International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 10 Issue: 06 | June 2023
p-ISSN: 2395-0072
www.irjet.net
“Comparative Analysis of Blast Load on Multi Storey R.C.C. Building at Different Locations” Rajvee Patel1, Aakash Suthar2 1Student, Civil Engineering Department, L.I.J.E.T. Ahmedabad, Gujarat, India
2Assistant Professor, Structural Engineering Department, L.J.I.E.T. Ahmedabad, Gujarat, India
---------------------------------------------------------------------***--------------------------------------------------------------------1.1 EXPLOSION & ITS TYPES Abstract - The increase in terrorist acts in recent years has made it clear that the effects of blast load on the structure are an important factor to be considered during the design phase. The primary goal of this article is to shed light on the comparative analysis of the building subjected to blast load is done by using Etabs software. Here 32 different load cases are taken, in which for external load with special emphasis placed on different standoff distances of blast that is 20m and 30m with incorporation of various TNT charge weights that is 50kgs, 100kgs, 200kgs and 300kgs in accordance with IS code 4991(1968). For internal load TNT charge of 50kgs, 40kgs, 30kgs and 20kgs are applied on corner column and central column of the building at various storeys. Response of models when subjected to blast load, in terms of storey displacement, storey drift and storey shear are analyzed using Time history analysis.
There are three kinds of explosions:
1.INTRODUCTION Due to increase in the no. of accidental explosion and terrorist bombing on the important building like govt. buildings and other civilian facilities, structural protection against explosive loads draws more and more attentions. Blast loads are extremely short in nature but have high intensity, therefore analysis and design of structure for static and less dynamic loads like earthquake, wave and wind loads cannot be applied for structural design of blast resistant buildings. Also, the material behavior and structural response under blast load are usually nonlinear, time dependent and have complex stresses. Current approaches for blast resistant building designs mainly based on single degree of freedom (SDOF) simplification. Field and laboratory tests are not safe and easy to carry out and are expensive, therefore various computer technology and software such as ETABS are used for getting more reliable and detailed numerical and structural responses. Various time-history functions such as displacement, velocity, drift, acceleration is compared and analyzed at various storeys.
|
Impact Factor value: 8.226
Unconfined explosions
•
Confined explosions
•
Explosions occurred when explosives are attached to the structure
Unconfined explosions are either air burst or surface bust. In an air burst explosion, the high explosive detonates above ground level, and intermediate ground reflection amplification of the wave occurs before the primary blast wave reaches a building. A front known as a Mach stem is created by the interaction of the initial wave and the reflected wave when the shock wave propagates outward along the ground surface. However, when the detonation takes place near or on the ground surface, an explosion known as a surface burst. When an explosion occurs within a building, the pressures associated with the initial shock front will be high and therefore will be amplified by their reflections within the building. This type of explosion is called a confined explosion. If a detonating explosive comes into contact with a structural element, such as a column, the arrival of the detonation wave at the explosive's surface will cause intense stress waves to form in the material, which will cause the material to be crushed.
Key Words: Blast Load, Standoff Distance, RCC structure, Etabs2020, Time History Analysis, Displacement, Drift, Storey Shear.
© 2023, IRJET
•
Fig.-1: Fully vented, partially vented and fully confined explosion
1.2 BLAST CHARACTERISTICS When an eruption takes place, an exothermic chemical reaction happens in a period of few milliseconds. The explosive material (in either continuous or liquid form) is converted to very intense, dense, high-pressure gas. This well compressed air, traveling radially outward from the
|
ISO 9001:2008 Certified Journal
|
Page 802