Study on performance level of prefabricated concrete walls under blast loading and seismic based on the standards of Iran

Document Type : Original Research

Authors
M. H. Taghavi Parsa 1
A. Geravand 2
1 IHU
2 Isfahan University
Abstract
Heeled concrete walls (T-Wall) are used for privacy, protection and some form of blockage. These walls can be built precast or cast in place and can be designed according to the possible loads such as blast loads, earthquakes, winds and so on. Also, the use of fiber concrete to absorb more energy and durability can be a good solution in the construction of such walls. Resistance, stability, and possibility of overturning of these walls due to the blast load and depth of buried walls are those that should be controlled by the designer. In addition to all the controls mentioned, one of the important issues is to optimize the cost of construction and consumables, so comparing reinforced concrete use with fiber reinforced concrete is of interest. In this study, six types of walls are considered: Type 1 and 2 walls with 3 m height and 2.5 m width, Type 3 and 4 walls with 4 m height and 2 m width and Type 5 and 6 walls with 5 m height and are 1.6 meters wide. Which, the walls of Type 5 and 6 are non-prismatic and are one meter buried in soil. In addition, type 1, 3 and 5 walls are made of fiber reinforced concrete and type 2, 4 and 6 walls are reinforced concrete. The purpose of this study is to investigate the resistance of concrete prefabricated walls against the impact and explosion. During an explosion, there is an explosive wave that spreads from the center of the explosion. Waves spreading at a later time are much faster than the speed of the initial waves. When a structure is exposed to the wave front, its surface pressure rises and reaches its maximum value in a very short time. This pressure affects the structure on all sides rapidly. This wave is a combination of high-pressure shock that emits outward from the center of the explosion and decreases as a function of the time and place of the explosion. The energy released by the explosion affects the structure in two ways. The first effect is the blast pressure, which is the key factor in determining the structural response, and the second effect is the dynamic pressure or the secondary pressure, which at high speed results in the debris being thrown around. Therefore, the most important parameter of an explosion is the forward blast pressure, the amount of which depends on the type of explosive and the weight of explosion. Hence, in order to find the above parameters, the 6 types of discussed wall modeled in Abacus software by CDP method. Also, the earthquake loading with different acceleration is applied to the walls and lateral displacements of them are calculated by using linear time history analysis with SAP2000 software. Finally, the performance level of walls under loads has been evaluated according to the national building earthquake loading criteria and 21th national building regulations. The results of the present study show that; the use of fibers has a positive effect on improving the performance level of prefabricated walls against dynamic loads such as explosion and earthquake.

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Modares Civil Engineering journal
Volume 20, Issue 4
November and December 2020
Pages 65-76