实习问题高手快来答吧..
梁计算结果
混凝土: C20 fc = 9.60N/mm2 ft = 1.10N/mm2
主筋: HRB335(20MnSi)
fy = 300.00N/mm2 Es = 2.0×105N/mm2
箍筋: HPB235(Q235)
fyv = 210N/mm2 肢数 = 2
尺寸: b×h = 400mm×600mm h0 = h - as = 565mm
弯矩设计值: M = 182.50kN?m
剪力设计值: V = 160.00kN
构件类型: 框架梁 抗震等级: 非抗震
计算跨度l0 = 8000 mm
1．主筋
1．1 相对界限受压区高度 ?b
?cu = 0.0033 - (fcu,k - 50)×10-5 = 0.0033 - (20 - 50)×10-5 = 0.0036 > 0.0033
取 ?cu = 0.0033
按规范公式(7.1.4-1)
?b = ?11 + fyEs?cu = 0.801 + 3002.0×105×0.0033 = 0.55
1．2 受压区高度x
按规范公式(7.2.1-1), A's = 0, A'p = 0
M = ?1fcbxh0 - x2
x = h0 - h02 - 2M?1fcb = 565 - 5652 - 2×182.50×1061.00×9.60×400 = 92mm
< ?bh0 = 0.55×565 = 310.75mm, 按计算不需要配置受压钢筋
1．3 受拉钢筋截面积As
按规范公式(7.2.1-2)
?1fcbx = fyAs
得 As = ?1fcbxfy = 1.00×9.60×400×92300 = 1172mm2
1．4 验算配筋率
验算最小配筋率时取? = Asbh = 1172400×600×100% = 0.49%
?min = 0.200%?min = 0.45ft/fy = 0.45×1.10/300 = 0.165%?min = 0.200% < ?
满足最小配筋率要求
实配受拉钢筋(梁底): 6B16, As = 1206mm2
受压钢筋按照规范第10.2.15条对架立钢筋的要求, 配置2B12
A's = 2×?×62 = 226mm2
实配受压钢筋(梁顶): 2B12, A's = 226mm2
2．箍筋
2．1 复核截面条件
按规范第7.5.1条
0.25?cfcbh0 = 0.25×1.00×9.60×400×565 = 542.4×103N
V = 160.0kN < 0.25?cfcbh0 = 542.4kN, 截面尺寸满足要求
2．2 验算构造配筋条件
按规范公式(7.5.7-1),Np0 = 0
0.7ftbh0 = 0.7×1.10×400×565 = 174.0×103N > V = 160.0kN
按构造配置箍筋
实际配置双肢箍筋 A8@200Asvs = 2×50.3200 = 0.5027 mm2/mm
柱设计资料
混凝土: C20 fc = 9.60N/mm2
主筋: HRB335(20MnSi) fy = 300N/mm2
箍筋: HPB235(Q235) fyv = 210N/mm2
尺寸: b × h = 370 mm × 370 mm
构件计算长度: l = 300mm
钢筋保护层厚度为35mm
轴压力: N = 208kN
抗震等级为3级 ?max = 0.005
按混凝土规范11.4.12, 取
?min = 0.007
柱类型: 框架中柱、边柱
结构体系: 框架结构
箍筋按加密区要求配置
非柱根处箍筋
轴压比限值: 0.60
二、计算结果
1．主筋
构件截面面积 A = b × h = 370 × 370 = 136900 mm2
因为l/b = 300 / 370 = 0.81
根据表7.3.1并插值得构件稳定系数 ? = 1.00
按规范公式(7.3.1)
A's = ?REN0.9? - fcAfy = 1.00 × 2080000.9 × 1.00 - 9.60 × 136900300 = -3610mm2
取A's = 0 mm2
计算纵向配筋率? = A's/A = 0.00 / 136900.00 = 0.00%
由于计算配筋率小于0.007，采用最小配筋率
计算受压钢筋面积: A's = A × ?min = 136900.00 × 0.0070 = 958.30 mm2
实配钢筋: 4B18 实际纵向配筋率? = Acr/A = 1017.88 / 136900.00 = 0.74%
2．箍筋
按规范10.3.2,
当纵向受力钢筋配筋率小于3％时
箍筋直径不小于6mm及主筋最小直径的四分之一，即18/4mm
箍筋直径取为8mm
箍筋间距不应大于400mm及纵向受力钢筋最小直径的15倍，即18 × 15mm
但同时，箍筋间距不应小于截面的短边尺寸，即 370mm
所以取箍筋间距s为144mm
单位长度实配箍筋截面积Asvs = 50.27144 = 0.35
其中: Asv表示单根箍筋面积
Asv = 3.14 × 82 / 4.0 = 50.27 mm2
3．轴压比验算
由用户输入的轴压比限值为0.60
实际轴压比为Uc = NfcA = 2080009.60 × 136900.00 = 0.16
轴压比满足要求