1、 1.受弯构件: 1.1 基本资料 1.1.1 工程名称:工程一 1.1.2 混凝土强度等级:C30 fc = 14.33N/mm ft = 1.43N/mm 1.1.3 钢筋强度设计值 fy = 360N/mm Es = 200000N/mm 1.1.4 由弯矩设计值 M 求配筋面积 As,弯矩 M = 120kN·m 1.1.5 截面尺寸 b×h = 250*500mm ho = h - as = 500-40 = 460mm 1.2 计算结果: 1.2.1 相对界限受
2、压区高度 ξb ξb = β1 / [1 + fy / (Es * εcu)] = 0.8/[1+360/(200000*0.0033)] = 0.518 1.2.2 受压区高度 x = ho - [ho ^ 2 - 2 * M / (α1 * fc * b)] ^ 0.5 = 460-[460^2-2*120000000/(1*14.33*250)]^0.5 = 80mm 1.2.3 相对受压区高度 ξ = x / ho = 80/460 = 0.173 ≤ ξb = 0.518 1.2.4
3、纵向受拉钢筋 As = α1 * fc * b * x / fy = 1*14.33*250*80/360 = 793mm 1.2.5 配筋率 ρ = As / (b * ho) = 793/(250*460) = 0.69% 最小配筋率 ρmin = Max{0.20%, 0.45ft/fy} = Max{0.20%, 0.18%} = 0.20% 2.受剪构件: (1)构造配筋 1.1 基本资料 1.1.1 工程名称:工程一 1.1.2 混凝土强度等级:C30 fc = 14.33N/mm ft = 1.43
4、N/mm 1.1.3 箍筋抗拉强度设计值 fyv = 210N/mm 箍筋间距 s = 200mm 1.1.4 由剪力设计值 V 求箍筋面积 Asv,剪力设计值 V = 100kN 1.1.5 截面尺寸 b×h = 250×500mm ho = h - as = 500-40 = 460mm 1.2 计算结果 1.2.1 0.7 * ft * b * ho = 0.7*1.43*250*460 = 115348N ≥ V = 100000N 1.2.2 当 V ≤ 0.7 * ft * b * ho、 300 <
5、 H ≤ 500mm 构造要求: 箍筋最小直径 Dmin = 6mm,箍筋最大间距 Smax = 300mm Dmin、Smax 的配箍面积 Asv# = Dmin ^ 2 * π / 4 * S / Smax = 19mm 最小配箍面积 Asv,min = 19mm (2)计算配筋 1.1 基本资料 1.1.1 工程名称:工程一 1.1.2 混凝土强度等级:C30 fc = 14.33N/mm ft = 1.43N/mm 1.1.3 箍筋抗拉强度设计值 fyv = 210N/mm
6、 箍筋间距 s = 200mm 1.1.4 由剪力设计值 V 求箍筋面积 Asv,剪力设计值 V = 200kN 1.1.5 截面尺寸 b×h = 250×500mm ho = h - as = 500-40 = 460mm 1.2 计算结果 1.2.1 0.7 * ft * b * ho = 0.7*1.43*250*460 = 115348N < V = 200000N 1.2.2 当 V > 0.7 * ft * b * ho、 300 < H ≤ 500mm 构造要求: 箍筋最小直径 Dmin = 6
7、mm,箍筋最大间距 Smax = 200mm 最小配箍面积 Asv,min = (0.24 * ft / fyv) * b * S = (0.24*1.43/210)*250*200 = 82mm 1.2.3 矩形受弯构件,其受剪截面应符合下式条件: 当 ho / b ≤ 4 时,V ≤ 0.25 * βc * fc * b * ho (混凝土规范 7.5.1-1) 0.25 * βc * fc * b * ho = 0.25*1*14.33*250*460
8、 = 412029N ≥ V = 200000N,满足要求。 1.2.4 矩形截面的一般受弯构件,其斜截面受剪承载力按下列公式计算: V ≤ 0.7 * ft * b * ho + 1.25 * fyv * Asv / S * ho (混凝土规范 7.5.4-2) Asv = (V - 0.7 * ft * b * ho) * S / (1.25 * Fyv * ho) = (200000-0.7*1.43*250*460)*200/(1.25*210*4
