Ramada Inns Inc. signed a contract with International Developers Inc. to begin construction on a 14-story, 800-room Ramada Renaissance Hotel as a part of the $250-million World Technology Trade Center (Techworld).

The Ramada Renaissance, occupying 559,000 square feet of the 1.46 million-square-foot Techworld, will be located across from the Washington Convention Center at K and 9th streets NW. It will be the largest of the Ramada hotels, offering 140,000 square feet of meeting and convention space.

According to International Developers President Giuseppe Cecchi, the $90 million convention hotel was selected to appeal to a broad range of visitors.

It will offer two types of accommodations: moderate and elaborate. A 175-room Club Tower will offer special rooms complete with computer hookups. The convention facilities will feature two ballrooms, a 300-seat auditorium, an 18,000-square-foot exhibition hall, 25 meeting rooms, a museum of technology, and a health club. Expected completion is late 1987.

Other recent developments in commercial realty in the Washington metropolitan area:

*The American Institute of Aeronautics and Astronautics and the Mutual Life Insurance Co. have entered a $55 million joint venture to build a 10-story, 380,000-square-foot Aerospace Center at 370 L'Enfant Promenade.

*Texas Instruments, a Dallas-based electronics company, has leased 13,688 square feet at 2750 Prosperity Ave. in Fairfax.

*Bellsouth D.C. Inc., a local telephone company, has leased 26,411 square feet at 1133 21 St. NW.

Analysis and Technology Inc., a $28.7 million research and consulting firm, has leased 41,100 of the 450,000 square feet at 2 Crystal Park.

*The Independent Bankers Association of America has leased 8,041 square feet at 1 Thomas Circle NW from Prudential Insurance Co.

*Eastport International, a national security firm, has leased 29,750 square feet at 501 Prince Georges Center in Upper Marlboro from Foreign Zone One.

*Putnam, Hayes & Bartlett Inc., an economic consulting firm, has leased 13,722 square feet at 1615 L St. NW.