Denis Mulligan’s office, in the Golden Gate Bridge’s Toll Plaza, has an enviable view: He can see the wind blowing across the bridge and the traffic roaring through the toll gates.
By Wes Starratt, PE
Published: November, 2010
First, the San Francisco native discussed his professional career: “In 1982, I graduated from UC Berkeley with a degree in civil engineering. I started my career as a junior engineer with Caltrans, and left Caltrans nineteen years later in February 2001 as manager of the Toll Bridge Program, responsible for the seismic retrofitting of all of the toll bridges on the Bay and the construction of four new bridges, plus the new West Span of the Bay Bridge.” He added modestly, “I had a very talented staff, but was very busy.”
Mulligan continued: “In March 2001, I came to work at the Golden Gate Bridge, Highway and Transportation District as chief engineer, which obviously included the Golden Gate Bridge itself, as well as the bus and ferry operations. I held that position until several months ago when the Board of Directors made me general manager and chief executive officer.”
Mulligan described his most challenging project at Golden Gate Transit: “It was certainly the seismic retrofit of the south end of the bridge, which comprised a series of very challenging and exciting engineering projects, including the south viaduct, the south anchorage house, the pylons, and the arch over Fort Point. That project won the prestigious ‘Outstanding Project and Leadership Award’ from the American Society of Civil Engineers in 2007.”
Mulligan also pointed to several challenging current projects that include replacing the movable median barrier on the bridge, and noted that “the bridge was constructed with six narrow traffic lanes, with the middle four lanes only 10 feet wide and the two outside lanes 11 feet wide. Northbound and southbound traffic continues to be separated by round plastic pylons that are inserted into the bridge pavement by hand from a specially-designed vehicle to provide four lanes of southbound commuter traffic on weekday mornings and four lanes of northbound traffic on weekday afternoons.” Mulligan said, “This is a slow and cumbersome process that obviously needs to be upgraded.”
Mulligan said that his organization has been working for some time with manufacturers of movable barrier systems, and is currently in the environmental phase of installing such a system on the bridge. The system will provide one-meter lengths of a movable barrier connected by heavy steel pins to form a continuous barrier that would be moved by a specially-designed barrier transfer machine at speeds up to 10 miles per hour, allowing the roadway to be quickly reconfigured to meet changing traffic needs.
Mulligan also discussed the sensitive topic of the bridge’s suicide barrier: “On average, we stop one person per week from committing suicide on the bridge. Earlier this year, we completed the environmental process for the project, and the board has selected an integrated stainless steel wire-rope barrier that will be 20 feet below the roadway and cantilevered out 20 feet.”
But the major ongoing engineering project for the bridge continues to be the $661 million seismic retrofit project, now in its third phase, with additional security measures added to aid in protecting against man-made threats. Current work includes the Marin anchorage housing and the north pylon, scheduled for completion in the Fall of 2012. The final phase will be retrofitting the main suspension span of the bridge, and the two main towers, making the bridge even more resistant to the forces of a major earthquake than when it was built. Going into such a project, the talents of an experienced civil engineer at the helm of the Golden Gate Bridge, Highway and Transportation District will undoubtedly prove essential.
The Ferries and Buses
Mulligan discussed the District’s other operations: “The District is in the unique position of not only owning and operating the bridge itself, but also the transit services that operate between San Francisco and Marin County.” He contunued, “We have been in the ferry business for 40 years; so, our facilities are reaching that age when they need major rehabilitation. But Jim Swindler, the manager of our Ferry Division, has been very creative in getting two used boats from Washington State Ferries. They were relatively new ferries that were just sitting at the dock when he purchased them for only $2 million each. We will do a complete overhaul of the ferries, with new engines, new interiors, and basically have two almost-new boats for the price of one new boat.”
Mulligan added, “If you want to get from Marin County to San Francisco, you must use our bridge, our boats, or our buses. The two transit businesses operate at a loss, but we don’t have any taxing authority to fund them; so, we must use our tolls to subsidize our transit operations, spending about half of our tolls on running the buses and the ferries.”
At the conclusion of the interview, Mulligan said: “Yes, the Golden Gate Bridge, Highway and Transportation District is a very interesting and unique organization, and I am proud to be a part of it. In the final analysis, our mission must be to protect the bridge and ensure that it is available to be enjoyed by future generations.”
