Curtain walls have become increasingly popular in recent years for their clean aesthetic appearance. Curtain walls are used on the exterior of a building to both protect the building and make it look good. Currently, they are considered the ideal way to protect buildings from the outdoor elements they may face like wind, rain, snow, and more.
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Curtain walls are primarily made from aluminum and glass, making them a lightweight alternative to many traditional building materials. Curtain walls are not designed to provide structural support to the building and can typically only support their own weight. Their design allows them to transfer force from outside elements like the wind to the building&#;s inner structure, which is much stronger and more solid. Installing curtain walls on the exterior of a building also provides an air and watertight seal to protect the inner structure.
There are three primary systems available for curtain walls. They vary based on how they maintain their seal and prevent air or water from entering the interior of the building. Deciding on the best curtain wall system for your project depends on your individual needs, and talking to a door and glass professional is the best way to make that decision.
Face sealed curtain wall systems require a perfect seal between each unit to create a watertight barrier for the building. These systems do not provide an airtight seal for the building.
Water-managed curtain wall systems have built-in drains to prevent moisture from entering the building. Unfortunately, they also do not provide an airtight barrier for the building.
The most secure and effective curtain wall is a pressure equalizing system. It uses pressure to maintain an airtight seal on the building&#;s interior. The design also allows water to easily flow over the framing and off of the building. Pressure equalized systems are by far the strongest curtain wall systems and should be utilized for structures that may be subject to heavy environmental stressors.
One of the most important features of curtain walls is their ability to move with the building. As large buildings are subject to heat, wind, and other natural forms of force, they may expand, contract, or even sway from side to side. Curtain walls are designed to move with the building and can withstand the effects of thermal expansion and contraction.
There are also multiple options when it comes to how you want your curtain walls to look. You can choose from several glazing options for the interior or exterior. There are also a variety of face covers that can be installed on top of the curtain wall system, providing you with complete control over the exterior design of your building.
Curtain walls are an excellent option for many buildings because of their many benefits. Curtain walls can be very affordable due to their lightweight material. The larger your building is, the more you will save with curtain walls.
Curtain walls are also energy efficient because they help keep water and air out of the interior of the building. This can save on heating and cooling costs as well as avoid potential damage repair costs down the road.
The versatility of curtain walls is also very attractive to many of our clients. There is a large amount of flexibility around the installation of curtain walls, and they can be used on virtually any size building and in a variety of arrangements. They also provide a modern look that many clients prefer.
If you&#;d like to learn more about curtain walls or are interested in using them in an upcoming project, our team at Cypress Door & Glass is ready to partner with you to bring your dreams to reality. Contact us today to get started with a free estimate on your next curtain wall project.
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Curtain Wall Design
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(Structural)
(OP)
20 Mar 15 23:37Hi 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.
Replies continue below
(Structural)
20 Mar 15 23:59There 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!
(Structural)
(OP)
21 Mar 15 02:00thank you Jike. What about the aluminum curtain wall/storefront system?
(Structural)
21 Mar 15 03:39kodstruct...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 E 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.
(Structural)
(OP)
21 Mar 15 13:07Thanks 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.
(Structural)
21 Mar 15 13:16Check with Kawneer or YKK...they can tell you packages you can use. Be careful of dedicated package software...they are usually limited and proprietary.
(Structural)
(OP)
21 Mar 15 14:54Fantastic Ron.. Thanks.
(Structural)
22 Mar 15 02:09Curtain 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.
(Structural)
(OP)
22 Mar 15 03:27@ 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.
(Structural)
23 Mar 15 15:58kostruct: 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. SAP 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.
(Structural)
23 Mar 15 17:39Quote (glass99)
Curtain wall design can be a good business, or it can be terrible.
Could you elaborate?
EIT
www.HowToEngineer.com
If you want to learn more, please visit our website Zhuzao.
(Structural)
23 Mar 15 21:44I 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.
(Structural)
24 Mar 15 10:31Thanks Glass!
EIT
www.HowToEngineer.com
(Structural)
24 Mar 15 10:45I 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
www.HowToEngineer.com
(Structural)
24 Mar 15 19:19While 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
www.HowToEngineer.com
(Structural)
(OP)
24 Mar 15 19:37Rfreund,
Great questions!!!
