Evaluation of Prestressed Dapped Girder with Cazaly Hangers

Abstract

The load carrying capacity of the hinge region of an existing highway overpass is evaluated using the strut-and-tie modeling technique. The overpass consists of a series of drop-in span girders that are supported at the center by doubly cantilevered pier girders. The hinge is achieved through the use of an incorporated steel piece, a Cazaly hanger, in the ends of the span girders. This paper will examine the disturbed end regions of both the span and pier girders. The strut-and-tie model demonstrates how the Cazaly hanger can be incorporated into the model. The girders are prestressed, which is taken into account by modeling the prestressing as equivalent forces applied to the concrete. This paper demonstrates how to evaluate the load carrying capacity of an existing concrete structure and how to develop a strut-and-tie model based on the existing reinforcement configuration.