Modelling of 25 storey building with the specified properties using ETABS

1. ^{Model Initialization in ETABS:}

• ^{Open ETABS software.}
• ^{Click on New Model.}
• ^{In the New Model Quick Template dialog, select Custom Grid Spacing.}
• ^{Click Edit Grid Data and set your custom grid spacing.}
• ^{After setting the grid, click OK.}

^{2. Story and Grid Data:}

• ^{Under Story Dimension, click Edit Story Data.}
• ^{Set the story data for the first three stories, with Story 1 as the master story.}
• ^{Right-click on the first column, select Add Story, and click Keep Existing Story Heights.}
• ^{Add 22 more stories (to make it a 25-storey building).}
• ^{Click OK.}

^{3. Defining Materials:}

• ^{Go to Define → Material Properties.}
• ^{Add new material for Concrete (Grade M30).}
• ^{Add new material for Steel Rebars (Fe 415).}
• ^{Click OK.}

^{4. Defining Sections:}

• ^{Go to Define → Section Properties → Frame Sections.}

• ^{Click Add New Property for Beam:}

  • ^{Select Rectangular shape and input beam dimensions: 300 × 400 mm.}

• ^{Add a new property for Column:}

  • ^{Input the column dimensions: 800 × 800 mm.}

• ^{Click OK.}

• ^{Go to Define → Section Properties → Slab Section.}

• ^{Select Add New Property for the slab, and set the thickness: 150 mm.}

^{5. Defining Load Patterns and Loads:}

• ^{Go to Define → Load Patterns to define the load types.}
• ^{Add load cases for Dead Load, Live Load, and Seismic Load.}

^{6. Defining Mass Source:}

• ^{Go to Define → Mass Source to assign mass to the building based on the load patterns.}
• ^{Define load cases under Define → Load Cases.}

^{7. Creating Load Combinations:}

• ^{Go to Define → Load Combinations to create necessary load combinations based on the seismic requirements (dead load, live load, seismic load, etc.).}

^{8. Drawing the Building:}

• ^{Quick Draw Columns: Use the Quick Draw Column tool to place columns in the model.}
• ^{Quick Draw Beams: Use Quick Draw Beams to place beams.}
• ^{Select the first horizontal and vertical beams and use Edit → Replicate to replicate them across the building.}
• ^{Draw the slab by selecting Quick Slab, ensuring that the slabs in all stories are similar.}

^{9. Assigning Loads:}

• ^{Select all beams and go to Assign → Frame Loads to assign distributed frame loads.}
• ^{Select the slabs and go to Assign → Shell Loads to assign uniform shell loads.}
• ^{Assign Diaphragm to the slabs by selecting the slabs from the Select tab and using Assign → Diaphragm.}

^{10. Running the Analysis:}

• ^{Save the model.}
• ^{Click Run Analysis from the analysis panel.}

^{11. Viewing Results:}

• ^{After the analysis, go to Display → Story Response Plot.}
• ^{Change the display type to Maximum Storey Drift.}
• ^{Select the desired load combination to view the results.}

^{Verification of Seismic Code Requirements:}

• ^{Ensure the building meets seismic design requirements as per IS 1893 (for India) or the relevant seismic code for the region.}
• ^{Review the story drift and base shear from the results to verify that the building is in compliance with the seismic codes.}
• ^{Check if the structural design and load combinations are in line with seismic force distribution, and validate the column and beam design based on seismic load effects}

^{Given data:}

^{Structural Element Sizes:}

• ^{Beams: 300 × 400 mm}
• ^{Columns: 800 × 800 mm}
• ^{Slab: 150 mm thick}

^{Material Properties:}

• ^{Grade of Concrete: M30}
• ^{Grade of Steel Reinforcement Bars: Fe 415}

^{Loading details:}

• ^{Dead Load on beams from infill wall: 10 kN/m (Let us assume the same for roof floor in view of parapet)}
• ^{Live load on floor: 3 KN/m2 (Let us assume the same for roof floor)}

1. ^{a) Buildings are assumed to be pinned at the base}
2. ^{b) All columns in all storey are of the same size}
3. ^{c) All beams in all storeys are of the same size}
4. ^{d) Building is located on Soil type-II and in Zone-III. Assume other factors if required.}

^Aim:

^{To model a 25-storey building using ETABS software and verify the seismic code requirement from ETABS analysis.}

^Procedure:

• ^{Open ETABS software.}
• ^{Click New model.}

• ^{Give model initialization setting as follow}

• ^{Click ok}
• ^{In the new model quick template dialog box , select custom grid spacing and click Edit grid data}
• ^{Give the following settings in grid system data dialog box.}
• ^{Click ok.}
• ^{Select custom story data under story dimension and click edit story data.}
• ^{Give the story data for first- three story as follow having story 1 as master story.}
• ^{Write click on the first column and select add story and click keep existing story heights.}
• ^{Give number of added story as 22.}
• ^{Click ok}
• ^{The following page opens}
• ^{Click Define--> Material properties}
• ^{Click Add new material for assigning concrete}
• ^.
• ^{Click Add new material for assigning Rebars}
• ^{Click ok}
• ^{Click Define--> Section properties--> Frame sections.}
• ^{Select Add new property in the dialog box.}
• ^{Select the concrete shape as rectangular and give the following settings for the Beam}
• ^{Beam property is added.}
• ^{Again, click Add new property for creating property for column.}
• ^{Column property is added.}
• ^{Click--> Section properties--> Slab section}
• ^{Select Add new property and give the following settings.}
• ^{Clickà Define--> Load pattern}
• ^{Define load patterns by its name}
• ^{Click Define--> Mass source}
• ^{Check load cases by click Define-->Load cases.}
• ^{Create load combinations, Define--> Load combinations}
• ^{Create Columns by Quick draw column.}
• ^{Select quick draw beams.}
• ^{Select the first horizontal and vertical beams and go to edit and select replicate.}
• ^{Select first floor in plan view}
• ^{Draw slab using quick slab by having similar stories in the status}
• ^{Select all the beams from select tab}
• ^{Assign frame loads as distributed from assign tab.}
• ^{Select the slabs}
• ^{Assign shell loads as uniform}
• ^{Select the slabs from select tab and assign as diaphragm from assign tab.}
• ^{Click run analysis in the panel after saving the file.}

^Result:

• ^{Click Display -->Story response plot. Change the display type to Maximum storey drift and desired combo to see the plots.}

^{Hence, as per the clause 7.11.1.1, the maximum inter-storey drift is limited to 0.004 for each story height, So it is satisfied .}