Thornton Tomasetti is the Structural Engineer-of-Record for Phase I of an iconic regional transportation hub providing multimodal transit services for rail, bus and roadway. Thornton Tomasetti also provided façade consulting services during the competition and early architectural design phases.The project includes the Intermodal Terminal, the Metrolink/Amtrak concourse bridge and the Stadium Pavilion bridge that provides pedestrian connectivity between the terminal and Angel Stadium. The 68,000-square-foot terminal building will house a grand hall, ticketing and retail space beneath a soaring open structure enclosed with inflated ETFE cushions.
The terminal features a grid shell vault structure and a three-story, interior terminal building that are structurally connected. Rising from a height of 80 feet at its southern end to 115 feet at the main entrance, the ARTIC structure will be 250 feet long and 180 feet wide. Thornton Tomasetti’s structural design employs long pieces of 14-inch-diameter curved, interlocking steel tubes to form the complex yet efficient structure’s diagrid shell to support the ETFE cushions and help accommodate bending and compression. This steel shell is clearly visible through the façade, creating a variety of impressive visual effects. The shell serves not only as a structural element but also as an architectural element and an iconic regional landmark. The enclosure for the diagrid shell will be the largest installation of ETFE membrane pillows in North America.
The transit center will be designed to achieve LEED Platinum certification by incorporating initiatives including energy and potable water consumption reduction, stormwater runoff, construction, operational waste, air emissions reduction, optimization of climate conditions and open space areas.