9、60) = 140mm 3.弯剪扭构件: (1)纯扭构件 1.1 基本资料 1.1.1 工程名称:工程一 1.1.2 混凝土强度:C30 fcu,k = 30N/mm fc = 14.33N/mm ft = 1.43N/mm 1.1.3 钢筋强度:fy = 360N/mm fy' = 360N/mm fyv = 210N/mm Es = 200000N/mm 1.1.4 弯矩设计值 M = 0kN·m 剪力设计值 V = 0kN 扭矩设计值 T = 8
10、0kN·m 箍筋间距 S = 200mm 1.1.5 矩形截面 截面尺寸 b×h = 350×600mm ho = 560mm 1.2 正截面受弯配筋计算 1.2.1 相对界限受压区高度 ξb = β1 / [1 + fy / (Es * εcu)] = 0.8/[1+360/(200000*0.0033)] = 0.518 1.2.2 单筋矩形截面或翼缘位于受拉边的T形截面受弯构件受压区高度 x 按下式计算: x = ho - [
11、ho ^ 2 - 2 * M / (α1 * fc * b)] ^ 0.5 = 560-(560^2-2*0/1/14.33/350)^0.5 = 0mm ≤ ξb * ho = 0.518*560 = 290mm 1.2.3 As = α1 * fc * b * x / fy = 1*14.33*350*0/360 = 0mm 1.2.4 相对受压区高度 ξ = x / ho = 0/560 = 0 ≤ 0.518 配筋率 ρ = As / (b * ho) = 0/(350*560) = 0.00% 最小配筋率 ρ
12、min = Max{0.20%, 0.45ft/fy} = Max{0.20%, 0.18%} = 0.20% As,min = b * h * ρmin = 420mm 1.3 斜截面承载力计算 1.3.1 0.7 * ft * b * ho = 0.7*1.43*350*560 = 196593N ≥ V = 0N 当 V ≤ 0.7 * ft * b * ho、500 < H ≤ 800mm 构造要求: 箍筋最小直径 Dmin = 6mm,箍筋最大间距 Smax = 350mm Dmin、Smax
13、的配箍面积 Asv# = Dmin ^ 2 * π / 4 * S / Smax = 16mm 最小配箍面积 Asv,min = 16mm 1.3.2 一般受弯构件,其斜截面受剪承载力按下列公式计算: V ≤ 0.7 * ft * b * ho + 1.25 * fyv * Asv/S * ho 0.7 * ft * b * ho = 0.7*1.43*350*560 = 196593N ≥ V = 0N,仅需按构造配箍 1.3.3 Asv,min = 16mm 箍筋最小直径 φ6 最大间距 @350
14、 1.4 扭曲截面承载力计算 1.4.1 矩形截面受扭塑性抵抗矩 Wt = b ^ 2 * (3h - b) / 6 = 350^2*(3*600-350)/6 = 29604167mm 1.4.2 一般剪扭构件混凝土受扭承载力降低系数 βt 按下式计算: βt = 1.5 / [1 + 0.5 * V * Wt / (T * b * ho)] = 1.5/[1+0.5*0*29604167/(80000000*350*560)] = 1.5 > 1.0,取 βt = 1.0 1.4.3 验算截
15、面适用条件 Hw / b = 560/350 = 1.6 < 6,截面高宽比满足要求 V / (b * ho) + T / (0.8 * Wt) = 0/(350*560)+80000000/(0.8*29604167) = 3.38N/mm ≤ 0.25 * βc * fc = 3.58N/mm, 满足截面尺寸要求 V / (b * ho) + T / Wt = 0/(350*560)+8
16、0000000/29604167 = 2.70N/mm > 0.7 * ft = 1.00N/mm,需进行剪扭计算 1.4.4 验算是否要考虑剪力、扭矩的影响 当 V ≤ 0.35 * ft * b * ho 时,可仅按纯扭构件计算受扭承载力 0.35 * ft * b * ho = 0.35*1.43*350*560 = 98296N ≥ V = 0N, 可不考虑剪力的影响 当 T ≤ 0.175 * ft * Wt
17、 时,可不进行受扭承载力计算 0.175 * ft * Wt = 0.175*1.43*29604167 = 7.423kN·m < T = 80.000kN·m,应进行受扭承载力计算 1.4.5 纯扭构件矩形截面腹板的受扭承载力应按下列公式计算: T ≤ 0.35 * ft * Wt + 1.2 * ζ^0.5 * fyv * Ast1 * Acor / S Acor = bcor * hcor = (350-2*30)*(600-2*30) = 156600mm A
