Museum of Westward Expansion

New centrepiece entrance to the museum, glass fronted and topped cantilever system to withstand high snow and wind loads in a seismic zone.


St Louis



James Carpenter Design Associates



City Arch River 2015

The Eero Saarinen’s emblematic 1950’s museum beneath the St Louis Arch, commemorates the Louisiana Purchase and the foundation of the modern United States. It's new centrepiece west entrance will create an expansion to the museum, and merges iconic historical architecture with modern technology.


The existing building, which is largely underground, is now supplemented with a curved glass facade entrance, the 300 foot long structure uses custom blast engineered structural glass panels.

Eckersley O’Callaghan developed an innovative prestressed structure with preloading tendons hidden within the glass joints, this allows the 30’ cantilever glass canopy to be achieved with minimal stainless steel framing and thus realising the Architect's brief for transparency.


The cantilever and rod system system uses 24 inch bolts to hold the cantilever in place and the structure is tuned for optimal blast performance using ductile plastic hinge failure mechanisms designed to absorb the dynamic shockwaves in this seismic zone.

Museum of Westward Expansion

St Louis



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