b'ENGINEERS CORNERCISC Engineers CornerIn this editions Engineers Corner, our engineering team has taken a brief break from preparing the next edition of the handbook to provide some recommendations on specifications for structural steel, with both Canadian supply and sustainability comments. These comments seemed timely and will hopefully prove helpful to the industry.LOGAN CALLELE, P.Eng.T heCISCengineeringClause No. 1Structural Material and Fabricationfor building and/or industrial structuresDirector of EngineeringOption (i) Clause Verbiage:CISC Commentary: CISC-ICCA teamhascompiledtheStructural wide flange (W) and tee (WT) shapesProviding the fabricator the ability to supply the W section, or WT shapes, which are cut from the W shall conform to CAN/CSA-G40.20/G40.21sections, the ability to choose from any of these material grades allows for best price and schedule informationinTable1Grade 350W or ASTM A992 or ASTM A570options. If minimum tested notch toughness is required for the project, then G40.20/.21 WT category Grade 50 (345 MPa). steel is recommended. This is not to say that other steel grades have no notch toughness; however, the establishment of a minimum level of notch toughness is best captured with G40 WT steel.toaiddesignersinspecifyingSee CISC Advantage Steel (Spring 2025 edition) for article on high-strength steel, ASTM A913, considerations for your project. Alternatively, ASTM A572 grade 65 material is also commonly rolled structuralsteelusedintypicalat mills as well. building projects in Canada. TheOption (ii) DO NOT SPEC WWF SECTIONS Welded wide-flange (WWF) shapes, as defined in CAN/CSA G40.20/.21, are no longer supplied in Canada. For new construction, where ASTM A992 material is not acceptable for the project design, a built-up, preferrable standardized, three-plate girder (TPS) should be specified. The plates can information provided gives specificbe sized for optimal structural efficiency and, where required, specified to have minimum notch toughness requirements. When built-up TPGs are used, the designer is recommended to work with general note information that maythe fabricator to optimize the web-to-flange weld. Avoid specifying a full strength weld along the full length of the web, though full strength welds may be required locally to transfer connection loads. beadopted,dependingontheFabrication tolerances for TPGs can be adopted from ISO 17607-3 Annex C. Option (iii) Hollow structural sections (HSS) shall conformA more favourable column design strength can be obtainedsee S16, by using G40.21 Class H needsoftheproject,aswellasto ASTM A500 Grade C (Fy=345 Moa) or CAN/ material. The material is heated to significantly reduce the residual stresses from the cold forming CSA-G40.20/G40.21 Grade 350W or ASTMprocess; however, availability should be confirmed prior to counting on this design. ASTM A500 somecommentaryonthingstoA1085 material. Grade C is also a very commonly available material; however, the sections design properties are based on 90 per cent of the nominal wall thicknesssee CISC handbook. For HSS braces used as the energy dissipating element in concentrically based frames, the use of 350W or A1085 may allow for watch out for that address someefficiencies over A500. HSS shapes up to and including 305x305 are made in Canada. G40 material is generally more available than A1085 in Canada.of the common issues we see here Option (iv)Structural angles (L) and channelssections shallCanadian mills supply angles in sizes from L25x25 to L203x203 and channels in sizes from at CISC. Lastly, and this may beconform to CAN/CSAG40.20/G40.21 grade 350WC75 to C250.to sizes as indicated on structural drawings. particularlyhelpfulasCanadiansOption (v) Structural plates, bars and flat plate connectionCISC Commentary: Canadian mills supply plates from 4.8 mm to 51 mm thick. Specify WT material components shall conform to CAN/CSA-G40.20/ for applications where minimum nominal notch toughness is required for the design. High-strength facetheincreasedtariffpressureG40.21 grade 350W or ASTM A572 Grade 50steel is generally available through this thickness range as well. (345 MPa). The minimum thickness of structuralNOTEit is recommended to specify 300W steel as a minimum, even for architectural features and plates and stiffeners, except as explicitly indicated,miscellaneous metals such as stairs and ladders, instead of ASTM A36 and G40.20/.21 300W