摘要:
对AISC 360-16《建筑钢结构标准》（简称《美国钢标》）受剪杆件设计方法进行了解读，并与GB 50017—2017《钢结构设计标准》（简称《17钢标》）受剪杆件的设计方法进行了比较。
《美国钢标》受剪杆件稳定的强度能力计算在G章。设计抗剪强度取ϕvVn，一般情况下抗剪抗力系数ϕv=0.9。
1）对于工字形截面和槽形截面，梁腹板受剪屈曲后会产生屈曲后强度，使腹板的抗剪能力提高。屈曲后强度来源之一为内力重分布，之二为腹板形成的拉力带作用。对不设置加劲肋及加劲肋间距a>3h的腹板，只有内力重分布的作用。对于加劲肋间距a≤3h的腹板，会存在两种作用。
2）不考虑腹板拉力带作用的抗剪强度，当h/tw ≤ 1.10 √kvE/Fy，抗剪强度由腹板剪切屈服提供，此时腹板抗剪承载力系数Cv1=1.0；当h/tw > 1.10 √kvE/Fy时，抗剪强度由腹板屈曲及屈曲后强度提供，此时Cv1 < 1.0。
3）无加劲肋，腹板剪切屈曲系数kv=5.34，剪切屈服与屈曲的高厚比分界点h/tw=1.10 √kvE/Fy=74√235/Fy，因此腹板高厚比74εk是屈服与屈曲的界限高厚比。
4）当腹板设置加劲肋且a/h ≤ 3时，拉力带将起作用。
对于梁的抗剪屈曲承载力计算，《17钢标》于第6.3.3条给出了不考虑屈曲后强度的腹板剪切屈曲应力的计算公式，并于第6.4节给出了腹板考虑屈曲后强度的计算公式。
1）当不考虑屈曲后强度时，《17钢标》式（6.3.3-8-12）给出了腹板剪切临界应力τcr与正则化宽厚比λn，s的关系式。简支梁，取η=1.11，则h0/tw=76εk，此值与《美国钢标》的74εk一致。《17钢标》取h0/tw=80εk为屈服与屈曲分界点，在6.3.1条指出，当h0/tw > 80εk，应计算梁腹板的屈曲稳定性。
2）当考虑屈曲后强度时，对于梁抗剪，《17钢标》考虑腹板屈曲后拉力带的作用。
由分析可知：《美国钢标》考虑腹板屈曲后强度给出抗剪计算公式，《17钢标》按考虑及不考虑腹板屈曲后强度给出抗剪计算公式。
Abstract:
The design method of members for shear in Specification for Structural Steel Buildings (AISC 360-16) is introduced and compared with that in Standard for Design of Steel Structures (GB 50017-2017).
The strength calculation of shear members is listed in Chapter G of AISC 360-16, in which the design shear strength takes ϕvVn, and the shear resistance coefficient ϕv=0. 9.
1)For I-shape and channel sections, post-buckling strength after shear buckling can improve the shear capacity of the web, which is induced by the internal force redistribution and tension field in the web. For the web without stiffeners or with the spacing between stiffeners a>3h, post-buckling strength is only provided by internal force redistribution. However, for the web with the spacing between stiffeners a ≤ 3h, both of them are contributors.
2) When shear strength without considering tension field of webs, h/tw ≤ 1. 10 √kvE/Fy:shear strength is supported by shear yielding of the web, namely Cv1=1. 0; h/tw > 1. 10 √kvE/Fy:shear strength originates from both buckling of the web and its post-buckling strength, namely Cv1 < 1. 0.
3)If there is no stiffener,the shear buckling coefficient of the web kv=5. 34, the cut-off point between heightto-thickness ratios under shear yielding and shear buckling is h/tw=1. 10 √kvE/Fy=74√235/Fy, so 74εk is the critical height-to-thickness ratios between yielding and buckling.
4)When the web has stiffeners and a/h ≤ 3, tension field works and shear strength of the web should be calculated.
For the calculation of buckling bearing capacity of members under shear, GB 50017-2017 provides the formulas to calculate the shear buckling stress of the web in Article 6. 3. 3 without considering post-buckling strength, and presents the formulas considering post-buckling strength of the web in Chapter 6. 4.
1) When shear buckling stress of the web without considering post-buckling strength, GB 50017-2017 (6. 3. 3-8-12) presents the relationship between critical shear stress τcr of web regardless of post-buckling strength and regularized width-to-thickness ratio λn,s. If η=1. 11 is adopted for simply supported beams, h0/tw=76εk, consistent with the value 74εk in AISC 360-16. GB 50017-2017 takes h0/tw=80εk as the cut-off point between yielding and buckling, and points out in Article 6. 3. 1 that buckling stability of the web should be computed when h0/tw > 80εk.
2)When the shear buckling of the web is considered post-buckling strength, for the beam under shear, GB 50017-2017 takes into account the effect of tension field after buckling.
Analyses reveal that:AISC 360-16 presents the strength calculation of shear members considering the postbuckling strength of web plates, and GB 50017-2017 provides the formulas for the shear strength with and without post-buckling strength of the web respectively.
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