18、st1 = (T - 0.35 * ft * Wt) * S / (1.2ζ^0.5 * fyv * Acor) = (80000000-0.35*1.43*29604167)*200/(1.2*1.2^0.5*210*156600) = 301mm Ucor = 2 * (bcor + hcor) = 2*(290+540) = 1660mm 取 ζ = fy * Astl * S / (fyv * Ast1 * Ucor) = 1.2 受扭计算中取对称布置的全部纵向非预应力钢筋截面面积 Astl 可由下式求得:
19、 Astl = fyv * Ast1 * Ucor * ζ / (fy * S) = 210*301*1660*1.2/(360*200) = 1751mm 1.4.6 剪扭构件中箍筋和纵筋的最小配筋面积 箍筋最小配筋率 ρsv,min = 0.28 * ft / fyv = 0.19% 受扭纵筋最小配筋率 ρtl,min = 0.6 * [T / (V * b)] ^ 0.5 * ft / fy = 0.34% 腹板箍筋计算配筋面积 Asvt = Asv + 2 * Ast1 = 0+2*3
20、01 = 603mm 腹板箍筋最小配筋面积 Asvt,min = ρsv,min * b * S = 134mm 按受扭计算 Ast1 = 301mm,当箍筋间距为 200 时,箍筋最小直径 φ20 腹板受扭纵筋最小配筋面积 Astl,min = ρtl,min * b * h = 709mm (2)剪扭构件: 1.1 基本资料 1.1.1 工程名称:工程一 1.1.2 混凝土强度:C30 fcu,k = 30N/mm fc = 14.33N/mm ft = 1.43
21、N/mm 1.1.3 钢筋强度:fy = 360N/mm fy' = 360N/mm fyv = 210N/mm Es = 200000N/mm 1.1.4 弯矩设计值 M = 0kN·m 剪力设计值 V = 50kN 扭矩设计值 T = 30kN·m 箍筋间距 S = 200mm 1.1.5 矩形截面 截面尺寸 b×h = 250×500mm ho = 460mm 1.2 正截面受弯配筋计算 1.2.1 相对界限受压区高度 ξb = β1 / [1 + fy
22、/ (Es * εcu)] = 0.8/[1+360/(200000*0.0033)] = 0.518 1.2.2 单筋矩形截面或翼缘位于受拉边的T形截面受弯构件受压区高度 x 按下式计算: x = ho - [ho ^ 2 - 2 * M / (α1 * fc * b)] ^ 0.5 = 460-(460^2-2*0/1/14.33/250)^0.5 = 0mm ≤ ξb * ho = 0.518*460 = 238mm 1.2.3 As = α1 * fc *
23、 b * x / fy = 1*14.33*250*0/360 = 0mm 1.2.4 相对受压区高度 ξ = x / ho = 0/460 = 0 ≤ 0.518 配筋率 ρ = As / (b * ho) = 0/(250*460) = 0.00% 最小配筋率 ρmin = Max{0.20%, 0.45ft/fy} = Max{0.20%, 0.18%} = 0.20% As,min = b * h * ρmin = 250mm 1.3 斜截面承载力计算 1.3.1 0.7 * ft * b * ho
24、 = 0.7*1.43*250*460 = 115348N ≥ V = 50000N 当 V ≤ 0.7 * ft * b * ho、300 < H ≤ 500mm 构造要求: 箍筋最小直径 Dmin = 6mm(规范10.2.11),箍筋最大间距 Smax = 300mm (规范表10.2.10) Dmin、Smax的配箍面积 Asv# = Dmin ^ 2 * π / 4 * S / Smax = 19mm 最小配箍面积 Asv,min = 19mm 1.3.2 一般受弯构件,其斜截面受剪承载力按下列公式计算: (
25、规范7.5.4) V ≤ 0.7 * ft * b * ho + 1.25 * fyv * Asv/S * ho 0.7 * ft * b * ho = 0.7*1.43*250*460 = 115348N ≥ V = 50000N,仅需按构造配箍 1.3.3 Asv,min = 19mm 箍筋最小直径 φ6 最大间距 @300 (规范10.2.10、规范10.2.11) 1.4 扭曲截面承载力计算 1.4.1 矩形截面受扭塑性抵抗矩 Wt = b ^ 2 * (3h - b) / 6 = 25
