## 1 Introduction  
Evaluating the degree of protection is an important factor in the design of military and civilian structures. Securing an adequate degree of protection in military facilities particularly plays a crucial role in achieving a national security strategy. One aspect of the protective structure evaluation is the structure's reliable degree of protection against blast loading. Empirical experiments are the most definite method of verifying the protective performance of structures subject to blast loading. However, repeating the experiment enough times to ensure reliable results is significantly expensive, and empirical experiments have numerous spatial, temporal, and economic constraints. Moreover, as the explosions for these empirical experiments can cause civilian damage due to noise and vibrations, they are conducted on a very limited basis. The installation of full-scale structures is another limitation that makes empirical experiments difficult to perform. Considering protective performance verification,protective facilities must be designed and verified to satisfy the Defense Military Facility Criteria (DMFC 4-70-00) depending on the facility under examination [1]. The required protective performance is specified in these criteria according to the protective facility type and purpose, and each structural member of the facility must be designed to satisfy these requirements. After evaluating the blast pressure and penetration of the weapon, the protective structure is finally adopted based on the effects requiring the highest protective performance. Generally, the structure requires a deeper thickness than the penetration depth of the weapon; however, direct hits are rarely set as an enemy threat outside of special cases. Artillery projectiles and aircraft bombs are evaluated based on the scenario of a near-miss explosion, considering the weapon's accuracy. Penetration from direct hits causes severe local damage to certain elements of the structure, whereas blast waves cause overall damage of a relatively lesser severity to the structure. Therefore, careful examination of the overall protective structure's safety against blast waves is required. Thus, while local damage from the penetration can be verified by assessing the degree of protection of the materials and structural elements, for blast waves, the safety of the overall structure must be evaluated. As a result, evaluating the degree of protection against blast waves introduces challenges involving the assessment of the building's overall structural behavior [2; 3; 4]. The designer of the protective structure must first analyze the weapon effects, design the structural members, and then evaluate the overall structure's safety through blast resistance tests, though there are several constraints in reality. Many researchers have recently used finite element analysis as an alternative to blast loading verification using actual structures [5; 6; 7; 8; 9; 10]. To verify protective performance through numerical analysis, the evaluator must first understand the loading effect of blasts on the structure. It is important to understand the structure's behavior when subject to blast loading. Because the numerical analysis of explosions concerns the structural behavior that manifests in a significantly short period of time, there are additional considerations such as inertial force, kinetic energy that differs from typical static numerical analyses [11; 12]. Accordingly, to evaluate the protective performance of protective structures, this study aims to derive a method for evaluating the protective performance according to the blast loading scenario and provide a protective performance verification method through numerical analysis based on a case study. To identify the appropriate blast loading scenario, the weapon effects and dynamic factors pertaining to mission, enemy, terrain and weather, troops and support available, time available, and civil consideration (METT+TC) were considered.