Behavior of RCC T-Beam Bridges with Cross Diaphragms in Nonlinear Range

Abstract

Behavior of reinforced cement concrete (RCC) T-beam bridges with cross diaphragms is studied for a realistic range of values of three parameters, such as span, type of loading (specified by Indian Roads Congress), and type of bridge deck layout. The method used for this study is based on the grillage idealization of RCC T-beam bridge superstructures. Material nonlinearity is considered through elastoplastic idealization of moment curvature and torque-twist relationships of the cross section. Geometrical nonlinearity has been neglected. The important conclusions which have emerged from this study are as follows: The behavior of RCC T-beam bridge superstructures can be broadly classified into two categories depending on the type and location of formation of the first plastic hinge. Category I is identified with the formation of first plastic hinge, which is a torsional hinge in the mid outer cross girders. Category II is identified with the formation of the first plastic hinge, which is a flexural hinge in the exterior longitudinal girder under the maximum loading. Bridge superstructures falling under Category I are associated with a greater degree of redistribution and more ductility as compared to those under Category II.