(北极星) 板式楼梯计算
1.1基本资料1.1.1工程名称:
1.1.2楼梯类型:板式 A 型 ( ╱ ) 支座条件:低端固定高端铰支
1.1.3踏步段水平净长 Lsn =1820mm
梯板净跨度 Ln =Lsn = 1820 = 1820mm 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{1820+ (200+200) / 2, 1.05Ln} = 1911mm
1.1.5梯板厚度 h1 = 70.778mm
1.1.6踏步段总高度 Hs = 1500mm 楼梯踏步级数 n =8
1.1.7线性恒荷标准值 Pk = 1kN/m 均布活荷标准值 qk = 0kN/m
ψc =0.7 ψq =0.3
1.1.8面层厚度 c1 = 25mm 面层容重 γc1 =25kN/m
顶棚厚度 c2 = 20mm 顶棚容重 γc2 =25kN/m
1.1.9楼梯自重容重 γb = 25kN/m
1.1.10混凝土强度等级:C20 fc = 9.55N/mm ft = 1.1N/mm
ftk = 1.54N/mm Ec = 25413N/mm
1.1.11钢筋强度设计值 fy =210N/mm Es = 210000N/mm
1.2楼梯几何参数
1.2.1踏步高度 hs = 161.1mm 踏步宽度 bs = 287.5mm
踏步段斜板的倾角 α =ArcTan(hs / bs) = ArcTan(161.1/287.5) = 0.51 = 29.3°
踏步段斜板的长度 Lx = Lsn / Cosα = 1820/ Cos0.5 = 2086mm
1.2.2踏步段梯板厚的垂直高度 h1' = h1 / Cosα= 70.778/ Cos0.5 = 81mm
踏步段梯板平均厚度 T =(hs + 2 * h1') / 2= (161.1 + 2 * 81.132) / 2 = 162mm
1.2.3梯板有效高度 h1o =h1 - aas = 70.778 - 25 = 46mm
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 = 1/1.15 = 0.87kN/m
1.3.2梯板自重 gk2 = γb * T = 25*0.162 = 4.04kN/m
1.3.3踏步段梯板面层自重
gk3 = γc1 * c1 * (n - 1) * (hs + bs) / Ln =
= 25 * 0.025* (8- 1) * (0.161 + 0.288) / 1.82 = 1.08kN/m
1.3.4梯板顶棚自重 gk4' = γc2 * c2 = 25*0.02 = 0.5kN/m
gk4 = gk4' * Lx / Ln = 0.5*2.09/1.8 = 0.57kN/m
1.3.5均布荷载标准值汇总 gk = gk = gk1 + gk2 + gk3 + gk4 = γb * T = 6.56kN/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= 1.2*6.56+1.4*0 = 7.88kN/m
由永久荷载控制的p(D)= 1.35 * gk + 1.4 * ψc * qk = 1.35*6.56+1.4*0.7*0 = 8.86kN/m
最不利的荷载设计值p= Maxp(L), p(D)= Max7.88,8.86 = 8.86kN/m
1.5梯板斜截面受剪承载力计算
Vmax ≤ 0.7 * ft * b * ho = 0.7 *1.1*1*45.778 = 35.3kN
Vmax = 5 / 8 * p * Ln * Cosα = 5 / 8 *8.86*1.8* Cos0.51 = 8.8kN<35.3kN
,满足要求。
1.6正截面受弯承载力计算
1.6.1跨中 Mmax = 9 / 128 * p * Lo ^ 2= 9 / 128 *8.86*1.911^ 2 = 2.28kN·m
ξ = 0.121? ρ = 0.55%? As = 252(mm2)
1号钢筋实配 φ6@110 (As = 257mm2?)
最大裂缝宽度 ωmax = 0.078mm
1.6.2支座 Mmin = - p * Lo ^ 2 / 8 = - 8.86*1.911^ 2 / 8 = -4.04kN·m
ξ = 0.228? ρ = 1.04%? As = 475(mm2)
3号钢筋实配 φ10@160 (As = 491mm2?)
最大裂缝宽度 ωmax = 0.116mm
1.6.3铰支端支座构造负筋 ρmin = 0.24% ASs* = 166.985(mm2)
2号钢筋实配 φ6@160 (As = 177mm2?)
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【北极星结构工程师助手 - 免费使用版 V1.5】 Date:2006-11-715:08:30
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