Curtain Wall Design 2

[kodstruct]

Hi there,

Lately I have been getting calls from contractors to design curtain walls and storefront systems for them So I am thinking to start my practice in the area.
Is there a good software out there for this?

Thanks.

 

[jike]

There is a definite need for engineers to design light gage framing. Our office typically would design projects with only a few light gage elements but if it was a large job we would put it under the responsibility of the contractor. Since I retired over a year ago, I cannot remember the names of software. You also need to develop some standard details.

Good Luck!

 

[kodstruct]

thank you Jike. What about the aluminum curtain wall/storefront system?

 

[Ron]

kodstruct...most any good FEA software will do. There are some dedicated software packages for light gage design (Check with Dietrich.....they supply light gage framing materials and I believe they have software as well.). If there will be aluminum and glass involved (storefront/curtain wall), you'll need Window Glass Design 5 for all the calcs required to comply with ASTM E1300 for the glass.

I have used RISA 3D for light gage framing analysis and design. I use it for lots of other stuff as well.

 

[kodstruct]

Thanks Ron... I use SteelSmart for metal stud or light gauge curtain wall design.
However I am looking for a software for aluminum curtain wall and storefront system, capable of designing mullions, and coming up with shop drawings.

 

[Ron]

Check with Kawneer or YKK...they can tell you packages you can use. Be careful of dedicated package software...they are usually limited and proprietary.

 

[kodstruct]

Fantastic Ron.. Thanks.

 

[glass99]

Curtain wall structural engineering is a whole specialty. The basic calculations are conventional beam theory, but there is a bunch of nitty gritty bits and pieces you have to learn. Fasteners are a big one (TEKS Screws, stainless bolts, machine screws, etc. You finish up with a lot of weird plastics. There is the glass. You need to get familiar with the Aluminum Design Manual. Custom extrusions can be a bit tricky with buckling.

 

[kodstruct]

@ glass99,

Do you gave any suggestion for any software out there?
You know how it works; once you do do couple designs with the right manual you get it. I would like to start my practice in specialty structural engineering like connection design, light gauge curtain wall design, certified welder inspector and storefront design. There is a huge market because many fumes don't design those things including the firm I am currently working at.

What I see so far, the revenues is more than typical structural engineering design.

Thanks.

 

[glass99]

kostruct: If you are looking for software that automates a lot of the checks involved in curtain wall design, there is not one that I know of. I use Strand7 (FEA), Window Glass Design (glass structural), DrBeam (1d beams), ACAD, Rhino, SolidWorks, Hilti Profis. A lot of people like MEPLA for glass, though I don't use it. SAP2000 has automated aluminum design features which I have heard of some people using. I will caveat this by saying aluminum extrusion related work is less than 5% of what I do. I am more of a structural glass guy.

Curtain wall design can be a good business, or it can be terrible.

 

[RFreund]

Curtain wall design can be a good business, or it can be terrible.

Could you elaborate?

EIT

http://www.HowToEngineer.com

 

[glass99]

I know facade consultants that drive Porsches and others who can barely afford gas for their '98 Camry. There is huge variation in fees for similar work, and it revolves around the attitude of the consultant. Client side and contractor side have pretty different schtick's. Generally client side is better, but not always.

The two things that make you valuable are the perception that you are either a rock star who's gonna make it awesome, or a Guardian of the Clients Rights and Specification Cop. Straight ahead calcs are kind of a commodity, but even there there are ways to do alright I guess.

To do well as a Specification Cop, you need gravitas, business sense, and an army of inspectors. To do well as a rock star designer, you need good ideas and swagger. To do well as a calc machine, you want to be as high in the analysis cleverness food chain as you can, and be efficient.

 

[RFreund]

Thanks Glass!

EIT

http://www.HowToEngineer.com

 

[RFreund]

I have now seen a few different curtain wall submitals and it is interesting how different they are. One basically copies in the manufactures tables, says spacing less than max spacing shown in the table; does a quick deflection check; then shows the capacity of a concrete mechanical anchor, then done. The second goes through and computes the section properties of the aluminum extrusion, get the load on the extrusion, checks the section. Then checks the metal fasteners for mullion to mullion connection. Also checks bending of the fasteners (seems a bit conservative given the geometry, but it's nice to see) and also checks anchors. The third does the same as the second but also checks drift and thermal expansion/contraction. They all seem to have a note which says they are not responsible for dissimilar metal contact.

EIT

http://www.HowToEngineer.com

 

[RFreund]

While on the subject a couple questions for any curtain wall designers:

Do you typically check the connection of horizontal to vertical mullion? It seems that you should. Do you typically get the fastener information from the manufacturer or do they provide some sort of maximum reaction?

For mullions which are comprised of two channel shaped members which "snap" together, do you typically treat these as individual channels or can they be treated a box? Maybe I am mis-understanding and these are mechanically fastened together...

How do you typically determine the design property values? Typically all I see in the manufacture info is moment of inertia, and section modulus. How do you determine warping constant, etc.? Are these supplied upon request or do you calculate them yourself?

Thanks!!




EIT

http://www.HowToEngineer.com

 

[kodstruct]

Rfreund,

Great questions!!!

I am currently looking for ways to get the properties from the manufacturers.
I think they should have them upon request.

 

[glass99]

If its an off the shelf system like Kawneer, they usually have all the relevant section properties figured out, and they are usually quoted in their manual. But a better way is to use their load charts because it gets you away from having to worry about all the Aluminum compressive strength formulas. You technically should check all the fasteners, including the horizontal mullions.

If its a custom extrusion, you need to check everything! Calculate your own section properties and have at it. Snap on caps are usually not rigidly enough attached to the other components to be composite. Buckling can be complicated.

 

[RFreund]

Thanks for the comments Glass!

It is interesting as I'm looking into this further... It seems that most of these calculations use the 2005 Aluminum design manual which as far as i can tell doesn't require "J" (torsional constant) or "C.w" (torsional warping constant) when finding allowable stresses for basically all configurations except angles. Conveniently enough it seems like the manufactures, don't have J and/or C.w values. The 2010 and 2015 ADM uses both for lateral torsional buckling. Unfortunately I'm not an ADM expert so maybe I'm missing something here... It reminds me of how the AISC 9th edition worked vs how the current versions work. It's accounted for, just differently. Unfortunately I'm not old enough to know the 9th edition very well. Maybe someone else can chime in on this?
However it does seem that the manufactures have pretty detailed autocad drawings. I suppose you could use autocad to get "J" but I don't think it will calc "C.w". I suppose you could/should use some other software.

EIT

http://www.HowToEngineer.com

 

[RFreund]

Also, fyi regarding the design charts... I asked if these charts accounted for the horizontal to vertical mullion connection. They told me that they did not and the fasteners should be checked. I am waiting for more fastener info though.

EIT

http://www.HowToEngineer.com

 

[RFreund]

Quick edit - You do need "J" for tubular sections but not channels. Although these typically aren't actually tubular. The section property calcs and allowable stresses gets a bit intense.

EIT

http://www.HowToEngineer.com