Most of the out-of-plane experimental studies of steel plate composite (SC) walls have used tie bars instead of tie plates. It has been postulated that tie plates with high aspect ratios (i.e., tie plates with wide widths) may lower the out-of-plane shear capacity of the SC wall as concrete interlock is eliminated along the slip planes between the tie plates and concrete infill. This paper presents a parametric study of contact conditions for an SC wall section subject to out-of-plane dynamic loading. The study is performed in LS-DYNA and uses a generalized cross section comprised of wall and plate sizes typical for nuclear construction. Tie plates, spanning between the exterior face plates, are modeled with two height-to-width aspect ratios. The interaction between the SC wall steel plates and concrete infill is established through contact definitions. The contact definitions are varied and include frictionless contact, several contacts with varying friction coefficients, and tied contact (i.e., fully bonded). The system is subjected to both impact and blast loading (i.e., high-energy, low duration) out-of-plane loading. The performance of the various configurations is compared. The results indicate that the load carrying capacity of the system depends on the tie plate aspect ratio and the friction modeled....