A method of evaluating flexible buried structures that have experienced some degree of flattening and of estimating the potential flattening of flexible structures is presented. The integrity of flexible structures depends on maintaining their shape without becoming too flat. If a flexible buried structure becomes too flat on the top or sides, it experiences distress and might ultimately collapse. A computer program, multspan, for evaluating the degree of flatness on the basis of measurements of chords and midordinates and for recommending remedial action for deflected structures is described. The recommendations include no action, lowering the load rating of the roadway, and closing the roadway (or airfield, etc.) Until further action is taken. A second program, soileval, which predicts movement of aflexible buried structure, is presented. The program uses soil typeto make projections of movement. The average characteristics of seven soil types are built into the program. It is possible to access the program using standard penetration data or other information concerning the degree of compaction. It is also possible to evaluate a flexible structure that is deflected and to predict additional deflection. Whether the ultimate deflection is likely to create collapse can be determined from the evaluation. The program was calibrated with actual data obtained from several deflected or collapsed structures. This paper appears in transportation research record no. 1315, Culverts and pipelines: design, monitoring, evaluation, and repair 1991.
Abstract