Field-Measured Response of an Integral Abutment Bridge

摘要

Integral Abutment Bridges (IAB) or jointless bridges are increasingly being used to eliminate undesirable effects of bridge joints on the long-term performance of bridges. However, the behavior of abutments in an IAB is poorly understood. This paper describes an effort to understand the complex soil-structure interactions occurring in IABs through field instrumentation. Data from the field monitoring of a 210 feet long, three span IAB with a 10° skew in Oklahoma are presented. Instrumentation includes pile strain gages, earth pressure cells, tiltmeters, crackmeters, and thermistors. Results collected over a year are presented and include a bridge temperature change of 94 °F (13.0 °F to 106.5 °F). Earth pressures on the abutments induced by thermal loading of the bridge are consistent with temperature changes. Recorded readings from crackmeters are also consistent with the expected behavior of abutments rotating outward during heating and rotating inward during cooling. Although fairly significant abutment back pressure has been recorded, there is no clear indication that the abutment piles have yielded.