LONG-TERM MONITORING AND ANALYSIS OF FULL SCALE CONCRETE PIPE TEST BEDS

摘要

Current design standards for concrete pipe bedding in Canada utilize the Indirect Design Methodrnfor the design of backfill and bedding. This approach does not fully account for the strength ofrnthe pipe and does not take into account the nature of the native soil, as every installation isrnconsidered to be the same. Consequently, the Indirect Design Method is overly conservative inrnmany cases where the pipe is installed in competent ground and the anticipated level of live loadsrnis minimal. The Standard Installation Direct Design (SIDD) system for design and installation ofrnconcrete pipes was developed through the American Concrete Pipe Association’s (ACPA) longtermrnresearch program. The method takes into account the inherent strength of the concrete pipernas well as insitu soil conditions. The SIDD design minimizes the use of imported material whilernmaking maximum use of native soils.rnThis paper describes the design, installation, long-term monitoring and Finite Element Modelingrnof full-scale SIDD Type 4 installations. Type 4 installations do not use any imported materialrnand require minimal backfill compaction. Pipe diameter is selected to be 600mm with a burialrndepth of 1.8m. The test sections are located in heavy traffic areas and simulate the worse casernscenario for pipe installation. The results from a 16-month monitoring period are reported andrncompared with predictions from the ASCE 15-93 specification, Marston-Spangler theory andrntwo finite element analyses. It was concluded based on nearly 40,000 data points that the SIDDrnmethod illustrates well the stress envelope around a buried rigid pipe installed using the cut-andcoverrnconstruction method.