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> I am a licensed civil engineer in California. The rules and procedures for little shit like a solar array foundation can be followed by almost anyone who can

• abduhl 4y ago
  No problem. People think that structural engineering is some kind of mystic art because the licensing and code regimes exist; however, the truth is that it's normally very straight forward if you have a basic grasp of Newtonian physics and a simple project (for some complex projects it is a mystic art - skyscrapers, tunnels, bridges, etc. are all situations where you have to invoke arcane spells like FEM, empirical approaches, and archaic portions of the code). This is especially true for shallow foundation design where the concrete behaves well (because the loading is so simple) and the code specified soil parameters are excessively conservative. Rather than looking at the code and going through the straight-forward analysis contained in the tiny little section that's applicable (and appropriately titled) most people will see that the code is hundreds of pages long with hundreds of sections and give up before realizing that the building code contains provisions for almost every scenario (building with concrete? there's a section. building with steel? there's a section. building with timber? there's a section. wall? section. beam? section. foundation? section. special circumstances like earthquake or wind or frost? section). Engaging with the code like you did assures that you are not taken for a ride by an unethical contractor or engineer, and it's something I would recommend every owner does before they embark on a project, but honestly a lot of the simple stuff (like a light foundation) is stuff that people used to just do themselves without designing anything and it's not any more safe because you have to get it stamped now. Your initial gut reaction for this simple stuff is usually within an order of magnitude, and often it will be more than is required because people don’t have a good sense of how strong modern building materials are. As an aside and based on your other post, a slab might not have been the most economical solution for your particular problem. You probably could have just installed some small diameter piles under each solar panel post. I'm surprised your engineer didn't recommend it as this would have much more easily addressed the wind loading issue. Value engineering like this is the real benefit of engaging a knowledgeable/experienced engineer. Cool Solidworks model. Easy 3D modeling has very much changed the game for small scale projects by allowing people to build a project on their computer and figure out all the little details that you'd normally screw up without an engineer. Having a working 3D model means that your design is probably at a higher level than most. It's cool to take something from an idea to a concept to physical reality.
  • robomartin 4y ago
    > You probably could have just installed some small diameter piles under each solar panel post. I'm surprised your engineer didn't recommend it as this would have much more easily addressed the wind loading issue. This is precisely what I designed and the Civil Engineer agreed would work fine. The LA County engineer, for lack of a better word, turned out to be a complete a-hole. Each footing ended-up being a 4 x 4 x 4 foot cube, each over 8000 lbs, eight of them. And then the slab on top of all of that. The story is a bit more complex than that. Before starting the design phase I put together 3D models of the basic idea and went to the permit office for a consultation. I spoke to zoning, fire and structural/safety/permit (forget what the official title was) engineers. Out of that came specifications for the kind and sizes of lumber I had to use in order to be in compliance...and more. A couple of months later, after much design work and spending money for a civil engineering firm to do their thing, I submit the plans. They get rejected by the guy who would later make my life miserable with all of that concrete. Why? He didn't like the size of the timber being used. You know, the material he recommended just a couple of months earlier. Nothing significant had changed in the design. He, for example, wanted 8x8 columns, rather than the 6x6 he said I should use. Because I had gone through that initial consultation I had a pile of lumber already purchased awaiting the permits being issued. I could use very little of it after his rejection. That cost me thousands of dollars and probably another two months. The entire experience was not fun at all. Unnecessary. I don't even want to imagine what it might be like to put a larger project through that office. The other interesting thing was that the inspector assigned to my project was just-about clueless. As long as it looked right, I probably could have gotten away with anything. My goal was to build a safe and durable structure, so no issues there. I don't even want to imagine what people wanting to cut corners might get away with once they realize their inspector is, for the most part, incompetent. > Cool Solidworks model. Easy 3D modeling has very much changed the game for small scale projects by allowing people to build a project on their computer and figure out all the little details that you'd normally screw up without an engineer. Yes, definitely. You can even model and evaluate fit and tolerances. And, of course, run finite element analysis on the whole thing both for structural and aerodynamics. I actually started with CAD way back during ACAD 1.0 days. I even did a bunch of 3D work in AutoCAD. This wasn't fun due to limitations. Once parametric modeling came into my life I haven't looked back. I still have AutoCAD because we need it for some of our work, but this is pretty much a Solidworks shop. We do product design from concept to prototyping and manufacturing for a range of industries, from commercial to aerospace. Here's part of the design of a full-scale aircraft simulator (Boeing 777) also done in SW: https://i.imgur.com/IrWlZRs.png https://i.imgur.com/IrWlZRs.png