This worker is tieing the bridge deck slab for the Route 56 Expressway in Johnstown Pennsylvania. The steel bars run in both directions on both the top and the bottom, at 6 inches on centers. The steel was tied at every overlap, which therefore required 8 rebar ties per square foot of bridge deck.
 

This photo shows the crew of reinforcing ironworkers on that project, and the vast expanse of steel they are tying.