I hope someone out there can help me out. I have a pergola type patio that I am putting a 3/12 roof over. Right now it is supported by 6 x 6 post that are 13 feet apart. There are 2 2x10's running between them which are bolted to the sides of each post and then supported from underneath by a 2 x4 which is attached to the side of the post. There are 3 of these structures spaced 8' feet apart. There are 2x8 joists spaced 24" running across the the entire length. Will these double 2x10s be able to support the trusses and roof (simple 2x4 trusses 24"oc with a 3/12 decked roof with metal cover. I estimate the entire roof will weigh around 2000 lbs max.