SolutionMilitary protection facilities
For corrugated steel plate military facilities , economical efficiency and constructability are important, but protection is even more important. If we compare the protective facilities constructed with corrugated steel sheet and concrete, concrete proceeds from cracking to fracture according to the strength of impact energy applied to the structure due to explosion, whereas corrugated steel sheet, a steel material, changes to deformation energy under the same conditions. . In other words, concrete exhibits considerable resistance to static compressive forces, but not to dynamic impacts applied instantaneously (Nano Second) such as explosions. In addition, although concrete has a high possibility of damage from debris caused by internal debris, secondary damage to the corrugated steel plate protective structure is very low or absent .
Through the 2002 experiment and FEA, 1m of circular corrugated steel sheet assembled with 3.2mm corrugated steel sheet was covered, and a 155mm shell (TNT 15lbs) was detonated on it. It was kept intact. If the concrete is 400mm thick under the same conditions, large cracks and fragments generated by back crushing may damage the personnel and equipment inside.
In conclusion, although the thickness of the corrugated steel sheet is thin, it is processed into a constant corrugation and the structural cross-sectional shape is circular and arcuate. (ADD, Hwarang University Research Institute, Military Academy, 2003)
In the case of military protection structures, the bomb penetrates the structure and explodes in the worst case, so for very important structures, direct penetration by the bomb is assumed. However, most general military structures are designed for local explosions in consideration of economic feasibility.
In the case of an explosion on the ground, storms and debris due to blasting occur, but generally, storms caused by blasting that can be predicted quantitatively are used as design variables. The storm effect is divided into "Blast overpressure" and "Impulse", and one of them is used as a design variable depending on the situation. On the other hand, in the case of an underground explosion, depending on the depth of the explosion, "Crater" is formed and the storm becomes dominant or "Ground shock" becomes dominant and affects the structure. If the explosion separation distance is the same, "Tamping" effect", the damage effect of underground explosions on structures may be greater.
Corrugated steel sheet ECM (Earth Covered Magazine) has the advantage that it can be economically constructed with high-thickness cover compared to concrete ECM. Therefore, whether it is a ground explosion or an underground explosion, the load transmitted to the structure is mainly "Ground shock", so the ground shock is the main factor in considering the resistance behavior of the structure against the explosion.
DESIGN CODE Corrugated steel plate ECM (Earth Covered Megazine) and protective facilities using corrugated steel plate are based on the Defense Design Standard (DMFC), It is designed and supplied in accordance with the US military design standards (UFC, ASTM). In addition, based on the research results of the 「Measures to apply steel materials for military facilities」 conducted by the Ministry of National Defense, 「Corrugated Steel Plate Underground Structure」 was published in 「National Defense/Military Facilities Standard」 in 2009. published in 2012 Corrugated steel plate design guidelines are included in 「Defense/Military facility standards」, 「Ammunition storage design guidelines」 and 「Steel protection tank design and construction guidelines」. etc. contains details.
Corrugated steel plate protection facilities, along with ECM, have been applied to hangars, K-9 protection facilities, 81mm mortar closures, and radar protection facilities in the Northwest Islands and DMZ sections since 2009, and have also been applied to civilian shelters.
The anti-condensation corrugated steel sheet ECM has improved ammunition storage efficiency and protection performance compared to the existing concrete ammunition storage, and has solved the problem of condensation through condensation research .
Corrugated steel plate protective wall Small lodging units in the platoon unit, which work on the front line of the front line, are mainly installed in prefabricated lodgings and do not have self-protection performance. Accordingly, depending on the situation of the military unit, it is the situation that the military dormitory protection wall is installed using earthen walls, waste tires, or waste drums. These existing defense walls are exposed to the threat of enemy mortars, and protection performance cannot be expected. Not only is this dangerous for a direct hit, but it can also cause massive casualties in melee explosions. The background of the application of the corrugated steel plate barrier in the 00 construction is that it has more protective performance than reinforced concrete, and the construction period is fast and secondary damage (rear fracturing) that occurs during enemy bombardment does not occur. The characteristics of steel barriers are as follows.
○ In the case of RC firewalls, secondary damage, such as human life and equipment, occurs due to back-fracture caused by shelling. However, steel-made firewalls ensure maximum survivability by securing protective performance against rear-facing fractures.
○ It is suitable for construction in mountainous terrain, remote areas, and winter season.
○ The construction period is shortened (50% compared to concrete) as no form, scaffolding, or RC curing is required.
○ Factory-manufactured, pre-quality inspection and on-site maintenance in case of damage are easy, and economical efficiency is excellent.