QUESTION: (SPRING2011) Should I aim for full composite action for composite beams in building structures? Otherwise, where do I begin? ANSWER: Due to the substantial increase in bending resistance gained from composite action, partial composite capacity for beams usually suffices. Factors other than the ultimate limit states of the composite beam often dictate the steel [...]

QUESTION: (SUMMER2015) As stated in the Commentary to S16-09, the slenderness expressions provided in Clause 13.3.3 for ‘Single-Angle Members in Compression’ are not intended for use in the design of braces in braced frames. I want to use equal-leg compression braces in a braced frame. How are these single-angle braces designed? ANSWER: When single-angle braces are [...]

QUESTION: (SUMMER2016) I am proportioning a mono-symmetric I-girder whose web-slenderness, h/w, marginally satisfies the Class 3 limit for W-shapes in pure bending in accordance with Table 2 of S16-09. Does this limit apply to mono-symmetric sections? ANSWER: No, the limits for I-sections are provided in Table 2 of S16-09 for sections with equal flanges. CSA [...]

(See General - Stability)

QUESTION: (WINTER2014/2015) How is the shear resistance for gross section of gusset plates determined – should I use Clause 13.4.3 of S16-09 on webs of flexural members not having two flanges or Clause 13.11 on block shear? They give very different results ANSWER: Neither. Clause 21.12, “Connected elements under combined tension and shear stresses”, a [...]

QUESTION: (SUMMER2014) I find the design requirements for pin-connected tension members as stipulated in CSA S16-09 very difficult to satisfy. They appear to mandate the use of eyebars. Have I missed something? ANSWER: The requirements in CSA S16-09 aim to ensure a gross-section yielding ultimate limit state and are therefore quite restrictive. New requirements have been [...]

QUESTION: (SUMMER2015) How are the torsional constants calculated for open sections in the CISC Handbook? Using general strength of material formulas, I can reproduce the values for angles, but I obtain different values for other shapes. ANSWER: Torsional section properties found in the Handbook include the St. Venant constant (J) and the warping constant (Cw). [...]

QUESTION: (WINTER2014/2015) What is the correct fatigue ‘Detail Category’ for a coped beam detail? S16-14 shows Category E1 whereas W59-13 and S16-09 show Category B ANSWER: Category E1 should apply to re-entrant corners of copes having a minimum radius of 35 mm and ground smooth as stipulated in S16-14. Category B should not be used [...]

QUESTION: (2014) What are the key characteristics of ASTM A1085 HSS as compared to A500 Grade C and CSA G40.20/21 products? ANSWER: In a nutshell, ASTM A1085 HSS are produced to meet requirements comparable to those of CSA G40.20/21 350WT Category 1. The material is required to conform to a minimum average Charpy V-notch impact [...]

QUESTION: (SUMMER2011) What are the major differences between Welded Wide Flange sections and welded I-girders? ANSWER: Limitations for WWF shapes versus welded I-girders WWF shapes are restricted to a maximum depth of 2,000 mm. WWF shapes are standardized sections, whereas plate girder cross-sectional dimensions may vary. WWF shapes are straight members. WWF shapes have a [...]