(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.

Biden said that in his last-gasp negotiations with Democrats to try to get the bill passed, he urged them, "Let's be reasonable."

"Last night we proved we can, on one big item, we delivered," he said of the bill, which includes https://www.reuters.com/world/us/roads-bridges-airports-details-bidens-1-trillion-infrastructure-bill-2021-11-05 tens of billions in investments in road, rail, public transport and broadband.

Biden was in an upbeat mood in taking questions from reporters, at one point playfully putting his hands over his eyes to pick out a journalist to call on.

He said he will sign the bipartisan bill "soon" in a formal signing ceremony that highlights all the people who worked on it, Democrats and Republicans alike.

He plans to visit some ports next week to promote the bill and Americans should see the impacts in coming months, he said, offering Democrats something to campaign on as they try to head off losses in next year's congressional elections.

The infrastructure bill will create "blue collar" jobs modernizing roads and bridges, and transform the transportation system, Biden said. The "vast majority" of the jobs created will not require a college degree, he said.

Americans "will see the effects of this bill probably starting within the next two to three months," he said. (Reporting by Steve Holland and Heather Timmons; editing by Diane Craft and Grant McCool)