ETABS Extended Three dimensional Analysis for Building System ********
SYLABUS:
1. Introduction & Modeling : -Introduction
- Objects
- Templates - Floor Information
- Modeling / geometry
2. Material & section Properties : - Material Properties
- Section properties - Wall/Slab/Deck sections.
3. Draw and options :
-Drawing of point, line and area objects. - Reference lines and Planes.
4 . View, selection & Options :
- View Management
- Object selection - Options and Preferences.
5. Assignment --Structural options :
- Point object assignments. - Line object assignments.
- Area object assignments.
6. Assignment – Loads - Load cases- Dead loads/Line loads/
Wind loads/ Earthquake loads. - Load Combinations
- Load assignment.
7. Analysis :
- Analysis options . - Analysis log.
8. Text & Graphical output :
- Text output - Un deformed shape and load plots.
- Deformed shape and result plots. - Energy plots.
9. Editing option :
- Cut, Copy and Paste. - Replicate.
- Frame and area meshing. - Point and line extrusion.
10. Text input and File Export / Import :
- Text input file - Export options
- Import options.
11. Concrete Design using Indian Code IS 456- 2000: - Design of concrete beams and columns.
- Design of Shear Walls and lintels. - Design of Composite Beam.
12. Steel Design using IS 800-2007 : - Design of Steel members.
- Optimization options.
****
ETABS CABABILITIES
o Construction sequence analysis.
o Push over analysis. o Shear wall design.
o Live load reduction for upper floors. o Earthquake forces can be applied in anu angle (not just X and Y
alone) o Modeling tapered concrete beams.
o Floor load for irregular panels, that is easy to do. o Design of columns with cross section of any arbitary shape (including
Y, L, +) o Diaphragm action.(with earthquake loads and wind loads
automatically applied on the diaphragm centre) o Automatic lumping of masses for earthquake .
o Choice of Eigen or Ritz vector for Response spectrum analysis.
o Auto calculation of beam reinforcements based on moments at column face, rather than at column centre line and column
reinforcements based on moments at beam soffit, rather than at beam centre line.
o Rigid Panel zone modifier. o Facility for design as per IS 13920 (Ductile drtailing)
o Additional software for foundation design especially mat (SAFE software).
o Not support for sloping roofs. o ETABS uses matrix method of structural analysis.
(Staad also uses Matrix method of structural analysis & FEA for plates.
o 3D rendering in ETABS: Go to view menu � Select set building view options. In first column
button, check Extrusion and object fill.
Disadvantages :
ETABS can not generate floor loads. You have to model slabs as plate element & mesh it and apply floor loads on it. Otherwise modeling
and rebar detailing is far easier in ETABS. ETABS documentation gives no details of the solver it uses other than
referring to it as “standard solver”.
ETABS TIPS
***** 1. Analysis options :
ETABS has many analysis option which includes - P delta analysis .
- Dynamic analysis - Eigen vectors analysis.
- Ritz vectors analysis. - Linear analysis.
- Non linear analysis. - Static Non linear analysis.
- Construction sequence analysis.
2. Locking and unlocking the model : From Main menu � Option � Lock model / unlock
Check model : Before running analysis use check model to ensure that objects do not
overlap and that objects are connected. From Main menu � Analysis � Check model ----
3. Editing the model :
Edit � edit grid data.
� edit storey data. � edit reference plane.
� edit reference line. � Add model from template (2D frame or 3D frame).
� merge areas.
� Joint lines/ Joining selected beams or selected columns.
4. Text/ Graphical output : To view loads :
From Main menu � Display � Show loads � Frame /Line ---
To view design info :
From Main menu � Design � Concrete frame design � Display design info.
To view other Tables :
From Main menu � Display Show Tables � Select required boxes.
Exporting the files :
From Main menu � File � Export � Save model as etabs.e2k text file (like a Staad editor file )
We can also export to SAP or SAFE or Excell data base or .dxf file.
Importing the file :
From Main menu � File � Import � ETABS.e2k. Text file or Staad file or Struds.
Options/Preferences:
From Main menu � Option � Preferences � Concrete frame design
(Select code and other parameters) - Shear wall design
- Reinforcement/bar sizes (add new dias or modify existing)
- Live load reduction.
Auto saving the model : From Main menu �Option � Auto save model � set time � Ok.
Loads :
Combination of existing loads - Envelope of combinations.
To draw Column or beam to required location :
There is no move command here. Set snap grid on and draw column or beam any where we want.
