本文发表在 rolia.net 枫下论坛Ir is pretty common for people to think that their "reinforcement" of a truss will somehow make it better or stronger. In reality, you can do more harm than good by altering a truss and completely changing the stress and tension points on the truss. My best advice would be to not alter the truss at all... your framing proposal is of no help.
Don't use 5/8" plywood as it only adds more weight... reducing the amount you can safely store. Use 3/8" or 1/2" plywood if you have to lay something down, and lay it perpendicular to the truss chords.
Use common sense and do not overload the trusses. The bottom chord CAN be overloaded, it is already in tension, meaning the tendency will be for it to pull apart (or break) at the point of stress or where it is fastened with a mending plate, whichever is greater. Your trusses were engineered to only hold x amount of weight. Generally that is only meant to be it's own weight, the weight of the building materials that are already on it (drywall, sheathing, roofing) plus potential snow load, wind load and live load. The live load is your "storage" and it is a limited amount in that equation... generally it is anywhere from 5-10 lbs per sq ft, but we can't say for sure.
How much your trusses are rated to hold is something only the mfg knows, or if you can find a tag or stamp, that might help.
So without knowing for sure... don't concentrate loads, and don't put more up there than 5-10lbs per sq ft. If spread evenly, a 25x20 garage "could" support 2500 lbs @ 5lbs/sf. But don't start by putting 500 lbs of plywood up there.更多精彩文章及讨论,请光临枫下论坛 rolia.net