Alder Drive / Blair Road Bridge Project Overview
Project OverviewEl Dorado County has an inventory of 79 bridges. Twenty-five of these bridges are in the Community Development Agency Transportation Division’s 2013 Capital Improvement Program (CIP). Two of the CIP bridge projects are crossings over the EID Canal. One bridge is located on Alder Drive at Pony Express Trail and the other is on Blair Road, 0.7 miles north of Pony Express Trail. Planning is currently underway to replace these two bridge structures which are both over 75 years old which is the typical life expectancy for these bridges.
Current Bridge Conditions The Alder Drive bridge was built in 1930 and is 83 years old. It is a one-lane crossing, 18-feet wide and 32-feet long. Approximately 2,000 vehicles use the crossing daily (both directions, 2010 traffic counts). The Blair Road bridge was built in 1935 and is 78 years old. It is a one-lane crossing, 15-feet wide and 35-feet long. Approximately 1,000 vehicles use the crossing daily (both directions, 2010 traffic counts). Both bridges are made of reinforced concrete slab with concrete barrier rail. The Alder Drive bridge embankments, which are functioning as abutments, are eroding and the barrier rail has exposed rebar. The Blair Road bridge has similar issues – the north abutment is eroding, there are diagonal cracks and exposed rebar on the barrier rail.
Existing Caltrans Sufficiency Issues The bridges are routinely inspected by Caltrans every two years and are given a Sufficiency Rating (SR) from 0 to 100 based on 140 elements. If the SR is less than 80, the bridge is eligible for rehabilitation. If it is less than 50, the bridge is eligible for replacement. The SR for the Alder Drive bridge was 53.2 in 2011 and the SR for the Blair Road bridge was 56.5 in 2010. Both bridges are classified by Caltrans as Functionally Obsolete. Highway Bridge Program (HBP) Funding The Alder Drive and Blair Road bridges meet federal criteria for rehabilitation or replacement and funding under the HBP Off Federal Aid System 100% Reimbursement Program. In April 2011, the County received federal authorization to complete the planning and environmental phase and scope the project. The HBP program requires this phase of work to be completed within 10 years of the initial authorization date.
Public Outreach during Planning Process An initial public informational meeting was held on July 29, 2013 at the Pollock Pines – Camino Community Center. Engineering staff from the Transportation Division provided an informational presentation on these two bridge projects. As the project advances, project updates will be posted on the County website. The public will also have the opportunity to review and comment on the draft environmental documents.
Anticipated PSR Project Schedule
Bridge Closures During ConstructionThe existing bridges will be required to be closed for approximately 60 days during construction with detours. The Alder Drive detour route is about 1/2 mile (two minutes travel time) on Cedar Drive to Fern Avenue to Pony Express Trail. The Blair Road detour route is three miles (six minutes travel time) north on Blair Road to Forebay Road to Pony Express Trail.