Instantaneous and time-dependent response and strength of jointless bridge beams

Abstract

The purpose of this study was to develop a generalized numerical solution for the analysis of deck-continuous, composite, multi-span bridge girders without joints. A finite element computer program has been developed, with the capability of performing instantaneous and time-dependent response analyses, and strength analyses, for a general type of bridge beams. Steel, reinforced or prestressed concrete girders, topped by a reinforced concrete deck-slab, under various sequences of construction and with different types of continuity may be equally analyzed by the proposed solution. An isoparametric beam element and a connection, spring-like element, have been modified for modeling the nonlinear intrinsic characteristics of the materials, as well as accounting for the presence of mild steel reinforcements, prestressing tendons and the effects of cracking. Timependent properties of the comprising materials are assumed to follow the simplified models suggested by the American Concrete Institute and Prestressed Concrete Institue. The effects of a superimposed temperature gradient are included also in the analysis. A thorough description of the problem and of the properties assumed in modeling the materials is given first, followed by development of the finite element formulation. The proposed solution is validated by the analyses of ten different beams, with comparisons being made with available analytical and experimental data. Two different cases of deckcontinuous, jointless, multi-span beams are investigated and their performances are compared to the extreme situations of non and full continuity. Their behaviors have been found to be very satisfactory under dead and service load conditions . Under vertical loading, the response of a deck-continuous beam may be comparable to the response of a non-or fully continuous beam, depending primarily on the imposed supporting conditions.