Parametric study and length limitations for prestressed concrete girder integral abutment bridges

This study establishes a practical limit for the maximum length of prestressed concrete girder integral abutment bridges (IABs) and identifies potential distress in IABs at extreme lengths. The nonlinear numerical models developed using detailed three-dimensional solid elements include soil-pile interaction, abutment-pile interaction, and construction joint detail. The loads on IABs were ambient temperature, temperature gradient, time-dependent loads, and backfill pressure. A parametric study was performed with an initial bridge length of 305 m considering the effects of: (a) abutment height; (b) soil stiffness; (c) backwall to abutment stiffness; and (d) pile orientation on IAB response. Results of the parametric study showed that taller abutments, moderate construction joint stiffness, low soil stiffness, and strong axis pile orientation are best suited for IABs at extreme lengths. The length limitation study identifies that pile moments and concrete stress at the abutment/pile connection, concrete stress and transverse threading reinforcement shear stress at girder/backwall connection, and construction joint reinforcement are critical components in IAB responses and limit the bridge length. Finally, this study suggested a maximum length of 457 m on the basis of IAB critical responses.