What are the special considerations required on the design of a steel structure?
Here are a few, from years of practical experience and which you may not find in textbooks and manuals.
1)Steel’s greatest drawback as a material of construction is its susceptibility to corrosion. Ensure that your connections are such that all parts are accessible for painting and re-painting in the future.
2)Don’t overdo the weight optimization during analysis and design. Be prepared for the non-availability of certain optimum shapes from the suppliers. Substitutions of these non-available shapes with whatever is available later cause delays in fabrication and erection. Newbies, fresh from college and proud of their computer skills, are most likely to overdo this “minimum weight design”.
3)Try to repeat sizes and shapes as far as possible, even at the cost of a little extra material. Repeatability and reusability at other places are of great value during erection.
4)Keep in mind erection feasibility always. Check crane approaches. Check clearances between columns, and between floors for equipment. Check if there is room to put your hand inside crevices and corners for bolt tightening or if there is access for welding. Check if there are interferences from stiffeners or other plates that make it impossible to place a structural element in position. A ship such items lose and weld them later. Everything looks great on the drawing. 3 -D modeling programs these days can check physical interference during fabrication by means of built-in ‘clash checks’ in the software, but they can’t check clashes with equipment and piping and hand access for bolting and welding, etc. at the site.
5)In bolted and welded connections, repeat, as far as possible, the hole diameters and weld sizes. Try to keep the variations in bolt diameters and bolt material specifications and weld sizes to the minimum to avoid errors at the site.
6)Pay attention to the sequence! In design, you may begin from the top, but at the site, everything starts from the bottom. Finalize drawings for the structures at the lower levels first.
This list covers is not usually mentioned in books and manuals and codes and specifications.