Structural Modelling using Etabs 2018

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

AIM

To model and analyze the G+7 Residential building at given architectural drawings by using Etabs Software.

PROCEDURE

STEP-1

• Open the new model in Etabs.
• Then open a another Tab of Given G+7 building model as included a floor plan, architectural plan, Typical cross sectional plan and elevation plan.
• To analyze and observe the data from given model.
• To set the Grid and story formation by custom.
• X-direction in A,B,C &D and Y-direction in 1,2,3,4&5 at given base dimension.
• The story are designed by G+7, each floor have 3 m in height.

STEP-2

• To add Material properties of section for steel and concrete
• Go to Define > Material properties > ADD.

STEP-3

• To add the section properties of Beam, column and slab.
• Go to section properties > frame > choose bram or column
• Here used beam size is B 250 mm x 500mm
• The column Size is C 400mm x 400mm, C 400 x 600.
• To create slab section of Slab 115, slab 125, slab 150mm thickness.
• Specially we add staircase slab of 200mm thickness.

STEP-4

• To create a shear wall of this structure to protect the more lateral forces Zone.
• Wall > section properties > wall section.
• For here used, wall 300 thick.
• The shear wall are covered as symmetric in nature for withstand the lateral shear force action.

STEP-5

• After completing the addition of all materials of required in modeling.
• Then we start to view the floor plan.
• To select the Quick Column for selecting the required dimension.
• Then, similarly to add the process of beam.
• For most concentration about to adding the beam, because we read the given plan and understand the appropriate requirement of place to add beam.
• If we want to delete or adding new beam inside the frame area.
• Choose To Divide and Joint action for fixing the beam layout like our given plan.
• 

STEP-6

• Next, we add the slab @ thickness of slab 115.
• Go to First floor, select all Stories after to add slab.
• Then, go to base floor deleted the slab @ base.

STEP-7

• To add the Shear wall of all Boundary condition and base point and mid portion of building as like a symmetric in nature.
• Thickness of shear wall is 300mm.

STEP-8

• Go to base plan and select one strory.
• After select the all joints.
• ASSIGN > Joints > Restraints > Fixed joints.

STEP-9

• Then, most important factors of addition of load .
• Define > load patterns > add the load 0f Dead, Live, Brickwall and Finishes.
• Addition of brick wall load > Assign > Frame load > Distributed load > brick wall is 3.5 KN/m.
• As the reference IS 1893 : 2016.

STEP-10

• Then addition of Live @ different categories with the reference of IS 875 :PART 2.
• Here assigned live of moving platform area is 3 KN/ m^2 and other room areas we put 2 KN/m^2.

STEP-11

• To assist the Live load Reduction factor.
• For this model is G+7, so definitely we need to consider the reduction factor.

STEP-12

• Then, to add the earthquake load.
• We need to natural period Ts = 0.49, as we find this from IS 1893:2016.
• Next, add the Earthquake load of positive and negative of both direction.

STEP-13

• To assign the Mass source with the condition of Specified load patterns
• To reference of IS 1893:2016, Clause 7.3.1

STEP-14

• The same we assign the Diaphragm of all stories.
• Assign > shell > Diaphragm > D1 > apply.

STEP-15

• Given the name to all pier of shear wall as like p1, p2, p3, p4, p5, p6, p7 & p8
• Assign > shell > pier label @ selected wall.

STEP-16

• To check and consideration of LOAD Combination @ all factors.

STEP-17

• Model cases to finf the direction of different mode shapes.
• Here we choosen 20 mode shapes.

STEP-18

• Then , to check the analysis of all load cases.
• RUN the analysis of model.

STEP-17

• To view the Model spectrum analysis.
• Define > Function > add the respected factors.
• Choose function type > add new function with the reference of 1893:2016.
• Then, to choose Load cases for adding all load cases into the both direction of response reduction factor.
• RSx and RSy.
• After adding this load, make the load combination as similarly we add this response spectrum load and check it.

STEP-18

• As well as we get the base shear value @ all loads, on there we need to know the spectrum value for we considering the scale factor value.
• Then, Re-run the analysis, to check the all base shear, combination, model shapes.
• And also we get the view Story drift of maximum value as our model.

RESULTS

Finally, we analyze the model of G+7 are successful.