grades fromourAmericanneighbours,is 9.5 mm. Stiffeners are to extend to the flangeit forces them to use a more expensive alloy design to meet a minimum yield strength but maximum tipsfull width unless noted otherwise NOTE: If tensile strength requirements.we provide some comments onhigh-strength steel plate is required by ASTM A572 Grade 65 (450 MPa) is available and meets Clause 5.1.3 of S16. Other high-strength plate steel grades what Canadian steel suppliers areare available, such as ASTM A656, a thermos-mechanical control process-produced steel better able to provide for your Canadiansuited for plate thickness less than 19 mm (better weldability, especially), but the designer will need construction projects.to satisfy Clause 5.1.1 of the S16 standard.Option (vi)Anchor rods shall conform to ASTM F1554CISC Commentary: Grade 55 is also available from Canadian steel suppliers. Grade 105 is currently TheCISCemphasizesthatGrade 36 (Fy=248MPa).imported from U.S. suppliers. Anchor rods are typically supplied with threaded ends, thus, it is recommended that the embedded end of the anchor rod has a washer (standard washer or plate washer, depending on design requirements) sandwiched between two ASTM A563 heavy hex nuts. although no Canadian mill currentlyThese are the standard heavy hex nuts used with A325 bolts. Anchor rods have up to a 25 mm tolerance on length, so it is recommended to add 25 mm (if the extra project past the nut is okay) to produces wide flange sections, it isyour calculated anchor rod length.Option (vii)Structural bolts and bolt assemblies shall conformCISC Commentary: Canadian Manufacturers supply heavy hex bolts in diameters from 1/2 to 1-1/4, an important factor in the supportto ASTM F1325/F3125M. Heavy hex bolts shallranging in length from 1-1/8 to 14, depending on the diameter specified. Tension control bolts be Grade A325 or high-strength heavy hexare available in diameters from 3.4 to 1-1/4, ranging in length from 1-3/4 to 13-1/2, depending ofdomesticsteelsupplyandbolts to Grade A490. Tension control bolts shallon the diameter specified. Metric sizes of heavy hex bolts M20 and M24 are available in lengths be to Grade F1852 or high-strength tensionranging from 35 mm to 170 mm; however, imperial bolt sizes are much more readily available and are control bolts to Grade F2280. Bolts can bepreferred for use on the vast majority of Canadian steel projects. fabricationthat,wherepossible,specified as Type 1 for carbon steel or Type 3 for weathering steel. Canadian steel products are used.Option (viii)Sheet steel roof, floor and composite decks shallCISC Commentary: Sheet steel produced by Canadian mills and commonly available include those be ASTM A653 material. Sheet steel cladding to bewith yield strengths between 33 and 50 ksi (230 to 350 MPa)see manufacturer technical data Thetableindicatesthevariousgrade ASTM A653 or A792. or discuss with your local supplier or fabricator for a more inclusive list of available strengths and thicknesses.plate, angle, channel, HSS and bolt sizestypicallyavailable,butnoteNOTE 1: Many Canadian jurisdictions are contemplating and enacting limitations on embodied carbon. CISC has guidance documents (see our website https://www.cisc-icca.ca/sustainability) that can help, but in general, recommend the following general approach:GOOD: Specify the per cent recycled steel contentapproximately 96 per cent for structural steel rolled shapes* and 70 per cent for sheet steel thattheremaybeopportunities* : recommended rolled steel plate recycled content is 70 per cent.BETTER: Specify a relative GWP reduction compared to the industry average equivalent emissions of the same product.forCanadiansteelsupplierstoBEST: Specify a maximum GWP limits as absolute targets to be achieved, supported by base-bid and alternate low-carbon big language.provide sizes beyond those listed,TABLE 1: Recommended steel specification notes. and therefore, close collaboration betweenthedesignteamandLet us know if you enjoyed this article and would like to see more recommendations, thesteelfabricator/supplieriswith commentary, on structural steel specifications. Please send us a comment on our encouraged. social media accounts or an email at engineering@cisc-icca.ca. ASQuestions on various aspects of design and construction of steel buildings and bridges are welcome. They may be submitted via email to info@cisc-icca.ca.10|SUMMER 2025 ADVANTAGE STEEL'