M. D. Chiranjeevi ¹, J. Simon ¹

Affiliations
1 Department of Civil and Chemical Engineering, VIT University, Vellore - 632014, Tamil Nadu, IN

Abstract

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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Burugula Subrahmanya Prasanth ¹, J. Simon ¹

Affiliations
1 School of Civil and Chemical Engineering, VIT University, Vellore - 632014, Tamil Nadu, IN

Abstract

Objective: Objective of this study is to find variation of parameters displacement, story drift, fundamental time period, base shear and column force with respect to geometry of building and of column. Methods/Statistical Analysis: Response spectrum analysis was done for all the models using ETABS software and all the above parameters are extracted from all the models including one reference model with rectangular geometry. All the models generated are compared with that of the base or reference models and the results are stated. Findings: It was found that the story drift was maximum at the bottom of the structure when compared to the above stories so as the displacement. Circular columns are found to have increased base shear when compared with remaining models. Improvements: Masonry in-fills induces stiffness which reduces the stiffness of the structure which decreases the displacement of building so inclusion of masonry in-fills can improve the stability of the building

Keywords

Asymmetrical Buildings, Column Orientation, Re-Entrant Corner Irregularity, Response Spectrum Analysis.

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