Rockfall Catchment Area Design Guide

009215392001Final ReportPDFTech ReportFHWA-OR-RD-02-04SPR-3(032)Design chartsField testsRockfallsSlopesDesignGeotechnologyHighwaysPlanning and ForecastingI21: Planning of Transport InfrastructureOregonUnited StatesUnited States. Federal Highway AdministrationGullixson, C. F.Pierson, Lawrence A.Chassie, Ronald GOregon. Department of TransportationUnited States. Federal Highway AdministrationUS Transportation CollectionThe data gathered from an extensive research project consisting of rolling approximately 11,250 rocks off vertical; 0.25H:1V; 0.5H:1V; 0.75H:1V; and 1.0H:1.0V slopes of three different heights (40, 60 and 80 ft) into three differently inclined catchment areas (flat, 6H:1V and 4H:1V) has been used to develop design charts for dimensioning rockfall catchment areas adjacent to highways. A standard suite of 250 rocks was rolled for each slope and catchment area configuration tested. The standard suite included 100 rocks averaging 1 ft in diameter, 75 rocks averaging 2 ft in diameter and 75 rocks averaging 3 ft in diameter. The data were evaluated using statistical and graphical methods. The design charts are presented in a "practitioner-friendly" form that can be used to rapidly dimension rockfall catchment areas that satisfy specific rock catching/retention requirements. Based on cut slope angle and height and catchment area slope, the design charts estimate the catchment area widths required to retain percentages of rockfall ranging up to 99%. Design guidelines and step-by-step design procedures are presented and illustrated with three worked example design problems. Seven actual highway project case study examples are also presented. They illustrate the practical application of the design procedure and design charts and/or use of site-specific rock rolling to aid in the rockfall mitigation design. This report documents the test methods, the fieldwork performed, the data gathered, the means of analysis, the research results and sample application of the design charts. The data results in both tabular and graphical form are included in the Appendices. The Appendices also include the detailed project case study application examples.82