How often should I bolt doubled/sistered joists?

[garyo]

I have floor joists over a 4.03 metre span that will be C16 75x195mm at 600mm centres. I want to double two up to support a timber stud wall and door frame above.

Are there tables that tell me how often I should bolt them together?

Thanks

Gary

 

[^woody^]

Four bolts, one 100mm in from each bearing and then space the other two out equally

Or skew nail (100mm nail) from each side every 600mm