To draw secondary beam at required distance
Set plan view to required floor in left window � Right click on the screen (not on the slab) � Plan fine grid spacing � Plan fine grid
spacing =500 (say) � Ok. From Main menu � Draw � Snap to � Fine Grid � From Main menu�Draw line objects� Draw line �
Property = --- (Moment release=Pinned and draw the beam at
required distance. To get out from line grid (above option):
Draw � Snap to � Fine grid. *****
ETABS Extended Three dimensional Analysis for Building System
Example 1: No. of stories : G+3
No. of bays in X Direction : 2 No. of bays in Y Direction : 3
Spacing in X Direction : 3500
Spacing in Y Direction : 4500 Typical Storey height : 3000
Basement height : 2000 Concrete Grade : M20
Steel Grade : Fy415 Column Sizes C1 (Corner Column) : 230 x 300
C2 (Side Column) : 230x 380 C2 (Inner Column) : 230x 460
Beams B1 : 230x 330 B2 : 230x 406
PB : 230x300 Slab Thickness : 125mm
C3 = 230 X 460
C1 = 230 X 300
C2 = 230 X 380
COLUMN:
PLINTH BEAM - PB 230 X 300
B2 = 230 X 406
B1 = 230 X 330
BEAMS:
B1B1
B1B1
B1B1
B2
B2
B2
C1C2C1
C2C3C2
B2
B2
B2
B2
B2
B2
C2C2 C3
C1
B1 B1
C1C2
CBA
4
3
2
1
4500
4500
45
00
35003500
STOREY-5
STOREY-4
STOREY-3
STOREY-2
30
00
STOREY-1
BASE
B1 B1
B1B1
B1 B1
PB1PB1
30
00
30
00
30
00
20
00
BEAMS:
B1 = 230 X 330
B2 = 230 X 406
PLINTH BEAM - PB 230 X 300
COLUMN:
C2 = 230 X 380C1 = 230 X 300
C3 = 230 X 460
STEP BY STEP PROCEURE:
STEP 1: (Creation of geometry) Open ETABS Program.
Set the units of the model in the drop down box in the lower right hand
corner of ETABS window , click the drop down box to set units in N. mm.
From Main menu � File � New Model � Select No.
Building Pan Grid System and Storey Data Definition will be displayed. � Uniform Grid Spacing
No. of lines in X Direction =3
No. of lines in Y Direction =4 Spacing in X Direction = 3500 mm
Spacing in y Direction = 4500 mm
� Simple Grid Data No. of stories =5
Typical Storey Height =3000 mm Bottom storey height =2000 mm
Select Grid only button � OK.
Note: You can change Grid spacing by choosing Custom Grid spacing, for
column varying spacing then click Edit Grid you can also change any storey height by choose Custom Storey Data, then click on Edit Storey Data.
Go to Main menu � Edit Storey data � Edit Storey.
Grid No.
Label Height Elevation Master Storey
Similar to Spice point
Spice height
6 Storey 5 3000 14000 Yes No 0
5 Storey 4 3000 11000 No Storey 5 No 0
4 Storey 3 3000 8000 No Storey 5 No 0
3 Storey 2 3000 5000 No Storey 5 No 0
2 Storey 1 2000 2000 No None No 0
1 Base 0
Change units N.mm.
STEP 2: (Define Material Properties)
From Main menu � Define � Material Property � Add new material �
Material Name =M20 Concrete cubic comp. strength fck =20
Bending Reinforcement yield strength fy =415 Shear Reinforcement yield strength fy =415 � Ok � Ok.
STEP 3: (Define Frame section)
Define Beam:
From Main menu � Define � Frame section � Add rectangular � Material name =M20 (select) � Section Name=B1
Dimensions: Depth (3) =330mm
Width (2) =230mm Click reinforcement
Select � Beam � Concrete cover to rebar center Top = 41 mm (clear cover(25mm)+stirrup dia (8mm)+Dia. Of rod/2 (16/2)
Bottom =41mm � Ok � Ok. In the same manner define other beams B2 and PB.
Define Column:
Add Rectangular � section Name =C1 Material name = M20
Dimensions :
Depth (3) =330mm Width (2) =230mm
Click reinforcement
Select � Column Select � Rectangular
Ties � Rectangular
Cover = 56 mm (clear cover(40mm)+Dia of stirrups(8mm)+Dia. Of rod /2(16/2))
Bar size =16 d Corner bar =16 d
� Reinforcement to be designed � Ok� Ok. In the same manner define column C2 and C3.
Define Slab:
From Main menu � define � Wall/Slab /Deck section � Add New slab �
Section name = S1 Material name = M20.
� Membrane Membrane =125 mm
Bending =125mm
Select � Membrane � Ok � Ok. STEP 5: (Drawing Beams, Columns and Slabs)
Drawing Beams: From Main menu � Draw � Draw line objects � Create lines in region
Property = - Select required beam size B1
Click or Select the beam B1 in Plan view (Left window) (with similar storey option) and select all beam B1.
Change Property = Beam B2 size and click on beam B2 (with Similar storey
option) � Select Plinth beam Property =PB and select all Plinth beams in Storey 1 in plan view (Left Window) with one storey option �Close.
Drawing Columns:
From Main menu � Draw � Draw line objects � Create column in region � Property = C1 �
Select or Click on the column joints in Plan view (Left window) with similar
storey option. If necessary change angle =90 � Change Property =C2 and C3 and click on respective column joints � Close.
Drawing Slab:
From Main menu � Draw � Draw area objects � Create areas at click (Draw
areas) (Plan) � Property =S1 � Click on the periphery of column joints and press enter (With similar storey option).
Note:
To view the assigned beam in plan
Select � Set Building Objects on top of Tool bar.
Select � Line sections under object view options.
