Levin & Associates Architects
Oakwood School Bridge over Magnolia Boulevard goes up overnight
Timelaspe video of the Oakwood Bridge installation shows teamwork and precise coordination
This year, MATT Construction delivered the Oakwood School Bridge by constructing the entire bridge offsite, driving it to the school, and setting it into place in one piece.
Stage one: transporting the bridge from Santa Fe Springs to North Hollywood
Oakwood School’s new footbridge had a long journey to get to its final home in North Hollywood. The bridge was pre-fabricated at Plas-Tal in Santa Fe Springs. When it was ready to be transported, it was both a wide load and a high load. As the bridge plus the trailer was over 14 feet, the route to Oakwood could not involve going under any bridges, and sign clearance along the freeway was a concern.
To find the optimal route, Plas-Tal worked with consultants who drove the proposed routes with a pole attached to their vehicle at the bridge height and tested clearances. Once the route was laid out, the plan had to go to the DOT in San Francisco for approval. “There are only a few people in California who can give this approval,” says Ankur Verma, Senior Project Manager for the bridge.
When the plan was approved, and the bridge was ready, the 114-foot-long bridge began its overnight journey to the Valley. The bridge rode on a two-trolley system. The back trolley had its own wheel system, controlled via power generator, that the crew switched on to slide the back end left or right to make tight turns and maneuver onto ramps.
Five CHP cars served as the bridge’s escort. “CHP was great,” relates Verma. “Our escort blocked both the right side, and sometimes the wrong side of the freeway. This allowed us to avoid low freeway signs by traveling on the other side of the freeway when necessary.” The team also had people raising power lines so the bridge could pass under safely.
Stage two: installing the bridge overnight
Upon arrival, MATT Construction staged the bridge on a nearby side street to add the roof, railings, lights and as much of the outfitting as possible. The team then rolled the bridge to the center of Magnolia Boulevard.
On Magnolia, a 350-ton crane was waiting to place the bridge on the waiting columns in one pick.
MATT built the bridge this way because it allowed the team to install the bridge with only one, eight-hour, overnight street closure. The alternative would have been a permanent lane closure on an important highway 170 access point for three to four months. The team would have had to close down the middle lane and build a support tower. Instead, they saved field time and labor and kept Magnolia Boulevard open throughout construction.
In addition, pre-fabricating the bridge meant that they did not have to do the critical weld in the middle of the bridge in the field, 16 feet in the air over traffic. It was easier and less costly to do the weld in the shop. This also allowed for it to be tested and gave greater quality assurance.
The Oakwood School Bridge now provides safe passage for students over the busy thoroughfare that bisects their campus.