QUESTION: (FALL2015) I am involved with the design of an unenclosed industrial structure for which neither the building code nor the bridge code applies. Should I specify notch-tough steel? Are notch-tough W-shapes available? How do I determine the appropriate level of notch-toughness? ANSWER: Brittle fracture is a complex subject. In order to limit the probability [...]

QUESTION: (FALL2010) CISC/CPMA Standard 1-73a versus CISC/CPMA Standard 2-75: What do they have in common and what are the major differences? ANSWER: These standards provide essentially the same laboratory requirements. The provision for surface preparation reflects the key difference. In addition to removal of grease and oil in accordance with SSPC Standard SP1, CISC/CPMA 2-75 [...]

QUESTION: (SUMMER2016) In National Building Code of Canada 2015, the period dependant Site Coefficient F(T), used for determination of seismic Design Spectral Accelerations, has replaced Site Coefficients Fa and Fv. CSA Standard S16-14, however, continues to reference Site Coefficients, Fa and Fv. Is S16-14 out of step with NBC 2015? ANSWER: CSA S16-14 is compatible [...]

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). [...]