This report documents and presents the results of research to develop, test, and evaluate instrumentation that would be both technically and economically feasible for use in measuring maximum scour depth at bridge piers and abutments. A variety of scour measuring and monitoring methods were tested in the laboratory and in the field, including sounding rods, driven rod devices, sonic fathometers, and buried devices. Two instrument systems, a low-cost bridge deck serviceable sonic fathometer and a magnetic sliding collar device using a driven rod approach, showed significant promise during initial testing. The project concentrated on installing and testing these two instrument systems under a wide range of bridge substructure geometry, flow, and geomorphic conditions. Both instrument systems met all of the mandatory and many of the desirable criteria established for this research. Co-operative efforts with state highway agencies proved that both systems can be installed with equipment and technical skills normally available to District level DOT maintenance and inspection personnel. This report provides, under separate cover, users and fabrication manuals giving design, fabrication, and installation specifications for the low-cost sonic instrument system and magnetic sliding collar devices (NCHRP Reports 397A and 397B). (A)
Samenvatting