Structural Modelling using Etabs 2018

The architectural drawings for a G+7 residential building in zone 5 has been provided. The floor plan is the same for all 7 floor levels. Possible column positions have also been provided. Conceptualize a framing plan layout and then model the building in Etabs. The following architectural drawings have been provided:

• Typical floor plan – The location and thickness of the brick walls and the use of the
  space (for estimating live load) can be obtained from this plan
• A building section through the staircase and lift core is provided
• Parking layout in the ground floor – the column/shear wall arrangement must not
  obstruct entry/exit of vehicles.
  The following loadings are to be taken into account:
• Brickwall made of AAC blocks
• Finishes – floor tiles of 75 mm thickness
• Live loads as per IS 875 part 2
• Water tank of 20 KL above the staircase at Mumty level
• Lift Machine room at mumty level above lift core

The structural model must comply with provisions of IS 1893 and IS 13920.
Run a modal response spectrum analysis and check analysis results of the etabs model for inter-storey drift requirements, vertical & planar irregularities, minimum shear wall requirements,maximum axial load ratio for column and shear walls, effective moment of inertia for beams
and columns etc.

Please note that the column positions shown in the architectural typical floor plan are only to provide an initial starting point for modelling. Participants will have to change its size, introduce shear walls, and add new vertical elements after running the analysis. You will have to run the analysis multiple times until a structural model is obtained that meets structural code requirements without compromising architectural functions. Also, there is no one ‘correct’ structural system for this challenge. There can be multiple possible solutions for this problem.

AIM : 

     To architectural drawings for a G+7 residential building in zone 5 has been provided. The floor plan is the same for all 7 floor levels. Possible column positions have also been provided. Conceptualize a framing plan layout and then model the building in Etabs. The following architectural drawings have been provided

INTRODUCTION :  

PROCEDURE : 

STEP : 1 

• Open the Etab software 
• On the left side top corner select the new model as shown below
• After click the new model there open the model initialization dialouge box
• In the box we can see a 3 option and then select the last option 
• Set the unit as " METRIC SI " and set the steel section data base as " indian " and set the code as 800:2007 for 3rd option. finally set the code 456:2000 for last option 
• After finishing the previous process then open new model quick template opened automatically 
• we can set the grid dimension as custom and also the story dimension
• Next we can set the number of storys and height of the story in x grid data 
• And also same the process in y grid data  and then ok 
• Next we open the story data and we need to add the story data upto 09 story and then added story data as shown below in picture
• And we give the name for the story as base, plint , story1, story2................7, roof.
• And set the height of the plinth as 1.5m and other all as 3m
• Then set the all story similar to story 1, except plinth 
• Finally click ok
• The model will be created sucessfully and the image shown below

 STEP : 2  

• Next we go to the define option and select the material properties 
• Then there open a define material box and select the add new material option 
• And select the region "INDIAN" , material type "concrete", standard "INDIAN", grade "M25"
• then click ok
• After here opening the material property data box
• Set the material name like M25
• Then material type "Concrete" 
• Others are automatically update with using code given
• Finally click ok
• Again click the add new material 
• again set add new material properties
• Here we can set the matrial properties as "rebar" 
• Make them two types of material grade 415 and 500

 STEP : 3  

• Next go the define option and select the section properties and go to the frame section
• Select the concrete rectangle and click ok 
• And set the material name as (B250 X 450) and material "M25"
• Go to the modify show rebar 
• And set the design type M3 beam and give the rebar material as HYSD 500 at top and HYSD 415 for bottom
• And then click ok
• Again Select the concrete rectangle and click ok 
• And set the material name as (B300 X 500) and material "M25"
• Go to the modify show rebar 
• And set the design type M3 beam and give the rebar material as HYSD 500 at top and HYSD 415 for bottom
• And then click ok

 STEP : 4 

• Next we can open the same concrete rectangle and select the column in here 
• And set the material name as (C400 X 900) and material "M30"
• Go to the modify show rebar 
• And set the rebar as HYSD 500 at top and HYSD 415 at bottom 
• Finally click ok
• Again we can open the same concrete rectangle and select the column in here 
• And set the material name as (C400 X 600) and material "M30"
• Go to the modify show rebar 
• And set the rebar as HYSD 500 at top and HYSD 415 at bottom 
• Finally click ok

 STEP : 5 

• Go to the define tab and select the section properties and then select the slab section 
• After there open a slab properties box
• and click modify option and then set properties name "slab 125"
• Give the slab material " M25"
• And modeling type " membrane"
• Give the thickness of slab as 125mm
• Finally click ok
• Again create the slab with name of STR slab 
• Give the slab material " M25"
• And modeling type " membrane"
• Give the thickness of slab as 125mm
• Go to the section properties and pick the wall section 
• wall section dialouge box has been open
• Give the propertie name wall 1
• and give shell thin and thickness 250 and m25 concrete material

 STEP : 6 

• Let now we can arrage the materials and loads on the design 
• go to the quick draw column option in the left to corner 
• After clicking the box will appear in left bottom corner
• Set the column in the grid by using properties option 
• Set four columns in center size of 400 x 900
• Set other columns as size of 400 x 600
• And go the plan view and and placed the coloumn on the grid . Is shown in the below image
• Just use the replicate option to make the multiple or copy paste the column to all the grid
• Next we want to rotate the column so use local axes option
• Go to the assign option 
• Select the frame and go to local axes
• Its automatically open the frame ' design ' dialouge box
• And rotate the angle as 90 degree and click ok

