The city is awaiting engineering plans on how to save the 122-year-old Gardner Building. Trinity Financial of Boston has proposed a $100 million downtown redevelopment project of apartments, commercial and business space, and parking that includes preserving the building. The former shoe factory had been deemed unsafe by the city, and Building Superintendent James Casieri had said that without acceptable structural changes he would recommend it be torn down. Trinity recently submitted preliminary plans that involved surrounding the four-story building with steel supports. “It looks like it would work,” Casieri said. “I mean, anything is possible if you go to extreme measures, and they're willing to go to extreme measures.” He said if proper engineered plans are submitted, building permits would follow. The state will give Trinity $600,000 in tax credits to preserve the brick exterior. Trinity wants to start work this summer.