BLAST RESISTANT BUILDINGS,
The design of buildings resistant to terrorism.
ABSTRACT:
Now all western democratic states are well aware of the apocalyptic consequences of a good attack on high-level government facilities and other related targets. Many of these buildings are constructed using historical, ornamental, modern and traditional techniques. The modern refrigerated commercial techniques used to protect these structures against terrorist attacks are numerous, ill-considered, intrusive or inappropriate.
However, security experts are well aware that while little can be done to defend a building against airstrikes, much can be done to defeat conventional car bombs and bullets. The structure discusses available methods available to the structural engineer to strengthen existing structures and provide resistance to the effects of blast attacks.
INTRODUCTION:
The design of civilian or commercial buildings is unlike the design of military installations or embassy buildings to prevent the effects of a terrorist explosion. The objectives of the "Structural Engineering Guidelines" for the design of new embassy buildings are to prevent heavy damage and structural collapse of the components. Adherence to the instruction clauses will minimize the loss of injuries and lives and facilitate the escape and rescue of survivors. The purpose of any commercial or public building explosion should be the same as the embassy structure, to prevent structural collapse, save lives and evacuate victims.
Architectural and structural features play an important role in determining how a building will respond to explosion loads. These features may include adjacent or underground parking, atriums, transfer girder, slab configuration, and structural frame systems. Distance is very important to keep in the design of explosive structures as it is the key parameter that determines the blast pressure that loads the building and its structural elements. The degree of fenestration is another key parameter as it determines the pressure that enters the structure. Small enclosures of doors and windows secured from embassies and military structures occupy safe spaces. By following these key parameters,
EXPLOSION-MAJOR OF ALL THE TERRORIST ACTIVITIES
The chances of any building accident or intentional explosion from damage are very low, but the cost to those who are not ready is very high.
1. EXPECTED TERRORIST BLASTS ON STRUCTURES.
• External
car bomb
• Internal
car bomb
• Internal
package
• Suicidal
car bombs
2. MAJOR CAUSES OF LIFE LOSS AFTER THE BLAST.
• Flying
debris
• Broken
glass
• Smoke
and fire
• Blocked
glass
• Power
loss
• Communications
breakdown
• Progressive
collapse of structure
3. GOALS OF BLAST RESISTANT DESIGN
The
goals of blast-resistant design are to:
• Reduce
the severity of the injury
• Facilitate
rescue
• Expedite
repair
• Accelerate
the speed of return to full operations.
BASIC REQUIREMENTS TO RESIST BLAST LOADS
To prevent the explosion,
- The first requirement is a risk assessment. The biggest threat is due to terrorist bombings. The risk for conventional bombs is defined equally by two key elements, the size of the bomb, or the charge weight and the standing distance. Minimum guaranteed distance between explosion source and targets
- The second requirement is to keep the bomb as far as possible by maintaining maximum distance. No matter what size the bomb is, the damage will be as severe as the target.
- The hardness of structure should, in fact, be the last way to protect a structure. Detection and prevention should be the first line of defense. Because the threat of terrorist attacks in Oklahoma City ranges from small-liter bombs to large truck bombs, traditional mechanics and their effects on the target must also be taken into account.
MECHANICS OF A CONVENTIONAL EXPLOSION
A massive explosion of TNTs at or near ground level, the peak blast pressure resulting in the elimination of this hemispherical explosion, disperses the source of the trauma, such as the frontal range. ۔ The high pressure of the event is heightened by a reflection factor as the shock wave faces an object or structure in its path.
Except for the specific focus of high-intensity shock waves at 45 ° incidence, these reflecting factors are usually greatest for normal events (relative to the source and length) and the source-specific length or length. The angles of the angular position are less than. Reflection factors depend on the severity of the shock wave, and in normal, normal events for large explosives, reflecting factors can increase incident pressure as much as charges close to a target's structure.
Has imposed a very satisfactory, high pressure on the locality of the structure. Remote charges produce low intensity, long-term uniform pressure distribution over the entire structure. In terms of pure geographical relationships, the larger the standout, the greater the pressure distribution on the target. After all, the whole structure is engulfed in a wave of shock, its reflection and reflection effects create a complex pattern of shadows and shadow zones around the structure. After the initial explosion wave, the structure is subjected to negative pressure, suction phase and finally a steady explosion. During this phase, weak structures can be affected by debris, which can cause additional damage.