Testing and Long-Term Monitoring of 9th Street Bridge Over I-235 in Des Moines: Integral Abutments Supported on Steel Pile/Concrete Drilled Shaft in Glacial Clay

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 environmental concerns--namely vibrations from pile driving--while also providing a long-lasting structure 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.