In ANSI/AISC 360-10, considering the length effects, the axial capacity of each reference point in the capacity curve is degraded。 Thus, the interaction diagrams in Fig。 10 indicates the nominal beam-column capacity of specimens。 Consequently, 3% of the axial capacity was decreased in E1 and E4, 2% in E3, and 12% in E2 and E5。 The reduction was the greatest in the rectangular Specimens E2 and E5 because of the greater slenderness  ratio。

In Fig。 10, all specimens, except E3 with mild steel, satisfied the nominal axial-flexural strength predicted by AISC specification。 Specimens E4 and E5 with stiffeners (high-strength steel compact sections) reached their plastic strengths (Method 2)。 Specimens E1 and E2 (high-strength steel slender sections) were close to the plas- tic strength, significantly exceeding the nominal strength (Method 1)。 In the case of E3, although the mild-steel compact section was used, the test strength was smaller than the prediction of Method 2。 As mentioned previously, Method 1 of ANSI/AISC 360-10 significantly underestimated the ultimate strength of the RCFT columns  E1  and  E2  with  high-strength  steel  slender  sections。

The overconservatism of Method 1 was also reported in previous studies for normal-strength steel (Lai et al。  2015)。

Fig。 10 also shows the interaction curve based on the recommen- dations of the Architectural Institute of Japan (AIJ) (Nakahara and Sakino 2003; AIJ 2008)。 In the method, which is similar to the rigid-plastic method for the steel tube, a uniform effective buckling stress is used for the compression zone and a uniform yield strength is used for the tension zone。 For the compressive stress of concrete, the stress distribution varies according to the strength of the concrete。 The predictions showed good agreement with the test results for the unstiffened CFT columns。 In the cases of E1 and

10。 Axial-flexural strengths of  specimens

E2, the prediction is much greater than that of Method 1 for the high-strength   steel  slender  section,  while  being    conservative

of discontinuous slips。 In order to define the inelastic  modulus, the slip theory was applied as follows (Lay   1965):

against the test strengths。 In the case of E3, the prediction is com-

parable to that of Method 2 for the mild-steel compact   section。

摘要：本实验是对薄壁矩形混凝土填充管（RCFT）柱的结构行为进行了研究。本研究主要集中在高强度钢细长部分对整体偏心压缩能力的影响。这项测试的参数包括钢材的高厚比，屈服强度和加劲肋的使用。五份试样在轴向偏心荷载下做了测试。在细长截面试样中尽管早期局部屈服，发展了显着的后收缩储备力。因此，当前规范的预测显著低估了细长截面试样的承载能力。带有垂直加强筋增强的试样表现出强度的增强和延展性，实现了组合截面的塑性能力。因此，针对高强度钢RCFT柱开发了垂直加强筋的设计方法。DOI：10。1061 /（ASCE）ST。1943-541X。0001724。 ©2016美国土木工程师协会。来*自-优=尔,论:文+网www.youerw.com

作者关键词：混凝土管; 高强度钢; 细长部分; 强化剂; 偏心轴向载荷; 金属和复合结构。

引言

在混凝土填充钢管（CFT）柱中，混凝土破碎受到钢管的横向约束，同时钢管的局部屈曲受到填充混凝土的约束。因此，CFT柱表现出优异的结构性能。此外，在CFT柱中，与混凝土包裹的钢柱不同，钢板位于横截面的周边。因此，钢截面对弯曲能力的贡献可以最大化，特别是当使用高强度钢时。从构造性的观点来看，使用高强度钢也是有利的，因为通过使用薄板可以减少焊接和提升重量。当高强度钢和高强度混凝土一起使用时，横截面积可以显着减小，这对于建筑设计和规划是优选的。最近在日本，实际使用了具有780MPa（拉伸强度）钢和150MPa混凝土的高强度CFT柱（Matsumoto等人2012）。