26、0^2*(3*500-250)/6 = 13020833mm 1.4.2 一般剪扭构件混凝土受扭承载力降低系数 βt 按下式计算: (规范7.6.8) βt = 1.5 / [1 + 0.5 * V * Wt / (T * b * ho)] = 1.5/[1+0.5*50000*13020833/(30000000*250*460)] = 1.37 > 1.0,取 βt = 1.0 1.4.3 验算截面适用条件 (规范7.6.1) Hw / b = 460/250 = 1.84 < 6,截面高
27、宽比满足要求 V / (b * ho) + T / (0.8 * Wt) = 50000/(250*460)+30000000/(0.8*13020833) = 3.31N/mm ≤ 0.25 * βc * fc = 3.58N/mm, 满足截面尺寸要求 V / (b * ho) + T / Wt = 50000/(250*460)+30000000/13020833 (规范7.6.2)
28、 = 2.74N/mm > 0.7 * ft = 1.00N/mm,需进行剪扭计算 1.4.4 验算是否要考虑剪力、扭矩的影响 当 V ≤ 0.35 * ft * b * ho 时,可仅按纯扭构件计算受扭承载力 (规范7.6.11) 0.35 * ft * b * ho = 0.35*1.43*250*460 = 57674N ≥ V = 50000N, 可不考虑剪力的影响 当 T ≤ 0.175 * ft * Wt 时,可不进行受扭承载力计
29、算 (规范7.6.11) 0.175 * ft * Wt = 0.175*1.43*13020833 = 3.265kN·m < T = 30.000kN·m,应进行受扭承载力计算 1.4.5 纯扭构件矩形截面腹板的受扭承载力应按下列公式计算: T ≤ 0.35 * ft * Wt + 1.2 * ζ^0.5 * fyv * Ast1 * Acor / S (规范式7.6.4-1) Acor = bcor * hcor = (250-2*30)*(500-2*30) = 83600mm
30、 Ast1 = (T - 0.35 * ft * Wt) * S / (1.2ζ^0.5 * fyv * Acor) = (30000000-0.35*1.43*13020833)*200/(1.2*1.2^0.5*210*83600) = 203mm Ucor = 2 * (bcor + hcor) = 2*(190+440) = 1260mm 取 ζ = fy * Astl * S / (fyv * Ast1 * Ucor) = 1.2 受扭计算中取对称布置的全部纵向非预应力钢筋截面面积 Astl 可
31、由下式求得: (规范式7.6.4-2) Astl = fyv * Ast1 * Ucor * ζ / (fy * S) = 210*203*1260*1.2/(360*200) = 897mm 1.4.6 剪扭构件中箍筋和纵筋的最小配筋面积 箍筋最小配筋率 ρsv,min = 0.28 * ft / fyv = 0.19% (规范10.2.12) 受扭纵筋最小配筋率 ρtl,min = 0.6 * [T / (V * b)] ^ 0.5 * ft / fy = 0.34% (规范式10.2.5)
32、腹板箍筋计算配筋面积 Asvt = Asv + 2 * Ast1 = 0+2*203 = 407mm 腹板箍筋最小配筋面积 Asvt,min = ρsv,min * b * S = 96mm 按受扭计算 Ast1 = 203mm,当箍筋间距为 200 时,箍筋最小直径 φ18 腹板受扭纵筋最小配筋面积 Astl,min = ρtl,min * b * h = 422mm (3)弯剪扭构件: 1.1 基本资料 1.1.1 工程名称:工程一 1.1.2 混凝土强度:C30 fcu,k = 30N
33、/mm fc = 14.33N/mm ft = 1.43N/mm 1.1.3 钢筋强度:fy = 360N/mm fy' = 360N/mm fyv = 210N/mm Es = 200000N/mm 1.1.4 弯矩设计值 M = 240kN·m 剪力设计值 V = 180kN 扭矩设计值 T = 80kN·m 箍筋间距 S = 200mm 1.1.5 矩形截面 截面尺寸 b×h = 350×700mm ho = 660mm 1.2 正截面受弯
