1 梁板式楼梯:TB-1
1.1 基本资料
1.1.1 工程名称:工程一
1.1.2 楼梯类型:板式 A 型 ( ╱ ) 支座条件:两端弹性
1.1.3 踏步段水平净长 Lsn = 3920mm 梯板净跨度 Ln = Lsn = 3920mm
梯板净宽度 B = 1150mm
1.1.4 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{4120, 4116} = 4116mm
1.1.5 梯板厚度 h1 = 140mm
1.1.6 踏步段总高度 Hs = 2400mm 楼梯踏步级数 n = 15
1.1.7 线性恒荷标准值 Pk = 1.00kN/m 均布活荷标准值 qk = 3.50kN/m ψc = 0.7 ψq = 0.4
1.1.8 面层厚度 c1 = 25mm 面层容重 γc1 =20.00kN/m 顶棚厚度 c2 = 20mm 顶棚容重 γc2 =18.00kN/m
1.1.9 楼梯自重容重 γb = 25.00kN/m
1.1.10 混凝土强度等级: C30 fc = 14.33N/mm ft = 1.43N/mm
ftk = 2.01N/mm Ec = 29791N/mm
1.1.11 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
1.2 楼梯几何参数
1.2.1 踏步高度 hs = Hs / n = 2400/15 = 160.0mm
踏步宽度 bs = Lsn / (n - 1) = 3920/(15-1) = 280.0mm
踏步段斜板的倾角 α = ArcTan(hs / bs) = ArcTan(160.0/280.0) = 29.7° 踏步段斜板的长度 Lx = Lsn / Cosα = 3920/Cos29.7°= 4515mm
1.2.2 踏步段梯板厚的垂直高度 h1' = h1 / Cosα = 140/Cos29.7°= 161mm
踏步段梯板平均厚度 T = (hs + 2 * h1') / 2 = (160+2*161)/2 = 241mm
1.2.3 梯板有效高度 h1o = h1 - as = 140-25 = 115mm
1.3 均布永久荷载标准值
1.3.1 梯板上的线形荷载换算成均布永久荷载
gk1 = Pk / B = 1.00/1.150 = 0.87kN/m
1.3.2 梯板自重 gk2 = γb * T = 25.00*0.241 = 6.03kN/m
1.3.3 踏步段梯板面层自重
gk3 = γc1 * c1 * (n - 1) * (hs + bs) / Ln
= 20.00*0.025*(15-1)*(0.160+0.280)/3.920 = 0.79kN/m
1.3.4 梯板顶棚自重 gk4' = γc2 * c2 = 18.00*0.020 = 0.36kN/m
gk4 = gk4' * Lx / Ln = 0.36*4.515/3.920 = 0.41kN/m
1.3.5 均布荷载标准值汇总 gk = gk1 + gk2 + gk3 + gk4 = 8.10kN/m
1.4 均布荷载设计值
由可变荷载控制的 p(L) = 1.2 * gk + 1.4 * qk = 14.62kN/m
由永久荷载控制的 p(D) = 1.35 * gk + 1.4 * ψc * qk = 14.37kN/m
最不利的荷载设计值 p = Max{p(L), p(D)} = 14.62kN/m
1.5 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*14.62*3920*Cos29.7° = 28658*0.8682 = 24882N
0.7 * ft * b * ho = 0.7*1.43*1000*115 = 115348N ≥ Vmax = 24882N,满足要求。
1.6 正截面受弯承载力计算
1.6.1 跨中 Mmax = p * Lo ^ 2 / 10 = 14.62*4.116^2/10 = 24.77kN·m
As = 644mm ξ = 0.141 ρ = 0.56%
实配 12@100 (As = 1131mm ) 最大裂缝宽度 ωmax = 0.113mm
1.6.2 支座 Mmin = - p * Lo ^ 2 / 20 = -14.62*4.116^2/20 = -12.39kN·m As = 310mm ξ = 0.068 ρ = 0.27%
实配 12@200 (As = 565mm ) 最大裂缝宽度 ωmax = 0.085mm
1.7 跨中挠度验算
1.7.1 挠度验算参数
Mk = 19.65kN·m Mq = 16.10kN·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
1.7.2 在荷载效应的标准组合作用下,受弯构件的短期刚度 Bs
1.7.2.1 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 = 19653849/(0.87*115*1131) = 174N/mm
矩形截面, Ate = 0.5 * b * h = 0.5*1000*140 = 70000mm
ρte = As / Ate (混凝土规范式 8.1.2-4)
ρte = 1131/70000 = 0.01616
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/(0.01616*174) = 0.635
1.7.2.2 钢筋弹性模量与混凝土模量的比值 αE
αE = Es / Ec = 200000/29791 = 6.71
1.7.2.3 受压翼缘面积与腹板有效面积的比值 γf'
矩形截面,γf' = 0
1.7.2.4 纵向受拉钢筋配筋率 ρ = As / (b * ho) = 1131/(1000*115) = 0.00983
1.7.2.5 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*1131*115^2/[1.15*0.635+0.2+6*6.71*0.00983/(1+3.5*0.000)] = 2254.63kN·m
1.7.3 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
1.7.4 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 = 19.65/[16.10*(2-1)+19.65]*2254.63 = 1239.50kN·m
1.7.5 跨中挠度 f
f = 2.9 / 384 * Qk * Lo ^ 4 / B = 0.00755*11.60*4.116^4/1239.50*1000 = 20.3mm
f / Lo = 20.3/4116 = 1/203
1.8 板式楼梯平面整体表示方法的注写内容
AT1, h = 140 160X15 = 2400 12@100
