Shared from California Builder and Engineer Magazine. Read the entire article here.
Traffic is the bane of every driver. Yet, everyone knows that they will periodically run into it. Californians, and Los Angeles area drivers, in particular, are familiar with busy highways and traffic congestion. The Orange County Transportation Authority (OCTA), in cooperation with The California Department of Transportation (Caltrans), is working on a massive infrastructure project – the I-405 improvement project – geared towards easing congestion for commuters in the Los Angeles area.
With an average daily traffic count of 370,000 vehicles a day, the I-405 in northwest Orange County at the border with Los Angeles County is one of the most heavily traveled highways in the nation. Both the regular lanes and carpool lanes are congested during rush hour and on the weekends and the traffic is expected to increase by 30 percent by 2040.
“The I-405 Improvement Project is critical to accommodate the expected growth in employment, population, and housing throughout the region,” explains Darrell E. Johnson, CEO of OCTA.
The project will cover a 16-mile stretch of highway which passes through nine cities with a population of about 1.1 million.
One regular lane in each direction of I-405 is being added along with a second lane in each direction that will combine with the existing carpool lanes to create the 405 Express Lanes.
In addition to the added lanes, the project involves reconstructing more than 18 bridges that span the freeway and improving interchanges and local streets. Improvements are being made to freeway entrances and exits. Finally, retaining walls and sound walls will be constructed at certain points along the interstate.
A Balancing Act
“For a project of this magnitude, with many stakeholders involved, it can be challenging to balance everyone's needs while maintaining good progress on the project,” says Johnson. To overcome this challenge, the project team is working with neighboring cities, business owners, and residents to address their needs prior to construction in order to not impact the construction schedule itself.
There's also coordination with multiple public and private partners. Johnson elaborates, “This project involves close coordination with state and local agencies, such as Caltrans, the County of Orange and the South Coast Air Quality Management District, as well as the neighboring cities. It is estimated that more than 200 sub-contractors and 300 material suppliers will have worked on the job over the life of the project, with 130 currently active subcontractors and consultants.”
Over the course of construction, the team has come across several unexpected issues along the site. Contaminated soil, groundwater, and other differing site conditions have arisen. To deal with these issues and mitigate potential delays, OCTA has worked closely with Caltrans, the cities, OC 405 Partners, and others to quickly gain consent to revise construction plans.
OC 405 Partners, a joint venture between OHL USA and Astaldi Construction, USA, is the contractor for the project. OCTA also relies on the contractor to find ways to make up time in other areas of the project.
Johnson gives an example of a strategy the team has put into place to keep the project on schedule. Some of the bridges that are being reconstructed as part of the I-405 Improvement Project are being demolished and reconstructed one half at a time, while others are being fully demolished and rebuilt in one stage. “To help save time on the overall project schedule, we worked with our contractor, Caltrans and the cities to convert four bridges that were originally planned to be rebuilt in two stages, to one stage,” Johnson says.
Utility relocation has also proven to be a challenge. During the planning phase, it was determined that certain utilities would not need to be relocated. However, as work on the project progressed, it became apparent that some of them would need to be moved. To maintain the schedule, OCTA has partnered with various utility owners to expeditiously relocate these utilities in time for work to continue.
Enabling a continuing traffic flow both on the interstate and local streets during construction has also been a concern. No surprise since the project includes replacing 18 bridges, widening four bridges, constructing four new bridges, reconstructing approximately 50 on- and off-ramps, widening the freeway itself, and constructing a significant amount of new retaining and sound walls. Therefore, OCTA developed a transportation management plan to minimize the impacts to drivers and improve safety and regularly updates it as needed.
Another challenge has been getting the word out about construction to the thousands of diverse residents and businesses near I-405. The team has used the traditional communication methods, including e-blasts, the project website, social media, and distributing fliers to homes and businesses. They also use geofencing campaigns to target residents and commuters that live and drive through specific areas of the I-405 Improvement Project.
“This method of advertising allows OCTA to select a 1-mile radius near major construction work,” Johnson says. “If someone enters that zone with their smartphone, laptop or tablet, they may begin seeing I-405 Improvement Project construction alerts on the apps they use.”
The total cost of the I-405 Improvement Project, which was awarded as a design-build contract, is expected to be $2.1 billion. Financing for the project is through a combination of local, state and federal funds, with the majority of funding coming from Measure M, Orange County's voter-approved half-cent sales tax for transportation improvements. Other funding sources include a federal Transportation Infrastructure Finance and Innovation Act (TIFIA) loan, State Highway Operation and Protection Program, Trade Corridor Improvement Fund, and Surface Transportation Block Grant.