34、配筋计算 1.2.1 相对界限受压区高度 ξb = β1 / [1 + fy / (Es * εcu)] = 0.8/[1+360/(200000*0.0033)] = 0.518 (规范式7.1.4-1) 1.2.2 单筋矩形截面或翼缘位于受拉边的T形截面受弯构件受压区高度 x 按下式计算: (假定As’=0) x = ho - [ho ^ 2 - 2 * M / (α1 * fc * b)] ^ 0.5 (规范式7.2.1-1) = 660-(660^2-2*240
35、000000/1/14.33/350)^0.5 = 77mm ≤ ξb * ho = 0.518*660 = 342mm 1.2.3 As = α1 * fc * b * x / fy = 1*14.33*350*77/360 = 1073mm (规范式7.2.1-2) 1.2.4 相对受压区高度 ξ = x / ho = 77/660 = 0.117 ≤ 0.518 配筋率 ρ = As / (b * ho) = 1073/(350*660) = 0.46% 最小配筋率 ρmin = Max{0.20%, 0.45ft
36、/fy} = Max{0.20%, 0.18%} = 0.20% (规范表9.5.1一侧受拉钢筋) As,min = b * h * ρmin = 490mm 1.3 斜截面承载力计算 1.3.1 0.7 * ft * b * ho = 0.7*1.43*350*660 = 231698N ≥ V = 180000N (规范式7.5.7-1) 当 V ≤ 0.7 * ft * b * ho、500 < H ≤ 800mm 构造要求: (规范表10.2.10) 箍筋最小直径 Dmin = 6mm,箍筋最大间距 Smax =
37、350mm Dmin、Smax的配箍面积 Asv# = Dmin ^ 2 * π / 4 * S / Smax = 16mm (?) 最小配箍面积 Asv,min = 16mm 1.3.2 一般受弯构件,其斜截面受剪承载力按下列公式计算: (规范式7.5.4-2) V ≤ 0.7 * ft * b * ho + 1.25 * fyv * Asv/S * ho 0.7 * ft * b * ho = 0.7*1.43*350*660 = 231698N ≥ V = 18
38、0000N,仅需按构造配箍 1.3.3 Asv,min = 16mm 箍筋最小直径 φ6 最大间距 @350 1.4 扭曲截面承载力计算 1.4.1 矩形截面受扭塑性抵抗矩 Wt = b ^ 2 * (3h - b) / 6 = 350^2*(3*700-350)/6 = 35729167mm (规范式7.6.3) 1.4.2 一般剪扭构件混凝土受扭承载力降低系数 βt 按下式计算: (规范式7.6.8-2) βt = 1.5 / [1 + 0.5 * V * Wt / (T * b * ho)]
39、 = 1.5/[1+0.5*180000*35729167/(80000000*350*660)] = 1.28 > 1.0,取 βt = 1.0 1.4.3 验算截面适用条件 Hw / b = 660/350 = 1.89 < 6,截面高宽比满足要求 (规范式7.6.1-1) V / (b * ho) + T / (0.8 * Wt) = 180000/(350*660)+80000000/(0.8*35729167) = 3.
40、58N/mm ≤ 0.25 * βc * fc = 3.58N/mm, 满足截面尺寸要求 V / (b * ho) + T / Wt = 180000/(350*660)+80000000/35729167 = 3.02N/mm > 0.7 * ft = 1.00N/mm,需进行剪扭计算 (规范式7.6.2-1) 1.4.4 验算是否要考虑剪力、扭矩的影响 当 V ≤ 0.35 * ft * b * ho 时,
41、可仅按纯扭构件计算受扭承载力 (规范7.6.11) 0.35 * ft * b * ho = 0.35*1.43*350*660 = 115849N < V = 180000N, 应考虑剪力的影响 当 T ≤ 0.175 * ft * Wt 时,可不进行受扭承载力计算 (规范7.6.11) 0.175 * ft * Wt = 0.175*1.43*35729167 = 8.959kN·m < T = 80.000kN·m,应进行受扭承载力计算
42、 1.4.5 在剪力和扭矩共同作用下矩形截面一般剪扭构件,其腹板受剪扭承载力应按下列公式计算: 1.4.5.1 剪扭构件的受剪承载力: V ≤ (1.5 - βt) * 0.7 * ft * b * ho + 1.25 * fyv * Asv/S * ho (规范式7.6.8-1) Asv = [V - (1.5 - βt) * 0.7 * ft * b * ho] * S / (1.25 * fyv * ho) = [180000-(1.5-1)*0.7*1.43*350*660]*200/(1.25*210*660) =
