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Drip edge on WF beams

Drip edge on WF beams

Drip edge on WF beams

(OP)
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?

RE: Drip edge on WF beams

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?

RE: Drip edge on WF beams

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.

RE: Drip edge on WF beams

(OP)
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?

RE: Drip edge on WF beams

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.

RE: Drip edge on WF beams

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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RE: Drip edge on WF beams

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.

RE: Drip edge on WF beams

Whatever happens, can you let us know the costs?

RE: Drip edge on WF beams

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.

RE: Drip edge on WF beams

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

RE: Drip edge on WF beams

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

RE: Drip edge on WF beams

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
www.americanconcrete.com

RE: Drip edge on WF beams

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. shadeshappy
Dave

Thaidavid

RE: Drip edge on WF beams

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

Thaidavid

RE: Drip edge on WF beams

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.

RE: Drip edge on WF beams

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

RE: Drip edge on WF beams

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

RE: Drip edge on WF beams

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

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RE: Drip edge on WF beams

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.

RE: Drip edge on WF beams

How much of the bottom flange is exposed? Is the inside edge of the bottom flange free or is it embedded/connected to the exterior wall?

If the bottom flange is completely free and does not come in contact with the exterior wall, don't do anything. Just let the water drip off the flange. It seems to me that any rain accumulating on the beam flange will be due to wind driven rain.

A few other ideas to combat the water.....choose and equivalent shape with tapered flanges, drill drainage holes in the bottom flange (and account for the holes in the beam design)

RE: Drip edge on WF beams

(OP)
Flange sticks out about 3" beyond face of wall. Bottom is 10'-8" above ground level, so it will be very visible. Beam is to be galvanized.

Inside edge is barely bearing on roof deck edge. We need plate brackets to attach it to the deck.

For tapered flange member, there is no 16" S shape - goes from 15" to 18".

The whole driver for this crazy detail is the Energy Code, requiring insulation on CMU walls and bunches in the roof! I've had a number of these driving structural to go through contortions to accommodate the Code and still have something that is not structurally unstable. Anyone else having else experiencing headaches like this?

RE: Drip edge on WF beams

all the lunchers out there selling proprietary continuous insulation structural system and attachments will be like 'nah nah, that beam flange isn't CI'

the energy code is very heavy-handed if it's not checked by comprehensive design process. the energy code would have you holding everything together with tape if you let it. z-girts and steel anchors still work great. too often prescriptive values are used w/o attempt to model for performance.

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