Orange County Branch Newsletter

March / April 2017

ASCE OC Programs

State College Grade Separation Technical Tour

By Nick Polichetti, P.E.


The City of Fullerton and Orange County Transportation Authority (OCTA) are currently constructing the grade separation between State College Blvd and the Burlington North Santa Fe (BNSF) tracks. Construction began in mid 2014 and is expected to be completed early 2018. Additional information can be found here.

Project Benefits:

  • Greater Driver/Pedestrian Safety
  • Shorter Emergency Response Times
  • Elimination of Delays
  • Easier Business Access
  • Enhanced Economic Vitality
  • Improved Air/Noise Conditions
  • Better Quality of Life

Tour Guide:

Mark Verrengia (RE) of Hill International led the job walk held on March 10th, 2017. He has over 20 years of experience in surveying, design, construction and did an excellent job explaining the project to the team.  Mark provided technical knowledge and insight while keeping it light adding in some humor. He addressed specific challenges encountered and explained the solutions developed in order to keep the project on schedule.

Mark Verrengia, Resident Engineer giving an introduction and safety check to the group

State College Blvd Grade Separation Project under construction

Proposed Design Rendition

Project Tour:

Fifteen people attended the grade separation tour.  The crowd was a mixture of professionals, students, and a local citizen.  After a brief project overview and lunch, we donned our personal protective equipment and headed out into the field to witness the construction activities. Mark, our tour guide, provided several examples of project challenges that a project of this magnitude can face such as how a simple power line will be impacted several times throughout the construction duration and will require the cooperation of several stakeholders.  

This project utilizes a “top down construction” method due to right of way constraints.  Top down construction allows for the retaining walls and the bridge to be drilled and poured at grade only to be revealed once excavation begins.  Mark informed us that this method can be challenging for residents as it does not allow for progress to be readily available/seen. It wasn’t until recently when the excavation began that the structures were exposed and residents were able to witness progress.

Above is a good example of the retaining walls exposed during excavation

Mark also discussed the challenges of constructing a grade separation project in an urban environment.  Residents and utility companies both pose unique challenges and the goal is to keep everyone happy.

Above is a good idea of what the finished retaining walls are going to look like

The picture above displays the bridge not being fully dug out. The structure’s bent has a very impressive 8' diameter shafts 120' down and smaller shafts for the columns at grade.

Some minor earthwork performed by contractors is shown above. Mark told us that the mound the excavator is on extended all the way to the camera the day before. Major dirt hauls off the day before

An in progress picture of the pump station is shown above

I would like to thank ASCE Orange County and Mark for setting up such a great tour.


Attendee Impressions:


Juliet Su (The Toll Roads) – “What a fantastic opportunity to go out to the field and see the results of so many hours of design. The RE, Mark, and the office engineer, Jeremy, had great insights to share regarding how sometimes design elements can seem to work on paper, but don't always work in reality; how having the right attitude when working with the community (businesses and residents) can go a long way in getting the project to completion; and how, as the construction manager, your job is to work both with the Contractor and engineer of record to solve difficult challenges encountered during construction.”


Ken Steele (AECOM) Grade separations are complex projects that pack many challenges in a relatively small area.  Mark did a good job sharing the challenges and successes of the State College Grade Separation project.”

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