ETABS-Oct12

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.

Elevation data:

Floor

Floor Height

Floor Level

L1

3m

0m

L2

3m

+3 m

L3

3m

+6 m

Roof

+9 m

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

Sectional dimensions: Member

Section mm

Beam

250 X 450

Column

250 X 250

Slab

125 (thickness)

Loads applied:

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)

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)

ETABS SCREEN

In order to create new model click this To open a previous project Select units here

Select Default

Previous project will be opened

Select the units

Give the details for grid as shown

Select the grid

Then Press ok

A grid will be formed as shown in the figure.For defining materials Go to Define(Menu)material propertiesmodify properties(steel/concrete) Select Plan, elevation etc

Select similar stories here

Select units here

Select modify

Draws columns in the regions of clicks

Give suitable properties & then press ok

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 to DefineSection PropertiesFrame SectionsAdd rectangle

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

Repeat the same process for columns

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

Select reinforcement to be designed.

Column here Select similar stories here Select I section symbol to draw columns

Go to Plan view to draw beams

Select beam here

Snap to grid intersections must be kept on

Defining and drawing slab section: Go to Define(menu)Slab/wall/deck sectionsModify/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 Viewset building view optionsselect 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 AssignJoint/pointRestraintfixed ok

Define static load cases: DefineStatic load casesAdd new load/modify load-->Ok

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

Assign Loads:(select the areas on which u want to apply the load) Assignshell/area loadsuniform

*After applying the load on a top floor

Select one story

*Repeat the same process at all floor levels

Go to Analyze menu Run analysis

Post Processing (Results) Display (Menu)Deformed shapes

Support Reactions

Bending moment diagram:

Slab stresses

Design In order to select the design standard (Here IS 456:2000) Go to Preferencesconcrete frame designSelect IS 456:2000

To start design Go to Designconcrete frame designstart design

After the design is complete the section properties are shown as in the figure

Verify analysis Vs Design Designconcrete frame designVerify 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 Designconcrete frame designselect design comboshow(select one combination)

To find the steel calculated Go to Designconcrete frame designDisplay design infoLongitudinal 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