Design of Members for Shear

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 ϕ_vV_n, and the shear resistance coefficient ϕ_v=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/t_w ≤ 1. 10 √k_vE/F_y:shear strength is supported by shear yielding of the web, namely C_v1=1. 0; h/t_w > 1. 10 √k_vE/F_y:shear strength originates from both buckling of the web and its post-buckling strength, namely C_v1 < 1. 0.
3)If there is no stiffener,the shear buckling coefficient of the web k_v=5. 34, the cut-off point between heightto-thickness ratios under shear yielding and shear buckling is h/t_w=1. 10 √k_vE/F_y=74√235/F_y, so 74ε_k 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 τ_cr of web regardless of post-buckling strength and regularized width-to-thickness ratio λ_n,s. If η=1. 11 is adopted for simply supported beams, h₀/t_w=76ε_k, consistent with the value 74ε_k in AISC 360-16. GB 50017-2017 takes h₀/t_w=80ε_k 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/t_w > 80ε_k.
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.