� Ok.
To view the rendered view
� Set Building view objects on top of Tool bar
� Line section.
Special Effects:
� Object Fill
� Extrusion
� Apply to all windows � Ok.
STEP 6:(Assigning Support Condition)
Set Base floor Plan view in left window � Set Column points (with mouse) From Main menu � Assign � Joint/Point � Restraints (supports) � Select
Fixed � Ok. To view Support assigned
From top Tool bar � Set Building view option �
Visible in view � Supports � Ok.
Go to Elevation view 1 and view . For other views click � � arrow at top of tool bar.
STEP 7: (Defining Loads) 1.Gravity Loads (Dead Load & Live Load)
From Main menu � Define � Static Load Cases � Load = SDL (Super Imposed Dead Load)
Type = Dead Self weight multiplier =0 � Add New Load � Ok.
Load = Wall Type= Dead
Self weight multiplier =0 � Add New Load � Ok.
Note:
For Self weight multiplier will be 1 for beams and columns of dead load. For all other loads, it will be zero.
Assigning the Loads:
Activate left window and set to Plan view � Activate or select similar storey option (at bottom) and select all slabs
� From Main menu � Assign �
Shell / Area loads � Uniform � Load case name =SDL
� Uniform load Load = 1.50 Kn/m2 (units Kn.m)
Direction Gravity � Ok.
In the same manner assign Load case name = Live � Uniform load
Load = 2.0 Kn/m2 (units Kn.m) Direction Gravity � Ok.
Assigning Wall loads:
9” wall load = 12Kn/m (For external or outer beams) 41/2” wall load=6 Kn/m (For internal beams).
In left side window select all outer beams in top floor by setting similar
storey options and view the status bar to know no. of beams selected � From Main menu � Assign � Frame /Line loads �
Distributed Load case name = wall. Unit Kn.m
� Forces Direction Gravity
Uniform load=12 Kn/m � Replace existing loads � Ok.
In the same manner apply 41/2” wall udl load to internal beams by setting “all floor options”.
To see the load assigned :
Right click the particular member corresponding load � Ok.
Note:
For point load : From Main menu � Assign � Joint/Point loads �
Load case name =Dead. Units Kn.m. � Replace existing loads
Forces Global =10 Kn � Ok.
2. Wind Loads :
In ETABS there are two ways to define lateral loads (Wind, earth quake). Built in option will automatically calculate lateral loads as per available
design codes. Define wind load parameters as per IS 875 --Part 3 (1987)
From Main menu � Define � Static Load cases � Load = X or Y
Type = Wind
Self weight multiplier =0 Auto Lateral load =IS 875—1987 � � Add New Load � Select wind X
load and click on modify lateral loads to specify required wind load parameter. As per IS 875 � Ok � Ok.
Creating dummy areas with property =None
Set required elevation view in right window � From Main menu � Draw
� Draw area objects � Draw rectangular areas � Property = None � Click on the perimeter of area and press enter.
Foot Note: Apply wind load for selections.
To select wind area Main menu � Select � By area object type � select none � Ok.
Assigning wind loads
Select drawing area of required elevation � From Main menu �
Assign � Shell/area loads � Wind Pressure coefficients � Wind load case name =Wind X
Coefficient Cp= - (Change if required) � Ok. To see wind load selection
� Set Building view option �
� Area section
� Line section � Ok.
3.Earthquake Analysis In building, slab is considered as single rigid member during earthquake
analysis. Select left side window.
Select all slabs by setting all floors/ similar storey option � From Main
menu � Define � Diaphragms � Select D1 � Modify/ Show diaphragms � Select � Rigid � Ok � Ok.
Define Mass Source
As per IS 1893-->2002 25% of Live load is considered on all floors of building.
From Main menu � Define � Mass source � select � From Loads �
Load =Dead; Multiplier -->1.0 � Add Load = Live; Multiplier =0.25 � Add
Load =SDL; Multiplier =1.0 � Add Load = Wall; Multiplier =1.0 � Add � Ok.
Define Earthquake Load (Static Method) From Main menu � Define � Static Load cases �
Load =EQX Type = Quake
Default Multiplier =0 Auto Lateral load = IS 1893—2002 � �
Add New Load � Select the load RQX � Modify lateral load � If required
change values as per IS 1893 � Select � X Direction Select � Program calc � per code =0.16 (change as per requirement) �
Ok � Ok.
Assigning Diaphragms
Set all storey option and select all slabs � From Main menu � Assign � Shell area � Diaphragms � D1 � Ok.
To view the Diaphragm
Go to � Set Building View objects
� Diaphragm
STEP 8 : ( Design)
Selecting Indian Code From Main menu � Options � Preferences � Concrete Frame � Design
code = Indian IS 456-2000. � Ok.
Defining Load Combination
From Main menu � Define � Load Combinations � Add New Load Comb �
Load Combination Name =DL+LL
Load Combination type =Add � Change scale factor =1.5 for DL and LL by clicking add button � Add New Load Comb �
Load Combination Name =DL+WL Load Combination type =Add � Change scale factor =1.5 for DL and WL by
clicking add button � Add New Load Comb �
Load Combination Name =DL+EQX Load Combination type =Add � Change scale factor =1.5 for DL and EQX by
clicking add button � Ok � Ok.
