Another winter storm is predicted for this weekend in the upper Midwest. By now, many producers are getting tired of winter. Between the very cold temperatures for the first few weeks of this year and the continued snow and ice accumulation, it has been a long winter.
A few weeks ago I wrote about reports of several roofs collapsing on production facilities in Minnesota after the Christmas day storm. At the Minnesota Pork Congress, I talked with several company representatives who were aware of additional barn roofs that have failed since that storm in Iowa and Minnesota.
One of the big unknowns at this time is whether there are common factors in the roof failures. Are there certain structure designs or installations that are more at risk of failure? For example, are 100 ft wide double wide wean-finish barns more at risk than 80 ft wide barns? Are double wide barns more at risk than single wide barns? Does the type or location of ridge vents (when considered relative to barn orientation to wind) alter snow loading enough to be a factor? Are older barns more at risk than newer barns?
At the 2009 Minnesota Pork Congress, Dr Dwaine Bundy, emeritus professor of Ag Engineering from Iowa State University gave an excellent presentation about some of these issues. His slides are available at http://www.mnpork.com/producers/seminars.php
In a effort to help extension ag engineers better understand the problem this winter I am using this weeks blog to ask for readers help. If you had a roof collapse, or know of a specific facility that had a roof failure this winter, please reply to this blog with some of the above information, including location of the barn. Your response will not be posted as all responses to this blog must be approved by me for posting. Rather than replying to the blog you may also contact the ag engineers directly with reports of failures.
I will pull together these responses and forward them to Dr Larry Jacobson at the University of Minnesota (firstname.lastname@example.org), Dr Jay Harmon at Iowa State University (email@example.com), Dr Steve Pohl at South Dakota State University (firstname.lastname@example.org) and Dr Rick Stowell at the University of Nebraska (email@example.com). Together, this group will try and identify whether there are any patterns to these failures and what barn owners can do to reduce the risk of a future failure.
It may be that this group comes up with no common factors. On the other hand, they may be able to develop a list of conditions such as ridge ventilators installed in a specific pattern or direction relative to the storm or an age estimate of risk or something else that increases the risk of a catastrophic snow load on the roof.