43、 74mm 1.4.5.2 剪扭构件的受扭承载力: T ≤ βt * 0.35 * ft * Wt + 1.2 * ζ^0.5 * fyv * Ast1 * Acor / S (规范式7.6.4-1) Acor = bcor * hcor = (350-2*30)*(700-2*30) = 185600mm 受扭计算中沿截面周边配置的箍筋单肢截面面积 Ast1 由下式求得: Ast1 = (T - βt * 0.35 * ft * Wt) * S / (1.2ζ^0.5 * fyv * Acor)
44、 = (80000000-1*0.35*1.43*35729167)*200/(1.2*1.2^0.5*210*185600) = 242mm Ucor = 2 * (bcor + hcor) = 2*(290+640) = 1860mm 取 ζ = fy * Astl * S / (fyv * Ast1 * Ucor) = 1.2 受扭计算中取对称布置的全部纵向非预应力钢筋截面面积 Astl 可由下式求得: (规范式7.6.4-2) Astl = fyv * Ast1 * Ucor * ζ / (fy * S) = 210
45、242*1860*1.2/(360*200) = 1578mm 1.4.6 剪扭构件中箍筋和纵筋的最小配筋面积 箍筋最小配筋率 ρsv,min = 0.28 * ft / fyv = 0.19% (规范10.2.12) 受扭纵筋最小配筋率 ρtl,min = 0.6 * [T / (V * b)] ^ 0.5 * ft / fy = 0.27% (规范式10.2.5) 腹板箍筋计算配筋面积 Asvt = Asv + 2 * Ast1 = 74+2*242 = 559mm (规范7.6.12)
46、腹板箍筋最小配筋面积 Asvt,min = ρsv,min * b * S = 134mm 按受扭计算 Ast1 = 242mm,当箍筋间距为 200 时,箍筋最小直径 φ18 (?) 腹板受扭纵筋最小配筋面积 Astl,min = ρtl,min * b * h = 659mm 4.双向板构件: 1.1 基本资料 1.1.1 工程名称:工程一 1.1.2 边界条件(左端/下端/右端/上端): 固端 / 固端 / 固端 / 固端 1.1.3 荷载标准值(按静力计算手册考虑活荷不利布置) 1.1.3.1 永
47、久荷载标准值 楼板自重: gk1 = 4.5kN/m 1.1.3.2 可变荷载标准值 均布荷载: qk1 = 2.5kN/m γQ = 1.4 ψc = 0.7 ψq = 0.4 1.1.4 计算跨度 Lx = 3600mm 计算跨度 Ly = 4800mm 板厚 h = 120mm (h = Lx / 30) 板底、板面纵筋合力点至近边距离:as = 20mm、as' = 20mm 1.1.5 混凝土强度等级:C30 fc = 14.33N/mm ft =
48、1.43N/mm ftk = 2.01N/mm Ec = 29791N/mm 1.1.6 钢筋抗拉强度设计值 fy = 360N/mm Es = 210000N/mm 1.2 弯矩计算结果 1.2.1 平行于 Lx 方向的跨中弯矩 Mx Mxgk1 = (0.0296+0.2*0.013)*4.5*3.6^2 = 1.88kN·m Mxqk1 = [(0.0296+0.2*0.013)*2.5*3.6^2+(0.062+0.2*0.0317)*2.5*3.6^2]/2
49、 = 1.63kN·m Mx = Max{Mx(L), Mx(D)} = Max{4.53, 4.13} = 4.53kN·m Mxk = 3.51kN·m Mxq = 2.53kN·m Asx = 128mm ρ = 0.13% ρmin = 0.20% Asx* = 240mm 12@200 (As = 565) ωmax = 0.020mm 1.2.2 平行于 Ly 方向的跨中弯矩 My Mygk1 = (0.013+0.2*0.
50、0296)*4.5*3.6^2 = 1.10kN·m Myqk1 = [(0.013+0.2*0.0296)*2.5*3.6^2+(0.0317+0.2*0.062)*2.5*3.6^2]/2 = 1.02kN·m My = Max{My(L), My(D)} = Max{2.75, 2.49} = 2.75kN·m Myk = 2.12kN·m Myq = 1.51kN·m Asy = 86mm ρ = 0.10% ρmin = 0.20% Asy* = 2