Selecting Design Load ( i.e. DL+LL) From Main menu � Design � Concrete Frame design � Select design comb
� Select our combination load from the list � Add � Ok.
STEP 9 : (Analysis)
From Main menu � Analysis � Run analysis. After completing process, the model automatically displaces deformed shape
view and the model is locked (you cannot do any changes ).
STEP 10 : (Running the Design Process)
From Main menu � Design � Concrete frame design � Start Design/ Check of Structure � Design results will be displayed on the model.
Graphical output:
Activate 3D view in right window by clicking title bar � Set elevation view
=1 � From Main menu � Display � Show member force/Stresses diagrams � Frame/Pier/Spandrel forces � Select any load case say DL +LL.
Select moment – 3 option � Uncheck the fill diagram.
If it is checked, we have to deselect. � check the showed values on the
diagram check box � Ok. Right click on any beam in right window which will display diagrams for the
beams. Select � scroll for values (Right top window which will show at different
distances along the beam.
To clear the display: Activate right window � From Main menu � Display � Show un deformed
shape � Click on 3D button from top tool bar to display 3D view.
To view reinforcement detail:
Running the Design Process From Main menu � Design � Concrete Frame Design � start design /Check
of Structure� Design results will be displayed in the model.
Set to Elevation view=1 in right window � Reinforcement area will be
displayed on the frame. Right click on any beam or column. We can select various options:
- Summary - Flexural details
- Shear details etc. - Envelope � Ok.
View the % of steel on beams and columns
From Main menu � Design � Concrete Frame Design � Display design
information � select � Design output=rebar% � Ok.
Example 2 :
No. of stories : 10 No. of bays in X Direction : 4
No. of bays in Y Direction : 5 Spacing in X Direction : 4500
Spacing in Y Direction : 3000 Typical Storey height : 3000
Basement height : 2000 Concrete Grade : M20 for beams & M25 for
Columns Steel Grade : Fy415
Column Sizes C1 : 230 x 460 C2 : 230x 530
C3 : 230x600 Beams B1 : 230x 406
B2 : 230x 380
PB : 230x300 Slab Thickness : 125mm
C2
C2C2C2
C2 C3 C3
C1C3C3C2
C2 C2 C1
C1
C1
FLOOR PLAN
4000 3000 3500
30
00
40
00
28
00
32
00
A B C D
1
2
3
4
5
B2
B2
B2
B2
B1 B1
B1
B2 B2
B2
B1B1
B2 B2 B2
B1 B1 B1
B1 B1
B2
B1
B2
BEAMS:
B1 = 230 X 330
B2 = 230 X 460
PLINTH BEAM - PB 230 X 380
COLUMN:
C2 = 230 X 530
C1 = 230 X 460
C3 = 230 X 600
X
Y
TYPICAL STOREY=3000 mmBOTTOM HEIGHT=2000 mm
350030004000
D
44
CB
44
A
STOREY-10
STOREY-9
STOREY-7
STOREY-5
STOREY-3
STOREY-2
STOREY-1
BASE
STEP BY STEP PROCEURE:
STEP 1: (Creation of geometry) Open ETABS Program.
Select units N. mm.
From Main menu � File � New Model � Select No.
Building Pan Grid System and Storey Data Definition will be displayed.
� Uniform Grid Spacing
No. of lines in X Direction =4 No. of lines in Y Direction =5
Spacing in X Direction = 4000 mm Spacing in y Direction = 3000 mm
� Uniform Grid Spacing Click Edit Grid
X Grid Data
Grid
ID
Ordinate Line type visibility Bubble
location
Grid color
A 0 Primary Show Top
B 4000 Primary Show Top
C 7000 Primary Show Top
D 10500 Primary Show Top
Y Grid data
Grid ID
Ordinate Line type visibility Bubble location
Grid color
1 0 Primary Show Left
2 3000 Primary Show Left
3 7100 Primary Show Left
4 9900 Primary Show Left
5 13100 Primary Show Left
� Ok.
Storey dimension: No. of storeys :10
Typical storey height :3000 Bottom storey height :2000
Go to Main menu � Edit � Edit storey data � Edit storey
Level Height Elevation Master
storey
Similar
storey
Splice
point
Splice
height
11 Storey 10 3000 29000 Yes -- No 0
10 Storey 9 3000 26000 No Storey 10 No 0
9 Storey 8 3000 23000 No Storey 10 No 0
8 Storey 7 3000 20000 No Storey 10 No 0
7 Storey 6 3000 17000 No Storey 10 No 0
6 Storey 5 3000 14000 No Storey 10 No 0
5 Storey 4 3000 11000 No Storey 10 No 0
4 Storey 3 3000 8000 No Storey 10 No 0
3 Storey 2 3000 5000 No Storey 10 No 0
2 Storey 1 2000 2000 No None No 0
1 Base -- 0
� Ok.
Change units N.mm. Select Grid only button � OK.
