Concrete Tells the Story of the Overstock.com Corporate Campus
The Overstock.com corporate headquarters, called the Peace Coliseum, embodies a vision. The only building material able to bring that vision to life was concrete. Okland Construction won a 2017 Excellence in Concrete Award from the American Concrete Institute Intermountain Chapter for helping make this vision a reality.
Early in the project, the owner considered using other building materials to display the vision of the company, but as one Overstock.com employee said, “we needed all the benefits from the most ubiquitous and successful building material in history: concrete.”
The result of using concrete is a corporate campus that represents the duality of the company’s business enterprise. The main circle resembles the ancient Roman Coliseum, and an inner nucleus connected by covered walkways makes the building look like the peace symbol when seen from the air. “The peace sign represents the caring attitude we extend to our colleagues, clients, and community,” said Overstock.com CEO Patrick Byrne. “The coliseum represents the toughness of our bold, capitalist spirit.”
The Challenges of Using Concrete
Using concrete the way Overstock.com wanted to created several challenges for Okland.
Combining Different Mixtures — Since the building is solid cast-in-place concrete, the exterior concrete was a different mixture (high air) than the interior concrete (low air). The two mixes of concrete had to be poured simultaneously with no cold joint between them. This required us to use two different mixes delivered by two separate concrete pumps.
Quality — The exposed concrete has little or no patching. This resulted from careful collaboration with the concrete supplier to ensure high-quality aggregates in the mix. Okland developed a rigorous quality-control process that followed a detailed pre-pour checklist to ensure we didn’t miss any steps.
Uniformity — We created concrete mockups that allowed all of the project stakeholders to evaluate different mixes and help choose the best concrete to ensure uniformity. We also employed a special inspector to test every truckload of concrete used for the building’s exterior.
Challenges of Constructing a Circular Building
Building a circular structure has different requirements than a conventional building, so we had to adapt our approach.
Reinforcing the Floor — Because of the building’s radius, the construction team could only pull the reinforcing floor cables in one direction. To accommodate the complications of reinforcing a circular floor, we placed intermediate pull pockets midway through the concrete slab. This allowed us to lay more than 292,000 lineal feet of post tension cable while maintaining the spacing and tension required for proper reinforcement.
Pouring Around the Perimeter — We poured the concrete around the entire building circle and then moved upward instead of pouring the building in four separate vertical sections. This helped reduce the risk of the ends of the circle not meeting evenly at completion. It also reduced the potential for differential settlement, because pouring four separate sections would have caused each section to settle at a different rate.
Reusable Forms — To save time and labor, we built reusable forms. We used these forms all the way around the circle to help us build on the exact radius required. The reusable forms didn’t have to be hand set every time we poured. We simply placed them with a crane and removed them after the concrete hardened.
We’re grateful to Overstock.com for choosing Okland to transform its vision into reality. We thank the excellent subcontractors and suppliers who helped make it possible. It was an honor to work with all of those who made this exceptional project a success.
