Designing Multi-Storied Buildings in E-Tabs

Feb 17, 2025

Lecture Notes: Design in E-Tabs as per IAS Code - Part 2

Overview

  • Part 1 Recap: Modeling a multi-storied building including basement, ramp, underground water tank, overhead water tank, and applying loads.
  • Part 2 Focus: Assigning diaphragm, applying seismic and wind loads, resolving warnings, assigning pier and dispensary levels, mass source sensitivity, analysis and design as per IS 456-2000.

Diaphragm Assignment

  • Assign diaphragm from basement roof, select xy plane.
  • Consider semi-rigid diaphragm for realistic simulation of in-plane stiffness.
  • Assign diaphragms appropriately across different floors.

Earthquake and Wind Loading

  • Seismic Loads: Follow IS 1893-2016.
    • Assign seismic zones based on location (Zone 3 used as an example).
    • Select site type based on soil conditions (medium soil example).
    • Importance factor varies by structure type (residential = 1.0).
    • Use special moment resisting frame with response reduction factor 5.0.
  • Wind Loads: Follow IS 875-2015.
    • Determine wind speed and terrain category based on location.
    • Consider similar parameters for topography (k3 factor, etc.).

Model Warnings and Null Beam Resolution

  • Check for model warnings and resolve issues by replacing null lines with null beams.
  • Define null beam properties to mitigate warnings.

Load Patterns and Mass Source

  • Ensure self-weight multiplier is used correctly to avoid over-design.
  • Define mass source considering partial live load and soil/water pressure.

Pier and Spandrel Assignment

  • Assign pier and spandrel levels following structural guidelines.
  • Use auto-pier assignment for basement walls with no openings.

Analysis and Design Considerations

  • Conduct analysis ensuring no model warnings.
  • Generate design combinations for concrete frames and shear walls.
  • Optimize column and beam design by adjusting sections, and using reinforcement effectively.
  • Rotate columns to better resist seismic forces when applicable.

Beam and Column Design

  • Modify beam size and use torsion release where compatible.
  • Provide shear walls at peripheral sides when larger column sections alone are inadequate.

Shear Wall and Spandrel Design

  • Assign shear wall design combinations.
  • Review shear wall reinforcement and design boundary elements as required.

Additional Tips

  • Respond to viewer comments and adjust approaches (e.g., stiffness modifier use, torsional constants).
  • Importance of checking model thoroughly before proceeding to final design.

Conclusion

  • Emphasize the importance of thorough checking and optimization of design elements.
  • Encourage viewing additional tutorials for detailed explanations on specific topics like shear wall design, spandrel design, etc.

Viewer Engagement

  • Suggestions to join as a subscriber to access resources and further support for tutorials.
  • Encourage community interaction through comments and joining tutorials for additional insights.