The attached Bridge Evaluation form is to be used only for the evaluation of temporary bridges, “standard” bridges, and culverts, as defined in the text of this Memorandum. This evaluation is intended to be used in meeting the requirements of Section 106 of the National Historic Preservation Act of 1966 (Amended), on a project basis. The form and its attachments shall be included in the Historic Property Survey Report prepared for each specific project.

The following bridge types will be evaluated according to this Memorandum:

1. Temporary Bridges: These are structures constructed generally without engineering design, which were often typically built from components originally intended for other use, to provide temporary access. These would include, but not be limited to, log stringer bridges, flat car bridges, or nonpermanent pontoon bridges. (Note: suspension bridges or truss bridges shall not be considered as temporary structures.)
   
   
2. “Standard” Bridges: These are bridges of typical design of the period using standard details. They were generally engineered specifically for the site or selected from a pre-engineered catalog of standard designs. These may include, but not be limited to, plain or reinforced concrete T-beams, flat slabs, or haunched slabs on pile bents, pre-stressed I-girders, inverted U-girders, precast slabs, rolled or welded steel girders, or timber trestles. (Note: this category would not generally include the prototype nor major examples of a given “standard” type, nor such types as truss or suspension bridges, nor concrete, steel, or masonry arch bridges.)
   
   
3. Culverts: These are normally bridge structures of less than twenty feet in length between faces of supporting walls; for the purpose of this memorandum, this category also includes bridges made up of multiple spans of culverts structures, such as multiple spans of reinforced concrete box culverts.

________o/s_________________________________Date ___________
Ann Barkley, Chief
Division of Transportation Planning
Caltrans

________o/s_________________________________Date ___________
Omar L. Homme
Division Administrator
Federal Highway Administration

________o/s_________________________________Date___________
Dr. Knox Mellon
State Historic Preservation Officer