UDOT Rockfall Hazard Rating System: Final Report and User's Manual

The purpose of the Rockfall Hazard Rating System and associated software is to evaluate the relative risk associated with rockfall on highways throughout the State of Utah. The system and software are designed specifically for the Utah Department of Transportation (UDOT) and are a tool for ranking sites relative to one another so as to better prioritize their rehabilitation. This manual provides the user with the necessary information to successfully obtain and understand results from a rockfall hazard rating analysis. Part I introduces preliminary analysis done in 2002 and the detailed analysis completed using three competing hazard rating systems developed in other states. These analyses served as the basis for developing the UDOT system. It provides background as to why the custom developed UDOT system is considered the preferred method for Utah. Part II is a tutorial and users' guide that systematically takes the user through the rockfall analysis and report/map making process. It is assumed that the user is familiar with geological engineering concepts in general and more specifically the characterization of rock masses. In almost all cases, the software will allow the user to enter any arbitrary value for a given parameter. If the user is unable to provide realistic parameters as inputs to the hazard rating system, then the results of the analysis are unpredictable. It is therefore highly recommended that only those with the appropriate professional background modify parameters within the database. The database software is implemented in Microsoft Access with custom programming in Visual Basic for Applications (VBA). The data are in a .mdb file structure used as both Microsoft Access data files and ESRI ArcGIS geodatabase files. MS Access provides a convenient environment for database management, the automatic computation of hazard ratings and the flexibility to produce a variety of custom reports. The ArcGIS environment provides a convenient environment for the generation of custom maps showing the location of the rockfall sites and labels representing key rockfall parameters. The software requires Microsoft Access 2003 or higher and ESRI ArcGIS 9.0 or higher. The user should be acquainted with the MS Access environment in order to review and update the database as well as generate custom reports. A basic understanding of routing and display functions of ArcGIS will allow the user to quickly view, symbolize and label the rockfall sites and overlay them on a variety of GIS database information.