tarek, scaffold design isn't overly complicated when you get down to the numbers, its more about your experience and having an eye for the details. My first suggestion to you would be to outsource this to someone familiar with scaffold design as this could be a daunting task for someone not familiar with scaffold.
If you're going to do this yourself, I suggest taking the following steps:
- Get a copy of all local and national standards that relate to scaffolding and suspended platforms
- Find out which specific manufacturer of scaffold will be used. Each manufacturer will have slightly different components and capacities available. The major suppliers should have online catalogs.
- Talk to the foreman/supervisor/contractor who will be responsible for erecting the scaffold (if one hasn't been chosen yet, find someone local you can talk to). These guys almost always have an idea how they want to build the scaffold. You will have to take their concept and check the numbers, but in my experience, if you can get a quality contractor, hes going to give you a great start on the concept.
-For a project this size, you're never going to be able to draw the scaffold as it will be built. There is just too much to work around. Best you can do is provide concept drawings for as many scenarios as necessary and then perform onsite inspections.
- Make sure you have a full understanding of the workers requirements before you start the design. Will the scaffold be hoarded in? If hoarded in, what is the maximum wind speed (wind speed to can be limited with break away tarps)? How long does it need to be erected? What are the live load requirements? Will there be any concentrated or lateral loading? Will there be a material hoist attached to the scaffold? Are you responsible for providing access (stair tower)?
I don't know if those pictures are of scaffolds that are already erected on your project. If I saw the larger picture of the suspended scaffold in my area, some of the first notes I would make are:
- There a no cleats on the underside of the planks to prevent slippage
- There are no check clamps on the suspended components. If a load bearing element (ledger, tube, truss) is suspended by a clamp, you should have a 2nd clamp (check clamp) on the supporting vertical, below the main clamp, in case the main clamp slips.
- Is the single tube supporting the decks made of aluminum or steel? If its aluminum you're not going to get much of an allowable span.
- Typically the scaffold trusses are rated for point loads at their panel points (where the webs meet the chords), it appears the tubes could be off center.
- Doesn't look like there are toeboards at the edges.
Like I said, when it comes down to checking the loads vs. allowable loads, scaffold is fairly straight forward. But you need to get a working concept before you can do the easy math. Hope this helps.
