The Des Moines City Council will vote tonight on a $1.97 million contract with Substance Architecture for design services on a revamped vision for the Seventh and Grand parking lot. Originally conceived as combination parking ramp and retail and residential build-out, the city scaled back its plans in order to have the project completed in time to connect to Principal Financial Group Inc.’s skywalk across High Street, part of the $248 million rehabilitation of its downtown campus. Substance will provide “design and construction phase services for the parking garage, demolition of the existing structures, clearing and restoration of the redevelopment site, skywalk bridges and corridors, and retail/commercial at ground and skywalk levels,” according to a report to the City Council. The parking ramp design also will include elements that could provide for future development above the parking garage. The estimated construction cost of the demolition and replacement of the parking ramp is $22 million.