Project 2_Design & Analysis of a Hostel building at Guwahati, Assam

Aim – To model and analyse a G+3 building in seismic zone and given data Etabs and its piles foundation in SAFE.

Procedure-

• Open Etabs 2020 and enter the grid data and story data for modelling.
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• Enter story data.
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• Define materials.
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• Define frame section for columns and beams.
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• Define slab property.
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• Add load patterns in etabs.
• AAC wall will be 3.5 kN/m.
• Live load will be 2 kN/m2
• Floor finish load will be 1.5 kN/m2
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• Define mass source for the structure.
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• Draw the model by adding column, beams and slabs in Etabs.
• Carefully assign loads to the structure.
• Terrace and mumty level will have less live loads compared to other floors.
• Brickwall loads on beams.
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• Live loads and floor finish loads on slabs.
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• Define load combinations in the structure.
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• Add diaphgram on the model.
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• Check the model for any errors.
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• Run analysis on the model.
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• Display tables> Modal participating ratios.
• Check for mode 1 and mode 2 10% difference.
• Check if first three modes make up 65%.
• Check that third mode is less than mode 1 and mode 2.
• All checks are done hence safe.
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• Check story response for max story drifts for seismic forces in x and y direction.
• Both are less than 4% hence safe.
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• Check for concrete frame design.
• Longitudinal reinforcing.
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• Shear reinforcing.
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• Check if any frame sections are over stressed in the model.
• If they are then increase the depth or width of the section.
• Our model is safe and does not have any over stressed sections.
• Design the columns and beams according to area of steel required and area of steel provided.
• Now export the model .f2k file for safe modelling.
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• Select all the above loads and all loads.
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• Open safe software and import that .f2k file in safe.
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• Check if all the loads are applied in the points.
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• Now define material and slab properties in the safe.
• Add column, pile caps and piles with a depth of 800mm.
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• Define frame section for tie beam for the pile caps.
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• Define point spring property data that is to be applied on the pile.
• Spring constant= EA/L = 490.87 kN/m
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• Now draw the pile caps, piles and columns in the safe model.
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• Assign point spring loads on the piles and point loads on the columns.
• Run analysis of the model.
• displacements.
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• Check for punching shear.
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• All punching shear value are less than 1 hence safe.
• If greater than 1 then increase the depth of the footing.
• Design strips for the model .

Results-

• The model of g+3 hostel building which is seismic zone 5 having soil type 3 which requires a pile foundation was designed in Etabs and safe. Reinforcements required for the frame sections was acquired. And designed accordingly.