A structural analysis is coming for three century-old Woodside bridges. The Town Council directed staff on Tuesday (March 11) to prepare a proposal to have an engineering firm examine the vulnerabilities of the single-span bridges over Union Creek, Bear Gulch Creek and Alimbique Creek (on Kings Mountain, Mountain Home and Portola roads).
The California Department of Transportation declared these bridges "structurally deficient" and "functionally obsolete" in 2009. Federal money is available to pay for 89 percent of the cost of repairing or replacing them, but at a price the council has been resisting mightily: a much wider roadway.
The traffic lanes of the current bridges are about 20 feet wide. Accepting federal funding would likely widen the lanes to about 28 feet. Adding the necessary pedestrian and equestrian crossings would bring the total width to about 40 feet.
A staff report listed the cost of the engineering analysis at about $159,000. The council was less than enthusiastic about that level of spending, but the cost of doing nothing could be much higher. Replacing them would run about $2 million each for the Kings Mountain Road and Mountain Home Road bridges and about $1 million for the Portola Road bridge.
The Kings Mountain and Mountain Home bridges are eligible to be designated as historic, but the council must address their weaknesses, if any, to indemnify the town should one of them collapse.
If an analysis finds one or more to be structurally unsound, the council will be looking for ways -- and funds -- to repair them without taking them down. The council may investigate ways to use federal funds if it can be done without compromising the character of the bridges.
The bridge on Portola Road over Alimbique Creek is the odd one among the three. It's a simpler structure in that it merely covers a culvert. It is not a candidate for historic significance, and its circumstances are also complicated by limitations on nearby rights of way around it and the character of the roadway leading to it.
The study of this bridge will split the focus between structural analysis and realigning the road to make crossing it less daunting to drivers.