Note: You can change Grid spacing by choosing Custom Grid spacing, for column varying spacing then click Edit Grid you can also change any storey
height by choose Custom Storey Data, then click on Edit Storey Data.
STEP 2: (Define Material Properties)
From Main menu � Define � Material Property � Add new material � Material Name =M25
Concrete cubic comp. strength fck =25
Bending Reinforcement yield strength fy =415 Shear Reinforcement yield strength fy =415 � Ok � Ok.
Similarly Define M20 concrete for beam.
STEP 3: (Define Frame section) Define Beam:
From Main menu � Define � Frame section � Add rectangular � Material name =M20 (select) � Section Name=B1
Dimensions:
Depth (3) =406mm Width (2) =230mm Click reinforcement Select � Beam � Concrete cover to rebar center Top =41 mm
Bottom =41mm � Ok � Ok.
In the same manner define other beams B2 and PB.
Define Column: Add Rectangular � section Name =C1
Material name = M25 Dimensions :
Depth (3) =460mm Width (2) =230mm
Click reinforcement Select � Column Select � Rectangular Ties � Rectangular
Cover = 58 mm Bar size =20 d
Corner bar =20d
� Reinforcement to be designed � Ok� Ok. In the same manner define column C2(230x530) and C3 (230x600).
Define Slab:
From Main menu � define � Wall/Slab /Deck section � Add New slab � Section name = S1
Material name = M20. � Membrane
Membrane =125 mm
Bending =125mm Select � Membrane � Ok � Ok.
STEP 5: (Drawing Beams, Columns and Slabs) Drawing Beams:
From Main menu � Draw � Draw line objects � Create lines in region
Property = - Select required beam size B1
Click or Select the beam B1 in Plan view (Left window) (with similar storey option) and select all beam B1.
Change Property = Beam B2 size and click on beam B2 (with Similar storey option) � Select Plinth beam Property =PB and select all Plinth beams in
Storey 1 in plan view (Left Window) with one storey option �Close.
Drawing Columns: From Main menu � Draw � Draw line objects � Create column in region �
Property = C1 �
Select or Click on the column joints in Plan view (Left window) with similar storey option. If necessary change angle =90 � Change Property =C2 and
C3 and click on respective column joints � Close.
Drawing Slab:
From Main menu � Draw � Draw area objects � Create areas at click (Draw areas) (Plan) � Property =S1 � Click on the periphery of column joints and
press enter (With similar storey option).
Note:
To view the assigned beam in plan
Select � Set Building Objects on top of Tool bar.
Select � Line sections under object view options.
Special effects:
� Object Fill
� Extrusion � Ok.
To view the rendered view
� Set Building view objects on top of Tool bar
� Line section.
Special Effects:
� Object Fill
� Extrusion
� Apply to all windows � Ok. STEP 6:(Assigning Support Condition)
Set Base floor Plan view in left window � Set Column points (with mouse) From Main menu � Assign � Joint/Point � Restraints (supports) � Select
Fixed � Ok.
To view Support assigned
From top Tool bar � Set Building view option � Visible in view
� Supports � Ok.
Go to Elevation view 1 and view . For other views click � � arrow at top of tool bar.
STEP 7: (Defining Loads)
1.Gravity Loads (Dead Load & Live Load) From Main menu � Define � Static Load Cases �
Load = SDL (Super Imposed Dead Load)
Type = Dead Self weight multiplier =0 � Add New Load � Ok.
Load = Wall Type= Dead
Self weight multiplier =0 � Add New Load � Ok.
Assigning the Loads: Activate left window and set to Plan view � Activate or select similar storey
option (at bottom) and select all slabs
� From Main menu � Assign � Shell / Area loads � Uniform �
Load case name =SDL � Uniform load
Load = 1.50 Kn/m2 (units Kn.m)
Direction Gravity � Ok. In the same manner assign Load case name = Live
� Uniform load Load = 2.0 Kn/m2 (units Kn.m)
Direction Gravity � Ok.
Assigning Wall loads:
9” wall load = 12Kn/m (For external or outer beams) 41/2” wall load=6 Kn/m (For internal beams).
In left side window select all outer beams in top floor by setting similar storey options and view the status bar to know no. of beams selected �
From Main menu � Assign � Frame /Line loads � Distributed Load case name = wall. Unit Kn.m
� Forces
Direction Gravity Uniform load=12 Kn/m
� Replace existing loads � Ok. In the same manner apply 41/2” wall udl load to internal beams by setting
“all floor options”.
To see the load assigned : Right click the particular member corresponding load � Ok.
Note: For point load :
From Main menu � Assign � Joint/Point loads � Load case name =Dead. Units Kn.m.
� Replace existing loads Forces Global =10 Kn � Ok.
2. Wind Loads :
Define wind load parameters as per IS 875 --Part 3 (1987) From Main menu � Define � Static Load cases �
Load = X or Y Type = Wind
Self weight multiplier =0 Auto Lateral load =IS 875—1987 � � Add New Load � Select wind X
load and click on modify lateral loads to specify required wind load parameter. As per IS 875 � Ok � Ok.
