A last-ditch effort by poor and working-class Hispanic residents to stop the construction of a 478-unit apartment complex in the Arlandia neighborhood failed Saturday as the Alexandria City Council approved plans for the development by a 6 to 1 vote.

Scores of residents turned out for the council’s vote, testifying that they had no knowledge of the development until it was too late to do anything but protest against the project, which they fear will drive up area rental rates.

The apartments, expected to rent for about $1,500 for a one-bedroom or $2,100 for a two-bedroom unit, are considered below market rate according to federal and city housing guidelines. And 28 units have been set aside to be rented at lower rates, expected to be $1,100 to $1,450, but area residents testified Saturday that even those prices were too expensive for them.

The planned six-story complex, with retail stores on the ground floor, will replace a strip shopping center and a surface parking lot on Mount Vernon Avenue.

After three hours of emotional testimony from supporters and opponents of the development, most council members pointed out that they have championed affordable housing and public housing, investing time and money in alternatives for residents.

Although no one will be displaced by the Arlandia development, residents fear that gentrification will push up rents in the relatively low-cost area.

“I feel like [council members] totally missed the point,” said Gabriel Rojo, executive director of Tenants and Workers United, which describes itself as a grass-roots low-income community organization. “Affordable housing is just a red herring. This is about developers getting a sweetheart deal and the community getting nothing.”

The developer, Arlandia Center, already had the right to build an apartment complex on the block. It wanted to add height to the project, which required special approval from the council. Tenants and Workers United tried to use that request to force a delay, which would allow the group to convene residents for input and to negotiate for jobs, more affordable apartments, improved parking and other benefits.

Duncan Blair, an attorney for the developer, said the project nearly died several times and just got under way in September.

Blair and Alexandria’s planning staff said Tenants and Workers United was invited, along with neighborhood groups and business associations, to meetings to discuss the development, but the group’s representatives didn’t show up and declined the city’s requests for another meeting.

Council member Rob Krupicka (D) said: “This [project] provides workforce housing, which we desperately, desperately need in Alexandria for someone just out of college, for our firefighters, teachers, administrative assistants. . . . That’s not to discount the need for low-income housing.”

There were some testy moments Saturday. When Alicia Hughes (I), the only council member to vote against the measure, read a message of solidarity to the gathered residents in Spanish — a language she does not regularly use — Vice Mayor Kerry Donley (D) sarcastically said, “Nice performance.”