National Trails Highway 3 Bridges Project (Project)

National Trails Highway 3 Bridges Project (Project)

The San Bernardino County Department of Public Works (County), in coordination with the California Department of Transportation (Caltrans), proposes to replace three (3) timber trestle bridges with concrete bridges on the National Trails Highway (NTH), formerly known as US Route 66. A summary of the existing bridges including their length, width, and locations is provided in the above table. The existing bridges were constructed in the 1930s and span over man-made ditches or "flash flood washes". The existing bridges vary in length but share similar construction components. The typical existing timber trestle bridges are composed of simply-supported timber stringer spans with a laminated timber deck supported on timber strutted abutments and bents consisting of timber piles. The bridges are approximately 28-feet wide with guardrails that do not meet current standards. Through the years, the bridges have been modified by various maintenance and repair work with the intent of maintaining public safety and prolonging the service life of the bridges. The proposed replacements will resolve the bridge deficiencies. The three existing, two-lane timber bridges will be replaced with bridges designed to American Association of State Highway and Transportation Officials (AASHTO) standards for two-lane concrete bridges, guardrail, guardrail end treatments, and approaches. The existing soil is sandy and susceptible to scour, so pile extensions would be utilized at the piers and the abutment foundation would be designed for scour. The bridge barrier would be a concrete barrier Type 85 with bicycle railing painted white which is Manual for Assessing Safety Hardware (MASH) approved and best matches the original railing. The bridge lengths would match the existing lengths, if possible, but would be lengthened as needed to convey the storm flows. Each replacement bridge would accommodate two 12-foot-wide lanes, two 3-foot-wide shoulders and two 2-foot-wide railings. The vertical profile of the bridges will remain close to the existing profile except for those bridges locations in which it is determined that additional vertical clearance is required to provide sufficient water conveyance beneath the bridge. It is anticipated that any such necessary changes in vertical profiles would be three feet or less, with the elevation gradually conforming to the existing roadway elevations. The National Trails Highway is posted at a speed limit of 55 miles per hour, with all the bridges located on straight segments of the road. The alignment would remain unchanged; however, up to 800 feet of pavement improvements on either side of each bridge may be needed to conform to the existing roadway vertical profile. Grading within the existing channels around the bridges may be needed to ensure sufficient storm conveyance and drainage of the area. A temporary, parallel road (also known as a “shoo-fly”) would be constructed at each bridge location to accommodate through-traffic during construction. Construction of each bridge replacement is expected to be completed in one season, limiting the time the detour would be in place to one season as well. Based on weather conditions and construction activities, it is possible that there could be intermittent closures of the temporary parallel road. Permanent acquisition of right-of-way is not anticipated; however, temporary construction easements may be needed to accommodate construction of the temporary detour routes. There is one existing utility, a fiber optic telecommunication line, which may require relocation as part of this project. All utility relocations would be included within the defined limits of the Project area. Typical equipment for roadway construction would include heavy construction earthmoving equipment, dump trucks and pavers. Typical bridge construction equipment would include cranes, pile drivers, drill rigs, excavators, concrete trucks, and concrete pumps.

unincorporated communities of Amboy and Chambless

San Bernardino

Southern California

California Air Resources Board (ARB), California Department of Conservation (DOC), California Department of Parks and Recreation, California Department of Toxic Substances Control (DTSC), California Department of Transportation, District 8 (DOT), California Department of Transportation, Division of Aeronautics (DOT), California Department of Transportation, Division of Transportation Planning (DOT), California Department of Water Resources (DWR), California Fish and Game Commission (CDFGC), California Governor's Office of Emergency Services (OES), California Natural Resources Agency, California Public Utilities Commission (CPUC), California Regional Water Quality Control Board, Colorado River Basin Region 7 (RWQCB), California Transportation Commission (CATC), Colorado River Board, Department of General Services (DGS), Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Water Quality, State Water Resources Control Board, Division of Water Rights, State Water Resources Control Board, Divison of Financial Assistance, California Native American Heritage Commission (NAHC), California Department of Fish and Wildlife, Inland Deserts Region 6 (CDFW), California Highway Patrol (CHP)

California Native American Heritage Commission (NAHC), California Department of Fish and Wildlife, Inland Deserts Region 6 (CDFW), California Highway Patrol (CHP)

Transportation (Bridge replacement.)

Activities consistent with current existing approvals.

Aesthetics, Air Quality, Biological Resources, Cultural Resources, Cumulative Effects, Drainage/Absorption, Flood Plain/Flooding, Geology/Soils, Hydrology/Water Quality, Noise, Public Services, Transportation, Tribal Cultural Resources, Wildfire