Repeated load testing of a model plane strain footing

Abstract

A study is reported of experiments on model plane strain footings subject to repeated loading. The load was returned to zero at the end of each cycle. This is characteristic of a train wheel load passing over a railroad tie.Four series of tests were conducted. Series A consisted of static tests, which provided a comparison with series B. Series B consists of applying a cyclic load on the footing between zero load and a constant upper value. The upper value was varied from test to test and ranged from 13.5 to 90% of the static failure load. Series C was acyclic test that was a continuation of series B after a considerable deformation had occurred. The berms caused by the cyclic load test of series B were removed and a second cyclic test was conducted on the same foundation soil as the original test. Series D was a static test that was done as a continuation of series B. After removing the berms, as in series C, a static test was conducted in a manner similar to that for series A.The results have been quantified by the use of a hyperbolic fit and show that wider footings should perform better than narrower ones. This has been substantiated by examination of experimental railroad tests conducted by the Association of American Railroads.