This was my main duty for the summer I worked on the S.R. 414 thru-truss in Jersey Mills, over Pine Creek, in Lycoming County, built circa 1934. I conducted a BAR 7 analysis of this bridge to determine the load ratings in various situations. The first task was determining the current condition of the bridge utilizing inspection reports, by taking consideration of section loss. This would aid in coming up with various solutions to rehabilitate the truss. A common trend with these old trusses is that the truss rates to today's standards, because the loads transfer up truss the same with both new and old generation vehicles.
Trucks are also generally much heavier today.
To help with the heavier trucks a common practice was to remove the heavy concrete decks and install lightweight steel grate decking to decrease the dead loading, which in turn increases the allowed live loading. A downfall of the open steel deck is that is leaves the floor system vulnerable to road salts, which corrode and weaken the section properties, due to section loss from rust. Several proposed solutions were tested using bar7 to see, which design would give the proper readings. One desire was to have a lightweight closed deck. 5-inch concrete partially filled steel grated decking, with steel guide rails.