中X向应增加的弯矩:
Mxa =(0.02571+0.07836/5)*(1.4* 1.25)* 2.2^2 = 0.37kN•m
Mx= 1.01 + 0.37 = 1.37kN•m
Asx= 240.00mm2,实配φ 8@200 (As = 251.mm2)
ρmin = 0.179% , ρ = 0.209%
My =(0.04686+0.01714/5)*(1.20* 4.80+1.40* 1.25)* 2.2^2= 1.91kN•m
考虑活载不利布置跨中Y向应增加的弯矩:
Mya =(0.07836+0.02571/5)*(1.4* 1.25)* 2.2^2 = 0.74kN•m
My= 1.91 + 0.74 = 2.65kN•m
Asy= 240.00mm2,实配φ 8@200 (As = 251.mm2)
ρmin = 0.179% , ρ = 0.209% 六层小学宿舍楼结构设计+CAD图纸(7):http://www.youerw.com/gongcheng/lunwen_22257.html