Rock Creek Parkway will get a new bridge this fall and realignment at the sharp curve where the parkway crosses over Rock Creek between the Pennsylvania Avenue and Whitehurst Freeway overpasses.

The "45-year-old bridge and the parkway don't exactly agree with each other," National Park Service spokesman George Berklacy said, "and there have been numerous accidents there."

The $800,000 project will take about a year to complete. While it is expected to slow traffic on the parkway, at least two lanes will be kept open for morning and evening rush hour traffic, Berklacy said. At other times the four-lane parkway is expected to have at least one traffic lane open in each direction.

The bridge has no name but is referred to by Park Service and highway officials as the crooked bridge, the iron bridge and the L Street Bridge, since L Street NW ends about 10 feet away, said Berklacy.

The project is expected to be advertised for bidding Aug. 1 and construction will probably begin early this fall.

It is one of more than $6 million in bridge-building projects the Park Service is expected to begin during the next year.Five new bridges for the George Washington Memorial Parkway, to replace deteriorating parkway bridges north of Rosslyn, are being requested in the Park Service's 1979 fiscal budget now before Congress. They are expected to cost about $5 million. The Rock Creek bridge replacement and realignment were approved by Congress last year.