Pier structure geometry data for side views of selected Montana bridge piers

The U.S. Geological Survey (USGS), in cooperation with the Montana Department of Transportation (MDT), collected various data at selected bridges in Montana. The data collected in the field included streambed cross-section data, longitudinal streambed profile data, and water-surface profile data. Efforts included overlaying pier structure geometry on the plots to demonstrate the position of the piers relative to the various data collected in the field. The pier data discussed in this metadata file pertain to the side view of a pier, or the view one would observe by standing under the bridge looking at the side of the pier with the stream flowing in a left to right direction relative to the observer. The term "pier structure geometry" includes all structural components of the pier including any piles, footings, seals, pads, and pier superstructure that extends upwards to the beams or girders. Pier structure geometry data were obtained from dimensions on MDT engineering drawings that reflect the as-built pier structures. The MDT dimension data were used with datum information obtained by USGS or MDT surveys to convert vertical dimension data to North American Vertical Datum of 1988 (NAVD88). The purpose of incorporating the pier structure geometry data with the data collected in the field is to determine if scour and channel instability occur in the vicinity of the bridge structures. Data were processed, analyzed, and compiled for bridge scour monitoring, facilitating better understanding, documentation, and prediction of scour processes.