Brent Pharesbphares@iastate.edu email >
Bridge Research Engineer, BEC
About the research
The 9th Street Bridge in Des Moines is the first bridge in Iowa that uses a unique integral abutment design. The integral abutments are supported on steel H-piles that are embedded into concrete drilled shafts, which are seated in glacial clay. This unique design was developed in an effort to address environemental concerns–namely vibrations from pile driving–while also providing a long-lasting stucture in the form of a jointless bridge. Although this innovative work is promising, it is unproven and will not become a common option unless adequate testing and monitoring are performed to validate design and behavior assumptions. A total of three pile/shaft elements will be instrumented and monitored over a minimum two-year period.