Currently Reading

HSS Help Steel Canopies Soar

Sponsored Content Steel Construction and Products

HSS Help Steel Canopies Soar

Overcoming Design Challenges at the World’s Busiest Airport

By Atlas Tube | September 22, 2021
HSS Help Steel Canopies Soar

Hartsfield-Jackson Atlanta International, the world’s busiest airport, is in the midst of a $6 billion, 20-year expansion and modernization program. A major part of that program is an overhaul of the Central Passenger Terminal Complex (CPTC), which serves as the airport’s entrance and exit for all domestic traffic. As part of the CPTC updates, Atlanta commissioned architecture firm HOK to design a massive pair of canopies to stretch over curbside pickup and dropoff areas, protecting passengers from the elements and giving the airport a pair of iconic architectural pieces. 


The Challenge 

Building anything at the busiest airport in the world is bound to involve logistical challenges, but planners had a truly ambitious goal in mind for this project: Build two soaring canopies — 864 feet long, 72 feet tall and 194 feet wide, arching over eight lanes of traffic each — without disrupting airport operations or the 275,000 passengers who pass through daily. To accomplish this feat, designers had to figure out how to construct and install intricate steel diagrid lattices without closing traffic lanes or blocking airport entrances with construction work. Further, the new structures would have to be largely supported by existing construction, as installing extensive new supports or pilings would cause too much disruption to airport operations. That meant no new columns at the terminal curb and a limited ability to reinforce existing supports.


Modeling Minimizes Disruption

The first step was figuring out exactly how to design the lattice so it could be erected with as little disruption as possible. HOK’s designers used HOK STREAM, a proprietary parametric modeling and optimization tool, to plan the lattice’s structure, making the most of existing supports while minimizing the amount of retrofit work required. Additionally, analytic desktop models, wind tunnel testing and computational fluid dynamics were used to aid design, finding optimal structural load paths and planning for the large temperature variations between Atlanta’s hot summers and cool winters. Using these tools, designers were able to come up with a plan that would minimize required construction time and put two-thirds of the new load onto support piers that could be installed with minimal disruption, with the rest of the load carried by pre-existing columns.


Logistical Heavy Lifting 

While every construction project has logistical components, the unique challenges facing the canopy designers meant logistics had to be top of mind from beginning to end. Major work was only possible during limited traffic shutdowns between 10:00 p.m. and 4:00 a.m. every day, so the steel had to be carefully fabricated to be rapidly erected in the available time. To make the best use of the time they had, the team created a 4D schedule that mapped out precisely when and where each piece had to be installed, detailed in a comprehensive 500-page plan. And to make sure that plan went off without a hitch, fabricators started working a full year before construction began, custom-making the components of the lattice’s 38 identical trusses out of more than 3,500 tons of domestic steel. 


HSS Solve for Efficiency and Easy Erection 

HSS from Atlas Tube helped designers find solutions to their logistical and structural challenges. Using 14", 18" and 20" HSS pipe for the trusses, fabricators were able to bend each section to precise tolerances and cut miters to exact specifications in order to minimize the time and material needed for on-site welding. The high strength-to-weight ratio of HSS helped as well, making it possible to design canopies strong enough to withstand structural and environmental forces with minimal new support. 


An Award-winning Effort 

Ultimately, all the planning paid off, and the second canopy was completed a month ahead of schedule in October 2019. By using high-efficiency HSS and advanced computer modeling, the team was able to create a pair of iconic landmarks for Atlanta’s gateway to the world without impeding the airport’s efficiency. And the world has taken notice, with the canopies winning several awards, including the American Institute of Steel Construction’s 2020 IDEAS² Award for Sculptures / Art Installations / Non-building Structures and an NCSEA Excellence in Structural Engineering Award in 2019.

Related Stories

Sponsored | BD+C University Course | Oct 15, 2021

7 game-changing trends in structural engineering

Here are seven key areas where innovation in structural engineering is driving evolution.

Steel Construction and Products | Apr 17, 2021

Speed Core wall system is used for the second time in office building in San Jose

The construction method is expected to knock off three months from the project’s schedule.

Steel Construction and Products | Jun 17, 2020

America's structural steel industry remains a success story

That structural steel supply chain has remained robust, active, and ready to build tomorrow’s landmark structures.

Steel Construction and Products | May 26, 2020

Visionary footbridge/elevated park concept wins AISC’s Forge Prize

An innovative cantilevered pedestrian bridge and elevated park concept by Rosannah Harding and Matthew Ostrow of HardingOstrow took top honors.

Steel Construction and Products | Jan 3, 2020

5 reasons to enter the $20,000 Forge Prize

Calling all emerging architects. Don’t miss out on your chance to enter the $20,000 Forge Prize. Submissions for Stage 1 judging are due January 15.

75 Top Products | Dec 16, 2019

Top Structural Products for 2019

Inpro’s Fireline 140 fire barrier and Owens Corning’s Foamglas cellular glass insulation are among the 10 structural products to make Building Design+Construction's 2019 101 Top Products report.

75 Top Products | Dec 16, 2019

101 Top Products for 2019

Building Design+Construction readers and editors select their top building products for the past 12 months in the fourth-annual 101 Top Products report.

Architects | Dec 10, 2019

Calling all emerging architects: Enter to win the $20,000 Forge Prize

This annual steel design competition will recognize three Finalists ($10,000 each) and one Grand Prize Winner ($20,000 total) for their novel concepts in steel-based structures. Entries are due Jan. 15, 2020.

Codes and Standards | Sep 9, 2019

Free app calculates maximum allowable heights and areas for buildings

A free app that calculates the maximum allowable heights and areas for buildings of various occupancy classifications and types of construction has been released.

Magazine Subscription

Get our Newsletters

Each day, our editors assemble the latest breaking industry news, hottest trends, and most relevant research, delivered to your inbox.


Follow BD+C: