Coping and Cost

[sdz]

In a previous thread I asked about web cope depths on beams; comparing the ASI 65mm deep cope to 35mm as used in most of my workplaces. Now here's the really important question. Will it make any difference to cost of fabricated steelwork?

Since I have never had an enquiry from a fabricator about depth of cope I suspect not. Does anyone have actual experience of a case where it made any difference?

 

[OzEng80]

Sdz
I don’t have a specific example for you but fabricators in my region tend to provide costs per ton. Unless there is many instances of your cope I would not expect any difference in cost.

 

[apsix]

With one there is less cutting.
With the other there is more scrap to sell back to Sims.
The cheaper one will be the one that is standard for the particular fabricator, if there is any difference at all.

 

[asixth]

Asking around my office, the cost for a coped-web side plate connection is around 50% more than the same connection uncoped. Like apsix mentioned, the main additional cost is from cutting the steel to cope the flanges.

I would expect the total cost of the connection to be in the region $AU200-300 (better ask your steel fabricator, I am taking this value from a decade ago, making adjustments for inflation plus the increase in steel price and the ever increasing labour cost over the same period). A Quantity Surveyor will probably be able to give you an answer as well.

I have found in my designs that despite a coped web side plate being more efficient in terms of reducing the beam reaction eccentricity, the connection is generally not critical. I keep my designs pretty standard, M20 bolts, 3 bolts for 300UB's, 4 bolts for 400UB's etc. 10 plate cleat and 6mm CFW. The critical aspect of the design is the weld shear that will increase will the greater eccentricity, but generally I have some capacity up my sleeve.

I wouldn't expect the savings in cost to be astronomical, and there are probably better ways to make the steel detailing more cost efficient.

 

[sdz]

I was thinking more that a cope of 35mm could be a problem to fabricate because it is so close to the flange, making it hard to drill the hole at the re-entrant corner of the cope; at least for the larger beams and columns.

The 65mm cope adopted by ASI means that the hole can be drilled clear of the flange and the fillet radius. (However a cope this large does not suit 200mm beams and channels.)

But is that reflected in any cost differential?