One Convention Place / McKay Tower

An addition to the Washington State Convention Center, this $39.5M public/private development is a 22-story structure that includes 308,580 sf of office space over 100,000 sf of convention expansion space over 120,000 sf of underground parking for 257 vehicles.

The project team was aware that underground telephone lines existed within the footprint of the new 4-1/2 level, underground parking garage, but the number and nature of the lines was unknown.  At the early stages of the mass excavation, the routing of the existing lines was identified and it was discovered that they were encased in concrete.  The concrete had to be removed while the telephone lines remained in service.  After carefully removing the concrete, it was discovered that the conduits were made of transite asbestos and that the lines combined telephone and fiber-optic systems that served half of downtown Seattle.  As soon as the nature of the lines was confirmed with the appropriate agencies and we received proper authorization from the owner, an abatement subcontractor removed the hazardous materials.  Then we encased the lines in a plywood box that was temporarily suspended off of the adjacent structure while the mass excavation proceeded below.  When the new structure was in place, the lines were permanently supported off the structure.  A change order was issued for the time and costs for all of the extra work related to this problem.