1 梁板式楼梯:TB-1
1.1 基本资料
1.1.1 工程名称:工程一
1.1.2 楼梯类型:板式 A 型 ( ╱ ) 支座条件:两端弹性
1.1.3 踏步段水平净长 Lsn = 3920mm 梯板净跨度 Ln = Lsn = 3920mm
梯板净宽度 B = 1150mm
1.1.4 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{4120, 4116} = 4116mm
1.1.5 梯板厚度 h1 = 140mm
1.1.6 踏步段总高度 Hs = 2400mm 楼梯踏步级数 n = 15
1.1.7 线性恒荷标准值 Pk = 1.00kN/m 均布活荷标准值 qk = 3.50kN/m ψc = 0.7 ψq = 0.4
1.1.8 面层厚度 c1 = 25mm 面层容重 γc1 =20.00kN/m 顶棚厚度 c2 = 20mm 顶棚容重 γc2 =18.00kN/m
1.1.9 楼梯自重容重 γb = 25.00kN/m
1.1.10 混凝土强度等级: C30 fc = 14.33N/mm ft = 1.43N/mm
ftk = 2.01N/mm Ec = 29791N/mm
1.1.11 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
1.2 楼梯几何参数
1.2.1 踏步高度 hs = Hs / n = 2400/15 = 160.0mm
踏步宽度 bs = Lsn / (n - 1) = 3920/(15-1) = 280.0mm
踏步段斜板的倾角 α = ArcTan(hs / bs) = ArcTan(160.0/280.0) = 29.7° 踏步段斜板的长度 Lx = Lsn / Cosα = 3920/Cos29.7°= 4515mm
1.2.2 踏步段梯板厚的垂直高度 h1' = h1 / Cosα = 140/Cos29.7°= 161mm
踏步段梯板平均厚度 T = (hs + 2 * h1') / 2 = (160+2*161)/2 = 241mm
1.2.3 梯板有效高度 h1o = h1 - as = 140-25 = 115mm
1.3 均布永久荷载标准值
1.3.1 梯板上的线形荷载换算成均布永久荷载
gk1 = Pk / B = 1.00/1.150 = 0.87kN/m
1.3.2 梯板自重 gk2 = γb * T = 25.00*0.241 = 6.03kN/m
1.3.3 踏步段梯板面层自重
gk3 = γc1 * c1 * (n - 1) * (hs + bs) / Ln
= 20.00*0.025*(15-1)*(0.160+0.280)/3.920 = 0.79kN/m
1.3.4 梯板顶棚自重 gk4' = γc2 * c2 = 18.00*0.020 = 0.36kN/m
gk4 = gk4' * Lx / Ln = 0.36*4.515/3.920 = 0.41kN/m
1.3.5 均布荷载标准值汇总 gk = gk1 + gk2 + gk3 + gk4 = 8.10kN/m
1.4 均布荷载设计值
由可变荷载控制的 p(L) = 1.2 * gk + 1.4 * qk = 14.62kN/m
由永久荷载控制的 p(D) = 1.35 * gk + 1.4 * ψc * qk = 14.37kN/m
最不利的荷载设计值 p = Max{p(L), p(D)} = 14.62kN/m
1.5 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*14.62*3920*Cos29.7° = 28658*0.8682 = 24882N
0.7 * ft * b * ho = 0.7*1.43*1000*115 = 115348N ≥ Vmax = 24882N,满足要求。
1.6 正截面受弯承载力计算
1.6.1 跨中 Mmax = p * Lo ^ 2 / 10 = 14.62*4.116^2/10 = 24.77kN·m
As = 644mm ξ = 0.141 ρ = 0.56%
实配 12@100 (As = 1131mm ) 最大裂缝宽度 ωmax = 0.113mm
1.6.2 支座 Mmin = - p * Lo ^ 2 / 20 = -14.62*4.116^2/20 = -12.39kN·m As = 310mm ξ = 0.068 ρ = 0.27%
实配 12@200 (As = 565mm ) 最大裂缝宽度 ωmax = 0.085mm
1.7 跨中挠度验算
1.7.1 挠度验算参数
Mk = 19.65kN·m Mq = 16.10kN·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
1.7.2 在荷载效应的标准组合作用下,受弯构件的短期刚度 Bs
1.7.2.1 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 = 19653849/(0.87*115*1131) = 174N/mm
矩形截面, Ate = 0.5 * b * h = 0.5*1000*140 = 70000mm
ρte = As / Ate (混凝土规范式 8.1.2-4)
ρte = 1131/70000 = 0.01616
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/(0.01616*174) = 0.635
1.7.2.2 钢筋弹性模量与混凝土模量的比值 αE
αE = Es / Ec = 200000/29791 = 6.71
1.7.2.3 受压翼缘面积与腹板有效面积的比值 γf'
矩形截面,γf' = 0
1.7.2.4 纵向受拉钢筋配筋率 ρ = As / (b * ho) = 1131/(1000*115) = 0.00983
1.7.2.5 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*1131*115^2/[1.15*0.635+0.2+6*6.71*0.00983/(1+3.5*0.000)] = 2254.63kN·m
1.7.3 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
1.7.4 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 = 19.65/[16.10*(2-1)+19.65]*2254.63 = 1239.50kN·m
1.7.5 跨中挠度 f
f = 2.9 / 384 * Qk * Lo ^ 4 / B = 0.00755*11.60*4.116^4/1239.50*1000 = 20.3mm
f / Lo = 20.3/4116 = 1/203
1.8 板式楼梯平面整体表示方法的注写内容
AT1, h = 140 160X15 = 2400 12@100