We see Lincoln Financial Field every Sunday when we watch the Eagles play but rarely stop to consider the engineering behind its design and what it takes to support a stadium of that size.

When the stadium site was proposed, the soft, water-saturated soils typically found near the Delaware River raised concerns. A structure with a 790’ by 825’ footprint (approximately 15 acres), made of concrete and steel, would require a very stable footing to ensure safety and stability. The engineers behind the stadium design developed a solution that would result in approximately 175,000 linear feet (roughly 33 miles) of concrete underneath the proposed stadium structure.

The process began as it does for most of our land development projects: a geotechnical investigation of the site soils. Through this investigation, soils suitable to bear the weight of the structure at various depths were identified. 20”-24” diameter steel pipes were then driven into the soils, with some requiring to go as deep as 90’ to reach the suitable soil.

After the piles were driven to the required depths, they were all inspected and then filled with concrete to provide the designed structural capacity. Approximately 3,200 piles were installed as part of this project to provide a stable base for the concrete foundation.

Why use thousands of piles instead of fewer, larger foundation elements? A properly designed pile group distributes the building’s loads across multiple support points to control foundation settlement and transfer loads to suitable soils below.

So when you watch the Eagles take the field on Monday (in spite of all the injuries), remember that a significant part of the engineering achievement is hidden from our eyes. Without that vast support system, this structure would not be possible.