This is my first post - found the forum after reading about its presence in an article in TOH mag. Happy to be here!
Anyway, we've moved into a 'new' old house (foundations laid in the 1680s), and are planning on putting a pergola over our (cement) porch, which sits just off the kitchen at the back of the house. The kitchen and porch are above grade, and the porch itself is actually the roof of a workshop which is attached to the basement level (walkout) of the house. The floor of the porch is about 8" thick, although I am unsure how it was poured, if it's reinforced, etc.
To support the pergola (~5 m x 3 m) we are going to use a ledger board attached to the exterior (stone) wall of the house. I am not worried about length of bolts for attaching the ledger as the walls are about 2.5 feet thick so I'll have PLENTY of support.
However for supporting the other side of the pergola, we are going to put down 6x6 posts anchored into these sort of 'top hat' footings that will be bolted into the cement floor (http://www.clicfixation.com/f-serie-pied-de-poteau-de-jardin-a-boulonner.html) with anchor bolts. However! The bolts themselves, due to the short depth of the floor slab, will not be able to be more than 4" in length.
My question, therefore, is: will 4x4" anchor bolts per post (3 posts total, one every 150cm) be enough to keep wind shear from ripping the posts and the bolts out of the floor slab?
Here's a picture of the side of the house for reference: https://pbs.twimg.com/media/BMdY6JGCIAADJ4S.jpg:large