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Iowa State University--Becoming the Best

Development of Rural Road Bridge Weigh-in-Motion System to Assess Weight and Configuration of Farm to Market Vehicles


Principal investigators:

Project status

In progress

Start date: 08/01/14
End date: 06/30/17



About the research


The weights and configurations of large vehicles traveling the primary interstate system are known with relative certainty due to the information collected at numerous weigh stations. It is uncommon, however, that farm to market vehicles and other implements of husbandry travel the interstate system, thus an accurate assessment of the characteristics of these vehicles is left unknown. Since these vehicles commonly travel rural roads, and often at weights exceeding the legal limit especially during harvest, an accurate understanding of low-volume road usage is necessary to properly plan for the near-term repair and replacement of structures and roadways; even more, the information collected will help improve the long-term performance and asset management activities. A current pooled-fund project, which the Iowa Department of Transportation (DOT) is leading, looks to assess the impact of implements of husbandry on bridges. These efforts have produced valuable information especially as it relates to lateral load distribution. Even so, the project was largely completed using a database of virtual vehicles developed through information provided by equipment manufacturers and rules-of-thumb. Though it is believed the database generally represented current vehicles, the accuracy cannot be verified without direct measurement of all vehicles. Further, one piece of missing information is the frequency with which those vehicles cross low-volume road bridges. The objective of this project is to develop a portable weigh-in-motion system using a rural road bridge to estimate the characteristics of vehicles traveling these roads. Because of the development of this system, decision makers will have objective qualitative information from which they can base their decisions.