![]() RE: FOS for Scaffold CANPRO (Structural) 12 Oct 15 22:05 His claims being that, his company has stamped and sealed the drawing, the capacity is what they say it is. I asked him to provide some literature to back up his claims. The Director of Engineering was who called me and surprised me, and him being a veteran I felt I was being muscled. This is why they are fighting it, especially because they are responsible per the bid. This is a big deal because its a huge area, we are talking 20,000ft^2 or more that will be affected, material is already here. I have checked many other of their drawings where they always reach a 4.0 FOS. This is the largest scaffold company in the US, their original calcs show a FOS of 4.0, it was the mistakes I found that brought this value down. So going to ultimate strength, we do not reach the 4.0. My reviewer has a popular wood design textbook that claims this is actually 2.5 so this actually gets me closer than 1.85. The FOS 1.85 is already stripping out the ASD FOS (which they claim is 1.66 per NDS 1997 commentary). ![]() I can see the logic here, as the dead load (plywood on top of the timber in my case) is part of the intended load. Originally this is how I interpreted OSHA, but my reviewer is on the side that says its 4.0 of the dead and live load. Thanks all, you bring up very good points. ![]() RE: FOS for Scaffold thaidavid40 (Structural) 12 Oct 15 21:16 I wanted to know the consensus on his statement that engineered scaffolding does not require 4.0 FOS. The 4.0 is more for people who don't know what they are doing.Įither way I am just a junior engineer grunt, it will not be up to me whether we accept this design. The EOR states that he does not need to reach a 4.0 FOS because this is an engineered system, and as EOR he can state what the capacity is. In talking with the company and our superintendents, this is a very big deal because the material is on site and they were going to begin assembling it this week, the area is a very large area so that this will impact quite a bit of material. Consequently the FOS is 1.85 and not 4.0. I found an error in that they were using repetitive member factors and size factors that were only applicable for 2"-4" thick members not the 6圆 members being used. Recently I reviewed a plan to use 6圆 timber to span 17.5' (16in OC). Per my company policy I need to review all 3rd-party engineered plans. Thank you in advance for your comments and insight.I work for a large construction company, and we outsource our scaffolding to a very large scaffolding company. The reason I ask is because in many facilities with platform grating, I noticed that even though the platforms are rated for 100psf or 125psf, the support steel are nowhere close to what they should be if the total live load is factored into the calculations for each base plate. What is the proper method of such calculations to ensure that the live load capacity is always met? If the platform is required to handle 100psf of live load, am I supposed to ensure that I factor the additional total 3,000 lbs into the reaction for base plate calculations? If I was interested in the values of the reaction at each support for base plate design, it would be a simple statics calculation based on the dead weight of all the steel involved. (Think coffee table)The grating span is reinforced by 5"x3"x1/4" angle, toe-up. I would like to pick the brains of you experts out there about the proper calculation method of a support structure for platform.įor discussion purposes, let's say that I have a platform 3' wide x 10' long (19W4, 1" x 1/8" grating) that is simply supported by tube steel at the ends.
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