The biggest project yet in the Pennsylvania Avenue redevelopment area is getting under way -- the $145 million complex at 14th Street and Pennsylvania Avenue NW that will be known as National Place.

A new 774-room flagship hotel for Marriott Corp., a through-the-block shopping mall and a 410,000-square-foot office building will be built where the bulldozers and cranes are now digging.

It is a joint venture of Marriott Corp., Quadrangle Development Corp., and the Aetna Life and Casualty Co., who were chosen by the Pennsylvania Avenue Development Corp. after a competition for the sought-after site.

The Z-shaped, 15-story building was designed by Washington architect Frank Schlesinger in association with Mitchell/Giurgola of Philadelphia.

Schlesinger who designed and Quadrangle developed the adjoining building at 1301 Pennsylvania Ave., giving the Washington firms a rare opportunity to leave their mark on a whole block of downtown Washington.

Cutting diagonally through the block, the National Place complex zig-zags around the National Press Building and the National Theater, both of which are scheduled for major renovation.

The hotel, to be called the J.W. Marriott, after the corporation's founder, will occupy the coner of 14th Street and Pennsylvania Avenue and rise behind an office block fronting on Pennsylvania Avenue.