【Steel Code】 10.5 COMPOSITE COLUMNS-优快云博客

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10.5 COMPOSITE COLUMNS 组合柱

10.5.1 General 总则

(1) This clause applies for the design of composite columns and composite compression members with fully encased H sections, partially encased H sections, and infilled rectangular and circular hollow sections, see Figure 10.17.
本条适用于完全包覆H型钢、部分包覆H型钢以及填充矩形和圆形空心截面的组合柱和组合压缩构件的设计，见图10.17。

(2) Composite columns or compression members of any cross-section shall be checked for:
任何截面的组合柱或压缩构件应检查以下内容：

resistance of the member in accordance with clause 10.5.2 or 10.5.3,
按照第10.5.2或10.5.3条检查构件的承载力
resistance to local buckling in accordance with clause 10.5.3.1(4),
按照第10.5.3.1(4)条检查局部屈曲承载力
introduction of loads in accordance with clause 10.5.4.2 and
按照第10.5.4.2条检查荷载引入
resistance to shear between steel and concrete elements in accordance with clause 10.5.4.
按照第10.5.4条检查钢材与混凝土之间的剪切承载力

(3) This clause applies to columns and compression members using steel sections with yield strengths between 235 and 460 N/mm², and normal weight concrete of strength classes C25 to C60.
本条适用于采用屈服强度在235至460 N/mm²之间的钢材截面，以及强度等级为C25至C60的普通重量混凝土的柱和压缩构件。

(4) This clause applies to isolated columns and composite compression members in framed structures where the other structural members are either composite or steel members.
本条适用于框架结构中的独立柱和组合压缩构件，其中其他结构构件可以是组合构件或钢构件。

(5) Two methods of design are given:
提供两种设计方法：

a general method in clause 10.5.2 whose scope includes members with non-symmetrical or non-uniform cross-sections over the column length and
第10.5.2条中的通用方法，适用范围包括柱长度范围内具有非对称或非均匀截面的构件
a simplified method in clause 10.5.3 for members of doubly symmetrical and uniform cross section over the member length.
第10.5.3条中的简化方法，适用于构件长度范围内具有双对称和均匀截面的构件。

(6) Refer to clause 3.1.2 for the design strength of the structural steel section, $p_y$ . The design strengths of the concrete, $f_{cd}$ , and the steel reinforcement, $f_{sd}$ , are given as follows:
结构钢截面的设计强度 $p_y$ 参见第3.1.2条。混凝土的设计强度 $f_{cd}$ 和钢筋的设计强度 $f_{sd}$ 规定如下：

where 其中：

$f_{cu}$ is the cube compressive strength of concrete;
$f_{cu}$ 是混凝土立方体抗压强度；
$f_y$ is the characteristic strength of steel reinforcement; and
$f_y$ 是钢筋的特征强度；
$\gamma_c$ , $\gamma_s$ are the partial safety factors of concrete and steel reinforcement, respectively.
$\gamma_c$ , $\gamma_s$ 分别是混凝土和钢筋的分项安全系数。

10.5.2 General method of design 设计通用方法

(1) Design for structural strength and stability shall take into the account of concrete crushing, and yielding of structural steel sections and steel reinforcement.
结构强度和稳定性设计应考虑混凝土压碎以及结构钢材截面和钢筋的屈服。

The design shall also ensure that instability does not occur for the most unfavourable combination of actions at the ultimate limit state and that the resistance of individual cross-sections subjected to bending, longitudinal force and shear is not exceeded.
设计还应确保在极限状态下最不利的作用组合不会发生失稳，且受弯、轴向力和剪力作用的各个截面的承载力不被超过。

Furthermore, second-order effects shall be incorporated including local buckling, residual stresses, geometrical imperfections, and long-term effects on concrete such as creeping and shrinkage of concrete.
此外，应考虑二阶效应，包括局部屈曲、残余应力、几何缺陷以及混凝土的徐变和收缩等长期效应。

Second-order effects shall also be considered in any direction in which failure might occur, if they affect the structural stability significantly. For simplification, instead of the effect of residual stresses and geometrical imperfections, equivalent initial bow imperfections (member imperfections) may be used in accordance with clause 10.5.3.3(3).
如果二阶效应显著影响结构稳定性，则应考虑可能发生破坏的任何方向上的二阶效应。为简化起见，可以按照第10.5.3.3(3)条采用等效初始弯曲缺陷（构件缺陷）来替代残余应力和几何缺陷的影响。

