I was a USMC helicopter pilot in my previous life, and would like to reinforce Ishvaaag's comments. Regardless of what James Bond can do, we never engaged the rotors (or even started the engine) of a helicopter inside a hanger or building. Visualizing such a scenario is enough to give me nightmares. Depending on the size of helicopter and it's type of landing gear, it will either be hand pushed or tractored into and out of the hanger. It will probably be at least one rotor diameter clear of the hanger before the rotors are engaged. The client will need to provide you with his expected operating procedures since they may profoundly impact your structure.
There are too many types and sizes of helicopters to be able to usefully estimate the weight. You need to ask your client which models he has under consideration, and then contact those vendors yourself. They can supply you with wheel (or skid) loadings, rotor diameters, height, etc. You'll need wheel loadings and spacing for floor slab design (and the roof deck if he intends to use the roof as a landing pad).
The rotor wash will not likely affect your main frame design, since the forces dissipate rapidly with distance, but you will want to pay special attention to overhangs, cladding and components that might be subject to those forces, since they will be multidirectional. Again, the manufacturer should be able to provide some guidance if you don't find it in Ishvaaag's reference.
Good luck.