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SAN FRANCISCO (CBS 5 / AP / BCN) ― Commuters confronted yet another day of heavy congestion Friday as state transportation officials said the San Francisco-Oakland Bay Bridge would likely stay closed through the weekend and were unsure if it would open in time for Monday's morning commute.

Construction crews continued a third full day of emergency repairs on Friday, but had to stop work at one point while they waited for new steel plates to arrive. The additional materials were needed to strengthen the troubled span before final tests could be run on the fix.

''There is still a lot of work that needs to be done,'' Bart Ney, a spokesman for the California Department of Transportation, said Friday evening.

He said workers were custom-fitting steel in their efforts to repair a section where two rods and a crossbar fell at the eastern span's upper deck Tuesday evening. Several cars were damaged but no one was seriously injured, however the bridge has been closed since then.

"We're still custom-fitting the steel on the deck of the bridge so that when we get the rods in place they won't move," Ney told reporters Friday evening.

He indicated that the goal for reopening the bridge was Monday, but he could not ensure it would happen.

The repair work "will take as long as it takes," Ney said.

Caltrans had ealier hinted at the possibility of reopening the span for the Friday commutes, then later backed off while waiting for more metal to be ordered. Bay Area Rapid Transit announced late Friday that it would run limited overnight service to accommodate those impaced over the weekend by the bridge closure.

The terrifying scene Tuesday evening stirred anger over the constant delays and soaring costs of the still-unfinished new eastern span of the 73-year-old bridge, which has become the largest public works project in California history.

The pieces that broke were part of major repairs done Labor Day weekend after state inspectors found a crack on a key structural beam. Those fixes failed due to vibrations caused by high winds.

Work was delayed Friday after new rods had been installed and engineers decided to use 2-inch thick steel plates to further strengthen the work, said Ed Puchi, spokesman for MCM Construction Inc., of Sacramento, the contractor doing the work.

"We're not sure how long it's going to take to make those modifications," Puchi said.

Once the custom-fitting of the steel plates was completed, Ney said workers would grind areas where steel is rubbing on steel so that those areas are smoother. 

Then there would be several hours of rigorous tests followed by enhancements to make the repair area safer, according to Ney.

Finally, engineers from the Federal Highway Administration planned to inspect the new repairs after they were finished to make sure the bridge was ready to handle traffic again, he said.

While the repair effort continues, many commuters have chosen to work from home or take public transportation as drivers clogged alternate bridges. 

BART ridership soared to record levels this week and the agency planned to run trains overnight Friday and Saturday since the Bay Bridge was to remain closed.

A total of 442,000 people rode BART trains Thursday, the highest number in the agency's 37-year history, according to agency spokesman Linton Johnson.

The ridership total was about 86,000 people higher than an average Thursday, Johnson said.

BART's previous record was set Wednesday, when the trains carried 437,200 riders. The record before this week was 405,400, which was set Sept. 8, 2008, a Monday when both the San Francisco Giants and Oakland Raiders were playing in the Bay Area. 

BART was not expected to set a new record Friday due to smaller amounts of workers who have to commute on Fridays, Johnson said.

The large number of riders taking the trains during the bridge closure "goes to show how important BART is to the region's mobility," he said. "We've been stepping up to the plate like we always do when there's crises like these." 

BART said it planned to provide 24-hour train service during the weekend. It normally ends service around midnight.

BART officials said trains would run hourly to 14 stations overnight Friday and Saturday. But the agency had no plans to run service overnight Sunday even if the bridge did not reopen by then.

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