Wringing out bridge cost- deck installation
Bill Tindall, E.Tn.
The situation. Putting a deck on a brige some feet off the ground, enough feet that OSHA has say in safety.
Originally the thought was to install ties and runners, then posts and enough rail to be OSHA compliant for rail, then deck and finally remaining rail. Hand carrying parts across up to 273 feet of bridge while walking on just runners with air beneath was slow. On the smaller bridges another option became possible. Install safety cable across the bridge on each side to provide a harness attachment point. Install ties and runners. Install deck. Now with a deck in place the posts and hardware and rail lumber can be carted to the point of installation. There is a secure work surface (the deck) to work off from. Things went times faster with this approach.
In the past the crew who had never installed hardwood floor proceeded as follows. A few feet of deck boards were laid down with #16 nails added as spacer between the boards. Then cleats were screwed to the runners. Wedges were driven in by the cleats to wedge the deck boards together. Chalk the screw lines and screw this section in place. Pull up spacer nails. Repeat. Slooooow!
Inspired by acres of hardwood floor installation we now lay deck as follows:
The most recent pack of deck boards ranged from 8'1/8" to 8'3/4". Clearly they must be cut to a uniform length. We have been installing both curbs and then cutting deck boards individually to fit between. There is a better way we will implement on future bridges (some suggestions are slow to take 
)
Ties provide a fulcrum. Now we lay deck boards until we get near a tie. Spacers consist of 1 x 1 x 1/8" Masonite squares I make by the hundreds, which we leave in place. A pipe is used to lever the boards together. The last board installed is screwed in place. Repeat. About every 12' we chalk the screw lines and screw.
I wish I had a solution to pictures rotating unexpectedly and needing to rotate 180 degrees right to get them to post correctly.
The massive cost savings of posts and rail installation will be covered next.
