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Interview with Adrian Cortez, Gilman Drive Bridge Resident Engineer/Construction Engineer Manager

img_Gilman_before_after_v1Q: How long have you worked for Caltrans? What led you to pursue a career in construction management? What projects do you currently oversee?

AC: Just last month, I hit my 20-year anniversary as a bridge engineer with Caltrans in the Structure Construction division. What originally led me to pursue a career in construction as a resident engineer is the opportunity to make a positive impact with projects that affect the traveling public. I really enjoy my work, and I like that as engineers for the state, we are public servants. 

As a resident engineer, we are responsible for delivering the project on schedule, ideally even when unexpected delays or construction issues may arise. I find project management extremely rewarding – when I meet the budget, help keep the contractor on schedule, and collaborate with colleagues and the contractor to problem solve, it gives me a sense of fulfillment. It’s also really important that we, as taxpayers, are getting an excellent product that will last for generations.

We are about to wrap up a major 25-month bridge project that I’ve been a lead on: the Gilman Drive Bridge. So at present, I’m beginning a new project as the structure representative for a section of the light rail from La Jolla Colony Drive to Nobel Drive that has shotcrete walls, a cut-and-cover tunnel, and two small bridges. 

Q: Are bridge projects a specialization for you? What made you interested in bridge construction?

AC: Bridge building in particular is my specialization and a true passion of mine, and yet I’ve overseen other non-bridge civil projects for the state. My first intership as a student assistant was on a bridge project. Prior to that intership, I had only considered working in roadway or building design. I find it interesting that bridges, in themselves, almost always solve some real problem. For example, they might connect people more readily with each other or make daily life simpler or more efficient. 

Q: The new Gilman Drive Bridge will unite existing UC San Diego campus roads on both sides of the I-5 Freeway. It has been a visible construction project over the I-5 for the last couple years. In your words, why is the bridge being built, and what benefit does it bring to the community?

AC: The new Gilman Bridge creates an additional travel lifeline for the campus. It will unite the west and east campuses by creating a thoroughfare over the I-5 Freeway, and it will complete UC San Diego’s internal loop. It will also improve mobility for the community and for students, faculty and staff, increasing the options for pedestrian traffic, promoting walking and cycling, and reducing roadway traffic, which in turn will help to increase personal and environmental health. 

Q: What have been some of the most challenging aspects about building the bridge?

AC: Several of the challenges with building this bridge were immediately evident in that it is an arch bridge with intricate geometry which gives it its elegant design. For example, every vertical surface is rotating ever so slightly and changing height along the arch legs and parabolic superstructure slopes. This added to the intricacy which required a special design for the falsework, the temporary wooden structure used to support the bridge during construction. Extra time and effort had to be taken with these temporary forms and supports during construction to ensure that the final lines and surfaces turned out per plan. 

One of the most common challenges in any bridge construction over a freeway is building it with the least amount of impact to the traveling public and community. One way we set out to accomplish this was by closing the freeway and constructing the bridge at night when traffic was least active. Another way we reduced community impacts was through constant coordination between adjacent projects, including our involvement with the Shift program, to share closures or avoid competition with other closures, which helps reduce the number of overall closures, saving time and money. 

Q: Can you share with us any fun facts about the bridge?

AC: The Gilman Bridge is a 405-foot concrete arch bridge with a multi-cell, post-tensioned box section. It is 62 feet wide with 10-foot and 6-foot sidewalks. The arch itself spans 317 feet and measures 37 feet from the roadway to the top midpoint of the arch. The bridge is supported on either side of the freeway by a spread footing supported by 48 micropiles that are 10 inches in diameter placed on an incline of 48 degrees from horizontal into the adjacent slopes, transferring the load down from the arch legs. 

The bridge superstructure, including the arch legs, consists of over 9 million pounds of concrete, and includes 25 miles of high-strength steel strands running through the bridge.  These strands were pulled with enough force to create over 14 million pounds of compression in the bridge, a process known as prestressing.  

Another interesting fact about the bridge is that it was built by way of nine separate concrete pouring sequences due to the various geometries. Typical, less complex box girder bridges only require two or three concrete pours.  

Q: What has been the most rewarding or your favorite part of your job managing this project?

AC: It was truly an honor to be a part of the professionalism, collaboration, commitment and pride with which all the various teams worked. From the designer, to iron workers, carpenters and laborers, to the Mid-Coast Trolley Contractor’s engineers and UC San Diego’s staff. I think we all had an understanding of how special this bridge is, and we wanted it to turn out great.

Q:The bridge is slated to be complete the first quarter of 2019. To you, what is the most exciting aspect about its opening?

AC: The most exciting aspect about its opening for me is how it will immediately serve the public and add to the beauty of our city. When I drive under similar arch bridges that span across the I-805 and the 15 Freeway, it feelslike a true gateway into San Diego. I’m excited for the Gilman Bridge to be added to the list of signature arch bridges here in our beautiful city. 

Q: Is there anything else you would like to share about your role managing this project and/or about the project itself?

AC: Including planning, the project has been in the works for over 10 years and has been made possible because of the collaboration between UC San Diego, SANDAG and Caltrans.