Legislation to extend the life of the Pennsylvania Avenue redevelopment program for five more years was broken loose yesterday from a pre-adjournment logjam and enacted by Congress.

First the Senate and then the House approved a bill that, once signed by the president, will empower the government-sponsored Pennsylvania Avenue Development Corp. to spend $140 million to refurbish the nation's foremost cremonial boulevard.

Just one day earlier, the futer of the program was cast in some doubt when the extention measure was blocked in the house.

The result is a case study of how legislation often is handled in the hectic final hours before a congressional adjournment.

The bill started out in the Senate as a relatively simple measure extending the spending power of the Pennsylvania Avenue corporation. On the floor, the Senate attached amendments authorizing several other national park and public works projects around the nation.

The House refused to accept the amendments, and Rep. john Ashbrook (R-Ohio), a persistent critic of the Pennsylvania Avenue project, blocked an attempt on Saturday to reach a compromise.

The Senate responded yesterday by tacking the Pennsylvania Avenue authorization onto a bill that deals chiefly with a park project in Louisiana. The bill won speedy approval in the House yesterday afternoon.

The passage legitimatizes an earlier vote by Congress granting the Pennsylvania Avenue corporation funds to continue operations until next Sept. 30.

F. David Harris, acting executive director of the Pennsylvania Avenue Development Corp., said the action also will permit his agency to seek a supplemental approriation from Congress early next year to expedite work soon to be refurbished.

Another local measure pending before Congress, to authorize further spending to complete the transformation of Union Station into National Visitor Center and transportation terminal, apparently died at the congressional session's end. Rep. Harold T. Johnson (D-Calif.), cheif sponsor of the House version of the measure, said he expects it to be reintroduced and acted upon early next year.