Caltrans crews completed construction work on the San Mateo-Hayward Bridge this morning and reopened the far right-hand lane that was closed after inspectors identified a structural flaw Thursday.

During a routine inspection, Caltrans engineers identified a crack in a wishbone-shaped steel beam located beneath the affected lane and immediately closed the lane.

The affected beam was originally installed as part of a seismic retrofit completed in 2001 that allows for the bridge to move back and forth during an earthquake, according to Caltrans.

Engineers quickly set to work on a repair design, which called for several high-strength steel plates to be bolted in place over the cracked section.

Over the weekend, Caltrans engineers regularly reviewed progress and designed additional repairs to maximize the beam's strength -- four plates were originally called for, but officials decided Friday to add at least one more.

Although the redesign required more time, Caltrans said the benefit of long-term safety for drivers outweighed the short-term inconvenience of the lane closure.

Crews worked to complete repairs ahead of a football showdown scheduled for 1:05 p.m. today at Candlestick Park in San Francisco pitting the San Francisco 49ers against the Oakland Raiders.

The lane was reopened at 3:19 a.m.

Caltrans said engineers will continue to monitor the repaired beam section, and additional off-peak lane closure may be required to ensure safe use of the lane.