I am currently looking for ways to get the properties from the manufacturers.
I think they should have them upon request.
(Structural)
24 Mar 15 19:48If 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.
(Structural)
24 Mar 15 21:21Thanks for the comments Glass!It is interesting as I'm looking into this further... It seems that most of these calculations use the 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 and 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
www.HowToEngineer.com
(Structural)
24 Mar 15 21:22Also, 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
www.HowToEngineer.com
(Structural)
25 Mar 15 14:58Quick 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
www.HowToEngineer.com
(Structural)
26 Mar 15 13:29Digging deeper...I'm still trying to get a feel for what is industry standard...I've contacted the manufacturer used for this project (a well known manufacture may have even been mentioned previously) and so far the information I'm trying to get seems to be difficult to get a hold of. Part of the problem seems to be that the shapes are proprietary so they don't want to give you the full geometry of the section. When asking for the section properties, they can give you S and I and c (section modulus, moment of inertia and distance from N/A to extreme fiber) for the shapes but they don't provide (atleast not commonly) J and C.w values. I also politely asked about talking with thier engineer and was told that is basically impossible (not saying that the people I was speaking with weren't very helpful, they were).It seems as though if you use the (allowable stress method) of Aluminum Design Manual (ADM) you only need J. From talking with the manufacture they seem to calculate J for tube and Channel section just using basic approximate formulas ignoring the 'kinks' in the shape and using an average thickness. I kinda feel like I'm trying to uncover some secret society.So below is where things are at and I'm curious if anyone can say hey your overdoing it or you're on the right track.1. Checking mullions: First check the tables provided by the manufacture. To me these are a bit misleading because they don't really determine where the horizontal mullions are applying point loads, however maybe they are conservative. So you could check your height and spacing and if you are withing the limits then you're good. You still however may need to check your horizontal mullion for lateral load as these may not be in the charts. So it seems c, I and S values are provided somewhat readily. So you can check deflection, but now what about strength. Well you you would need J and if using ADM you many need C.w. Now the question is what is the standard level of analysis used. I see a number of ways this could go - (1) The manufacture provides detailed geometry and we calculate the section properties. As noted previously I think they are hesitant to do this given the proprietary shape. (2) The manufacture gives you all the required values (check out ADM illustrated examples curtain wall and you will see there are many variables). Also my experience thus far has been like pulling teeth. (3) You estimate the the sectional properties neglecting the kinds/bends. This currently seems like it is done. (4) You are within the range of the charts and it is likely strength (at least LTB) is not a concern. Check other limit states (i.e. local buckling, section strength). Maybe use this in combination with option (3).2. Checking fasteners - I was told that the charts do not consider fastener strength. Therefore the screw/fastener properties need to be obtained from the MFG. Or the the allowable loads. This has actually been a somewhat difficult task as well however I believe I know have this information. It would be nice if they provided an allowable load as this again is a long calculation (Although I refer the reader to AAMA TIR A9 for info.3. Anchoring to substrate - this seems to be the most straight forward as I get to select the anchor.4. As Glass had mentioned think long and hard about your fee and willingness to get into curtain wall design. I haven't even started on some of the other considerations that other submittals that I reviewed seem to have overlooked or discluded.Any comments are appreciated. Thanks!
EIT
www.HowToEngineer.com
(Structural)
(OP)
26 Mar 15 14:17@RFreund,
Thanks for the information.
I got a signed proposal this morning for my first project and I am in the same boat as you.
The specs from the Architect calls for Kawneer product.
I went to their webiste for information. However, I don't think they have all the shape they use to manufacture their curtain wall system. I am to use the SS system and they only have few members with I & S values in their wind load chart section.
@RFreund, do you have a technical catalog or CAD file of all their shapes? You are right about the approach you described in your previous, at least it makes sense to me.
The design process itself is straightforward if we have something to work with especially, the Architect (Specs) says NO substitution. So I have to use Kawneer.
I will call Kawneer to see if theyc an help.
Thanks.
(Structural)
26 Mar 15 15:52That will make 2 of us.I have no such cad file but you can download their details online. These have the shapes but I'm not sure if they are drawn exactly to scale. Also try to find their estimating guide which relates sizes to part numbers.If you some how get to their guarded engineers. Let me know what they have to say, I'd like to pose these questions to them and try to understand their tables. Also for their clearwall system they actually tape a component to the glass which attaches to a toggle.
