Arcadis recently marked the grand opening of the new L.A. Regional Connector, having worked with key client Los Angeles County Metropolitan Transportation Authority (L.A. Metro) to provide construction management support services to help drive development since 2014. 

The new 1.9-mile underground light-rail extension will now support riders with a one-seat journey from downtown L.A. to the communities of Azusa, Pasadena, East Los Angeles, Santa Monica, and Long Beach.  

“To be part of such a historic project is truly exciting,” said Jaydeep Pendse, Regional Connector project manager at Arcadis. “The project literally connected the City’s East and West Light Rail Transit infrastructures to function as one integrated system. Passengers will be able to travel between Azusa and Long Beach, and between East Los Angeles and Santa Monica, without transferring lines. It will improve connections, bringing together the current Metro L (Gold), A (Blue), E (Expo), B (Red), and D (Purple) Lines at the 7th Street/Metro Center Station, and increase opportunities for jobs, education, and essential services.”

Overcoming Early Challenges of Regional Connector

The Regional Connector will provide residents with much-needed access to public transit options and create equitable mobility to some of L.A.’s key business, educational, and cultural hubs, but the process leading to the grand reveal wasn’t always smooth.

“Any large infrastructure project in a dense urban area is likely to face challenges and this project was no different,” Pendse said. “Specific to this project, unknown utility relocations significantly impacted our construction schedule. The entire project team worked tirelessly as a collaborative team to overcome this challenge by re-sequencing construction efforts to offset the utility delays.” 

For the efforts to be successful, Arcadis worked closely with the L.A. City family and Utility providers to ensure timely decisions and approvals avoiding further delays. 

The project team continued to engage the community through all phases of construction activities and the majority of the community Stakeholders were supportive of the project. 

“The project team went above and beyond to ensure compliance with the requirements of the contract which resulted in a favorable judgment for L.A. Metro during the project,” Pendse said.

Construction History, Sequential Excavation Mining

Construction on the Regional Connector began in 2014, with Arcadis drawing on more than 40 years of global experience to provide Construction Management Support Services to drive development. 

One of the key parts of the project was the strategic use of sequential excavation method mining (SEM), which is well-suited for tunneling in areas prone to earthquakes, such as Los Angeles, and doesn’t disturb existing building foundations and utilities. 

“Sequential Excavation Mining method of mining was utilized to construct the crossover cavern near the Historic Broadway station,” Pendse said. “The SEM cavern was approximately 300 feet long and was constructed after the tunnels were mined. This critical operation required that excavation be performed in a designed sequence, utilizing specialized equipment while the operation was carefully monitored by extensive instrumentation to ensure that there was minimal ground surface movement.”

The actual field data collected from the cavern excavation was almost identical to the theoretical values that were developed during the design process, according to Pendse.

The SEM mining procedures allowed for the construction of the station box to be concurrent with the crossover cavern construction. Only the portion adjacent to the crossover cavern was left to be completed, resulting in time savings to the construction schedule for the Broadway Station Complex.

Digital solutions also played an important role, including the use of a digital traffic model during planning to help understand anticipated traffic patterns and help mitigate disruption during construction.

Arcadis made adjustments to implement the digital traffic model.

“Digital model was developed during the early phase of the project to visualize how the construction will impact the actual traffic flow along Flower Street, a key artery that feeds Los Angeles downtown,”  Pendse said. “Further adjustments were made to the traffic control plans that reduced traffic impacts due to construction activities within the area.”

In addition, detailed phasing plans were also developed to ensure access to downtown parking structures. 

Pendse said Arcadis is looking forward to working with L.A. Metro in the future.

“It was an honor to support Metro during the construction of the Regional Connector project,” he said. “The experience gained by our team over the past several years is being applied to other transit projects throughout LA county and California. Arcadis remains committed to partnering with Metro, to deliver responsible transportation solutions which improve the quality of life for Angelenos.”