Creating dummy areas with Property =None. Set required elevation view in right window � From Main menu � Draw
� Draw area objects � Draw rectangular areas � Property = None � Click on the perimeter of area and press enter.
Foot Note: Apply wind load for selections.
To select wind area Main menu � Select � By area object type � select none � Ok.
Assigning wind loads
Select drawing area of required elevation � From Main menu � Assign � Shell/area loads � Wind Pressure coefficients � Wind load
case name =Wind X
Coefficient Cp= - (Change if required) � Ok.
To see wind load selection � Set Building view option �
� Area section
� Line section � Ok.
3.Earthquake Analysis
Select left side window.
Select all slabs by setting all floors/ similar storey option � From Main
menu � Define � Diaphragms � Select D1 � Modify/ Show diaphragms � Select � Rigid � Ok � Ok.
Define Mass Source
As per IS 1893--2002 25% of Live load is considered on all floors of building.
From Main menu � Define � Mass source � select � From Loads �
Load =Dead; Multiplier -->1.0 � Add Load = Live; Multiplier =0.25 � Add
Load =SDL; Multiplier =1.0 � Add
Load = Wall; Multiplier =1.0 � Add � Ok.
Define Earthquake Load (Static Method) From Main menu � Define � Static Load cases �
Load =EQX Type = Quake
Default Multiplier =0
Auto Lateral load = IS 1893—2002 � � Add New Load � Select the load RQX � Modify lateral load � If required
change values as per IS 1893 � Select � X Direction Select � Program calc � per code =0.16 (change as per requirement) �
Ok � Ok.
Assigning Diaphragms
Set all storey option and select all slabs � From Main menu � Assign � Shell area � Diaphragms � D1 � Ok.
To view the Diaphragm Go to � Set Building View objects
� Diaphragm
STEP 8 : ( Design)
Selecting Indian Code
From Main menu � Options � Preferences � Concrete Frame � Design code = Indian IS 456-2000. � Ok.
Defining Load Combination
From Main menu � Define � Load Combinations � Add New Load Comb � Load Combination Name =DL+LL
Load Combination type =Add � Change scale factor =1.5 for DL and LL by
clicking add button � Add New Load Comb � Load Combination Name =DL+WL
Load Combination type =Add � Change scale factor =1.5 for DL and WL by clicking add button � Add New Load Comb �
Load Combination Name =DL+EQX
Load Combination type =Add � Change scale factor =1.5 for DL and EQX by clicking add button � Ok � Ok.
Selecting Design Load ( i.e. DL+LL)
From Main menu � Design � Concrete Frame design � Select design comb
� Select our combination load from the list � Add � Ok.
STEP 9 : (Analysis) From Main menu � Analysis � Run analysis.
After completing process, the model automatically displaces deformed shape
view and the model is locked (you cannot do any changes ).
STEP 10 : (Running the Design Process) From Main menu � Design � Concrete frame design � Start Design/
Check of Structure � Design results will be displayed on the model.
Graphical output: Activate 3D view in right window by clicking title bar �
Set elevation view =1 �
From Main menu � Display � Show member force/Stresses diagrams � Frame/Pier/Spandrel forces � Select any load case say DL +LL.
Select moment – 3 option
� Uncheck the fill diagram. If it is checked, we have to deselect. � check the showed values on the
diagram check box � Ok. Right click on any beam in right window which will display diagrams for the
beams. Select � scroll for values (Right top window which will show at different
distances along the beam.
To clear the display:
Activate right window � From Main menu � Display � Show un deformed shape � Click on 3D button from top tool bar to display 3D view.
To view reinforcement detail:
Running the Design Process
From Main menu � Design � Concrete Frame Design � start design /Check of Structure� Design results will be displayed in the model.
Set to Elevation view=1 in right window � Reinforcement area will be
displayed on the frame. Right click on any beam or column. We can select
various options:
- Summary
- Flexural details - Shear details etc.
- Envelope � Ok.
To View the % of steel on beams and columns From Main menu � Design � Concrete Frame Design � Display design
information � select � Design output=rebar% � Ok.
Example 3:
No. of bays in X Direction : 4
No. of bays in Y Direction : 3 Spacing in X Direction : 5000
Spacing in Y Direction : 4000 Typical Storey height : 3200
Basement height : 3200 Concrete Grade : M25
Steel Grade : Fy415 Column Sizes : 300 x 450
Beam : 300x 450
Slab Thickness : 120mm
STEP BY STEP PROCEURE: STEP 1: (Creation of geometry)
Open the ETABS Program.
Set the units of the model in the drop down box in the lower right hand corner of ETABS window , click the drop down box to set units in Kn.m.
From Main menu � File � New Model � Select No.
Building Pan Grid System and Storey Data Definition will be displayed. � Uniform Grid Spacing
No. of lines in X Direction =5 No. of lines in Y Direction =4
Spacing in X Direction = 5m Spacing in y Direction = 4m
� Simple Grid Data
No. of stories =5
Typical Storey Height =3.2m Bottom storey height =3.2m
Select Grid only button � OK.
Note: You can change Grid spacing by choosing Custom Grid spacing, for column varying spacing then click Edit Grid you can also change any storey
height by choose Custom Storey Data, then click on Edit Storey Data.
