英语翻译2.Short columns under Combined Axial Force and Moment Wh

英语翻译
2.Short columns under Combined Axial Force and Moment
When a member is subjected to combined axial compression N and moment M ,such as in Figure 4.28a it is usually convenient to replace the axial load and moment with an equal load N applied at eccentricity e = M / N ,as in Figure 4.28b .The two loadings are statically equivalent .All columns may then be classified in terms of the equivalent eccentricity .
(1) Failure modes of columns
Under the combined actions of axial force and moment ,there are two types of failure modes of column (a) balanced failure ,(b) compression failure ,when the neutral axis is outside the section ,causing compression throughout the section ,and (c) tension failure ,when the neutral axis is within the section ,developing tensile strain on the left of the neutral axis .
Balanced failure
Under this mode of failure ,yielding of the tensile steel on the far side of the column occurs simultaneously with the attainment of limit compressive strain of 0.0033 in concrete .
Compression failure
Compression failure of the column occurs when (a) the relative eccentricity e0 / h0 is small ,or (b) although the relative eccentricity e0 / h0 is large ,the tension reinforcement ratio is large .Columns having small relative eccentricity are generally characterized by compression over the entire concrete section ,but section .Columns of this type fail by crushing of the concrete and compressive yielding of the steel on the side near the load ,while the reinforcement on the side farthest from the load does not yield .See Figure 4.29b
Tension failure
Tension failure occurs when (a) the relative eccentricity e0 / h0 is large ,and (b) the tension reinforcement ratio is moderate .The longitudinal steel on the side farthest from the load yields first .Gradually ,with the increase of tensile strain ,the compressive strain reaches 0.0033 at the compressive edge and compression reinforcement yields .
(2) Capacity of short columns under combined axial force and moment Figure 4.29 Failure modes of columns
Under the combined actions of axial force and moment ,a strength interaction diagram (see Figure 4.30) generally describes the capacity envelope of a column .The strength interaction diagram defines the failure load and failure moment for given column for full ranges of eccentricity from zero to infinity .For any eccentricity ,there is a unique pair of value of (Mu ,Nu ) that will produce the incipient failure .That pair of values can be plotted as a point on a graph relating Mu and Nu .Any radical line represents a particular eccentricity e0 = M / N.Load demand points (M,N) from all load combinations must fall inside the (Mu ,Nu) capacity envelope ;otherwise ,the column is considered inadequate and should be redesigned .

联合作用下轴力和弯矩2.Short列
当一个成员是受到诸如图4.28a为联合轴向压力N和弯矩M,它通常是便于更换,如图4.28b轴向负荷及力矩负荷N与平等适用于偏心距e = M / N可, .这两个静态等效荷载.所有列然后可以在同等条件分类偏心.
列（1）失效模式
根据轴力和弯矩共同作用,有两种类型的列的失效模式（一）平衡失败,（二）压缩失败,当外面的中性轴节,造成整个节压缩,以及（三）拉破坏,当是在中性轴节,发展上的中性轴向左拉伸应变.
平衡失败
在这种模式的失败对列的另一边拉钢材屈服,同时发生的极限压应变的0.0033具体的实现.
压缩破坏
列压缩时出现故障（一）相对偏心的e0 / H0为小,或（b）虽然相对偏心的e0 / H0为大,拉力钢筋比大.列有小的相对偏心压缩一般特点在整个具体部分,但部分.这种类型的列不能由破碎的混凝土和抗压在靠近负载端降伏,而侧面加固从负载最远不会屈服.见图4.29b
拉破坏
紧张时发生故障（一）相对偏心的e0 / H0为大,（b）在紧张配筋率是温和的.侧面的纵向上最远从负载钢产量第一.逐步与拉伸应变的增加,在压缩应变达到压缩的压缩力和增强收益0.0033.
（2）能力和轴向力共同作用下瞬间图4.29柱破坏模式,短柱
根据轴向力和力矩,一种力量交互图（见图4.30）一般描述了一个柱容量的信封.交互图的力量给予定义为从零到全系列列偏心破坏荷载和破坏的时刻联合行动无穷大.对于任何偏心,有一个值（亩,怒江）的独特一双会产生早期失效.这两个值可以被绘制为一个有关亩,怒江图点.任何激进路线代表特定偏心的e0 =米/全负荷的需求点,从所有的负载组合（M和N）必须属于内（穆,怒族）能力信封,否则,列被视为不足,应重新设计.