Research on the co-working behaviour of a corrugated steel plate with a sinusoidal cross section and concrete has rarely been published. Despite the fact that the conventionally used concrete trapezoidal-cross-sectional metal sheet composite slab has been widely investigated and exhibits several geometrical similarities with the corrugated-steel-plate–concrete (CSPC) composite slab, a significant difference exists in the co-working behaviour, requiring detailed study. Substantial research work is necessary before the CSPC composite member can be employed in the construction of buried culverts as expected, as an alternative to concrete and metal culverts. In this study, a newly proposed small-scale push test was conducted to investigate the longitudinal shear behaviour of CSPC composite members. Specimens with conventional stud shear connectors and newly designed inverted umbrella connectors were tested to validate the effects of the connector shank diameter, shank length and spacing on the shear behaviour and resistance of the two connector types. The lower-than-expected test results of shear resistance and slip capacity were discussed compared with the results from analytical methods and optimized numerical models. Finite element models were constructed in the ABAQUS software to verify the feasibility of nonlinear finite element method analysis on CSPC composite members. Optimisation suggestions for the small-scale test were finally proposed concerning other factors such as the support condition, significantly greater shank length and concrete thickness.