21-781, TR-798, SPR-RE22(009)-8H-00
Iowa Department of Transportation
Iowa Highway Research Board
Justin Dahlbergdahlberg@iastate.edu email >
Brent Pharesbphares@iastate.edu email >
Bridge Research Engineer, BEC
About the research
Recent legislation in the State of Iowa has increased the allowable axle weight of certain implements of husbandry to 25 kips. This change poses a particular concern to those who oversee and manage the construction and preservation of bridge structures. Based upon initial estimates, it is expected that the resulting structural response of bridges will exceed that which would be otherwise seen from current legal loads. This project aims to identify the load response of Iowa bridges to the increased live load limit and develop recommendations for load factors, live load distribution factors, and impact factors for Iowa bridges. Additionally, an Iowa-specific notional vehicle to be used for load rating bridges for recently legislated 25 kip axle vehicles will be developed and proposed.