Analysis and Design of 3-Story RC Building

ETABS Version 8.5.5

Lecture 1

Structure to be analyzed and design:

The data of the structure is in the upcoming slides.

Floor Floor Height Floor Level

L1 3 m 0 m

L2 3 m +3 m

L3 3m +6 m

Roof +9 m

Elevation data:

Material properties:

Type Value (N/m2)

Young's Modulus of concrete 25000

Young's Modulus of steel 200000

Grade of concrete M 25

Main reinforcement yield strength 415

Shear reinforcement yield strength 250

Member Section mm

Beam 250 X 450

Column 250 X 250

Slab 125 (thickness)

Sectional dimensions:

Load Case Value

Dead load (Unit weight of concrete) As per IS 875:1987(Part 1)

Live load As per IS 875:1987(Part 2)

Loads applied:

Other details:• All supports are fixed at the base.• There are 4 bays in X direction and 3 bays in the Y direction of the

building. • Bay widths are 5 m in both directions.• Assume suitable data where needed.• Live load in roof is 50% of load on other floors.Analysis Results:• Show slab stresses.• Show bending moment diagram.• Support reactions.• Show deformed shapes.Design Results:• Use IS 456:2000 for design.• Show design combinations.• Show the calculated steel reinforcement.• Verify analysis Vs design.(check whether your design is safe or not)

In order to create new model click

this

ETABS SCREEN

To open a previous project

Select units here

Select Default

Previous project will be opened

Select the units

Select the grid

Give the details for

grid as shown

Then Press ok

A grid will be formed as shown in the figure.For defining materials Go to Define(Menu)material propertiesmodify properties(steel/concrete)

Select units here

Select similar stories here

Select Plan, elevation

etc

Give suitable properties & then press ok

Select modify

Draws columns in the regions

of clicks

Repeat the same process for steel for

giving material properties and then

press ok

Defining sections:In order to draw beams and columns, we have to create sections.Go toDefineSection PropertiesFrame SectionsAdd rectangle

Select concrete.Give the depth and width & cover.And then press OK.

Repeat the same process for columns

Select reinforcement to be designed.

Next we draw beams and columns in the plan and apply to all levels by selecting similar stories.

Select I section symbol to draw

columns

Column here

Select similar stories here

Snap to grid intersections must be kept

on

Go to Plan view to draw beams

Select beam here

Defining and drawing slab section:

Go to Define(menu)Slab/wall/deck sectionsModify/show section(select slab here)

Select shell here & give all other properties

Use the one click area command to draw areas

Select slab.After drawing areas we

have this

Go to Viewset building view optionsselect object fill(apply to all windows)

Apply fixed support to all the columns at their bases

Go to plan at base level, select all the supports & then Go to

AssignJoint/pointRestraintfixedok

As we have only 2 load cases there is no need of defining

new cases

Define static load cases:DefineStatic load casesAdd new load/modify load-->Ok

Assign Loads:(select the areas on which u want to apply the load)

Assignshell/area loadsuniform

*Repeat the same process at all floor levels

Select one

story*After applying the load on a top floor

Go to

Analyze menu Run analysis

Post Processing (Results)Display (Menu)Deformed shapes

Support Reactions

Bending moment diagram:

Slab stresses

DesignIn order to select the design standard (Here IS 456:2000)Go to Preferencesconcrete frame designSelect IS 456:2000

To start design Go to Designconcrete frame designstart design

After the design is complete the section properties are shown

as in the figure

Verify analysis Vs DesignDesignconcrete frame designVerify analysis Vs Design

Message says that analysis and design sections are same

To check the load combinations we have used in the design, Go to Designconcrete frame designselect design comboshow(select one combination)

To find the steel calculated Go to Designconcrete frame designDisplay design infoLongitudinal steel etc

Select different parameters like

Longitudinal reinforcement

You can also view the percentage of steel by selecting percentage in the drop down menu

above(rebar percentage)

To View results in detail:Right click on any column

To see the interaction curve for columns select Interaction

Select B/C details to view Beam to column capacity ratio

Select flexural details to see the cross section details

Select Shear details to see the shear reinforcement details

Thank you