W.C. Maloney (WCM) was retained by Granite Construction as part of Caltrans’ Cosumnes River Bridge Replacement Project on Highway 99 in Elk Grove, CA.
The original Cosumnes River Bridge was built in the 1950s and had seen considerable wear over time, with structural and seismic deficiencies, and critical scour conditions. The project included the removal of four river bridges and two railroad bridges and the construction of three replacement bridges. It also included the construction of two miles of associated roadway improvements to carry State Route (SR) 99 traffic over the critical north/south Union Pacific Railroad (UPRR) track and Cosumnes River floodplain.
WCM’s scope included the demolition and disposal of the four traffic bridges and two railroad bridges, while protecting the railroad tracks. One of these was an actual railroad bridge and the other was the original Highway 99 bridge that spanned the tracks. Timing and coordination with the general contractor was critical for all the bridges, including the scheduling of trucks to transport demolition debris to the disposal sites.
Working days were limited by closure restrictions, and WCM was allotted a small 14-hour railroad outage on a Sunday to remove the final two bridges. WCM faced a seven-day timeline to demo the four 700 foot long, 22,400 square foot bridges on Highway 99. This was especially difficult as the bridges crossed over waterways, requiring WCM to keep debris from falling in and contaminating the water and possibly endangering the wildlife in the area.
The most difficult portion of the bridge demolition project — requiring impeccable timing — was the work done on the active railroad and railroad overcrossing bridges. WCM had six weeks of prep removing the deck of the bridges with sometimes only a 45-minute work window between trains. WCM then had a 14-hour window on a single Sunday to remove two railroad bridges and clear the way for the general contractor to reconnect the railroad tracks before the trains were scheduled to start running through again.
WCM took special care to time the removal of the bridge over the railroad, the northbound lanes of Highway 99, and the rail bridge that went over Highway 99’s southbound lanes with the railroad schedule and 14-hour shutdown window. In order to leave access for the new railroad tracks to be built, and not damage or block the tracks when the trains began to run again, each girder of the overhead railroad bridge was picked up with a crane and removed from the area. The same precision and care was used when demoing the Highway 99 overcrossing. WCM finished ahead of schedule by several hours, seamlessly turning the work site over to the general contractor to begin their work on the tracks.
To further assist, WCM stepped up to help move new railroad track pieces when it was realized there were electrical lines between where they were staged and the work area. A crane could not be used to move them so WCM took the initiative with two excavators working in tandem to move the railroad materials where they were needed.
WCM beat the project schedule by removing the four traffic bridges in four days instead of the seven days allotted. The demolition work had no safety incidents, and helped the general contractor accelerate the remaining timeline for completion, ultimately finishing the Cosumnes River Bridge Replacement Project two years ahead of schedule. Both the general contractor and the railroad representatives were extremely pleased.