SKEWED BRIDGES WITH INTEGRAL ABUTMENTS

As background to a theoretical investigation to establish tentative recommendations on maximum safe lengths and skew angles for concrete and steel skewed bridges with integral abutments, a survey of the highway departments of all 50 states was made to obtain information on the design and performance of skewed bridges with integral abutments. The findings of the survey are summarized, including various design criteria and limitations being used; typical pile orientations being used in bridge design by the different states and types of analysis used for thermal expansion and contraction; assumptions being made regarding selected design parameters; specific construction details being used, such as approach slab, backfill, and pile cap; long-term performance of skewed bridges with integral abutments; and previous research on skewed bridges with integral abutments. The variation in design assumptions and length limitations among the various states in their approaches to the use of integral abutments is discussed. The problems associated with thermal-induced abutment movement and the solutions developed by the different states for most of the ill effects of abutment movement are summarized. In view of the lack of theoretical and experimental research in this area, it is hoped that the survey will provide some useful empirical experience and information on the design of skewed bridges with integral abutments. (Author)