ETABS Structural Design Workflow

A reference for setting up, analyzing, and designing a structure in ETABS — from grids and materials through final design checks.

01

Gather Basic Project Information

• Review the architectural drawings thoroughly before starting the model.
• On the initial ETABS screen, choose the working units and the applicable design codes.
• Lay out the structural grid to match the drawings.
• Enter the correct story data (heights and levels) for the building.
• Confirm the units used for length, force, and acceleration are consistent.
• Save the model file.

02

Set Up Material Properties

• Create the reinforced concrete (RCC) material.
• Create the structural steel material.
• Create the reinforcement/rebar material.

Note: If using ETABS' default materials, still verify their design property data before proceeding.

03

Set Reinforcement Bar Sizes

• Define the set of rebar sizes needed for the project.

04

Define Frame and Area Sections

• Define the correct material, modifiers, and rebar for BEAM sections, following a consistent naming convention.
• Define the correct material, modifiers, and rebar for COLUMN sections using a similar naming format.
• Define the correct material, modifiers, and rebar for WALL sections using a similar naming format.
• Define the correct material, modifiers, and rebar for SLAB sections using a similar naming format.
• Define the correct material, modifiers, and rebar for DECK sections using a similar naming format.

05

Define Diaphragms, Piers, and Spandrels

• Create one diaphragm label for each floor.
• Create pier labels matching the number of piers in the structure.
• Create spandrel labels only where spandrels will actually be modeled.

06

Verify Snap Settings

• Open Draw > Snap Options and confirm the required snap settings are enabled.

07

Build the Structural Model

• Draw the columns, beams, slabs, and walls, paying attention to whether you are working on a single story or all stories.
• Check the layout for cantilevered slabs, projections, water tanks, planters, ramps, or staircases.
• Assign fixed or pinned supports at the foundation level, as required.
• Model retaining walls where applicable.
• Assign end releases to beams as needed.
• Apply the diaphragms, pier labels, and spandrel labels as required.
• Review the model for any modeling errors and correct them.

08

Define Seismic FunctionsFor Dynamic Analysis

• Create the response spectrum and/or time history function(s) required for the analysis.
• Name each function clearly so it can be identified later.

09

Define Load Patterns

• Dead Load
• Super Dead Load (SIDL)
• Live Load (LL)
• Seismic Load in X (ELX)
• Seismic Load in X with +5% eccentricity (ELX+E)
• Seismic Load in X with −5% eccentricity (ELX−E)
• Seismic Load in Y (ELY)
• Seismic Load in Y with +5% eccentricity (ELY+E)
• Seismic Load in Y with −5% eccentricity (ELY−E)
• Wind Load in +X (WLX)
• Wind Load in +Y (WLY)
• Wind Load in −X (WL−X)
• Wind Load in −Y (WL−Y)
• Thermal Load, if the building length exceeds 45 m
• Fire Tender Load
• Snow Load, if applicable
• FATO (rooftop helipad) load, if applicable
• Mass source, clearly named for later use

10

Apply the Loads

• Apply Dead Load, joint load, frame, or shell load, as appropriate.
• Apply Super Dead Load in the same manner.
• Apply Live Load in the same manner.
• Apply Wind Load in X.
• Apply Wind Load in Y.
• Apply Seismic Load in X.
• Apply Seismic Load in Y.
• Apply Thermal Load.
• Apply the fire tender shell load.
• Apply snow shell loads.
• Apply helicopter (FATO) loads.
• Set the live load reduction factors.

11

Define Load Cases

• Confirm every load pattern has a corresponding load case in ETABS.
• Define the Response Spectrum case in X, using the appropriate default scale factor, and verify the acceleration units.
• Define the Response Spectrum case in Y using the same scaling approach and unit check.
• Define modal load cases (Eigen or Ritz) as required — CSI generally recommends Ritz analysis.
• Set up P-Delta or pushover options if the project requires them.

12

Define Load Combinations

• Set up the load combinations in accordance with BNBC 2020.

13

Configure Analysis Options

• Apply meshing to frame and shell elements based on project needs and model size.
• Recheck the model for errors.
• Use Edit > Auto Relabel All to clean up labeling.
• Verify active degrees of freedom (relevant when analyzing trusses or single-plane frames).
• Confirm which load cases are set to run.
• Review the Advanced SAPFire analysis options to control analysis sophistication.
• Run the analysis and check the diaphragm center of rigidity.

14

Review Analysis Results

• Check the “Show Details” log for instability warnings; if the model is unstable or ill-conditioned, return to Step 7 and check for excessive deflection or displacement.
• Review the analysis log and any result warnings.
• Spot-check the global forces against approximate hand calculations.
• Review the deformed shapes for the first and second mode against expected behavior.
• If the first or second mode shows torsional behavior, return to Step 7 and adjust the wall layout (add or remove walls) to reduce torsion — checking the center of rigidity can help locate the issue.

15

Scale the Seismic Functions

• Determine the scale factors required for the response spectrum in X and Y.
• Unlock the model and apply the scale factors to the response spectrum functions.

16

Re-run Analysis and Verify Code Compliance

• Confirm the response spectrum scaling was applied correctly.
• Check the mass participation factors for the first three modes and cumulatively across all modes.
• Check inter-story drift and overall deflections, including under service load conditions.
• Review stiffness, deflection, and other key design values from the result tables.
• If any results do not meet code requirements, return to Step 7 and revise the model.

17

Design the Structure

• Review or update the design preferences for concrete, steel, and shear wall design.
• Confirm which combinations are required for designing each component (e.g., beams).
• Run the design check and identify any members that fail.
• If a member fails, revise its section, unlock the model, save it, and repeat the analysis from Step 13.
• Begin detailing or prepare the structural drawings manually.
• Review the support reactions and export them to CSI SAFE if needed.