When I worked in concrete, we used 6'x6' hardwood ties for cribbing. I used to haul those off the the trailers, drag them under a building, stack them as we raised the building, and then do the same in reverse once the new foundation was in place. Our timbers ranged from 2' to 12'.
Like Lorddiesel, the bulging disc in my back won't ever let me forget those good times. To think I made just over minimum wage as a "laborer" for that hell...