B09_Amentd_0002_1570-022P_-_Lava_Creek_-_RG350_0002.pdf

This is a technical engineering drawing document from the U.S. Department of Agriculture Bureau of Public Roads for the Lava Creek Bridge project within the Grand Loop Highway Yellowstone National Park Project. The drawing set, dated September 1932, provides detailed architectural and structural specifications for a reinforced concrete bridge design.

The drawings include comprehensive specifications for bridge construction, including downstream and upstream elevations, plan views, and detailed cross-sections showing reinforcement placement, bearing details, and structural dimensions. Key structural components detailed include the concrete superstructure with specifications for Class B concrete, steel reinforcement with dimensions relating to reinforcement bars, expansion joints, and bridge deck construction. Material quantities are estimated at approximately 273 cubic yards of structural steel, 450 cubic yards of concrete, and various steel hardware components. The document specifies that all concrete must be Class B (2000 PSI), with maximum aggregate size of one-half inch and special provisions for surface finishing and drainage. Technical notes indicate requirements for steel specifications, construction methodology, and shop plan approvals by the engineer prior to fabrication. The bridge design accommodates a 26-foot clear span with finished slope lines and architectural detailing of curbs, railings, and abutments. Sheet references indicate this is Sheet 2 of 3 Sheets in the complete drawing set (RG-850-B).