Effectiveness of continuity diaphragm for skewed continuous prestressed concrete girder bridges

Continuity diaphragms have caused difficulties in detailing and construction when used in bridges composed of prestressed concrete girders supported on skewed bents. This study investigates the effect of full-depth continuity diaphragms on the deflection of, and stress in, skewed precast, prestressed concrete girders. Bridge models used in this study had the following parameters: girder type and spacing, bridge skew angle, span length, and diaphragm type. As either the skew angle increases or the girder spacing decreases in these types of bridges, construction becomes more difficult and the effectiveness of the diaphragms becomes questionable. If diaphragms are determined to be unnecessary as an outcome of this research, the construction and maintenance costs of these types of bridges could possibly be reduced. The objectives of this research were to determine the need for continuity diaphragms in skewed, precast, prestressed concrete girder bridges; study the load transfer mechanism through full-depth continuity diaphragms; and determine the minimum skew angle at which a diaphragm becomes ineffective in performing its function.