From your comment, I have some questions as below.
1. Item 1: For the clear height at GL 1, àyou would like to have min 4m. so should we fixed the roof slope and push the whole roof up or just change the slope of the roof by extend the column at GL1 to make CH = 4 m. Please advise
2. Item 2: For the grating, Between TG deck and platform, àhow much is Live load on the grating?
3. Item 3: Extended opening sizeàIs this for the grating? Are there the grating around the TG deck (on the short side either)?