Finite Element Analysis of Dapped-Ended Concrete Girders Reinforced with Steel Headed Studs

Abstract

The application of dapped-ended girders in concrete construction arises in situations where it is desired to maintain continuity between adjacent members. Dapping involves recessing the end of a girder such that it can be placed on to supporting components. Due to the sudden decrease in cross sectional area, significant shear strength in the member is lost and the introduction of a re-entrant corner makes the girder prone to shear cracking. Careful shear reinforcement must therefore be provided at the re-entrant corner. Using headed studs in place of conventional reinforcement was first proposed by Herzinger and El-Badry (2007) at the University of Calgary. They performed experiments which showed that headed studs were effective in maintaining the strength and ductility of girders reinforced using a combination of horizontal, vertical, and inclined configurations. The experimental data was compared with the shear friction and diagonal bending methods of analysis. Overall, the experiments and analytical methods showed good agreement, but the accuracy of the methods varied in certain situations depending on the layout of the headed studs. The current study is a finite element analysis (FEA) of seven of the specimens tested by Herzinger and El-Badry (2007) using software ABAQUS. Results show that the diagonal bending method is more suited for specimens with inclined reinforcement while shear friction best predicts members with only horizontal and vertical reinforcement. As well, in analyzing dapped-ended concrete girders, a variety of parameters can impact the results of the model, but proper calibration can lead to the models’ suitability in being used for future parametric studies.