Go to Main menu � Edit Storey data � Edit Storey.
Grid No.
Label Height Elevation Master Storey
Similar to Spice point
Spice height
6 Storey 5 3.2 16 Yes No 0
5 Storey 4 3.2 12.6 No Storey 5 No 0
4 Storey 3 3.2 9.6 No Storey 5 No 0
3 Storey 2 3.2 6.4 No Storey 5 No 0
2 Storey 1 3.2 3.2 No None No 0
1 Base 0
Change units N.mm.
STEP 2: (Design Preference code) From Main menu � Options � Preferences � Concrete Frame design
Design code =Indian IS456-2000. ���� Ok.
STEP 3: (Define Material Properties)
From Main menu � Define � Material Property � Add new material � Material Name =M25
Concrete cubic comp. strength fck =25 Bending Reinforcement yield strength fy =415
Shear Reinforcement yield strength fy =415 � Ok � Ok.
STEP 4: (Define Frame section)
Define Beam: From Main menu � Define � Frame section � Add rectangular � Material
name =M25 (select) � Section Name=B300x450. Dimensions:
Depth (3) =0.45m
Width (2) =0.30m Click reinforcement
Select � Beam � Concrete cover to rebar center Top = 0.041m(=25+8+16/2=41 mm)
Bottom =41mm � Ok � Ok. Define Column:
Add Rectangular � section Name =C300x450.
Material name = M25 Dimensions :
Depth (3) =0.3m Width (2) =0.45m
Click reinforcement
Select � Column Select � Rectangular
Ties � Rectangular
Cover to rebar centre= 0.056 (40+8+16/2=56mm) Bar size =16 d
Corner bar =16 d � Reinforcement to be designed � Ok� Ok.
Define Slab:
From Main menu � define � Wall/Slab /Deck section � Add New slab �
Section name = S1 Material name = M25.
� Membrane Membrane =0.120 m
Bending =0.125m Select � Membrane � Ok � Ok.
STEP 6: (Drawing Beams, Columns and Slabs) Drawing Beams:
From Main menu � Draw � Draw line objects � Create lines in regions or at clicks(plan,Elev.,3D)
Property = - Select required beam size B300x450
Click or Select the beam B300x450 in Plan view (Left window) (with similar storey option) and select all beam B300x450.
�Close.
Drawing Columns:
From Main menu � Draw � Draw line objects � Create column in region or clicks(plan) �
Property = C300x450 �
Select or Click on the column joints in Plan view (Left window) with similar storey option. If necessary change angle =90 � Close.
Drawing Slab:
From Main menu � Draw � Draw area objects � Create areas at click or click (Plan, Elev.) (Plan) � Property =S120 � Click on the periphery of
column joints and press enter (With similar storey option).
Note:
To view the assigned beam in plan
Select � Set Building Objects on top of Tool bar.
Select � Line sections under object view options.
� Ok.
To view the rendered view
� Set Building view objects on top of Tool bar
� Line section.
Special Effects:
� Object Fill
� Extrusion
� Apply to all windows � Ok.
STEP 7:(Assigning Support Condition)
Set Base floor Plan view in left window � Set Column points (with mouse) From Main menu � Assign � Joint/Point � Restraints (supports) � Select
Fixed � Ok.
To view Support assigned From top Tool bar � Set Building view option �
Visible in view � Supports � Ok.
Go to Elevation view 1 and view . For other views click � � arrow at top of
tool bar.
STEP 8 : (Defining Loads) 1.Gravity Loads (Dead Load & Live Load)
From Main menu � Define � Static Load Cases � Load = SDL (Super Imposed Dead Load)
Type = Dead Self weight multiplier =0 � Add New Load � Ok.
Load = Wall
Type= Dead Self weight multiplier =0 � Add New Load � Ok.
Note:
For Self weight multiplier will be 1 for beams and columns of dead load. For all other loads, it will be zero.
Assigning the Loads:
Activate left window and set to Plan view � Activate or select similar storey
option (at bottom) and select all slabs � From Main menu � Assign �
Shell / Area loads � Uniform � Load case name =SDL
� Uniform load
Load = 1.50 Kn/m2 (units Kn.m) Direction Gravity � Ok.
In the same manner assign Load case name = Live � Uniform load
Load = 2.0 Kn/m2 (units Kn.m) Direction Gravity � Ok.
Assigning Wall loads: 9” wall load = 12Kn/m (For external or outer beams)
41/2” wall load=6 Kn/m (For internal beams). In left side window select all outer beams in top floor by setting similar
storey options and view the status bar to know no. of beams selected � From Main menu � Assign � Frame /Line loads �
Distributed Load case name = wall. Unit Kn.m
� Forces Direction Gravity
Uniform load=12 Kn/m � Replace existing loads � Ok.
In the same manner apply 41/2” wall udl load to internal beams by setting “all floor options”.
To see the load assigned :
Right click the particular member corresponding load � Ok.
Note:
For point load : From Main menu � Assign � Joint/Point loads � Forces
Load case name =Dead. Units Kn.m. Forces Global =10 Kn
� Replace existing loads
� Ok.
