Moment-curvature Model for Steel Plate-concrete Composite Beams

Abstract

The rapid development of composite structures has led to a new design concept of the steel plate-concrete composite beam in which a thin steel plate is attached to the reinforced concrete beam. The shear connection is established by the use of headed studs and the joined parts can act as a unit due to the adequate bond between the steel and concrete. The behavior of this type of structures can be classified as intermediate between composite and reinforced concrete structures.The experimental studies have shown that the methods described in standard codes allow to determine the ultimate load of the structure, while the structure's deflection is underdetermined. More sophisticated analyses of beams are more accurate but they are used in practical design rather reluctantly. The purpose of this paper is to present a moment-curvature model which can be used in simplified calculation of deflection of steel plate-concrete composite beams. Instead of adopting the complex theoretical analysis, a trilinear model is represented by pre-cracking, post-crack and post-yielding stages. The additional deflection due to shear slip at the interface plane is taken into account. The slip effect always exists both in fully and partially composite beams and experimental studies have shown that it has a significant impact on the response of the structure. Tension stiffening effects are also considered since beam rigidity is reduced when cracking is developing due to an increase of the applied load. For validation purposes a theoretical analysis based on the presented model was performed and compared with the experimental results. The predicted results of the analytical studies were compared with the measurements of the tested beam to confirm the validity of the proposed method. It was confirmed that including the shear slip effect has significantly improved the accuracy of prediction.