# 7577 / Implementation of moving loads on ice in NRMM Title: Implementation of moving loads on ice in NRMM Authors: Susan Frankenstein and Kathleen Jones Abstract: Fording capabilities are common in cross country mobility models. They are limited in capability however due to their dependence on timely water level inputs and are best used for planning purposes based on monthly averages. Few, if any, include water velocity effects when crossing rivers and stream. Less common still are winter crossing considerations. To accurately predict vehicle speed on an ice cover the ice thickness, ice properties, and water depth are required. To solve for the speed an iterative process is needed which is prohibitive in mobility models. In order to implement in NRMM critical speed curves were generated for 37 ice thicknesses ranging from 0.01 – 5 m and 3000 water depths spanning 0.1 – 300 m. Using these curves, two equations, one for the steady state velocity and a second for the critical velocity as functions of water depth and ice thickness were developed. If the water depth is known, the final speed is the minimum of the two otherwise it is set to 6.7 m/s. In NRMM, the minimum ice thickness needed to support a single non-moving vehicle is calculated. Adjustments to the minimum ice thickness can be made for weaker ice. If the ice thickness is greater than the minimum thickness, then the speed and minimum vehicle spacing are calculated. Order the full paper: ISTVS members: receive three papers per year as part of your membership via the ISTVS Member Portal: --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://2023.istvs.org/submissions/papers/7577.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.