2. Wind Loads : In ETABS there are two ways to define lateral loads (Wind, earth quake).
Built in option will automatically calculate lateral loads as per available design codes.
Define wind load parameters as per IS 875 --Part 3 (1987) From Main menu � Define � Static Load cases �
Load = X or Y
Type = Wind Self weight multiplier =0
Auto Lateral load =IS 875—1987 � � Add New Load � Select wind X
load and click on modify lateral loads to specify required wind load parameter. As per IS 875 � Ok � Ok.
Creating dummy areas with property =None
Set required elevation view in right window � From Main menu � Draw � Draw area objects � Draw rectangular areas � Property = None �
Click on the perimeter of area and press enter.
Foot Note: Apply wind load for selections.
To select wind area Main menu � Select � By area object type � select none � Ok.
Assigning wind loads
Select drawing area of required elevation � From Main menu �
Assign � Shell/area loads � Wind Pressure coefficients � Wind load case name =Wind X
Coefficient Cp= - (Change if required) � Ok.
To see wind load selection � Set Building view option �
� Area section
� Line section � Ok.
3. Earthquake Analysis In building, slab is considered as single rigid member during earthquake
analysis. Select left side window.
Select all slabs by setting all floors/ similar storey option � From Main
menu � Define � Diaphragms � Select D1 � Modify/ Show diaphragms � Select � Rigid � Ok � Ok.
Define Mass Source
As per IS 1893--2002 25% of Live load is considered on all floors of building.
From Main menu � Define � Mass source � select � From Loads �
Load =Dead; Multiplier --1.0 � Add Load = Live; Multiplier =0.25 � Add
Load =SDL; Multiplier =1.0 � Add
Load = Wall; Multiplier =1.0 � Add � Ok.
Define Earthquake Load (Static Method) From Main menu � Define � Static Load cases �
Load =EQX Type = Quake
Default Multiplier =0 Auto Lateral load = IS 1893—2002 � �
Add New Load � Select the load EQX � Modify lateral load � If required
change values as per IS 1893 � Select � X Direction Select � Program calc � per code =0.16 (change as per requirement) �
Ok � Ok.
Assigning Diaphragms
Set all storey option and select all slabs � From Main menu � Assign � Shell area � Diaphragms � D1 � Ok.
Define Earthquake Load (Response Spectrum or Dynamic method) From Main menu � Define � Response Spectrum Functions � IS 1893 -
2002 � select IS 1893-2002Spectrum � Ok. Select IS1893 �
Modify/Show Spectrum � Spectrum case name =IS1893 Damping =0.05 Modal combination � CQC Directed Combination � SRSS
Function name=1893; Function damping ration=0.05 Seismic zone factor z=0.16 ; Soil type =1 � Ok.
To view the Diaphragm Go to � Set Building View objects
� Diaphragm
STEP 8 : ( Design)
Selecting Indian Code
From Main menu � Options � Preferences � Concrete Frame � Design code = Indian IS 456-2000. � Ok.
Defining Load Combination
From Main menu � Define � Load Combinations � Add New Load Comb � Load Combination Name =DL+LL
Load Combination type =Add � Change scale factor =1.5 for DL and LL by
clicking add button � Add New Load Comb � Load Combination Name =DL+WL
Load Combination type =Add � Change scale factor =1.5 for DL and WL by clicking add button � Add New Load Comb �
Load Combination Name =DL+EQX
Load Combination type =Add � Change scale factor =1.5 for DL and EQX by clicking add button � Ok � Ok.
Selecting Design Load ( i.e. DL+LL)
From Main menu � Design � Concrete Frame design � Select design comb
� Select our combination load from the list � Add � Ok.
STEP 9 : (Analysis) From Main menu � Analysis � Run analysis.
After completing process, the model automatically displaces deformed shape view and the model is locked (you cannot do any changes ).
STEP 10 : (Running the Design Process)
From Main menu � Design � Concrete frame design � Start Design/ Check of Structure � Design results will be displayed on the model.
Graphical output:
Activate 3D view in right window by clicking title bar � Set elevation view =1 � From Main menu � Display � Show member force/Stresses diagrams
� Frame/Pier/Spandrel forces � Select any load case say DL +LL.
Select moment – 3 option � Uncheck the fill diagram.
If it is checked, we have to deselect. � check the showed values on the
diagram check box � Ok. Right click on any beam in right window which will display diagrams for the
beams. Select � scroll for values (Right top window which will show at different
distances along the beam.
To clear the display:
Activate right window � From Main menu � Display � Show un deformed shape � Click on 3D button from top tool bar to display 3D view.
To view reinforcement detail:
Running the Design Process From Main menu � Design � Concrete Frame Design � start design /Check
of Structure� Design results will be displayed in the model.
Set to Elevation view=1 in right window � Reinforcement area will be
displayed on the frame. Right click on any beam or column. We can select various options:
- Summary - Flexural details
- Shear details etc. - Envelope � Ok.
View the % of steel on beams and columns From Main menu � Design � Concrete Frame Design � Display design
information � select � Design output=rebar percentage � Ok.