Structural behavior of steel-concrete composite box girders in ultimate limit state under the interaction of bending, shear and torsion forces. Theoretical and experimental study

Author: Dr. Alejandro Giraldo Soto
Director: Prof. Dr. Alejandro Pérez Caldentey

Members of the academic tribunal

President: Prof. Dr. Hugo Corres Peiretti, HOD of Polytechnic University of Madrid
Secretary: Prof. Dr. J. M. Francisco Millanes Mato, HOD of Polytechnic University of Madrid
Member: Prof. Dr. Antonio R. Marí Bernat, HOD of Polytechnic University of Catalonia
Member: Prof. Dr. Pedro F. Miguel Sosa, HOD of Polytechnic University of Valencia
Member: Prof. Dr. Walter Kaufmann, professor of ETH Zürich


This thesis presents a theoretical and experimental study regarding the behavior in Ultimate Limit State of composite box girders composed of a reinforced concrete slab and a steel box. These girders, which represent an usual typology in composite road bridges, are subjected to the interaction of bending, shear and torsional forces. In addition, some considerations regarding the connection between concrete and steel are made and the influence of torsion in composite road bridges is evaluated.

The experimental results of two series of laboratory tests are presented and interpreted: the first one (EN-MV), developed in the 1990’s within the framework of the Structural Concrete Research Group (GHE) of the Technical University of Madrid, involved 8 tests that were carried out on composite box beams under the interaction of bending and shear; and the second one (EN-MVT), carried out recently by the same research group, in which the previous tests were reproduced, with slight adaptations, including torsion in the force interaction.

The experimental results are compared and discussed with respect to the theoretical models included in the specifications of the European regulations (Eurocodes), as well as those included in the Recommendations for the Design of Composite Road Bridges (RPX-95).

In addition, an easy-to-apply methodology, based on the specifications of the Eurocodes, is presented, which allows the design of composite box sections subjected to the interaction of bending, shear and torsion actions in Ultimate Limit State.

The review of earlier works reveals a lack of experimental studies with these characteristics. With the goal of serving as support for future research, an extensive compilation of all results and measurements related to the experimental tests (EN-MVT) are presented.


Composite steel-concrete, box girders, force interaction, influence of the connection, plate buckling, curved bridges, slip, torsion

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