Weight limit on Live Oak Park Road bridge to be removed

The weight restriction on the Live Oak Park Road bridge will be repealed.

A 5-0 San Diego County Board of Supervisors vote Aug. 2 approved the first reading and introduction of the ordinance. The second reading and adoption is scheduled for Sept. 13, and approval of that would create an Oct. 13 repeal date.

In May 2010, the Board of Supervisors approved a weight restriction of five tons per truck, ten tons per semi-trailer combination, and 12 tons per truck and full trailer on the bridge on Live Oak Park Road over the San Luis Rey River tributary crossing which is 160 feet south of Gum Tree Lane.

Live Oak Park Road is a two-lane road which is not classified in the mobility element of the county's general plan. The road narrows in width from 33 feet to 23 feet in the vicinity of the bridge. Its 35 mph speed limit is certified for radar. A March 2010 traffic survey taken north of Alvarado Street revealed a two-way average daily traffic volume of 2,760 vehicles.

The bridge on Live Oak Park Road has served traffic since the 1950s and includes three corrugated metal pipe arch culverts with Portland cement concrete headwall and endwall composition. A bridge inspection shortly before the 2010 weight limit implementation determined a mid-span vertical deflection of 1 1/2 feet, and water leaking from one culvert to another was observed.

County staff performed temporary repairs to the bridge which are designed to strengthen the bridge until a replacement bridge is constructed. The work included placing concrete to reinforce the bottom of the existing culvert and reinforcing the deflection inside the culvert section at mid-span between two connecting culverts by excavating above the culvert and encasing that section of pipe in concrete.

The California Department of Transportation has a structure maintenance and investigation team, and the structural evaluation rating by the Caltrans inspectors after the county's work was improved from 2 to 6. The Caltrans inspectors also indicated that the culvert weight limit restriction could be removed.

The county's Traffic Advisory Committee addressed the proposed weight limit repeal June 9 and recommended that the weight restriction be removed. "It now has a positive structural rating," said TAC secretary Kenton Jones.

The sufficiency rating of structurally deficient qualified the bridge for the Federal Highway Administration's Highway Bridge Program which would fund 88.53 percent of the estimated construction cost to replace the bridge. The Federal Highway Administration provides the funding and the state transportation departments distribute that funding and approve projects, so the county sent an application to replace the bridge to the California Department of Transportation.

"That bridge is slated for replacement as well," Jones said.

Caltrans has approved the 88.53 percent funding for the bridge replacement, which is currently in the design phase. The county's Department of Public Works expects construction on the new bridge to begin in summer 2018 and be complete during spring 2019.