Demolition - Seattle Memorial Stadium

In November 2025, Dickson Co., in collaboration with Applied Science International (ASI), successfully demolished the Memorial Stadium, located in Seattle, Washington. The demolition scenario of the structure achieved its objectives as planned. This successful outcome highlights the effectiveness of the precise planning and execution.

Seattle Memorial Stadium features a reinforced concrete cantilever roof structure supported at the rear by a reinforced concrete wall and near the midspan by a box girder, creating a 40 ft cantilever projecting toward the field. The roof framing consists of 24 secondary reinforced concrete beams acting as the main cross-span load-carrying members, arranged on both sides of the girder in a ribbed system and shaped with an asymmetric trapezoidal depth profile. Two longitudinal reinforced concrete struts run parallel to the girder, tying the beam tops together to improve lateral stiffness. The main girder is a box section 6 ft wide by 8 ft deep, supported by four composite reinforced concrete columns with a height of 78.5 ft.

Dickson Co. contracted ASI to perform a detailed demolition analysis for the reinforced concrete roof structure of the stadium, leveraging ASI’s expertise from more than 50 demolition simulation and planning projects. ASI employed its proprietary Extreme Loading for Structures (ELS) software to develop a detailed numerical model. This model was crucial for analyzing the structural behavior during the planned demolition, guiding the formulation of the demolition strategy, and ensuring a controlled collapse.

The ELS software, which utilizes the Applied Element Method (AEM), provides a numerical technique capable of simulating the behavior of complex reinforced concrete and steel structures from the linear elastic stage through cracking and reinforcement yielding to complete collapse. This capability enabled ASI to deliver precise recommendations that optimized the demolition process and effectively reduced potential hazards.

An analysis was conducted to evaluate slab deformation and induced stresses during demolition using a Brokk 70 robot. Results showed that the maximum tensile stresses in the reinforcement reached 15 ksi (37% of the yield strength), while the maximum concrete compressive stresses were 0.7 ksi (35% of the compressive strength). Both values, along with the overall slab deformations, remained within acceptable limits. Additionally, analysis of the roof beams demolition sequence showed that stresses in the beam and back wall remained below 1.2 ksi, confirming that all deformations and stresses were within acceptable limits.

In the final stage, the column was pulled by a cable; analysis showed that a force of 10 kips is sufficient to overturn the column and complete the demolition.

The successful demolition of Seattle Memorial Stadium demonstrates how advanced engineering and careful planning can work together to achieve project goals. By combining precise structural analysis with a well-coordinated execution strategy, the project was completed safely and efficiently. This achievement highlights our ability to apply technical innovation and engineering expertise to solve complex structural challenges.