(Adds Biden comments, steel workers' union reaction, bill details)

By Steve Holland and Heather Timmons

WASHINGTON, Nov 6 (Reuters) - A giddy President Joe Biden on Saturday hailed congressional passage of a long-delayed $1 trillion infrastructure bill as a "once in a generation" investment and predicted a broader social safety net plan will be approved despite tense negotiations.

Biden and Vice President Kamala Harris appeared in the White House State Dining Room about 12 hours after moderate and progressive Democrats in the House of Representative overcame internal bickering and delivered the president his biggest legislative win thus far.

"Finally, infrastructure week," Biden said with a chuckle. "I'm so happy to say that - infrastructure week!"

The president's comment referred to a running joke in recent years after Biden's Republican predecessor Donald Trump declared https://www.reuters.com/article/us-usa-trump-russia-week/confluence-of-crises-crashes-trumps-infrastructure-week-idUSKCN1G02M6 "Infrastructure week" in 2018 but was unable to pass a bill after multiple tries during his presidency.

The bipartisan bill's passage gives Biden a jolt of good news https://www.reuters.com/world/us/with-infrastructure-vote-congress-gives-biden-long-needed-jolt-good-news-2021-11-06 after sobering election losses for his Democratic party this week and a drop in his approval ratings. Referring to the losses, Biden said they showed American people "want us to deliver."

"I think the one message that came across was - 'get something done. It's time to get something done - stop talking,'" said Biden.

The United Steelworkers union welcomed the bill's passage.

"The House has passed the #InfrastructureBill, which would provide roughly $1 trillion for upgrading the nation’s critical infrastructure. This is a big freakin' deal for us because Steelworkers supply America in so many ways!" the union tweeted.

The bill had been caught up for months in bitter fighting between Democrats and the impasse had raised questions about Biden's effectiveness.

With Biden making multiple phone calls to lawmakers urging a compromise, an agreement was worked out late on Friday for the House to vote by Nov. 15 on Biden's proposed $1.75 trillion Build Back Better social safety net plan.

This allowed lawmakers to go forward on the infrastructure bill and it passed with backing from 215 Democrats, and in a move that annoyed the conservative right, 13 Republicans helped provide the margin of victory. A half dozen progressive Democrats voted no.