While building codes are advancing, to keep up with the increasing creativity and complexity of modern building structures, there is still the need for expert interpretation of the code. In some cases, the building code cannot provide all the potential snow loading patterns on a structure, particularly when there are sloped or curved roofs or otherwise complex shapes.
It is in these special cases, for the design of proposed buildings, assessment of existing buildings or for the forensic analysis of collapsed buildings, that a snow loading analysis would be suitable.
RWDI provides the following levels of analysis:
Roof Snow Load Review
Using the relevant building code, building calculations are conducted. In addition, RWDI's experience and previous studies with similar buildings, are employed to augment the code calculations with additional load cases where necessary. These additional load cases can reflect sliding snow, moving loads and other potential snow loading anomalies, and are based on RWDI's experience will similar buildings. While this kind of review cannot lower the recommended building code snow loads, it can provide a better interpretation.
Roof Snow Load Assessment
This review combines the above code review with a scale model constructed and tested in the water flume. This analysis will examine six to eight key wind directions, based on a Meteorological analysis, in order to determine the potential for unusual loading patterns. Though a more conclusive review than the above, this kind of review cannot lower the snow loads below those recommended by the relevant building code.
Roof Snow Load Optimization
Roof Snow Loading Optimization Study uses the Finite Area Element method.
A scale model of the proposed building in its surroundings is built, instrumented and then tested in the wind tunnel to map wind flows for drifting across the roof. The wind tunnel data is combined with a computer-based model of the building and long-term meteorological data to simulate, on an hour-by-hour basis, 30 to 50 winters worth of snowfall, drifting and melting on the roofs. These kind of analysis allows for snow loads to be optimized and potentially reduced below code-recommended loads. Unbalanced and sliding loads are also provided for, where necessary.
Litigation Support
Through decades of experience RWDI Microclimate Specialists have gained recognition as experts in the field of wind, snow and ice issues. We have written many papers and conducted numerous studies on the subject of snow. They have appeared as expert witnesses in litigation cases and mediation related to highway accidents, roof collapses and snow accumulation issues.
