The 76-year-old South Park Bridge on 14th Avenue South-one of two King County steel-deck truss bridges-remains a concern, according to the recently published 2006 King County Annual Bridge Report.

A recent inspection found that while it is safe, the South Park Bridge is reaching the end of its useful life. The sufficiency rating was only 4 on a 0-100 scale.

Engineers said close monitoring should continue, but that the bridge needs to be replaced or torn down by the end of this decade.

Replacement is estimated at $150 million, $110 of which is included in a fall ballot measure.

Other aging bridges in need of replacement include the Alvord T. Bridge spanning the Green River Near Kent and the Berrydale Overcrossing on Kent-Black Diamond Road.

Construction of 17 new bridges in the last decade and near-completion of a 14-year earthquake retrofit program have helped increase the reliability of the county's bridges.

As a result of an ambitious decade of bridge replacements and upgrades, King County has seen the average sufficiency rating of its bridges climb from 64.1 to 68.3 over the past five years.

"Safe, reliable bridges are part of the basic infrastructure residents rely on that we have made a priority," said King County Executive Ron Sims.

"Replacement of aging bridges is expensive and takes years of planning and construction. This report shows King County is making significant headway in preserving its vital bridges."

The 2007 county budget, which emphasized the importance of investing in infrastructure, included acceleration of an aggressive Short Span Bridge Program aimed at replacing 57 bridges that are less than 20-feet long.

County engineers are aiming to replace 24 of the county's short span bridges over the next six years at a cost of $17 million.

The county is also nearing completion of a major 14-year seismic retrofit program. By the end of 2008, the King County Road Services Division expects to strengthen the remaining five bridges needing retrofitting.

Similar projects have already been completed on 110 county spans. That work will help prevent bridge collapses during an earthquake.

The 2006 Annual Bridge Report is available online at: www.metrokc.gov/kcdot/roads/eng/bridge/index.cfm#annualreports.