The new infill addition is a two-storey building with full basement located between three existing buildings, a two-story CIP concrete building and two steel framed buildings, one a single story and the other a two-story. The new addition is a steel frame structure with composite steel beams and composite concrete floor slabs. Moment connections were used to resist wind and seismic loads. Special connections were designed for the exterior walls of all three existing buildings to support new concrete precast panels that ties the new and the old buildings together.