Safety of Partially Prestressed Highway Bridges

The safety of partially prestressed bridges has been a matter of some concern since the fretting fatigue phenomena was discovered in the mid-1980s. This phenomena is not easy to assess due to the random nature of variables influencing fatigue. In this paper, reliability methods have been used to assess the overall safety against fatigue of a wide range of partially prestressed concrete highway bridges. Safety against fatigue is represented by a reliability index (probability of failure) calculated with respect to reinforcing and prestressing steel. Fatigue tests have shown that these elements are particularly critical for post-tensioned partially prestressed bridges in which fretting fatigue is a potential problem.