Modelling of 25 storey building with the specified properties using ETABS

1. Model a 25 story height building on ETABS with structural properties as specified below. Ground floor or plinth floor level cab be taken at a height of 1.5 meters from the base. Each of the successive 25 storys has a story height of 3 meters.

ANSWER

Step 1

• OPEN on ETABS Application.
• Click file, select the option of NEW model and click it.
• After choosing the new model, automatically the dialog will arrive that is called model initialization.
• Next, we choose Built-in setting, as there type the data and unit of our structural plan.
• Choose Custom Grid setting, to set the grid by custom at a given dimension of X & Y direction.
• Here we can see about a Grid data an spacing & Grid spacing an ordinates by choose our convenient.
• As well as should add the CUSTOM story Data for plinth to 1^st story height is 1.5m and other all 25 story height is 3 m.
• To consider the 1^st story is master story.
• Then, click ok we get the model frame structure in windows.

Step 2

• Add the material properties of concrete & rebar.
• Choose DEFINE tool > material properties > add materials.

• The Same we add the material properties of beam & column.
• Choose DEFINE > section properties > frames section.

• The beam size is 300mm x 400mm.
• The column size is 800mm x 800mm.
• As we can modify the reinforcement details and rebar materials and also should provide the clear cover of both the section.
• To check and modify the properties in section.
• For here, we have to take the reference from IS 1893:2016 For structural analysis, moment of inertia.
• To add the slab at thickness of 150mm.
• Choose DEFINE > section properties > slab section.

Step 3

• To add the column on structure by selecting the quick draw column(3D plan).
• Before we select the column details Of C 800mm x 800mm.

• The same we add the beam by selecting the beam draw tool at the selection of all beam grids.
• To select the beam size is B 300mm x 400mm.

• Similarly, we can add the slab to choose from 1^st story as similar to all other 24 story with the thickness of 150mm.

Step 4

• To add the joint details at the base story at foundation functions.
• Choose ASSIGN > joints > Restraints.
• Here we select Pinned joints at the base level.

Step 5

• To set the appropriate load values and properties about a structure.
• Choose DEFINE > Load patterns > Add loads.
• For loads are live, dead, brick wall, earthquake in X & Y direction.

Step 6

• To assign the live loads in a floors as we add the given data of 3 kn/m^2.
• Choose EDIT > edit stories from templates > modify data.
• Choose ASSIGN > shell loads > Uniforms.
• The values of live load id 3 kn/m^2.
• It can similar to all other stories by we selecting option under similar.

Step 6

• Simultaneously we add same procedure of adding the dead load.
• Choose ASSIGN > frame loads > Distributed loads.
• The dead of brick wall infill is 10 kN/m.

Step 7

• To add data about mass of seismic properties.
• Choose DEFINE > mass source > modify show mass source.
• As we define the data of dead load, brickwall infills ad 25% of live loads.

Step 8

• Here automatically analyze the load combination about whole structure.
• Choose DEFINE > load combination > Add default design combination.

Step 9

• To applied the diaphragms.
• Choose SELECT > object type > floor ( slab).
• Choose ASSIGN > shell > Diaphragm .

Step 10

• To analyze the structure.
• Choose ANALYZE > check model .
• Then, click ok.

Step 11

• We analyze the whole structure of checking the deformation patterns in frame.
• As well as we can see visualize the effect of structure deformation.

Step 12

• Finally, we find out the model response under 12 modal shapes.
• Choose DISPLAY > show table >analysis > structure output > modal information > table –modal participant mass ratios.
• We get the time period about all modal shapes under seismic forces.