Challenge

Structural Modelling using Etabs 2018

MMohit Kumar27 Jul 2023

STRUCTURAL MODELLING OF RESIDENTIAL BUILDING USING E-TABS 2018

Q :-

The architectural drawings for a G+7 residential building in zone 5 has been provided. The floor plan is the same for all 7 floor levels. Possible column positions have also been provided. Conceptualize a framing plan layout and then model the building in Etabs. The following architectural drawings have been provided:

Typical floor plan – The location and thickness of the brick walls and the use of the
space (for estimating live load) can be obtained from this plan
A building section through the staircase and lift core is provided
Parking layout in the ground floor – the column/shear wall arrangement must not
obstruct entry/exit of vehicles.
The following loadings are to be taken into account:
Brickwall made of AAC blocks
Finishes – floor tiles of 75 mm thickness
Live loads as per IS 875 part 2
Water tank of 20 KL above the staircase at Mumty level
Lift Machine room at mumty level above lift core

The structural model must comply with provisions of IS 1893 and IS 13920.
Run a modal response spectrum analysis and check analysis results of the E-Tabs model for inter-story drift requirements, vertical & planar irregularities, minimum shear wall requirements,maximum axial load ratio for column and shear walls, an effective moment of inertia for beams
and columns etc.

Please note that the column positions shown in the architectural typical floor plan are only to provide an initial starting point for modelling. Participants will have to change its size, introduce shear walls, and add new vertical elements after running the analysis. You will have to run the analysis multiple times until a structural model is obtained that meets structural code requirements without compromising architectural functions. Also, there is no one ‘correct’ structural system for this challenge. There can be multiple possible solutions for this problem.

ANS :-

Aim :-

To model and analyze the G+7 residential building from the given architectural drawings using the ETABS 2018.

Introduction :-

Buildings with multiple stories are analyzed and designed using engineering software called ETABS.
Modeling tools and templates, code-based load prescriptions, analysis methods, and solution
approaches all take into account the grid-like geometry that is unique to this type of construction.
No matter how complex a system is, E-TABS can be used to analyze both static and dynamic systems.
According to the generalization known as ETABS modeling, multi-story buildings frequently have floor designs that repeat vertically and are identical or closely related.
modeling components that make it easier to create analytical models and simulate modern seismic systems.
After modeling is complete, E-TABS automatically generates and assigns code-based loading conditions for gravity, seismic, wind, and thermal forces.

Procedure :-

Step :- 01

First we have to open the etabs software.
Then, as shown below, click on the file option in the top left corner and choose the new model.

After choosing the new model, a new tab appears in which we must choose the 'Use Built-in Settings with' option as shown below.

When the model Initialization is set, the templates tab will appear. Choose Grid Only and click OK.
The settings for the Grid system data must then be made, as shown below.

Then, as shown below, we must add the stories—up to a total of seven—to the Story Data.
The Story Data has been updated to include the 7 stories, as seen below.

Step :- 02

The plan views can then be seen in the etabs screen, as displayed below.
The 3d-view must then be opened, as demonstrated in the figure below.

Step :- 03

Next we need to define option and select material properties, as shown below.

The new tab appears after selecting the material properties, and we add new materials by choosing the Add new material option as shown below.

Step :- 04

Now we need to add material type as concrete and grade as M25.
Next we need to check the material property data, as shown below.

Step :- 05.

Rebar is the new material type and HYSD Grade 415 is the new grade that must be added.
The material property data needs to be checked next, as shown below.

Step :- 06

Rebar is the new material type and HYSD Grade 500 is the new grade that must be added.
The material property data needs to be checked next, as shown below.

Step :- 07

Now we need to select the section properties and click on the frame sections, as shown below.

Step :- 08

After selecting the frame sections the new tab will be visible, in that we need to select the Add New Property, as shown below.

The new tab appears after choosing Add New Property.
As shown below, we choose the Concrete shape type of the Rectangular in that new tab.

The data for the frame section's properties will then become visible. Here, we add the beam size of B250x450, as shown below.
Next, as shown below, we must choose the Modify/Show Rebar option.

After selecting the Modify/Show Rebar option the new tab appears, In that we select the design type as M3 Design only (Beam).
Next we select longitudinal bars with the grade of HYSD500.
Next we select Confinement bars with the grade of HYSD415.

Again we have to select Rectangular shape type in concrete, as shown below.

The data for the frame section's properties will then be visible. We have added a column size of B300x500 to this data, as shown below.
Next, as shown below, we must choose the Modify/Show Rebar option.

After selecting the Modify/Show Rebar option the new tab appears, In that we select the design type as M3 Design only (Beam).
Next we select longitudinal bars with the grade of HYSD500.
Next we select Confinement bars with the grade of HYSD415.

Step :- 09

Next we have to add the column size as 400X400 in the frame section property data, as shown below.

As shown below, we must once more add a new column with the dimensions 400 x 600 to the frame section property data.

Step :- 10

Next we select the slab section option from the section properties, as shown below.

The slab properties tab will then become visible, and we can then choose to modify or show the property as in the example below.

After selecting the Modify/Show Property option, the new tab appears.
In that we need to put the slab name as Slab 125, it means slab with the thickness of 125mm.
And we take the concrete grade as M25, as shown below.
Next we have to click the ok option.

Now we take the slab thickness separately for staircase with the thickness of 200mm, as shown below.

Step :- 11

Next we have to add the wall properties in the wall property data, as shown below.

Step :- 12

Next we need to add the columns using the Quick draw columns option, as shown below.

