AbstractThis study examines punching shear failure at edge supported flat slab. Due to the significant dearth of research on punching shear at edge steel column, this study focuses on the design and performance of a novel shearhead system proposed for edge connection. By considering multi-stage processes and parameters that influence punching shear failure, both numerical and experimental studies were adopted. Firstly linear finite element analysis was employed to study the relationship between the continuous structure and the representative specimen; in order to support decisions on boundary conditions that create the similitude.
A nonlinear (NLFEA) model was proposed where various concrete material constitutive models were compared and contrasted. The Total Strain crack model was adopted on the ground that it accounts for the tensile strength of cracked concrete which was ignored in previous theoretical model that lead to poor prediction of punching shear. By considering the appropriate material constitutive model for concrete and steel, material parameters, appropriate modelling scheme capable of predicting punching shear was formulated. The adopted modelling scheme was validated using previous research work. Numerical results reveal that punching shear is influenced most significantly by concrete tensile strength, fracture energy.
The shearhead assembly was design with using ACI318-05 and Newzealand codes recommendations with some modifications. These are only codes that provide design guidance on shearhead. Experimental and numerical results show that the shearhead contributes appreciably to punching shear capacity of the edge connection.
Various design codes on punching shear were compared; Eurocode 2 provides a good prediction of punching shear at edge support; which correlate well with experimental result. Hence, it was adopted to propose an equation for punching shear for edge connection with shearheads.
Most importantly, appropriate design guidance and analytical equation have been proposed for shearhead connection. The design guidance and equation would enable practising Engineers to design shearheads without going through the rigor of experimental or numerical investigation. This study has contributed appreciably to the applicability of steel column in flat slab construction.
|Date of Award
|Adegoke Olubanwo (Supervisor), Neil Tsang (Supervisor) & John Karadelis (Supervisor)
- Iron & Steel