Inside Seven
Current Issue: September 2014
Safely hoisting the drilling equipment over the bridge to the river floor was a challenge.

by  Maria Raptis
Issue Date: 01/2007

A small project in northeast Los Angeles County is now on the fast track to rehabilitation.

A portion of State Route 39, approximately two miles south of the bridge, has been closed to traffic since the winter of 2004 due to storm damage. 


What started out as a small project in 1999 has advanced to the fast track towards rehabilitation for this year.  In just the Design phase, it has posed equipment challenges, conquered logistical feats in coordinating multi-departmental teamwork and has confronted the dangers of snakes even as it remains neatly in Design.   


"This project demonstrates the type of creative thinking and never give up culture the District has in delivering our projects," said Bill Reagan, District 7 Deputy Director of Design, "and this highlights the teamwork involved and required from all on the Project Development Team to be successful in the design process."


District 7 has plans to retrofit the existing pier at the North Fork San Gabriel River Bridge to address progressive scouring at the bridge structure on State Route 39, located in a rural area within the Angeles National Forest, 15 miles north of Azusa. 


What extreme adventures and challenges can a Design team face, you say? 


“This has been quite an adventure,” says Oji Kalu, Senior Transportation Engineer of the District 7 Group B Design, grinning as if he and his team were Harrison Ford in the movie “Raiders of the Lost Ark,” meeting every challenge head-on and unscathed.  He and the team members can now laugh as they recall the snakes coiled under rocks and equipment, unlike the fright they experienced at the riverbed drilling site. 


“Locating, scheduling and positioning the right equipment with all the right teams in place at the same time was very challenging, but exciting once it all happened,” Kalu said. 


Last October, the Design team literally worked around the clock for seven days on the bridge just to find the proper equipment that would not damage the bridge, but strong enough to lift and hoist the drilling equipment over the rails and down to the riverbed for the drilling operation.  The instant that the right crane and rig were found, the weights and leveling were calculated, plans were set and phone calls were made.  The equipment and drilling team came down from Sacramento, Environmental Planning shuffled schedules to be on-site and the permits were in place.  The only thing that went wrong was the lack of cell phone reception in that area; the satellite phones were the way to go!


The drilling equipment was laid down on three levels of protective plastic sheets to minimize pollutants and contamination of any sort into the river and the environment.  Twenty soil samples were taken at five-foot intervals as the drilling continued 100 feet down.


“Over the past 30 to 40 years, the river’s water pressure has eroded away the dirt surrounding the foundation. The San Gabriel River flows directly into the single pier which has degraded over time and has now become an issue because the existing bridge footing and foundation have been exposed,” said John K. Lee, Project Manager.


The one column and single pier bridge will be replaced with two columns and two piers.  Piles, which are posts made of re-bar, will hit the bedrock at 30 feet below, but Caltrans plans to continue drilling into 60 feet of bedrock to ensure a sturdy foundation in this mountain terrain.  


“When it is open," says Lee, “recreational traffic is the main generator but the road is a lifeline to those who reside adjacent to the forest. Caltrans is working to secure the strength of the columns and footing through all kinds of weather and natural events and greatly improving its safety and stability for many years to come.”


A local resident, Miss Bambi, gave the crew a surprise. Just ask Andy Liao.  Venom serum was on hand, but not needed.  On-site Environmental Planning staff ensured the snakes protection.  Andy is okay, too. San Gabriel River North Fork Bridge on Highway 39. Two new columns and piers will replace the existing single column. (l to r) Dan Tran, Oji Kalu, Andy Liao of District 7 Design Services and Tom Harrington, Office Chief of HQ Drillling Services.  The rig was balanced and leveled to perfection, using outriggers to avoid tipping over and damaging the bridge.