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ASCE 41-17 Steel Beams & Columns — Nonlinear Modeling Parameters & Acceptance Criteria

Table 9-7.1 (flexural actions), taken from ASCE's own published Errata 1 to ASCE/SEI 41-17, which reprints the corrected table. Columns in compression use the regression equations adopted in 2017 (220 tests); beams use multiples of θ_y with interpolation between the compact and slender lines. Turkish counterpart: TBDY Chapter 15 steel plastic-rotation limits.

Member

F_ye (expected) ksi

b_f/2t_f

h/t_w

Z in³

I in⁴

Length L in

r_y (columns) in

A_g (columns) in²

P_G (gravity, columns) kip

Results

Classification—

θ_y rad—

a · b rad · c—

Acceptance IO · LS · CP rad—

ColumnsLine 1 (compact): a = 0.8(1 − P_G/P_ye)^2.2(0.1L/r_y + 0.8h/t_w)⁻¹ − 0.0035 ≥ 0; b = 7.4(1 − P_G/P_ye)^2.3(0.5L/r_y + 2.9h/t_w)⁻¹ − 0.006 ≥ 0; c = 0.9 − 0.9P_G/P_ye. Elastic in flexure when a = 0 or P_G/P_ye > 0.6. Slender/intermediate columns (lines 2–3) are not implemented.

BeamsLine 1: a = 9θ_y, b = 11θ_y, c = 0.6; line 2: a = 4θ_y, b = 6θ_y, c = 0.2; in between, interpolate separately for flange and web and use the lower.

θ_yMechanics of a member in double curvature: θ = ML/(6EI); beams θ_y = ZF_yeL/(6EI), columns × (1 − P_G/P_ye) with P = P_G (note b).

CautionAcceptance criteria (columns IO 0.5a / LS 0.75b / CP b; beams line 1 IO 0.25a / LS a / CP b, line 2 IO 0.25a / LS 0.75a / CP a) are read from the text extraction of the errata, where each entry appears twice — confirm against the table. A NIST study states beam criteria did not change from 41-13 to 41-17, which conflicts with this reading.

VerifyHand calculation (regression test): W14×257 column, F_ye 55 ksi, L 156 in, P_G 600 kip → a 0.04407, b 0.1007, c 0.770 rad. ASCE 41-23 changed its reference steel standard — for a 41-23 evaluation confirm against the referenced steel provisions.

Preliminary calculation tool. Final design requires the full text of the referenced standard (see the sources on this page) and review by a licensed PE.