I've recently begun designing and building structural updates to my house. For example, I've built some shelving units and a cabinet space. Everything has gone well so far, but I'm about to tackle something more significant, a self-designed backyard shed, and I want to be sure that it is structurally sound.
The design will have non-traditional elements, such that copying an existing design would not be straight-forward and could not be relied on.
Is there a software tool or online resource that can help an average DIY'er calculate the load capacity for different structures using different materials? For example, if I use a 2 by 4 here it will be able to hold X weight, versus using a 1 by 3 can hold Y weight.
Or maybe there's are rules like 2 x 4 braced every 2 feet can hold 200 pounds. If this is the case is there a book or website that can provide me with guidance like this?