第1个回答 2013-12-16
3300-240-560(梯井宽)=2500
2500/2=1250
5100-2500=2600(楼梯长)
3300+500=3800(总高)11步173高260宽踏步
2.1 基本资料
2.1.1 工程名称:19-SLT3
2.1.2 楼梯类型:板式 A 型 ( ╱ ) 支座条件:两端铰支
2.1.3 踏步段水平净长 Lsn = 2600mm 梯板净跨度 Ln = Lsn = 2600mm
梯板净宽度 B = 1300mm
2.1.4 低端支座宽度 dl = 200mm 高端支座宽度 dh = 200mm
计算跨度 Lo = Min{Ln + (dl + dh) / 2, 1.05Ln} = Min{2800, 2730} = 2730mm
2.1.5 梯板厚度 h1 = 120mm
2.1.6 踏步段总高度 Hs = 1200mm 楼梯踏步级数 n = 11
2.1.7 线性恒荷标准值 Pk = 1kN/m 均布活荷标准值 qk = 3.5kN/m ψc = 0.7
ψq = 0.4
2.1.8 面层厚度 c1 = 30mm 面层容重 γc1 =20kN/m 顶棚厚度 c2 = 20mm
顶棚容重 γc2 =20kN/m
2.1.9 楼梯自重容重 γb = 25kN/m
2.1.10 混凝土强度等级: C30 fc = 14.33N/mm ft = 1.43N/mm
ftk = 2.01N/mm Ec = 29791N/mm
2.1.11 钢筋强度设计值 fy = 360N/mm Es = 200000N/mm
纵筋合力点至近边距离 as = 25mm
2.2 楼梯几何参数
2.2.1 踏步高度 hs = Hs / n = 1200/11 = 109.1mm
踏步宽度 bs = Lsn / (n - 1) = 2600/(11-1) = 260mm
踏步段斜板的倾角 α = ArcTan(hs / bs) = ArcTan(109.1/260) = 22.8°
踏步段斜板的长度 Lx = Lsn / Cosα = 2600/Cos22.8°= 2820mm
2.2.2 踏步段梯板厚的垂直高度 h1' = h1 / Cosα = 120/Cos22.8°= 130mm
踏步段梯板平均厚度 T = (hs + 2 * h1') / 2 = (109+2*130)/2 = 185mm
2.2.3 梯板有效高度 h1o = h1 - as = 120-25 = 95mm
2.3 均布永久荷载标准值
2.3.1 梯板上的线形荷载换算成均布永久荷载 gk1 = Pk / B = 1/1.3 = 0.77kN/m
2.3.2 梯板自重 gk2 = γb * T = 25*0.185 = 4.62kN/m
2.3.3 踏步段梯板面层自重
gk3 = γc1 * c1 * (n - 1) * (hs + bs) / Ln = 20*0.03*(11-1)*(0.109+0.26)/2.6
= 0.85kN/m
2.3.4 梯板顶棚自重 gk4' = γc2 * c2 = 20*0.02 = 0.40kN/m
gk4 = gk4' * Lx / Ln = 0.4*2.82/2.6 = 0.43kN/m
2.3.5 均布荷载标准值汇总 gk = gk1 + gk2 + gk3 + gk4 = 6.67kN/m
2.4 均布荷载设计值
由可变荷载控制的 p(L) = 1.2 * gk + 1.4 * qk = 12.91kN/m
由永久荷载控制的 p(D) = 1.35 * gk + 1.4 * ψc * qk = 12.44kN/m
最不利的荷载设计值 p = Max{p(L), p(D)} = 12.91kN/m
2.5 支座反力
永久荷载作用下均布反力标准值 Rk(D) = 8.67kN/m
可变荷载作用下均布反力标准值 Rk(L) = 4.55kN/m
最不利的均布反力基本组合值 R = 16.78kN/m
2.6 梯板斜截面受剪承载力计算
Vmax ≤ 0.7 * ft * b * ho
Vmax = 0.5 * p * Ln * Cosα = 0.5*12.91*2.6*Cos22.8° = 15.5kN
0.7 * ft * b * ho = 0.7*1.43*1000*0.095
= 95.3kN ≥ Vmax = 15.5kN,满足要求。
2.7 正截面受弯承载力计算
2.7.1 跨中 Mmax = p * Lo ^ 2 / 8 = 12.91*2.73^2/8 = 12.02kN·m
As = 370mm ξ = 0.098 ρ = 0.39%
实配 10@200 (As = 393mm) 最大裂缝宽度 ωmax = 0.236mm
2.7.2 支座构造负筋 ρmin = 0.20% As* = 240mm
实配 8@200 (As = 251mm)
2.8 跨中挠度验算
2.8.1 挠度验算参数
Mk = 9.48kN·m Mq = 7.52kN·m
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
2.8.2 在荷载效应的标准组合作用下,受弯构件的短期刚度 Bs
2.8.2.1 裂缝间纵向受拉钢筋应变不均匀系数 ψ
σsk = Mk / (0.87 * ho * As) (混凝土规范式 8.1.3-3)
σsk = 9476149/(0.87*95*393) = 292N/mm
矩形截面, Ate = 0.5 * b * h = 0.5*1000*120 = 60000mm
ρte = As / Ate (混凝土规范式 8.1.2-4)
ρte = 393/60000 = 0.00655 <0.01,取 ρte = 0.01
ψ = 1.1 - 0.65 * ftk / (ρte * σsk) (混凝土规范式 8.1.2-2)
ψ = 1.1-0.65*2.01/(0.01*292) = 0.653
2.8.2.2 钢筋弹性模量与混凝土模量的比值 αE
αE = Es / Ec = 200000/29791 = 6.71
2.8.2.3 受压翼缘面积与腹板有效面积的比值 γf'
矩形截面,γf' = 0
2.8.2.4 纵向受拉钢筋配筋率 ρ = As / (b * ho) = 393/(1000*95) = 0.00414
2.8.2.5 钢筋混凝土受弯构件的 Bs 按混凝土规范式 8.2.3-1 计算:
Bs = Es * As * ho ^ 2 / [1.15ψ + 0.2 + 6 * αE * ρ / (1 + 3.5γf')]
= 200000*393*95^2/[1.15*0.653+0.2+6*6.71*0.00414/(1+3.5*0)]
= 634.70kN·m
2.8.3 考虑荷载长期效应组合对挠度影响增大影响系数 θ
按混凝土规范第 8.2.5 条,当 ρ' = 0 时,θ = 2.0
2.8.4 受弯构件的长期刚度 B,可按混凝土规范式 8.2.2 计算:
B = Mk / [Mq * (θ - 1) + Mk] * Bs = 9.48/[7.52*(2-1)+9.48]*634.7
= 353.88kN·m
2.8.5 跨中挠度 f
挠度验算时考虑踏步刚度,踏步段等效高度 heq = 160mm 挠度折减系数 η = 0.42
f = 0.42 * 5 / 384 * Qk * Lo ^ 4 / B = 0.00547*10.17*2.73^4/353.88*1000
= 8.7mm
f / Lo = 8.7/2730 = 1/313
2.9 板式楼梯平面整体表示方法的注写内容
AT2, h = 120 109.1X11 = 1200 10@200
置于画图,首先你要给我一张图,我才能知道你的具体式样。