EIT
www.HowToEngineer.com
(Structural)
26 Mar 15 16:04Maybe it is indeed a 'secret society', outside the USA too.
When I had to check a aluminium section from an Australian manufacturer (Capral) for a project I had to obtain a company issued login to their online site to get the info. Once logged in, I had access to a lot of data, including CAD drawings of sections etc.
Good luck.
(Structural)
(OP)
26 Mar 15 16:14Then it's serious.
if they manufacture something and want Architects to specify them then they should have catalogs where engineers will get the data just like Verco, Vulcraft, etc.....
At the end of the day, the products will be shipped from their warehouses, so i don't see the issue.
Is it like that? Seriously... How curtain wall engineers do? I have 3 weeks to complete the design & shop drawings.
Any help?
Thanks.
(Structural)
26 Mar 15 16:14Generally speaking if you are doing standard Kawneer with no funny business, you don't need their CAD files. Lateral buckling is not really a thing with tubular sections. However if you feel you need it, CAD sections are available on their website.
(Structural)
26 Mar 15 16:28kostruct: three whole weeks? Welcome to the glazer's schedule. When you work for an owner or arch your schedule is measured in years, when you work for a glazer its weeks. Its a pretty jarring difference. If you do the same thing in the middle east its measured in days. Spoke to an engineer in Dubai a couple of years back who designed a 100m span roof with complex geometry, custom milled steel nodes and a funky islamic pattern for the structural members in two weeks. It was insane.
(Structural)
(OP)
26 Mar 15 16:53@Glass,
Great info. thanks.....
Yes 3 weeks, lol...I thought I could access the manufacturer catalog when I wrote the proposal.
I clicked on the link you sent and they only have few types (, , vertical mullions). I hope these types work with the wind my design.
Thanks a bunch.
(Structural)
26 Mar 15 17:45Yeah we the have same time frame.I found the cad files as well, however it seems odd that they would have a to scale cad file with exact dimensions but not distribute a dimensioned drawing. I did a Massprop in autocad and it appears to match the I values published in the wind load charts so maybe that is accurate.So it seems like if you're layout is fairly typical there isn't too much to worry about and could perhaps use simplified geometric properties. But then that begs the question, what if it's not such a simple case.It would be nice just to see a detailed strength design calc from the manufacture similar to in the ADM for the curtain wall example. Then you'd have all the values. I know this is a bit much and would take all the fun out of it. But I'm assuming they must have went through this procedure at some point.
EIT
www.HowToEngineer.com
(Structural)
(OP)
26 Mar 15 18:27RFreund,
That's right....I just did the massprop as well and it matches.
My curtain walls are 13' so i hope these sizes work. If it doesn't I will add aluminum C channel or something for reinforcement.
(Structural)
9 Apr 15 20:19Another question here...Are sills typically designed to carry the dead load (and lateral load) of the glass between vertical mullions even if there is substrate below (Similar to intermediate horizontal mullions)? Usually there is gap between the bottom sill and the substrate but you could add blocking in which case you wouldn't need to span the sill between the vertical mullions. However unless the substrate is foundation the member is probably not designed to support glass vertically. So I suppose any situation other than the blocking between foundation and sill the sill would need to span between vertical mullions, no?Is the only connection to the substrate then typically at the T&F anchors at the vertical mullions or is the sill (or head for that matter) ever fastened to the substrate as well? I would think not, as you would want to allow for differential movement and the only way this is accomplished with through the T&F anchors, right?Thanks!
EIT
www.HowToEngineer.com
(Structural)
16 Jun 15 16:59kodstruct...
I'm new to this forum. I actually joined after I read this CW thread. I'm an Engineering Team Lead for a company that designs custom unitized curtain wall. Prior to this, I was Engineering Manager for a similar company that only used stick systems (Kawneer, Efco, Tubelite, etc...) I've also done contract work for glazing and ACM panel companies. You are correct in your assessment of the industry. It is a niche. A lot of our interns or new hires have degrees in Mechanical or Structural Engineering, but there is a lot of intense facade specific training that we give them. I'd like to know how you are doing in your "infiltration" into the CW world. lol. Maybe I can help.
Thanks
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