Steel: A History of Strength. A Future of Possibilities.

Canadian Institute of Steel Construction

   

Frequently Asked Questions

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General Questions

Torsional Constant
How is the torsional constant J calculated for W sections, C sections, rectangular and round HSS? – L.P.

Availability of a Specific Steel Shape and/or Grade
I had designed my structure using a specific steel section and steel grade but was told by the fabricator it was unavailable and the fabricator made a request to substitute another section and grade. Why does this happen and how can I avoid it happening again?

Fillet Radii and k1 Value
I have been working with architects who needed to know the cross sectional dimensions and geometry of a rolled open steel section. For example what would be the radius of the tip of the leg of a 1.5"x1.5"x0.25 angle? I know you have an answer for every question. – C.C.Y.

Irregular Sections
I received several questions on irregular sections, so I thought I would regroup them into a three-part question just as in the previous edition for questions related to big tubes!

Ductile Connections
I'm looking at Clause 27 of CSA Standard S16-01, I read that connections must be ductile. Can you elaborate? – J.M.

Limitations on Brackets For Crane Beams
On page 21 of the CISC publication “Crane-Supporting Steel Structures: Design Guide”, item 3 states that brackets should not be used to support crane beams with unfactored reactions greater than about 250 kN. Can you give a brief explanation for this requirement? – P.T.

Steel Castings
Our firm is involved in a joint-venture effort for the design of a new series of LRT platforms. We think that a number of components in our steel superstructure lend themselves to steel castings. Can you provide information? – V.H.

Reinforcement of Steel Columns
Our firm will be involved in modernizing a hospital. The building is in steel and we have to reinforce the existing columns for seismic rehabilitation and increased gravity loads due to additional floors. Unfortunately, we have found very little literature on the subject of steel column reinforcement under load. Do you know of a good source of references? - P.M.

Is a/h > 3 ok?
The requirement for maximum spacing of transverse stiffeners in CSA S6-00 appears unclear. Must the aspect ratios, a/h, be restricted to 3 or smaller throughout the girder when the web requires transverse stiffeners to resist shear in the high shear regions only?

Winding Route to Crane Loads
The route one takes through the Code [National Building Code of Canada] and Standard [CAN/CSA-S16-01] to arrive at the crane loading is confusing. Taking into account that CSA is a Standards Development Organization (SDO) and the NRC/IRC is a government agency (NBCC 2005 becoming the law once it is adopted by provincial statute), does the Guide supersede the NBCC and CSA-S16? - A.L.

Stainless steel
What type of stainless steel should I be asking for in my specifications? The structure is made of small tubular sections, 60 mm in diameter, welded onto plates, then bolted. - S. C.-M.

Staggered Trusses
Where can I find design information on the staggered truss system?

Some recent questions

Class 4 Beam
How do I calculate the moment resistance of a Class 4 beam?

Resistance of an Existing Structure
I am presently calculating the resistance of an existing structure. Can I use a Φ factor of 0.80 on the bolted connections? — S.C.-Q.

Hole Sizes
What are typical suggested hole diameters for anchor rods? - G.H.

15% Rule for Fastener Holes
A fabricator introduced holes in flanges of a Gerber roof system that I designed stating that it was a new safety regulation. I remember Mike Gilmor mentioning that we could "ignore" the holes as long as they didn't represent more than 15% of the section. Is this true? – N.L.