Indian Journal of Science and Technology
Year: 2016, Volume: 9, Issue: 30, Pages: 1-6
M. D. Chiranjeevi* and J. Simon
Objectives: The main objective of this paper is to prevent the structures from blast loading and familiarize with design methods followed as per UFC guidelines. To prevent from these extreme loads we have adopted alternate path method for design. Methodology: Blast loads are generally dynamic in nature, so that it varies with time comprising of two phases namely positive phase and negative phase. In this paper for analysis of structure, we have considered only positive phase for the analysis. The load is applied as a triangular impulse loading as a time history variant neglecting the negative phase of the loading. The numerical model of this structure is created and analysed using the STADD. Pro software. The load values required for the model are obtained from IS:4991, the blast parameter values are found for a standoff distance of 20m,30m and 40m by varying charge weight as 100KG, 500KG and 1000KG. Analysis is carried out for different grades of concrete in STADD. Pro and results are compared and analysed. Progressive collapse is also checked by providing plastic hinges in the structure as per FEMA 356 provisions using SAP2000 as per UFC guidelines. Findings: The alternate approach followed shows the structure is safe by removing columns at different positions. The results obtained shows the plastic hinges formed in the corner column are higher compared to any internal columns. Improvements: Further improvements adopted can be by applying special design for reinforcements apart from general design.
Keywords: Blast Load, Positive Phase, Progressive Collapse, Plastic Hinges, Standoff Distance, Triangular Impulse Loading
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