Step :- 13

Next we need to add the beams using the Quick draw beams option, as shown below.

Step :- 14

Next we need to add the secondary beams using the Quick draw beams option, as shown below.

Step :- 15

Then, as shown below, we add the shear walls where they are needed in the residential building.

Step :- 16

Next we need to add the slabs using the Quick draw floor/wall option, as shown below.

Step :- 17

Now we go to the base plan and select all base joints.
Next we select the Restraints from joint option, as shown below.

Now we need to select the fixed joint and click on apply and then click on close button, as shown below.

Step :- 18

Next we need to select the load patterns from the define option, as shown below.

Now we should add Dead load, live load, Brickwall load, and earthquake load, as shown below.

Step :- 19

Next we need to select the distributed load from the frame loads, as shown below.

After that, a new tab will appear in which we choose Brickwall as the load pattern and 3.5 kN/m as the uniform load.
After that, press the apply button before closing.

Step :- 20

The Uniform option must then be chosen from the list of shell loads after clicking on the assign option, as shown below.

Here we apply the 3 KN/m^2 live load for the staircase portion, varanda, and lift core area.

Next we apply the 2 KN/m^2 live load for the remaining portions in the residential building, as shown below..

Step :- 21

Next we have to select live load reduction factors from the design option, as shown below.

Now we add the reduction factor by decreasing 10% from 1st floor to 7th floor, as shown below.

Step :- 22

Next, from the define option we select the mass source, as shown below.

The Mass Source Data load patterns are then added, as shown below.

Step :- 23

In the select option we select object type option, as shown below.

When the object type option is chosen, a new tab will appear where you can choose the floors, click the select button, and then close it.

Next we have to select the Diaphragms from the shell option, as shown below.

After selecting the diaphragms the new tab will appear, in that select D1 .
click on the apply button and close.

Step :- 24

Next we have to select the Pier label from the shell option, as shown below.

Before going to the shear wall design we have to assign the names for the shear walls (P1,P2,P3,P4,P5,P6,P7,P8), as shown below.

Step :- 25

Next, from the define option we select the load combinations, as shown below.

The new tab becomes visible after choosing the load combinations, and we choose the 'Add Default Design Combos' option there.

Next, we choose "concrete frame design" and "concrete shear wall design" in the 'Add Default Design Combinations' as shown below.

Now we can see here that the load combinations are visible, as shown below.

Step :- 26

Next we select the Modal cases from the Define option, as shown below.

After choosing the modal cases, a new tab appears. In this tab, we identify the modal case as Modal 1 and specify a maximum of 20 modes, as shown below.

Step :- 27

Next we have to check the model by clicking the check model option, as shown below.

When the model is checked, the warning tab becomes visible and indicates that no warning messages are present, as shown in the example below.

Step :- 28

Now we select the Response spectrum from the Functions from define option, as shown below.

After the model is checked, then the warning tab will be visible and it tells that there is no warning messages, as shown below.

After choosing the modify/show spectrum option, a new tab will appear. In this tab, we enter the function name "IS FUNCTION," and the remaining details will be determined by the software; we don't need to alter any of the settings, as shown below.

Step :- 29

Next we have to select the Load cases from the Define option, as shown below.

Next the Load cases tab will be visible, In that we select the 'Add new case', as shown below.

Now we have to enter the details of load case in the 'Load case data', as shown below.

Now we have to do the run analysis, as shown below.

Step :- 30

Next, from the display option we select the show tables option, as shown below.

The new tab will be visible after choosing the show tables option.
As shown below, we now choose the Base Reactions and press the "OK" button.

Next the Base Reactions table will be visible, as shown below.
Here we have to check that EQ should be closer to the RS, to get the closer to each other we should calculate that, (EQRS)×">(EQ/RS)×Scale factor of Response spectrum.
Now substituting the values from the table, at X-direction (2844.6348900.7656)×(9806.65)">(2844.6348/900.7656)×(9806.65), at Y-direction (2844.63481002.1982)×9806.65">(2844.6348/1002.1982)×9806.65

At X-direction we get, 30969.6
At Y-direction we get, 27835.15
In the load case data, we scale the response spectrum in the X and Y directions using the aforementioned values.
The EQ is closer to the RS from the base reaction table as shown below after we enter these values for the response spectrum as scale factors at the X and Y directions in load case data.

Step :- 31

Next, from the display option we select the show tables option, as shown below.

After selecting the show tables option the new tab will be visible.
Now we select the Modal Participating Mass Ratios and click on the ok button, as shown below.

Now the Modal Participating Mass Ratios table will be visible, as shown below.

Step :- 32

Next we select the Story response plots from the Display option, as shown below.

The story response for maximum story drifts at X & Y directions, should not be more than 4%.

Step :- 33

Next we open the select plan view tab and select the base floor, as shown below.

Next we have to open the reactions tab, then we select the eartquake load towards X-direction(EQX) in the load case.
then click on the ok buttion as shown below.

The base shear reactions will now manifest, as illustrated below.
The percentage of the shear forces absorbed by the shear wall is calculated by dividing the base shear of the shear wall by the total base shear of the building.
And the more shear walls we need to build into the structure if that figure is lower than 80%.

RESULT :-

The G+7 residential building has been modelled and analyzed successfully using the ETABS 2018 .

The ETABS 2018 has been successfully used to model and analyze the G+7 residential building.

Structural Modelling using Etabs 2018

Ship work like this
in your own course.

Talk to a career counsellor

Ship work like thisin your own course.

Talk to a career counsellor

Ship work like this
in your own course.