Keddie Resort Road Bridge Project

Proposed Mitigated Negative Declaration

Introduction

Plumas County Department of Public Works is proposing to replace a structurally deficient and functionally obsolete single-lane bridge on Keddie Resort Road over Spanish Creek. The Project will replace the existing bridge with a two-lane structure on an improved alignment. The existing bridge will remain in place during construction to maintain access across Spanish Creek.

Project Location

The existing Keddie Resort Road Bridge is located on Keddie Resort Road, 7 miles north of Quincy off Highway 70 in the central part of Plumas County. The Keddie Resort Road Bridge over Spanish Creek provides the sole access to the community of Keddie and the maintenance facility for the Union Pacific Railroad. Keddie Resort Road is a local rural two-lane road while the Keddie Resort Road Bridge is a single-lane bridge.

The Keddie Resort Road Bridge is located at latitude 40º00'48" North and longitude 120º57'48" West and at an elevation of 3122 feet

Looking southwest from upstream at Keddie Resort Road Bridge. Quincy Engineering, Inc. - July 2008 Site Visit

Existing Bridge and Site Description

The existing Keddie Resort Road Bridge was constructed in 1914 and a pedestrian walkway was added to the southern side in 1965. The existing structure is a single-span Warren Pony Truss carrying a system of steel floor beams and stringers that support a corrugated steel deck overlaid with asphalt concrete, supported by reinforced concrete spread footing abutments. The roadway approaches are paved and approximately 20 feet wide. Each roadway approach to the bridge has a sharp low-speed horizontal curve. Due to the tight horizontal alignment and narrow bridge, the existing operated speed within the project limits is below 25 mph.

Looking east across Keddie Resort Road Bridge – towards Keddie Resort. Quincy Engineering, Inc – March 2010 Site Visit

Need for Project

The existing Keddie Resort Road Bridge is classified by Caltrans bridge inspectors as functionally obsolete and structurally deficient due to its narrow width and failing paint. The existing structure also has significant cracking along the asphalt concrete deck and undermining at the west abutment. Currently, there is no permit loading allowed across the structure.

A bridge with a sufficiency rating of less than or equal to 50 and is also Structurally Deficient or Functionally Obsolete is eligible for replacement under the federal Highway Bridge Program (HBP). The existing Keddie Resort Road Bridge has a sufficiency rating of 5.0.

Proposed Project

The proposed replacement bridge will be 28 feet wide (26 feet clear between bridge rails), a two-lane structure with a design speed of 25 mph. The County is currently investigating bridge types, but the replacement structure will likely be a combination of precast/prestressed concrete and cast-in-place reinforced concrete elements. A new roadway will be constructed to meet the new structure and will conform back to the existing road within approximately 200 feet on either approach.

Project Timetable

Project Consultants

Quincy Engineering, Inc., from Sacramento, is the prime consultant for this project.

Sub-consultants are
– Environmental Document
– Bridge Hydraulic Studies
– Preliminary Geotechnical Investigation and Foundation Design/Initial Site Assessment
– Architectural Historian Support