Urban Land Interests has passed a major hurdle in its bid to update the iconic US Bank Plaza building on Capitol Square.

The city's Plan Commission on Monday decided that the proposed changes can be approved administratively, meaning staff can give the final go ahead.

Mark Olinger, the city's planning and development director, said he intends to approve the changes, which would update the structure, cut its energy consumption by perhaps 25 percent and bring it closer to its initial vision.

Katherine Rankin, the city's historic preservation planner, has endorsed the changers and the Urban Design Commission has approved the plans.

The nine-story building, 1 S. Pinckney St., designed in 1972 by noted architect Bruce Graham of the firm Skidmore, Owings & Merrill, has a transparent facade that was supposed to save energy by letting sunlight pour through while drawing the identity and vibrancy of the Square inside.

Graham, who designed the Sears Tower, John Hancock Building and other famed structures, hoped the bank building would serve as a winter garden and summer public space.

But the building, completed just before the energy crisis of the 1970s, has glass walls with no solar shading and little insulation, and its sloped atriums are sheathed with simple polished plate glass.

As a result, the building consumes enormous amounts of energy, while dark-colored film and shades installed to reduce glare and heat gain appear as black masses that obscure views of the Capitol and mar the look of the structure.