Analytical investigations to the specimen size effect on the shear resistance of the perfobond shear connector in the push-out test

Perfobond shear connectors (PSCs) are widely used in steel-concrete composite structures as an available alternative to the shear studs which have a limited shear resistance, and are prone to fatigue problems. The evaluation of the structural performance of PSC ribs is mainly obtained through a destructive test known as the push-out test (POT). However, the size of the specimen in the POT is varied significantly. The main objectives of this study are (i) to examine the effect of the POT specimen size on the predicted shear resistance of the PSCs by conducting numerous numerical analyses to the design parameters that affect the shear resistance obtained from POT test. The numerical investigations were conducted utilising several empirical shear resistance equations which are originally derived from the regression analysis of the POT results. These investigations were performed on Eurocode-4 (EC-4) and British Standard-5 (BS-5) POT specimens as the size of these specimens is varied significantly. Furthermore, (ii) to quantify the scale of the influence of the design parameters in the POT on the resulting shear resistance by conducting several sensitivity numerical analyses as the design parameters have variable effects on PSCs shear resistance The results of this study suggest that the size of the POT specimen has a minor effect on the predicted shear resistance which might have the same effect on the actual shear resistance from the push-out test. In addition, the results of the sensitivity numerical analyses have shown that both the diameter of the holes and the rebars are the most influential factors on the shear resistance of the PSC, and the thickness of the connector has the least influence among the other design parameters, and the effect of the design parameters on the PSC shear resistance is varied according to the geometry of the connector. Further, a more efficient design for PSCs is presented by selecting large holes in a small number instead of small holes in a large number for the same cross-sectional area of the connector. This efficient design has the potential to increase the PSC shear resistance which directly affects the bending resistance and deflection of the composite beams that employ the perfobonds as a shear connector.