Drip edge on WF beams 1

[Sawbux]

Architect is using W16x40 to put a horizontal band around the roof edge of a 1 story building. The length will be about 150 feet!

Initially he showed a 1/4 x 1/4" groove machined on the underside of the bottom flange. I didn't think that was very economical and suggested a piece of bar stock welded to underside - he didn't like that for appearance reasons. I called around and couldn't find any fabricators capable of milling such a groove.

He also didn't like idea of just butting some sheet metal flashing to the underside and using some good sealant.

Now, he has called for a weld bead to form the drip. I can't see that looking too good either!

Anyone done something similar?

 

[OldBldgGuy]

I work with someone who loves structural shapes as aesthetic elements; typically for wide flange shapes I try to get the drip on the top flange, i.e. a metal flashing on top of the beam or at least a sheet metal drip at the edge of the top flange. It is not very visible and the water that will run down the beam below is negligible.

You say machining a drip isn't economical. A W16x40 fascia is?

 

[BUGGAR]

Why not just fillet weld a bar drip on the outside edge of the flange. Have it laser cut into fancy shapes if that makes the Architect happy.

 

[Sawbux]

The roof of the bldg. consists of hollow core plank. On top of this is up to 12" of board insulation, then the roof membrane. A pedestrian deck consisting of concrete tiles sitting on pedestals sits 16" up from top of concrete deck. For aesthetic reasons architect and review board want a flanged steel look around the top. The top flange of the W16 supports a cable handrailing system.

We originally had HSS 16x6 around the top, but changed to W16. Need width of flange to project out from face of wall and attach handrail!

He resisted the welded on bar drip!

Fab shops had plasma cutters & other fancy equipment, but said they couldn't cut groove. Maybe a diamond blade in a Skill saw?

 

[IFRs]

You need a shop with a large milling machine. There is one near what used to be Bethlehem Steel with I think a 20 foot bed. If you are near a steel mill call around.

 

[JAE]

Just fabricate the beam on a slight tile about its axis such that any water will drip off the tip of the flanges.

Or epoxy a 9 gage steel wire to the bottom.

Or a series of overlapping yellow sticky notes.

Or tell the architect..*&%^%%^^$##%^*(&*^%^

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[Ron]

The architect won't like the weld bead. Won't be consistent enough. Use a diamond blade on an angle grinder. Clamp a guide on the beam to keep the line straight. If you screw up, weld over it, grind flush and do it again. You'll go through several blades but they're not that expensive and cheaper than machining.

 

[BUGGAR]

Whatever happens, can you let us know the costs?

 

[racookpe1978]

Cost of tilting the WF slightly, so water runs off the edge? Near zero - The (heavy!) thing has to be hund up there anyway, at least according to this arch. Will not the inside (uphill) side of the lower flange trap moisture and condensation over time? Bird nests? Squirrels and raccoons?


Cost of milling a notch in the flange? Ship it to milling machine, run and load WF through milling machine, pick up back off table and ship back, etc, etc, etc. Lots!

Cost of welding the edge? Lots per foot of weld.

 

[thaidavid40]

Your description of this beam makes it sound like AESS. From what distance will the underside of this beam be visible? If the distance is 20 feet, or more, you could put petrified bird doo on it, and no one would be the wiser, or could tell the difference. Do what is cheapest, and know that no one will see the difference (except the person who repaints it in the far future).
Dave

Thaidavid

 

[Ron]

td40....you're right, but trying to convince an architect that his monument will be preserved by such action is another story!

 

[TehMightyEngineer]

What about cutting the drip edge into flat plate and then creating a built-up beam of similar proportions?

Professional and Structural Engineer (ME, NH)
American Concrete Industries

http://www.americanconcrete.com

 

[thaidavid40]

If you still want to try the welded bead idea, you might make that look a little more even, and aesthetic, by welding against a continuous, removable, ceramic backing bar. That would at least give you one, clean, consistent edge. Maybe.
Dave

Thaidavid

 

[thaidavid40]

As for the petrified bird doo: tell the architect he gets LEED points for that!

Thaidavid

 

[dhengr]

Sawbux:
Seems to me there are several options, once you understand how absolutely essential this detail is to the Architect’s ego and his winning of that world design award. And, you are standing in the way of his future fame and fortune. Have the Arch. go to the rolling mill with his purty pitcher of the shape he wants. For a nominal fee they can have some rolls made just for his beautifuler section and he can use that on every building from now on, he can even patent the shape. Think of all the machining costs he will save. Have him order the W16's early and have them delivered to his home or office. Then he can get out there during his extra time, with his trusty vice grips and just bend the tip of the flange down a few degrees to make the drip lip. He could buy a DREMEL tool and grind drip lips or grooves anyplace his little heart ane mind desires. Remind him that he should do this on the outside flange tip so it will drain outward. Some of them aren’t too sure of this concept of keeping the water out of their bldgs., given how many of their bldgs. leak.

Why are you worried about this? That’s an Arch. detail and on the arch. budget. Soon enough he will be asking you to eliminate every other beam and column, to help pay for this special detail, since your structure is causing the bldg. budget to explode.

 

[darthsoilsguy2]

Today's Architectural Award is Tomorrow's Forensic Engineering Job

 

[BUGGAR]

Wait a minute. Doesn't Arcelor Meteor, or somebody like that, roll some WF pile shapes with thickened edge lips for sheet pile attachment?

 

[JAE]

I still think that simply epoxying a 9 gage wire to the bottom of the flange would work.

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[ajk1]

9 gauge wire (0.15") seems very thin to be making a positive drip. Are you sure that surface tension effects will not permit the water to go up the back side of the wire, or the wind to blow it across the wire? Might be prudent to try it out before proposing it to the architect (although maybe does not matter since the architect doesn't accept it). Since the drip is architectural, not sure why the architect has asked you to do it. Maybe if he made his own inquiries he would be more inclined to accept what the steel fabricator tells him and/or to reach an architecturally acceptable solution with the steel fabricator.

 

[JAE]

OK - a larger diameter wire then.

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