Professional Development – Truss Design: A Trick My Day Job Never Taught Me That GDI Did – Part 2 During the day, I work for a good-sized lumber… Read more “Professional Development – Truss Design: A Trick My Day Job Never Taught Me That GDI Did – Part 2”
Curtain Wall Loading Requirements, Steve Kastner, P.E. Curtain walls (CW) aka moveable partition walls can produce problems both in the field during construction (and possibly in the… Read more “Curtain Wall Loading Requirements, Steve Kastner, P.E.”
How To Share MiTek Sapphire Files With Apple iOS Users I know that I have had trouble in the past explaining to framers and customers how a… Read more “How To Share MiTek Sapphire Files With Apple iOS Users”
Truss Design and Partially Enclosed Buildings, by Steve Kastner, P.E. When truss designers are designing a roof system in a high wind area of the country there… Read more “Truss Design and Partially Enclosed Buildings, by Steve Kastner, P.E.”
How to convert a PDF to DWG format with Adobe Illustrator As remote designers we often find ourselves needing missing dimensions. We often have to wait for… Read more “How to convert a PDF to DWG format with Adobe Illustrator”
How To Import a PDF Into MiTek Sapphire Some of you may ask; why would I want to import a PDF into Sapphire? Why to be proactive of… Read more “How To Import a PDF Into MiTek Sapphire”
Steeple Loading – Did You Know? In an earlier post I touched on special loading situations that you may encounter when designing a truss system. One of… Read more “Steeple Loading – Did You Know?”
HIP RIDGE Rafters – Do You Know How to Calculate Them? In this computer aided age, our brain really needs some exercise – at least every once… Read more “HIP RIDGE Rafters – Do You Know How to Calculate Them?”
Design Considerations – Special Loading Many factors go into the design of a roof and/or floor structure. As component design professionals, we need to be aware of… Read more “Design Considerations – Special Loading”
Many of us component designers try to be as efficient as possible with our time, especially if you work remotely. We all want to get though as many designs as we can throughout the day. In a remote designers eyes, the more designs you get done, the more money you make. Time efficiency is directly related to your income, therefore making it imperative that you learn to design fast and accurately. These are some simple steps that I use when starting a new design. Many of us do things differently, so don’t take this as set in stone.
What am I designing?
My first question is what am I designing? Am I doing a floor system? Am I designing just the roof? Am I bidding wall panels or is this production work? Figure out if your just throwing a number at it or if it needs to be optimized for the shop. This will make a big difference in how detailed you need to be with your designs. For this post, we will say we need to design the lower and upper roof of a single family home.
Now you get into the arch plans and start pulling out the information you need:
- Wall Heights
Depending on the plans, wall height dim should be on your elevations or your section views (depending on the architect). If you have a plane coming from the 1st floor to 2nd floor, knowing the floor depth and floor board depth are needed as well. This will give you your overall height to the 2nd floor wall height from the 1st. Also look for ceiling height differences in the house as well. This could burn you down the road if your walls are not correct. Make sure your wall thickness is correct. I could go on forever about how some use a 6″ bearing for a 2×6 wall but I won’t. At GDI, we say “live in reality” so we go 5 1/2″. We then look to see if there is any cladding involved such as brick or stucco. Many people use a 5″ offset for brick and a 2″ offset for stucco. Cladding is very important because it can affect your overall truss span.
- Roof Info
Now we get into the roof itself. The first things I start looking for are plane locations and pitch, heel height and overall overhang length. I usually look for this info on the elevations and section views. Sometimes the architect will make a specific end detail giving you everything you need, other times you will search for what seems like forever to find this information. If you aren’t sure about what you find, ASK QUESTIONS!! Too many times have I just assumed and it has come back only to create more work for myself. Once you find everything, you want to start applying the planes and cutting them in. Your next step should be to look for interior bearings that can help you in your design and ceiling conditions( coffers, trays, cathedrals etc). I find that colored highlighters help when dissecting a set of plans. If you use the same colors for the same types of conditions, such as green for int bearing or pink for ceiling conditions, your brain associates the condition with the color. This makes it easier to visualize the structure in your mind. At least it does for me.
Truss Input and Design
Now that all of your information is found (hopefully) and your walls and planes are in correctly, it is time to lay in trusses. This process can be done so many different ways. In my case, I start by looking at what customer I am designing for. Each truss plant has specific design criteria. From the setback length of there hips to the web pattern of the trusses. Make sure you know who you are designing for.
Depending on the roof, I will either start from the hip ends or Gable ends and work my way in. It is a good idea to plan ahead with truss layout. You can sometimes design yourself into a corner and have to waste more valuable time getting out of it so be careful. Girders have a tendency of doing this. You lay out all your trusses, design them in engineering and get to the girder trusses and they don’t work. If you are worried about the loading, design girders first. That way you won’t waste time having to go back and change design. Remember, time is very valuable to you and your company.
Once all trusses are in to your liking, make sure they are cut to the correct planes. Are you over-framing? Are you cutting in your valleys? I use 3D religiously to make sure I have the correct profiles in. Also make sure your ends of the trusses are correctly cut in. No one likes getting that call that the trusses are too short! You need to make sure you are being accurate in your design.
Your last and final step is labeling and engineering your trusses. I try to group as many trusses as I can together by span and condition. This helps the shop build like trusses and so they are stacked in order of erection. Once labeled, we will engineer. When bringing trusses into engineering, It is very important you make sure your main default settings are correct. If not, it will cost you a lot of time fixing each one individually. These are my main areas of concern:
- Loading – make sure your using the correct GSL (ground snowload), wind speed, and extra dead loads.
- Bracing – T-bracing or CLB
- Lumber Files – make sure you are using the right lumber file. If you design with lumber they don’t carry, you are in big trouble.
- Plate inventory – Always make sure your plate file is correct. It is usually setup correctly and most of us don’t have to worry about this step, but if you design for multiple clients, this is a needed check.
- Heel Options – In some cases with a large heel, it saves a lot of time to adjust the heel options before importing to have all heel details correct. Otherwise, you are changing the heel detail for every truss. This can waste a lot of design time so think ahead!
After all settings have been checked, it’s time to design. I try to start with the smaller trusses and jacks unless I have a girder that I’m worried about, then I will focus on the girders first. Take your time and don’t rush. Keep in mind the shop workers that are building these trusses. Make them as easy as possible to build. Try to get rid of big nasty plates at joints. Try to single cut webs or flip them to make it plate better. Think symmetrical. The more like webs the less work the shop has.
A Component designer not only affects how a design is laid out and built, but also the cost of the build and the margin the plant gets after invoicing. We play an integral part in the way this industry flows and how profitable we all are. Always keep that in mind no matter if your designing a bid or production work. Take pride in everything you do and have Integrity. It will take you very far in your career as a designer.