(2) Internal forces shall be determined by elastic-plastic analysis.
内力应通过弹塑性分析确定。

Plane sections may be assumed to remain plane after bending.
可假定平截面在弯曲后仍保持平面。

The influence of local buckling of the structural steel section on the resistance shall be considered in design.
设计时应考虑结构钢材截面局部屈曲对承载力的影响。

(3) The following stress-strain relationships shall be used in the non-linear analysis:
非线性分析应采用以下应力-应变关系：

for concrete in compression as given in HKCC;
按照HKCC规定的受压混凝土；
for reinforcing steel as given in HKCC;
按照HKCC规定的钢筋；
for structural steel as given in section 3.
按照第3章规定的结构钢材。

The tensile strength of concrete shall be neglected. The influence of tension stiffening of concrete between cracks on the flexural stiffness may be taken into account.
应忽略混凝土的抗拉强度。可考虑裂缝间混凝土的拉应力刚化对弯曲刚度的影响。

(4) The steel contribution ratio δ shall fulfill the following condition:
钢材贡献率δ应满足以下条件：

where 其中
δ is defined in clause 10.5.3.2(2).
δ在第10.5.3.2(2)条中定义。

(5) Shrinkage and creep effects shall be considered if they are likely to reduce the structural stability significantly.
如果收缩和徐变效应可能显著降低结构稳定性，则应予以考虑。

For simplification, creep and shrinkage effects may be ignored if the increase in the first-order bending moments due to creep deformations and longitudinal force resulting from permanent loads is not greater than 10%.
为简化起见，如果由永久荷载引起的徐变变形和轴向力导致的一阶弯矩增加不超过10%，可忽略徐变和收缩效应。

(6) For composite compression members subjected to bending moments and normal forces resulting from independent actions, the partial safety factor $\gamma_f$ for those internal forces that lead to an increase of resistance should be reduced to 80%.
对于受独立作用产生的弯矩和轴向力作用的组合压缩构件，导致承载力增加的内力的分项安全系数 $\gamma_f$ 应降低到80%。

10.5.3 Simplified method of design 简化设计方法

10.5.3.1 General and scope 总则和适用范围

(1) The scope of this simplified method is limited to members of doubly symmetrical and uniform cross-section over the member length with rolled, cold-formed or welded steel sections.
本简化方法的适用范围限于构件长度范围内具有双对称和均匀截面的轧制、冷弯或焊接钢材截面的构件。

However, this method is not applicable if the structural steel component consists of two or more unconnected sections. All internal forces and moments for member design against structural adequacy should be evaluated with second-order analysis.
但是，如果结构钢构件由两个或更多未连接的截面组成，则本方法不适用。进行结构适应性构件设计时，所有内力和弯矩都应通过二阶分析评估。

(2) The steel contribution ratio δ shall fulfill the following condition:
钢材贡献率δ应满足以下条件：
0.2 ≤ δ ≤ 0.9 (10.52)

where 其中
δ is defined in clause 10.5.3.2(2).
δ在第10.5.3.2(2)条中定义。

(3) The relative slenderness λ̄ defined in clause 10.5.3.3 shall fulfill the following condition:
在第10.5.3.3条中定义的相对细长度λ̄应满足以下条件：
λ̄ ≤ 2.0 (10.53)

(4) The effect of local plate buckling in the elements of a steel section may be neglected if the steel section is fully encased in accordance with clause 10.5.5.1(2), and also for other types of cross-section provided the maximum values of Table 10.11 are not exceeded. Hence, the entire composite cross-sections are effective.
如果钢材截面按照第10.5.5.1(2)条完全包覆，或者对于其他类型的截面，只要不超过表10.11的最大值，则可以忽略钢材截面构件中的局部板屈曲效应。因此，整个组合截面都是有效的。

(5) The longitudinal reinforcement that may be used in calculation shall not exceed 6% of the concrete area.
计算中可采用的纵向钢筋不应超过混凝土面积的6%。

(6) For a fully encased steel section, see Figure 10.17a, limits to the maximum thickness of concrete cover that may be used in calculation are:
对于完全包裹钢截面（见图10.17a），计算中可采用的最大混凝土保护层厚度限值为：

$max\ c_y = 0.3D \qquad max\ c_x = 0.4B$ (10.54)

