AISC Verification Problem Example II.A-20

Problem Statement

This document presents a comparative study between the published American Institute of Steel Construction (AISC) Design Examples Version 16.0 and the results generated by SDS2 version 2025.01 connection software for Example II.A-20. The central problem statement is to verify the available strength of an all-bolted singled plate shear splice of a beam-to-beam connection. This connection involves an ASTM A992 W24×68 beam and an ASTM A992 W24×55 beam with end reactions of R_D = 10 kips and R_L = 30 kips, using an ASTM A572 Grade 50 shear splice plate. The connection is shown in Figure 1.

Figure 1. Example II.A-20 elevation view

Connection design report output from SDS2 for this connection:

• Allowable Stress Design (ASD).pdf
• Load and Resistance Factor Design (LRFD).pdf

Note: To view the 3D model (U3D) of the structural joint in the PDF files, open the PDF using Bluebeam or Adobe Acrobat Reader.

Validation Method

The connection as shown in the AISC design example II.A-20 (see reference 1) was modeled in SDS2 and a connection design report was generated for both the ASD and LRFD design methods.

The core of this report features a comparison table for each connection limit state, showcasing the calculated capacities from both SDS2 and AISC. The order of the limit state table generally mirrors the sequence in which it was presented in the AISC example problem. This table also highlights the percent difference (% Δ) between these calculated values, providing a clear measure of any discrepancy, if any.

To further enhance understanding, this report includes relevant notes that discuss any differences or assumptions made during the calculation process. In certain cases where AISC did not calculate a connection capacity for a limit state, the connection capacity was back calculated based on the limit state values and documentation for this calculation is provided in the notes. The goal of this comparative study is to evaluate the precision and efficiency of the SDS2 connection design software in contrast to the AISC Design Examples and serves as a guide for better understanding and application of these two design calculations.

Comparison

Comparisons of the limit state checks are presented in Table 1 for ASD and Table 2 for LRFD. The limit state checks and calculated values aligned well between the published AISC Design Example document and the calculation generated by SDS2. The minor differences in calculated values, except where noted, were a result of rounding differences.

Table 1. Capacity comparison table for ASD
Limit state (ASD)	SDS2 Capacity	AISC Capacity	%Δ	Notes
Bolt shear of web bolts	16.2 kips / bolt	16.2 kips / bolt	0.0%
Bolt bearing of web plate	25.6 kips / bolt	25.6 kips / bolt	0.0%
Bolt tearout of web plate at edge bolt	15.1 kips / bolt	15.1 kips / bolt	0.0%
Bolt tearout of web plate at non-edge bolt	30.2 kips / bolt	-	-	1
Coefficient for eccentrically load bolt group, C	3.08	3.07	0.3%
Bolt shear of web bolt group	50.0 kips	-	-	2
Bolt bearing on web plate	49.1 kips	46.4 kips	5.5%	3
Bolt bearing on W24x68 beam web	50.0 kips	-	-	4
Bolt bearing on W24x55 beam web	50.0 kips	-	-	4
Flexure yielding of web plate (limit state)	404 kip-in	404 kip-in	0.0%
Flexure yielding of web plate (shear capacity)	162 kips	162 kips	0.0%	5
Flexure rupture of web plate (limit state)	293 kip-in	293 kip-in	0.0%
Flexure rupture of web plate (shear capacity)	117 kips	117 kips	0.0%	6
Shear yielding of web plate	90.0 kips	90.0 kips	0.0%
Shear rupture of web plate	58.5 kips	58.5 kips	0.0%
Block shear rupture of web plate	63.4 kips	63.6 kips	-0.3%
Shear yielding of beam web	186.4 kips	-	-	7
Connection capacity	49.1 kips	46.4 kips	5.5%

Table 2. Capacity comparison table for LRFD
Limit state (LRFD)	SDS2 Capacity	AISC Capacity	%Δ	Notes
Bolt shear of web bolts	24.4 kips / bolt	24.3 kips / bolt	0.4%
Bolt bearing of web plate	38.4 kips / bolt	38.4 kips / bolt	0.0%
Bolt tearout of web plate at edge bolt	22.6 kips / bolt	22.6 kips / bolt	0.0%
Bolt tearout of web plate at non-edge bolt	45.2 kips / bolt	-	-	1
Coefficient for eccentrically load bolt group, C	3.08	3.07	0.3%
Bolt shear of web bolt group	75.0 kips	-	-	2
Bolt bearing on web plate	73.7 kips	69.4 kips	5.8%	3
Bolt bearing on W24x68 beam web	75.0 kips	-	-	4
Bolt bearing on W24x55 beam web	75.0 kips	-	-	4
Flexure yielding of web plate (limit state)	608 kip-in	608 kip-in	0.0%
Flexure yielding of web plate (shear capacity)	243 kips	243 kips	0.0%	5
Flexure rupture of web plate (limit state)	439 kip-in	439 kip-in	0.0%
Flexure rupture of web plate (shear capacity)	176 kips	176 kips	0.0%	6
Shear yielding of web plate	135.0 kips	135.0 kips	0.0%
Shear rupture of web plate	87.8 kips	87.8 kips	0.0%
Block shear rupture of web plate	95.1 kips	95.2 kips	-0.1%
Shear yielding of beam web	279.7 kips	-	-	7
Connection capacity	73.7 kips	69.4 kips	5.8%

Table Notes

Note 1: AISC notes that edge bolts will conservatively be used for all the bolts.

Note 2: AISC does not calculate a capacity and notes that tearout controls over bearing and shear of bolts.

Note 3: The AISC capacity is not calculated directly in the example but is back calculated below. AISC uses the minimum bolt tearout capacity (and notes this is conservative) to design the bolts for tearout in this example. In other AISC examples, such as Ex. II.A-18 (pg. IIA-203), when calculating the bolt group capacity with the instantaneous center of rotation method with C, AISC uses the average of the individual bolt capacities. SDS2 uses an average of individual bolt capacities considering the number of edge bolts and non-edge bolts across all connection types for consistency.

LRFD	ASD
AISC bolt group capacity:	AISC bolt group capacity:

Note 4: AISC notes that by inspection bearing and tearout on beam web will not govern.

Note 5: Both AISC and SDS2 calculate a moment capacity of 404 kip-in (ASD) or 608 kip-in (LRFD) which resolve into an equivalent shear load of 162 kips (ASD) or 243 kips (LRFD)

Note 6: Both AISC and SDS2 calculate a moment capacity of 293 kip-in (ASD) or 439 kip-in (LRFD) which resolve into an equivalent shear load of 117 kips (ASD) or 176 kips (LRFD) when accounting for the eccentricity.

Note 7: Not checked by AISC.

References

1. AISC Committee on Manuals, Companion to the AISC Steel Construction Manual Volume 1: Design Examples, Version 16.0, American Institute of Steel Construction, 2023, https://www.aisc.org/publications/steel-construction-manual-resources/16th-ed-steel-construction-manual/manual-companion-for-16th-edition/.