ACEC 2025 Engineering Excellence Award Winners

With its 516-foot-diameter and 366-foot height, Las Vegas’ Sphere is the world’s largest spherical structure, enclosing a bowl-shaped theater for 17,600 guests seated beneath a domed roof and suspended media plane. Designed using advanced engineering modeling tools, Sphere was prefabricated in sections to facilitate construction and reduce the need for temporary support. Through sophisticated detailing and carefully controlled tolerances, Sphere’s prefabricated 400-foot dome was delivered to within about one inch of ideal geometry. Sustainability was a priority in the design of Sphere, as well as mitigating the unique challenges of a desert climate. Recycled materials were used throughout the structure, while the Exosphere’s design allows for thermal expansion.

The Portland International Airport (PDX) Terminal Core Redevelopment Project modernizes and expands one of America’s favorite airports. Between outdated facilities, seismic vulnerabilities, and projections that showed travel demand would soon exceed terminal capacity, PDX needed a solution that would create more space, safer space, and do so while still delivering peerless passenger experience. In the interest of both time and efficiency, the team modernized the existing terminal in phases to minimize disruption, with the new expansion designed to exceed code for seismic resilience. The project features a 400,000-square-foot mass timber roof supported by more than 30 Y-shaped columns equipped with seismic isolators.

The Seattle Aquarium’s Ocean Pavilion is a cutting-edge project centered around an innovative “Supertank,” a one-of-a-kind sculptural concrete structure that holds 500,000 gallons of water and serves as the primary frame of the building. Optimized for marine life behaviors and benefits, this Supertank supports both public spaces and research labs. The tank also provides earthquake and windstorm protection by concentrating the weight of the building to mitigate soft soil that is liquefiable during an earthquake. The Supertank features a 50-foot cantilever, creating a column-free entry that offers visitors an immersive aquarium experience.

The new home of the NBA’s Los Angeles Clippers, Intuit Dome, is the fulfillment of owner Steve Ballmer’s vision for an iconic, environmentally friendly, community-and-fan-focused arena. The 18,000-seat venue anchors the 1.14-million-square-foot complex, which includes training facilities, team offices, and community courts. Because the complex is located just 1.25 miles from the Newport-Inglewood fault, seismic safety was of paramount concern. The team addressed this via an ingenious design that allows the roof to move independently from the main structure, “swishing like a hula skirt” around the rigid frame during earthquakes. As a fully electric facility with sufficient solar panels and batteries to power the arena for an entire concert or basketball game, Intuit Dome is the first NBA arena to achieve LEED Platinum certification under LEED v4.

The Native Salmonid Conservation Facility is an initiative by Seattle City Light to protect and establish self-sustaining, naturally producing threatened Westslope cutthroat trout in the Pend Oreille River watershed. The state-of-the-art facility captures genetically pure fish from the basin’s tributaries, spawns them, and returns the progeny to the natal streams. The facility also rescues trout from local streams and nurtures them through advanced aquaculture techniques, enhancing their survival chances, and aims to include endangered bull trout or mountain whitefish at the hatchery in the future. The project team overcame challenges such as site conditions and severe weather to provide extensive underground utility work and eight facility structures and three residences for facilities staff.

The Saddle Creek High Rate Treatment Basin (HRTB) marks a milestone achievement in the Clean Solutions for Omaha program aimed at reducing the impacts of combined sewer overflows (CSO) by 2027. Previously, untreated sewage overflowed into the Little Papillon Creek dozens of times per year. As Nebraska’s first remote HRTB, Saddle Creek captures and treats combined sewage during storms, providing “equivalent to primary” treatment for flows up to 160 million gallons per day, and can screen, remove grit, and disinfect flows up to 320 million gallons per day during extreme events. Saddle Creek uses a gravity-flow-through design that moves flows in and out of the facility without major pumping. On the sustainability side, the project site involved remediating a former construction debris landfill, with more than 330,000 tons of piping, street debris, and fill material removed.

Brightline is the 235-mile rail line that connects Orlando and Miami, two of America’s biggest vacation and tourist destinations. For this project, the team completed a 38-mile east-west expansion of the line, connecting Cocoa and Orlando. Touted as a potential game-changer in American travel, Brightline sets a precedent for expanding the breadth and scope of the U.S. rail system by linking city pairs that are too far to drive but too close to fly. The Brightline Florida East-West Connector project is composed of more than 30 bridges, grading, drainage, communications, signal layout, and utility relocation. Delivered on time and within budget, the connector also has contributed to Brightline’s sustainability impact, helping to remove three million vehicles from Florida’s highways annually.

The Lynnwood Link Extension expands the Sound Transit Link Light Rail system by 8.5 miles, stretching from Northgate Station in north Seattle to Lynnwood Transit Center, marking the system’s first reach into Snohomish County. The project addresses the demand for sustainable, efficient transit in one of Washington State’s most congested corridors. Lynnwood Link Extension offers seamless, traffic-free access to destinations such as downtown Seattle, University of Washington, and Sea-Tac International Airport. Link trains run every four to six minutes during peak hours; the service is expected to carry as many as 55,000 daily passengers within the next year. Through innovative tools like 3-D modeling, the project team was able to start construction before the full design was finalized.