2026 Dennis & Leslie Drag Distinguished Lecture

SoFi Stadium

Divide and conquer: How a multi-billion-dollar challenge was met through careful and creative division into manageable components

A Presentation by Rafael Sabelli S.E., Senior Principal & Director of Seismic Design and
Mark Waggoner S.E., Managing Principal of Walter P Moore

Wednesday, November 11, 2026
4:30pm – ME G061

Faculty and Students are invited to a reception in Wood Commons (Hampton Hall) at 3:30 pm before the lecture

The state-of-the-art SoFi Stadium has been showcased in a Super Bowl, an NCAA National Championship Game, the World Cup, and most importantly Taylor Swift concerts, a fitting nod to several years of design and construction work. This project posed a tremendous structural and geotechnical challenge, including deep excavation, dramatic soil retention high seismicity, and long spans. To meet this challenge, the design team divided the project to create a small set of large, but manageable, component projects.

The first carve-out was the 100-foot, 2.4M cubic yard open cut excavation and massive 265,000 square foot mechanically stabilized earth retention system. This deep excavation was required in order to keep the overall building height below the clearance needed for aircraft approaching nearby Los Angeles International Airport. The independent retention system permitted structural design without retention forces. To further clarify the structural design, the roof structure was placed on columns separate from the stadium bowl structure.

This project involved design and construction of multiple geotechnical and geostructural elements. In addition to the excavation and retention system, there were: approximately 700 continuous flight auger and cast-in-drilled-hole piles with diameters ranging from 24 in. to 72 in.; mat foundations, plinth columns, butterfly caps, and posttensioned grade strut and anchor blocks; and working platform stability for a 1,600 metric ton crane for roof erection.

Complicating all design scenarios was a highly seismic environment, with the Newport-Inglewood Fault and Compton Blind-Thrust Fault nearby the stadium site.  The underlying seismic complication to all geotechnical and structural designs was the need for the free-standing cable-net stadium roof to be completely isolated from the stadium structure and the MSE wall system, the base of which was founded nearly 120 ft below existing ground surface.

This presentation will discuss in detail the specialty design and construction management of all of these systems, the difficulties in having four separate geotechnical consultants/designers on a project, the challenges of formulating an independent peer review panel and obtaining their review consensus on a complex series of designs, managing interaction between the City of Inglewood plan check process and the peer review panel, and constructing geotechnical and structural work separate from the rest of the stadium bowl, all on the critical path.

Speaker Bios

Rafael Sabelli, S.E. is a Senior Principal and Director of Seismic Design at Walter P Moore. Rafael has earned a Lifetime Achievement Award and a Special Achievement Award from AISC, as well as the T.R. Higgins Lectureship award. He is a member of the AISC Committee on Specifications, where he is vice-chair of the Technical Committee on the Seismic Provisions, and a member of the AISC Committee on Manuals, where he is chair of the Seismic Design Manual committee.

Mark Waggoner, S.E. is a Managing Principal in the Austin, Texas office of Walter P Moore. His work focuses on long-span roofs and other complex structures and has contributed to the design of more than a dozen long-span roofs for professional sports facilities in the US and internationally. He was recently inducted into the National Academy of Engineering.