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
3500 3500 45 00 45 00 45 00 1 2 3 4 A B C C2 C1 B1 B1 C1 C3 C2 C2 B2 B2 B2 B2 B2 B2 C2 C3 C2 C1 C2 C1 B2 B2 B2 B1 B1 B1 B1 B1 B1 BEAMS: B1 = 230 X 330 B2 = 230 X 406 PLINTH BEAM - PB 230 X 300 COLUMN: C2 = 230 X 380 C1 = 230 X 300 C3 = 230 X 460 C3 = 230 X 460 C1 = 230 X 300 C2 = 230 X 380 COLUMN: PLINTH BEAM - PB 230 X 300B2 = 230 X 406 B1 = 230 X 330BEAMS: 2 0 0 0 3 0 0 0 3 0 0 0 3 0 0 0 PB1 PB1 B1 B1 B1 B1 B1 B1 BASE STOREY-1 3 0 0 0 STOREY-2 STOREY-3 STOREY-4 STOREY-5
STEP BY STEP PROCEURE:
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 MasterStorey Similar to Spicepoint 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.
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 =25 mm
Bottom =25mm 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 = 40 mm Bar size =12 d Corner bar =12 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.
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. 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
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)
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.
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 Y X C3 = 230 X 600 C1 = 230 X 460 C2 = 230 X 530 COLUMN: PLINTH BEAM - PB 230 X 380 B2 = 230 X 460 B1 = 230 X 330 BEAMS: B2 B1 B2 B1 B1 B1 B1 B1 B2 B2 B2 B1 B1 B2 B2 B2 B1 B1 B1 B2 B2 B2 B2 5 4 3 2 1 D C B A 3 20 0 2 80 0 4 00 0 3 00 0 3500 3000 4000 FLOOR PLAN C1 C1 C1 C2 C2 C2 C3 C3 C1 C3 C3 C2 C2 C2 C2 C2
BASE STOREY-1 STOREY-2 STOREY-3 STOREY-5 STOREY-7 STOREY-9 STOREY-10 A 4 4 B C 4 4 D 4000 3000 3500 BOTTOM HEIGHT=2000 mm TYPICAL STOREY=3000 mm
STEP BY STEP PROCEURE:
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
Level Height Elevation Master
storey Similar storey Splicepoint 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 =25 mm
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 = 40 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
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 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
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.
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:
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 MasterStorey Similar to Spicepoint 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. Special effects:
Object Fill
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
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.
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.
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.
- 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 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.
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.
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.
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 Ductile detailing as per IS 13920.
o Additional software for foundation design especially mat (SAFE software).
o Not support for sloping roofs.
(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.
4000 3000 3500 3 0 0 0 4 0 0 0 2 8 0 0 3 2 0 0 A B C D 1 2 3 4 5 B2 B2 B2 B2 B1 B1 B1 B2 B2 B2 B1 B1 B2 B2 B2 B1 B1 B1 B1 B1 B2 B1 B2 NO. OF FLOORS: 10 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 FLOOR PLAN UP TO FOURTH STOREY
X Y C1 C1 C1 C1 C1 C2 C2 C2 C1 C2 C3 C3 C3 C3 C2 C2 C2 C2 C2
Y X C3 = 230 X 600 C1 = 230 X 460 C2 = 230 X 530 COLUMN: PLINTH BEAM - PB 230 X 380 B2 = 230 X 460 B1 = 230 X 330 BEAMS: B2 B1 B2 B1 B1 B1 B1 B1 B2 B2 B2 B1 B1 B2 B2 B2 B1 B1 B1 B2 B2 B2 B2 5 4 3 2 1 D C B A 3 2 0 0 2 8 0 0 4 0 0 0 3 0 0 0 3500 3000 4000
FLOOR PLAN ABOVE FOURTH STOREY
C1 C1 C1 C2 C2 C2 C3 C3 C1 C3 C3 C2 C2 C2 C2 C2
BASE STOREY-1 STOREY-2 STOREY-3 STOREY-5 STOREY-7 STOREY-9 STOREY-10 A 4 4 B C 4 4 D 4000 3000 3500 BOTTOM HEIGHT=2000 mm TYPICAL STOREY=3000 mm