Visitors to Chicago’s Navy Pier can now enjoy a show inside one of the world’s most flexible theatres, which has been constructed inside the attraction's Skyline Stage.

Theatre design consultancy Charcoalblue and design firm Adrian Smith + Gordon Gill Architecture (AS+GG) have collaborated on the ambitious reuse project, called The Yard at Chicago Shakespeare. Rather than constructing a new theatre from scratch, the duo instead designed a fully enclosed, year-round chamber inside the vast tent, with fewer than six inches of clearance at the narrowest point between the steel beams and the canopy.

Eighteen 95ft-long (29m) micropiles were driven into the lake’s bedrock below Navy Pier to support the additional weight of The Yard, and the 33,000sq ft (3,000sq m) site has been connected to Chicago Shakespeare’s existing theatre via a new two-level mirrored glass lobby. Meanwhile, the old Skyline’s Stage backstage support areas have all refurbished for reuse.

“At the foundation of my philosophy is the idea that ‘form follows performance’ – and nowhere is that more clear than in The Yard at Chicago Shakespeare,” said AS+GG founding partner Gordon Gill. “Its ability to adjust and adapt to the needs of the art is genuinely innovative, and we’ve accomplished it in a sustainable and cost-conscious way, which I believe will make it a model for theatres to come.”

Flexibility is central to The Yard. Nine audience seating towers, each the size of a London double-decker bus, can be rearranged in twelve different configurations, with audience capacities ranging from 150 to 850. Compressed air skid technology, often used in the aeronautical industry, lifts each of the 15.8 tonne towers marginally off the ground on a bed of air, allowing them to be moved by a three-person team.

“This theatre is going to be unique in the world,” said Andy Hayles, managing partner of Charcoalblue. “You can’t really appreciate it unless you come again and again to experience how different this room can feel for each production. It’s not just going to be what is on the stage, but where is the stage.”

The Chicago Shakespeare Theater's executive director Criss Henderson added: “The versatility of the space means that it is perfectly suited to the widest range of our work: from large-scale musicals and new commissioned works, to international imports and programs for young audiences, and, of course, bold imaginings of Shakespeare’s plays and the classics.”

Construction on the project began in March 2016, and was completed in 18 months at a cost of only US$35m (€30m, £26m) – under half of what would have been required to build a new venue from scratch.

More than 200 architects, engineers and designers, and 400 construction workers contributed to the complex build, which incorporated 2,500 tons of concrete, 375 tons of steel and 15 miles of electrical conduit.