BETHLEHEM, Pa. (AP) _ A steel mill that made sections of the Empire State Building and Golden Gate Bridge is closing and 1,690 workers will lose their jobs, Bethlehem Steel Corp. said Friday.

Bethlehem is shutting most of its Structural Products Plant here and cutting two-thirds of its workers over the next 13 months.

Spokeswoman Bette Kovach said fewer skyscrapers are being built as developers turn to making buildings of two to three stories.

''As the market shifted and the architectural desire changed, they became buildings that didn't need heavy wide flange shapes, which was one of our major product lines,'' Kovach said.

She said two smaller steel-making divisions in Bethlehem - BethForge and Centec - will not be affected.

The company said Structural Products' force of 2,500 hourly workers is scheduled to be slashed to 1,100 after November 1995 and that salaried ranks will drop from 440 to 150. The remaining employees will be working in other operations.

The big steel mill currently operates on the day shift only, but that was enough for some famous projects including 22,000 tons of beams for the new Atlantic City Convention Center, 2,600 tons for the new Cleveland Indians stadium and 1,600 tons for the Rock and Roll Hall of Fame and Museum in Cleveland.

A Bethlehem Steel magazine recently said the mill plans to produce at least another 8,000 tons of beams for a new arena in Philadelphia, and expansions at National Airport in Washington, D.C., and Mount Sinai Hospital in New York.

The company was once 30,000 workers strong during World War II and again in the early 1960s. About 10,000 employees remained in the early 1980s, but that number has decreased to about 5,000 over the last five years, Kovach said.

''We saw this coming for a bunch of years,'' said plant worker Brent Zimmer of Kunkletown, who used company-paid training for a degree in nursing. ''You have to read the signs. If all the buildings are empty, your building is next.''