Study of the Impacts of Implements of Husbandry on Iowa Bridges

Project status

In progress

Start date: 01/25/10
End date: 05/31/17


Principal investigators:

Co-principal investigators:

About the research

The objectives of this study are to develop guidance for engineers on how husbandry implement loads are resisted by traditional highway bridges, with a specific focus on bridges commonly found on the secondary road system, to provide recommendations for accurately analyzing bridges for their loading effects, and to make recommendations for the rating and posting of such bridges.

To achieve these objectives, the distribution of live load and dynamic impact effects for different types of farm vehicles on three general bridge types were investigated by load testing and analytical modeling. The types of equipment studied include but were not limited to grain wagons/grain carts, manure tank wagons, agriculture fertilizer applicators, and tractors.

Once the effects of these vehicles had been determined, a parametric study was carried out to develop live load distribution factor (LLDF) equations including the effect of husbandry vehicle loadings. Similarly, recommendations for dynamic effects were also developed. Finally, recommendations on the analysis, rating, and posting of bridges for implements of husbandry are being developed.


Related publication: A Study of the Effects on Bridge Behavior from Implements of Husbandry on Farm-to-Market Roads During Harvest Season Aug 2015



  • Federal Highway Administration Transportation Pooled Fund
  • Iowa Department of Transportation
  • Iowa Highway Research Board