Mortenson released details Tuesday on its redevelopment ­concept for the Nicollet Hotel block, a city-owned parcel in Minneapolis' Gateway District that received three other proposals last week.

The Golden Valley-based development and construction company was the last of four local companies to reveal renderings and specifics about the proposal it submitted to the city of Minneapolis.

The site has functioned as a ­surface parking lot since the Nicollet Hotel was demolished in 1991.

After three unsuccessful attempts to develop the parcel, Minneapolis was finally able to get the federally mandated requirements for transit use lifted from the site last year. When the city cast its net for ideas this time, it had bites from several companies.

Mortenson's plan includes a 31-story apartment tower with more than 250 units, a seven-story hotel with more than 170 guest rooms, underground parking a five-story office building and a public plaza.

The Star Tribune reported the other three proposals Friday. Minneapolis-based Doran Development is proposing a 30-story residential building and a six-story Graves Hotel. Bloomington-based United Properties wants to build a 36-story building with a Hilton Hotel, 300 residential units, retail, restaurants and offices. And Minneapolis newcomer Duval Development is proposing an eyebrow-raising 80-story hotel, apartment and office tower.

The city made its ambitions for the site clear in its request for proposals: an iconic building and public park space that connects the central business district, the trendy North Loop neighborhood, and the Mississippi riverfront.

On the site among 3rd Street, Washington Avenue, Hennepin Avenue and Nicollet, the city is aiming for a building that includes some mix of office, hotel, residential and ground-level retail, and allows streetcar access around or through the property. This project's prominence is amplified by the $50 million renovation of Minneapolis' signature shopping street, Nicollet Mall, that will begin next year.

The preliminary renderings and site plans show the broad brush strokes of each team's vision. On paper, its difficult for observers to see major differences other than the appearance.

"There's a lot of similarities between them. It seems to me that it is going to boil down to which one the city likes aesthetically," said Herb Tousley, head of the real estate program at the University of St. Thomas. "I think any of those would be a good development and would be a good addition to the community. But if I were the city, I would be asking some more questions to flesh out what the differences are."

The city has made it clear that the site, in addition to whatever commercial activity the development stirs up, must offer a design that is ­inviting for pedestrians and public engagement.

"We embrace the city's vision for an iconic design and sustainable urban space that connects the Gateway District and welcomes the community," said Bob Solfelt, vice president and general manager of Mortenson Development, in a statement. "Our proposal is for a vibrant, financially feasible project that will bridge neighborhoods and become a true landmark."

Mortenson's project team includes the Excelsior Group, Coen+Partners, ESG Architects and RSP Architects, all of the Twin Cities.

Kristen Leigh Painter • 612-673-4767