Saving materials requires action at both large and small scales. Every little helps, as they say. Here is one interesting variation to a standard detail that can help reduce the steel used on a project.
While it is best to have a floor-slab above steel support beams, there can be a desire to have the top of the concrete deck flush with the top of the steel. Using metal deck formwork, a very standard detail might be as below. The dimension of the steel angle is set by the need to install the steel sheets.
The lightest angle than can be used weighs 17kg/m. If the detail receives little care and attention, then an angle weighing 26kg/m might be suggested.
The alternative detail below, which is simpler to weld in place, uses a "T" section that weighs no more than 11.5kg/m. The lighter section saves carbon and is easier to handle, so this is an easy win.