 STEP : 7 

• We want to make a beam placed into interior of the grid 
• so use the replicate option to place the beam were we want
• just pick replicate and go to linear
• select the "pick two point" option
• Suppose we want to cut the beam please use the divide frame option
• Go to the edit option 
• select the edit frame and pick the divide frame
• And use the " break at intersection " option

 STEP : 8 

• Select the draw wall option as given below
• draw the wall as given in architecture drawing
• the wall placed image as given below
• Also use the replicate and divide frame option 

 STEP : 9 

• Use the quick draw floor option to make a slab
• And go to property and select slab 125 
• And pick into the grid to make slab
• Use the divide shell option to divide the slab
• just divide the slab and delete the slab what we not wanted
• create the mummty level on edit grid option 
• draw the head room for stair case on mummty level
• Go to the plan option and select base level
• delete all the slab in base level 
• Set the joint at the base by using joint option
• Go to the assign select joint 
• pick the restraint and select the 1st option and then click ok

 STEP : 10 

• Go to the define and select the load patterns
• set or make the loads like dead, live, wall
• Here wall load as set super dead load
• And create finishers and set super dead load
• open the selected plan views 
• select the story 1 option
• And then select the similar story option
• Go to the assign tab select the frame load
• And assign the distributed load
• Select the load pattern name as "wall" (sdl)
• give the load value of 3.5 KN/m
• Select the some slab to give load 3 and some slab as 2 KN
• the slab selected image as given below 

 STEP : 11 

• Go to the design option 
• select the live load reduction factore
• Create the 1 to 9 and set 1,0.9,0.8,0.7,0.6,0.6,0.6,0.6,0.6
• Go to the define and select the load patterns
• set or make the loads like EQX, EQY,EQX+, EQX-, EQY+, EQY-
• Give the IS code value for EXQ, EXY,EQX+, EQX-, EQY+, EQY-
• Taken the both load and set the (DIRECTION AND ECCENTRICITY)
• EXQ - only select the x-dirction
• EXY - only select the y-dirction
• Set other as given below image 
• And set the seismic zone factor for per code as per the rule of code book (0.36) 
• And set the site type as (II)
• This process is same for both the EQX, EQY,EQX+, EQX-, EQY+, EQY-
• Go to the load cases and check once
• Taken the define option and select the mass source
• After opening the mass source dialouge box
• Just give a modify option to modify it
• Just select only the specify load pattern and other then unselect it
• And give the load patterns as dead load, live load, wall load, finisher load
• Give the value of the dead load, finisher and wall load as (1)
• give the value of live load as (0.25)
• Then click ok

 STEP : 12 

• Go to the assign tab 
• Then select the shell and pick the diaphragms
• tHere automatically open the shell assignment dialouge box
• In the dialouge box select the (d1) option
• the diaphragms as placed at the center of the building
• Next go the assign select the shell
• pick the pier label
• make the p1 ,p2 .......p18
• And just place the pier label into the wall
• go to load combination and select all combo and delete
• pick the modify option
• And select the concrete frame design and select concrete shell wall design and select converet to user combination and click ok

 STEP : 13 

• Go to the define option and select the model cases
• Given the materila and value as by given below image
• Go to the analysis option and select the set load case run
• Select the calculation diaphragm then click ok
• Go to the analysis option and check model
• Go to define option and select the define option 
• pick the responce spectram
• select the modify option and give the value of given below image
• Go to the define option go to load cases
• Create rax and ray
• Next the bae reactions table will be visible,as shown below.
• Here we have to check that EQ should be closer to the RS ,to get the closer to each other we should calculate
  that,(EQ/RS)X scale fasctor of response spectrum.
• Now substituting the values from the table,as X-direction (284406348/900.7656) x (9806.65), at Y-direction
  (2844.6348/1002.1982)x 9806.65.

• AtX- direction we get,30969.6.
• At Y- direction we get,27835.15.
• we put the above values as scale factor for response spectrum at X and Y directions in the load case data.
• After we enter these values for response specrtrum as scale factors at X and Y directioons in load Case datd then the EQ is closer to the RS from the bas reaction table,as shown below. 

 STEP : 14 

• Next we have to select the diaphrams from the shell option.as shown below.
• After selecting the diaphrams the new tab will appears,in that select Di and click on the apply Button and close.
• Next we have to select the pier lable from the shell option,as shown belowN.
• Before goning to the shear wall design we have to assign the names for the shear walls (P1,P2,P3,P4,P5,P5, P6,P7,P8,P9),as shown below.

 STEP : 15 

• Next from the difine option we select the show tabbles option,as shown below.

• Atter selecting the show tables option the new tab will be visible.In that we selct add default design combo option

• NoW we Select the modal participating mass ratios and click on the click on the ok button,as shown Delow.

• Now the modal participating mass ratios table will be visible,as shown below.

• Next we select the story respoonse plots from the display option,as shown below. P Type here to search

• The story response for maximun story drifts at X &Y directions should not be more than 4%.

   

   

   

• Next we open the select plan view tab and select the base floor,as shown below.

• Next we have to open the reactions tab,then we select the earthquake load towards X-direction (EQX) in the load case,then click on the ok button as shown below.

• Now the base shear reactions will nmappears,as showrn below.

• When we divide the base shear taken up by the shear wall divided by the total base shear of buiding WIl get the % of the shear forces taken up by the shear wall.

• And if that is less than 80% ,then the more shear walls we need to add to the structure.
  
  

   

   

RESULT : 

•  The G+7 residential building has been modelled and analyzed successfully using the ETABS 2018.