Structural Modelling using Etabs 2018

AIM -

The architectural drawings for a G+7 residential building in zone 5 have 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 on 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-story drift requirements, vertical & planar irregularities, minimum shear wall requirements, maximum axial load ratio for column and shear walls, an 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 modeling. 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 to this problem.

ANS -

In the aim of designing a building in Etab, the following considerations are provided.

1. in typical floor plan column position provided.

2. Ground floor parking provided.

DESIGN A MODEL -

1. OPening a new model - to create a new model click on open new model and set use built setting. and

set the display unit as a metric SI,

region for default material India,

steel section database Indian,

steel design code IS 800-2007,

concrete design code IS 456-200. CLICK OK.

GRID SETTING -

Setting a grid According to provided architectural plan. when a new model quick template opens select and custom grid spacing and custom story data. for customizable selection.

For Custom Grid, the setting use a provided typical plan and create grids in x and y directions according to provided typical floor plan.

Referring a provided floor plan and create a grid according to the floor plan.

Storey setting -

Setting a storey According to provided architectural plan. when a new model quick template opens and selects custom storey spacing. for customizable selection.

referring to an elevation plan and creating a storey according to. I have created ground floor to 8 storey g+7 and added another mumty level. providing a 3-meter height on each storey which has a total length is. 24 meter.

Frame section / column beam -

To create a frame secton of the column and beam select the frame-section from the section property and select add a new property.

Define Material Property -

to define material property select define>material property > add new material

adding a material according to our requirements.

Adding New Material -

to add a new section select add material and add the column. I am adding a column having a side is 450x600, and 400x500 BEAM. Adding a slab having 150 mm thickness. and shear wall having 300mm thickness.

adding a new material > select concrete as a rectangular

Adding a column having 450x600 size and modifying its property by modifying/show rebar

selecting HYSD500 for longitudinal rebar and HYSD415 for confinement bar. for column 450x600

Beam -

provide a beam for a given architecture model is 400x500. doing the same process as used for the column 450x600.

After that select HYSD500 FOR LONGITUDINAL REBAR and select HYSD415 FOR confinement rebar for beam.

Slab Section -

For adding the slab section select section property after that select slab section.

adding slab 150 and providing m25 grade of concrete.

after that select the modeling type membrane.

click ok.

Shear Wall -

Adding shear wall select define and after that section property and select a wall section.

After that click on add new property. and create a shear wall thickness. rename as wall 300, and select grade m25,select modeling type shell-thin,and thickness provide 300,

DRAW COLUMN -

Before draw column selects all story and after that select quick draw column option from the draw panel. and draw the column center grid point of the building. and rotate the column were need to rotate about 90 degrees. column size alredy created from the define material section which is 450x600

Draw Beam -

select the quick draw beam option and select a beam size that i have created from the defined material section. and draw the total beams from column to column. doing adjustments of the beam according to provided floor plan by replicating and dividing options.

Replicating beams -

for creating and providing the proper and exact location of beams to the floor use replicate command and set beams according to our requirement.

1. Grid 1A -

in the grid, 1A replicating the beam 1.35m. in -y direction and +1.25 in x direction. after that divide the frame and delete the nonrequirement beams. and creating a shear wall. with having a thickness 300mm.

Adding Grid - from the center portion of the modal select a beam and replicate 2m. and adding a grid from its joint.

2. Grids 1A And 1C - after creating grids .adding a beam between grids 1a and 1c.

3. Grid 6D - from grid, 6D select a bream and replicate -3.275 in the -x direction.

4. Grid 1-8 -

in center of the of grids 6d and 6c, there is created grid 8. creating the center beam with the help of the center grid and creating a shear wall having a thickness 300mm.

5. Grid 6c -

Replicate a beam in1.25m. -y direction. and from that joint create a long grid in the x- direction. and create a shear wall having thickness 300mm.

6. Grid 4 and 3 -

Create shear wall with the help of grid. select a joint to create shear wall.

7. LIFT CORE AREA -

For creating a shear wall around lift core area take grid from the grid-d -2.7 in y direction. and replicate the Grid-c beam for 1.8meter. and create a grid-10.

taking shear wall and creating a 250mm thickness of the shear wall.

8. Shear wall near staircase -

Replicate the beam from grid 5 and relocate the location of the shear wall. create a shear wall having 300mm thickness.

Creating Slab -

creating a slab at mumty level and after that creating a slab in a similar storey.

open plan view of mumty level and create a slab near lift core area and staircase area.

select quick draw slab and select 150mm thickness of slab and after that draw on mumty level.

Create slab into all similar storey -

select a slab having 150mm thickness. and apply it to all similar storey.

Load Pattern -

From the define option select load pattern and add a load like dead load, live load, brick wall load, floor finish load, or rs in x and y directions.

Assign a brick wall load -

to assign a brick wall load select beams where the load is acting on it after that select load distribution from the assign option.

After that select a brickwall which i have selected in load pattern and applied as a 3.5 kn. and click apply.

Assign Live load - Assign 3kn. to lift core area. and staircase area. select distributed load and after that assign. the load.

After that apply liveload on remaining space like bathroom kitchen etc. which is 2kn.

Apply floor finish load -

florr finish load 2kn.

live load Reduction -

select live load reduction from the design option and reduction the live load according to floor.

Mass Source -

selecting a mass source for a building. and taking all three loads which is dead load, floor finishes, brickwall taking full and live load is taking .25% because applied upto 3kn by is code 1893-2016.

Apply Diaphragm -

select all the floors and assign a diaphragm to all the floors. from assign select shell and after that click on diaphragm and apply into all the story of the building.

Pier label - select an elevation 6. after that select all shear wall and select pier label from shell and aplly pier label p1.

after that continuously apply pier labels to all the shear walls. like p2,p3,p4,p5,p6,p7,p8,

Load combination -

to add load combination select load combination from defined option and select concrete frame desig and concrete sear wall design.

Check Model Casses -

Run the Analysis - select play button and run analysis.

Model participating mass Ratio -

Model participating mass ratio -

Storey response plot -

RSX DIRECTION

RSY DURECTION -

Both the value is below the 0.004. so it is acceptable.