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Three T.Y. Lin International Projects Win 2021 Project of the Year Awards from ASCE Los Angeles Section

Three T.Y. Lin International Projects Win 2021 Project of the Year Awards from ASCE Los Angeles Section

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2021 ASCE_Atwater-Oso-I-5

T.Y. Lin International (TYLI), a globally recognized full-service infrastructure consulting firm, announces that three TYLI projects have won 2021 Project of the Year Awards from the American Society of Civil Engineers (ASCE) Los Angeles Section in California. First, the North Atwater Non-Motorized Multimodal Bridge in Los Angeles was honored as 2021 Bridge Project of the Year. Next, the I-5 High-Occupancy Vehicle (HOV) Improvement Project in Santa Ana won as 2021 Construction Project of the Year. Finally, the Oso Parkway Bridge at State Route 241 in Orange County was named 2021 Roadway & Highway Project of the Year.

For the North Atwater Bridge, TYLI provided construction engineering and significant design support throughout construction under an on-call contract with the City of Los Angeles Department of Public Works, Bureau of Engineering. The new 325-foot‑long bridge accommodates pedestrians, cyclists, and equestrians and is possibly the first cable-stayed equestrian bridge in the world.

TYLI served as Prime Design Consultant for the final design phase of the I-5 HOV Improvement Project, working closely with the Orange County Transportation Authority (OCTA), California Department of Transportation (Caltrans) District 12, and the City of Santa Ana. The project provides a significant benefit to the traveling public by repurposing the existing width of the I-5 freeway and adding a second HOV lane in each direction between SR 55 and SR 57.

For the Oso Parkway Bridge Project, TYLI provided final design services to the project owner, Transportation Corridor Agencies, and worked closely with Caltrans and the County of Orange. The new bridge offers vehicular traffic with a direct connection between Los Patrones Parkway and SR 241, improving safety and traffic flow on Oso Parkway and under the bridge.

About the North Atwater Non-Motorized Multimodal Bridge (2021 Bridge Project of the Year):

Under an on-call contract with the City of Los Angeles Department of Public Works, Bureau of Engineering, TYLI provided construction engineering and significant design support throughout construction for the North Atwater Non-Motorized Multimodal Bridge in Los Angeles, California. Possibly the world's first cable-stayed equestrian bridge, the new 325-foot‑long crossing is the first of three bridges to be completed in the Glendale Narrows section of the Los Angeles River.

Featuring a dramatic, 125‑foot‑high mast and steel suspension cables, the North Atwater Bridge is located between the growing community of Atwater Village and Griffith Park, one of the largest urban parks in the United States. The signature structure offers users a safe, more efficient connection to the Los Angeles River Bike Path and Los Angeles River Greenway Trail that run along both river banks.

The bridge deck is divided into two separate 12-foot‑wide pathways to accommodate pedestrians, bicyclists, and equestrians. While the pedestrian/bicycle path uses a hardwood deck and stainless-steel mesh railings, the equestrian side is topped with horse-friendly rubber pavers and a less transparent wooden picket railing system.

The dynamic behavior of the bridge was a significant design consideration due to the slender, lightweight deck and relatively heavy equestrian live loads. A system of tuned mass dampers was designed to mitigate the potential for resonant vibrations as groups of riders cross the bridge.

About the I-5 HOV Improvement Project (2021 Construction Project of the Year):

Working closely with the OCTA, Caltrans District 12, and the City of Santa Ana, TYLI served as Prime Design Consultant for the final design phase of the I-5 HOV Improvement Project in Santa Ana, California.

The project provides a significant benefit to the traveling public by repurposing the existing width of the I-5 freeway and adding a second HOV lane in each direction between SR 55 and SR 57. In total, the project added close to six lane miles of HOV lanes to a congested portion of I-5, which will be traveled by 400,000 vehicles each day by 2035.

Project challenges included replacing the single-lane northbound and southbound HOV lanes with two southbound HOV lanes while realigning two northbound HOV lanes into an area previously used for northbound general-purpose lanes. Innovative solutions included constructing a retaining wall under the abutment of an existing railroad bridge to create the space needed to accommodate the northbound general-purpose lanes. Using creative geometric designs to "thread" the four HOV lanes under bridges eliminated the need for widening in the southbound direction.

TYLI excelled at proactively identifying potential issues and risks, allowing sufficient time to develop resolutions and partner with stakeholders to reach a consensus on final decisions. In addition, by anticipating problems, the firm generated cost savings while meeting budget and schedule requirements.

About the Oso Parkway Bridge at State Route 241 Project (2021 Roadway & Highway Project of the Year):

TYLI provided final design services to the project owner, Transportation Corridor Agencies, and worked closely with Caltrans and the County of Orange for the Oso Parkway Bridge Project on SR 241 in Orange County, California.

Completed on a very accelerated schedule, the Oso Parkway Bridge provides vehicular traffic with a direct connection between Los Patrones Parkway and SR 241, improving safety, connectivity, and traffic flow. Before this project, drivers were forced to access SR 241 or Los Patrones Parkway by exiting via an off-ramp, waiting at a signalized intersection, and using an on-ramp to access either roadway.

The Oso Parkway Bridge provides three lanes in each direction and dedicated bike lanes and pedestrian sidewalks to enhance user safety. A new sidewalk was also constructed on the south side of Oso Parkway for students to access Tesoro High School.

The bridge design involved local roadway improvements, including asphalt pavement, a storm drain, curb and gutter, sidewalks, Americans with Disabilities Act (ADA) improvements, utility relocations, signing, striping, drainage improvements, and traffic signal modifications.

Project challenges included significant utility relocations due to bridge construction and right-of-way (ROW) processing requirements. Additionally, drainage design had to meet Orange County and Caltrans standards based on various ownerships and ROW within the project limits.

TYLI also provided design support services during construction to the County on an as-needed basis. Staged construction included pedestrian detours to maintain a travel path for students at the adjacent Tesoro High School during each construction stage.

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