dhengr..To clarify on drifting...the drift begins at the top of the roof snow load depth-The drifting load being in addition to the base roof snow load. With top of module at ~1.5 ft and 1-2 ft between rows, the snow fills in there pretty uniformly. I can't remember what depth a 20 psf pg...
I wouldn't risk it, not with my license on the line...especially if it's that close. Modules themselves (without racking, wiring, etc) increase dead loading by 2.5 psf. I doubt this is less than a 5% increase.
Skiis, regarding drifting, I have given this much thought and run through many...
JAE: In this case, I read SteelHead's post as if he was being paid to review someone else's work, and then give it a "thumbs up". If I read it correctly, then I would say he does carry some liability, and (if it was me) require the proprietary calculations - with a confidentiality agreement -...
My opinions, as a former (15 years) plan reviewer and currently a designer.
First, in Ohio, I did my best to review stamped plans, but in all reality, there is no way I could have gotten through everything. If everything looks OK and a PE is willing to put his/her license on the line, then...
I guess you can only upload one file at a time...http://files.engineering.com/getfile.aspx?folder=340a5f11-a846-46d5-b310-88024028af5d&file=Whole_roof.JPG
I have been pondering this for a while now, and decided to see if anyone has any perspectives on this issue.
Refer to the attached jpg showing a roof being considered for a solar array.
The attached detail shows a hip roof with multiple dormers; three dormers on the SE corner of this building...
Well, I have been away from computer access all weekend, but the points made here are exactly what I am struggling with.
-Regarding snow loading: these are at 10 degree tilt in landscape; by the time drifting becomes a controlling factor (20 psf flat roof load), the array is completely...
Hi, everyone, hoping for a little enlightenment...
I am holding up a permit application for a solar array installation because I won't sign off on the structural section without doing a full review. This is residential structure with a flat roof. I have the original building plans and truss...
Sorry I'm a little late getting in on this, but hopefully, this will help. It's a very recent guidance document written on this exact subject.
I have been providing it to code agencies that question my calculation methods, and all of them (so far) have been quite receptive...
Thank you, JAE. Advice taken. I know I'm going to run into resistance on this, especially when it comes to welding.
The good news is that it is apparent (after reviewing the joist capacities compared to what is there) that this section of the building was designed to supports some hefty...
Hello, all. I am currently working on establishing a connection method for solar thermal collectors to a roof deck.
We're good with the additional dead load, but I am concerned with the proposed attachment method.
Background:
The system consists of two parallel timber "curbs" 6"x12"x 24'...
I was out yesterday taking care of kids on a snow day, so sorry for the late response.
As far as weighing the sample and calculating the density based on core volume, that was my intention. I was expecting a full report. Needing the info ASAP, I called the roofer, and he said that's not part...
Here is a photo of the core that was taken. Lots of air and no aggregate. This is obviously a very friable concrete.http://files.engineering.com/getfile.aspx?folder=00949e8b-f0a1-43f1-97b2-1d6c1a2cdeb4&file=Roof_core_sample_from_7_Easton_oval_003.jpg
Thanks for the feedback. Unfortunately, I am to the point of guessing, and I need to make a reasonable determination. What would you all do?
I know that standard "lightweight concrete" is too heavy for this roof. It's just a matter of making an educated guess at what is actually there. It's...
Not knowing much about these systems, I've been looking on the 'net for info.
This is one that I had come across, with a description of "typical densities and uses...
http://www.litebuilt.com/lightweight-concrete-handbook.html#D-1
Hello, everyone.
I have been trying to figure out a concrete density for a month or so now. I went so far as to have a core sample of the roof taken. Unfortunately, I didn't call for the sample personally; it went through the building owner, and calculating density wasn't part of the job.
In...
Thanks for all of the tips. And, SteelPE, luckily I am working for a company where the owners respect my opinions and actually value me as an employee!!! When I say no-go, we all sit down and look for an acceptable alternative. Nice change from where I used to work!
Oh...and Jed...I hope I didn't come across as belittling the evaluation of existing structures. I have a great deal of respect for all of you "true" structural engineers. Being in a position where it is ME that has to put the stamp on the plans has shown me how exhausting even a "simple" roof...
Thank you; sounds like I am on track. I appreciate discussion about the "little" details when doing this. One recent project was a relatively new (10 year old) commercial building with EPDM, lightweight insulating concrete, decking, and a maze of different bar joists and I beams. This is one...
