The Archer Building, an anchor in the Tulsa Arts District, is home to art studios, apartments, and several locally owned retail and restaurant tenants.  Existing structural systems included a two-way concrete flat slab with drop panels and column capitals, a draped mesh concrete slab on steel lumber-joist roof, and a prestressed concrete girder and precast plank system.  Key project challenges included structural reinforcement of an existing roof system for outdoor assembly space use, structural reinforcement around new floor openings for elevator shafts and mechanical chases, and a 550 square foot basement expansion.