DEVELOPMENT OF ANALYTICAL MODELS FOR PREDICTING THE FLEXURAL BEHAVIOUR OF ENGINEERED CEMENTITIOUS COMPOSITES – HIGH STRENGTH STEEL COMPOSITE BEAMS

Abstract

This paper presents the results of three-dimensional (3D) finite element (FE) and analytical models on the prediction of the flexural behaviour of composite beams comprising high strength steel (HSS) I-section and Engineered Cementitious Composite (ECC) slab. In the FE approach, 108 composite beam models which cover a wide range of key parameters including HSS grade, ECC compressive strength, HSS section depth, ECC slab thickness, ECC slab width were generated and analysed. The flexural strength of these composite beam models was subsequently employed to validate the accuracies of some commonly used flexural strength prediction methods that are originally based on the rigid plastic analysis (RPA). It was found that these methods generally underpredicted the flexural strength of the ECC-HSS composite beams. Hence, a simple analytical model was proposed, and validation results of its accuracy showed that this simple analytical model produced more accurate predictions than the RPA methods. In order to allow designers to obtain the load-deflection curves of the beams, a full analytical model which is based on strain compatibility and force equilibrium was also developed. Validations against both FE model and test results showed that this full analytical model produced the most accurate flexural strength predictions.