| Résumé | Winter road networks generally comprise segments that run over land and/or over floating ice expanses (rivers and lakes). The latter commonly are weak links in these operations, because they rely on cold temperatures to achieve a thickness that is safe enough for the intended traffic. These are thus vulnerable to warmer air temperatures. Risks of breakthroughs are also a serious consideration. One option is to increase the predictability of these over-ice segments as well as their ability to support a load and resist failure. This may be achieved if the ice cover is artificially reinforced. A laboratory study, building on past investigations by other research groups, was conducted to provide additional information on this topic and also to guide a follow-up plate testing program. Four-point beam bending tests were conducted on freshwater ice without and with reinforcement, for comparison purposes. Threaded steel rods, a steel mesh and a polypropylene geogrid were used as reinforcement material. In all tests, the load and the loading rate increases with time up to a peak load. For the non-reinforced ice, there is a sudden drop in load at which point the tests end. For the reinforced ice, a drop in load also follows the peak load, but the load climbs again up to another peak in a repetitive fashion, so as to produce a saw tooth pattern, extending to a significant amount of time. The ice reinforced with the threaded rods had the highest resistance (exceeding the load cell capacity). Thin section observations showed that the crystal structure was forming around the material. However, cleavage surfaces along the ice/material interface after beam failure indicate that the interface could be a strength reduction factor. |
|---|
