The structural system designed for the Seismic Replacement Building II (SRB II) is comprised of 6 levels of structural steel construction, EBF seismic frames, perimeter basement concrete shear walls and exterior concrete precast panel system. Special engineering challenges included long span built-up transfer steel girders at the 2nd floor above the loading dock area; very high (16'-19') roof parapets for coverage of the extensive mechanical equipment; concrete tunnels to connect the new building to the adjacent buildings; architectural sunscreens at the building perimeter; architectural feature circular grand stair and stringent vibration analysis and design for the sensitive laboratory equipment.