Construction Zone: Parking restoration

The Fletcher Street Parking Garage at the University of Michigan, Ann Arbor, is an underground, six-level structure with a top-level pedestrian plaza. A performing-arts center and classroom building are positioned directly on the perimeter foundation wall on the north and south sides, creating one large complex.

Restoration required the removal of significant portions of the structural floors. Since the garage served as part of the foundation for the adjacent buildings, these removals created a challenging design problem.

A restoration consultant developed methods that would allow the 40-year-old structure to be repaired in place without affecting the adjacent structures. The $10 million restoration program will provide another 30 years of useful service life. It involves major structural repairs to the floors, beams, columns and walls, along with partial replacement of 80 percent of the floor slabs (more than 200,000 square feet). Hydrodemolition is used on concrete slabs to achieve better structural repair and to eliminate vibration transfer to adjacent buildings. Areas susceptible to deterioration are being redesigned for long-term durability.

The consultant is Walker Restoration Consultants (Elgin, Ill.), and Western Waterproofing Company (Livonia, Mich.) is the contractor.