When concrete with high flowability is cast into compartments of sandwich members, there is possibility that the concrete is not filled completely in these compartments.
　To know influence of incompletely filled parts to mechanical properties of the sandwich members, static loading tests are carried out. In test specimens, the unfilled part is exsisted between the upper steel plate and the flange of steel angles.
　Through the loading tests, decrease of strength of the incompltely filled sandwich members is at most 20% in comparision with the completely filled sandwich member. Failure mechanism of the incompletely filled sandwich member as to bending moment and shear is not appreciable different from that of the completely filled sandwich member.