Vehicle barriers shall be designed with dimensions and loads per HB-17 or CBC Chapter 16 except where bridges qualify as low-volume roads. Most bridges will qualify as low-volume roads. Low-volume road bridges may have curbs designed per Design and Evaluation of Two Bridge Railings for Low-Volume Roads (USDA 1995). Low-volume roads serve residential parcels and are generally single lane with a 15 mph limit.
Design and Evaluation of Two Bridge Railings for Low-Volume Roads (PDF)
Bridges with separate walkways for pedestrian traffic shall have Guards designed per California Building/Residential Code.
Bridges are required to have minimum 1 foot freeboard above the 100-year water surface elevation (Sonoma County Water Agency, Flood Control Design Criteria). A hydrology and hydraulic calculation will need to be prepared by a civil engineer. The Storm Water Section of Permit Sonoma will review any deviations from the minimum 1 foot requirement. If the bridge is expected to be submerged in 100-year flood event, the bridge shall be design for hydrostatic, hydrodynamic, and debris impact loads.
Existing bridges where the abutments remain and bridge deck elevation does not change will be permitted to remain below the 100-year flood level with the bridge designed for hydrostatic, hydrodynamic, and debris impact loads. For existing bridges, anchor bolts of bridge decking to girders and embedded anchorage of girders into concrete may be considered by the engineer of record to resist these loads.
Bridges shall be provided with a skid resistant wearing surface (HB-17 Sec. 1.8). Wood non-structural longitudinal runners suffice for wood bridges.
Signage shall be provided to identify the design load of the bridge and certification date of the load. The proposed text shall be provided to the Fire Section for review prior to permit issuance. See sign template, last page.
505.2.6 Signs identifying traffic access limitations. (CFC SoCo Addition)
A sign identifying traffic access or flow limitations, including, but not limited to weight or vertical clearance limitations, dead-end road, one-way road (or single land conditions) shall be placed: (a) at the intersection preceding the traffic access limitation, and (b) no more than one hundred feet (100’) before such traffic access limitation.
505.2.1 Size of letters, numbers and symbols for street and road signs. (CFC SoCo Addition)
Size of letters, numbers, and symbols for street and road signs shall be a minimum of three inches (3”) for letter height with a three-eighths inch (3/8”) stroke, reflectorized, and contrasting with the background color of the sign.
Sec. 13-43. Orientation and height of road signs. (FSS)
All road signs shall have an orientation and height in conformance with county road standards.