Bradlees Department Stores will move into 11 former Memco stores this summer in a bid to become--in a single move--a $100 million-a-year factor in the Washington retail market.

The Boston-based chain will open a ring of 10 stores around the Washington Beltway and another in Richmond on Aug. 11 and in November will add another unit in Burke.

Chairman Harold Frank said the stores are aimed at filling the gap in the retail market left by the closing of the Memco, Woolco and Korvettes discount stores in recent years.

The goal, he said, is to establish Bradlees midway between the Woodward & Lothrop and Hecht's department stores and the K mart and Zayre discounters.

"We have filled the niche the department stores gave up as they moved their direction up" in pursuit of bigger ticket sales and higher profit margins, he said.

Regarded in the retail trade as an upscale discount department store, Bradlees does not call itself a discounter, and Frank said it does not attempt to compete with so-called "off price" retailers like T.H. Mandy that sell labeled and unlabeled brand-name merchandise at lower prices than conventional stores. "The customer seems to recognize us as more of a budget department store," targeted toward shoppers "who want fashion merchandise but have budget constraints," he said.

But Bradlees parent organization, The Stop and Shop Companies Inc., does compete in the off-price market through a separate chain called Off The Rax. Stop and Shop supermarkets produced about 60 percent of the company's $2.3 billion sales last year, but general merchandise will become a bigger factor as a result of Bradlees' rapid expansion this year.

Bradlees has been expanding south from New England for several years, has already opened six stores this year and will have 123 units after the 11 open in Maryland and Virginia. Sales last year totaled $871.6 million.

The 10-store Washington blitz will be the biggest single day's openings ever for Bradlees and is believed to be the biggest retail invasion ever of the Washington market.

Frank said the new Washington area stores will be slightly larger than the average Bradlees unit and are expected to meet the chain-wide average of about $9.1 million a year in sales. If the stores meet their goals, Bradlees will become one of Washington's half dozen biggest general merchandise retailers.

Bradlees made a deal to buy the Memco stores earlier this year after that California-based company decided to abandon its East Coast operations. The chain is hiring about 1,400 workers. Former Memco employes were invited to apply for jobs but were not given a preference in hiring.

The Memco sites are "excellent real estate," Frank said, but will be merchandised and operated much differently by their new owners.

Though the parent company is a major supermarket operator, Bradlees does not sell groceries and the former food sections of Memco will be used for general merchandise.

"Ours is a very different kind of store," he said. Bradlees gets almost 70 percent of its sales from clothing and other soft goods. While Memco charged a membership fee and aimed its advertising at card-carrying customers, Bradlees is an aggressively promotional chain that will advertise heavily.