Generalized formulation for shear resistance on Y-type perfobond rib shear connectors

This study investigates the performances of Y-type perfobond rib shear connectors subjected to shear forces and vertical separations in steel-concrete composite girders through an experimental and numerical method. In previous studies, a series of push-out test specimens was used to investigate the effect of various parameters on the connector performance. Empirical formulas were proposed based on a regression analysis of various test results to estimate the ultimate shear resistance of the connector. However, the validity of these formulas has been verified for only the limited variables considered in the experimental program. Push-out tests covering wider ranges of design variables than previous studies are conducted in this study, and the numerical simulation model is adopted to evaluate the performance of various additional specimens as well, especially larger specimens with up to ten ribs. The effect of the hole diameter, transverse rebar diameter, and edge distance is also evaluated numerically. The changes in increasing rates of the ultimate shear resistance owing to the additional one-pair of ribs are found to converge to 44%p from a two- to a four-, six-, eight-, and ten-rib system. A formula to predict the ultimate shear resistance, which is a function of the rib shape dimensions, reduction factor due to an increase in the number of ribs, and concrete strength, is newly proposed based on the experimental and numerical results obtained from many different design variable combinations. With some additional refinements, the proposed formula may yield consistently reliable results. The proposed formula shows wider validity than existing formulas and is more applicable to various steel-concrete composite girders.