The county has completed an earthquake retrofitting project involving the Glassell Street bridge over the Santa Ana River.
A contractor completed the $85,000 project on Dec. 7, two months ahead of schedule, officials said.
Workers added structural reinforcements for the bridge so that it now complies with state seismic requirements.
The county has also completed an expansion project at a radio communication building high atop the Cleveland National Forest.
The building is on Santiago Peak, the highest point in Orange County. The project involved building a 400-square-foot addition for the structure and reworking the electrical system.
A contractor completed the work late last year for about $350,000.