(7) The depth to width ratio $D_c/B_c$ of fully encased composite cross-sections as shown in Figure 10.17a shall be within the limits $0.2 < D_c/B_c < 5.0$ .
如图10.17a所示的完全包裹组合截面的高宽比 $D_c/B_c$ 应在限值 $0.2 < D_c/B_c < 5.0$ 范围内。

(8) For the determination of the internal forces, the design value of effective flexural stiffness $EI)_{e,1}$ shall be determined from the following expression:
确定内力时，有效抗弯刚度的设计值 $EI)_{e,1}$ 应按下式确定：

$EI)_{e,1} = 0.9(EI + E_sI_s + 0.5E_{cm}I_c)$ (10.55)

Long-term effects should be taken into account in accordance with clause 10.5.3.3(6).
应按照第10.5.3.3(6)条考虑长期效应。

(9) Second-order effects need not to be considered where the elastic critical buckling load is determined with the flexural stiffness $EI)_{e,1}$ in accordance with clause 10.5.3.1(8).
当按照第10.5.3.1(8)条用抗弯刚度 $EI)_{e,1}$ 确定弹性临界屈曲荷载时，可不考虑二阶效应。

(10) Within the column length, second-order effects may be allowed for by increasing the greatest first-order design bending moment M by a factor k given by:
在柱长范围内，可通过将最大一阶设计弯矩M乘以系数k来考虑二阶效应：

$\frac{\beta}{1-P/P_{cp,cr}}$ (10.56)

where 其中：

$P_{cp,cr}$ is the critical buckling load for the relevant axis and corresponding to the effective flexural stiffness given in clause 10.5.3.1(8), with the effective length taken as the column length;
$P_{cp,cr}$ 是相关轴向的临界屈曲荷载，对应于第10.5.3.1(8)条给出的有效抗弯刚度，有效长度取为柱长；

$P_{cp,cr} = \frac{\pi^2(EI)_{e,1}}{L_E^2}$ (10.57)

β is an equivalent moment factor given in Table 10.12.
β 是表10.12中给出的等效弯矩系数。

(11) The influence of geometrical and structural imperfections may be taken into account by equivalent geometrical imperfections. Equivalent member imperfections for composite columns are given in Table 10.13, where L is the column length.
几何和结构缺陷的影响可通过等效几何缺陷考虑。组合柱的等效构件缺陷在表10.13中给出，其中L为柱长。

10.5.3.2 Compression capacity 压缩承载力

(1) The compression capacity Pcp of a composite cross-section shall be calculated by adding the compression capacities of its components:
组合截面的压缩承载力Pcp应通过叠加各组成部分的压缩承载力计算：

For fully encased and partially encased H sections:
对于完全包覆和部分包覆H型钢截面：
$P_{cp} = A_s p_y + 0.45 A_c f_{cu} + A_s f_{sd}$ (10.58a)

For infilled rectangular hollow sections:
对于填充矩形空心截面：
$P_{cp} = A_s p_y + 0.53 A_c f_{cu} + A_s f_{sd}$ (10.58b)

where As, Ac, As are the areas of the steel section, the concrete and the reinforcements respectively.
其中As、Ac、As分别为钢材截面、混凝土和钢筋的面积。

(2) The steel contribution ratio δ is defined as:
钢材贡献率δ定义为：
$\delta = \frac{A_s p_y}{P_{cp}}$ (10.59)

where 其中：

$P_{cp}$ is the compression capacity of the composite cross-section defined in clause 10.5.3.2(1).
$P_{cp}$ 是第10.5.3.2(1)条定义的组合截面的压缩承载力。

(3) For infilled circular hollow sections, account may be taken of increase in strength of concrete caused by confinement provided that the relative slenderness $\bar{\lambda}$ defined in clause 10.5.3.3(3) does not exceed 0.5 and $\frac{e}{d} < 0.1$ , where e is the eccentricity of loading given by $M / P$ and d is the external diameter of the column. The compression capacity for infilled circular hollow sections shall be calculated as follows:
对于填充圆形空心截面，当第10.5.3.3(3)条定义的相对细长度 $\bar{\lambda}$ 不超过0.5且 $\frac{e}{d} < 0.1$ 时（其中e是由 $M / P$ 给出的荷载偏心距，d是柱的外径），可考虑约束作用引起的混凝土强度增加。