Project 1 - MODELLING, ANALYSIS & DESIGN OF TALL BUILDINGS IN ETABS

A 30 - 40hr project on modelling, analysis & design of a state-of-the-art tall building using ETABS software.

Key Highlights:

a. Modelling

• To comprehend the architectural plan provided by the architect and look-out for the key information from the drawings.
• Import the architectural floor plan (provided by the architect) in ETABS model to start with the modelling.
• Create grid lines, story levels & story heights to set-up a project.
• Create material definitions for the concrete, rebar & structural steel
• Create slab, beam, column & wall properties to be used further in the project.
• Model typical floor plate using shell & frame elements as indicated in architectural plan.

b. Loadings & Load combinations

• Define load patterns for gravity cases
• Define load patterns for the lateral load cases using the wind & seismic parameters provided.
• Create service & ultimate load combinations as per IS 456:2000
• Define mass source for the earthquake loads

c. Structural Analysis

• Obtain the shear force & moment diagram for the floor beams & columns
• Check the gravity load path in the structure if it follows the designer’s intent.
• Perform quick hand calculations to confirm the base reactions for the gravity load cases.

d. Design of structural members

• Select appropriate parameters for the design of the members
• Interpret the design results
• Re-design and restrict the member utilization within 0.9
• Identify the reinforcement requirements for each structural member

Key Deliverables:

• Manual calculations for the base reactions in gravity load cases (in excel / word document)
• Submit ETABS model with the complete model of the tall building (exported .e2k format, do not attach .EDB format directly)
• The model should pass all design and serviceability requirements.
• A comprehensive project report from the ETABS software (as PDF file)

ANS :

Open New Model in ETABS and Set the unit to metric SI as per Indian Standard

Customise the grid system data and story data and press OK

Go to Define tab ------- Material Properties ------- Add New property ------ Give material type as concrete and Grade as M30 And steel and grade as HYSD 415

Go to Define tab ------ Section Properties ------- Frame Sections ------ Add New Property and Add Column 1000 x 1000 and Beam 750 x 1000

Go to Define tab ------ Section Properties ------- Slab Sections ------ Add New Property and Add Slab 150

Go to Define tab ------ Section Properties ------- wall Sections ------ Add New Property and Add shear wall 250

Place Columns, beams, slabs and walls as per the architectural drawing

Go to Edit tab ----- Replicate ----- story and select the story to be replicated and apply

Go to base and select all the joints

Go to assign tab ------ joint restaints and select fixed support for all the directions and click on apply

Go to define tab ------ Load Patterns and add Dead, Live, Earthquake and Wind Load

Go to define tab ------ Load Combinations ------ Add default design combos------ Concrete frame design

Go to define tab ------ Mass source ------ Modify Mass Source

Go to define tab ------ P-Delta options

Go to Select tab ------ Properties ------ Frame sections ----- Select beam 750 x 1000

Go to Assign Tab ------ Frame Loads ------ Distributed Load and assign the load to the beams

Go to Select tab ------ Properties ------ Slab sections ----- Select slab 150

Go to Assign Tab ------ Shell Loads ------ Distributed Load and assign the load to the Slabs

Go to Select tab ----- Select ------ Object Type ----- Floor

Go to Assign tab ------ Shell ------ diaphragms ------ D1

Go to Analyze tab ------ Check model

Go to Analyze tab ------ Ran Analysis

select reactions tab and select earthquake load toward x direction in the load case and click ok. Now base shear reaction will appear

Slab thickness = 150mm

Beam size= 300mm X 300mm

Live load = 2 KN/m2

Floor finish= 1.5 KN.m2

Brickwall load= 3.5 KN/m

Self weight of slab = 0.150 X 25 KN/m2 = 3.75 KN/m2

Total load in slab = 3.75 + 2 + 1.5 = 7.25 KN/m2

Load in each end of B1:-

Area 2(Trapezoidal area)

A1 = 1/2 * (1.529 + 4.587) * 2.5 = 7.645 m2

Bay width of B2 = A1/L or L/4

= 7.645/4.587 = 1.66 m or 1.14m

UDL transferred from slab-1 to Beam-2 = B.W X Slab-2 load

= 1.66 X 7.25 = 12.035 KN/m

Beam-1 Self weight = 0.4*0.4*25 = 4 KN/m2

Total UDL on B1 = 4 + 12.035 + 3.5 = 19.535 KN/m

Total load on B1 = (19.535 X 4.857) = 89.607 KN

Load on each end for B1 is 44.804 KN

Load in each end of B2:-

Area 2(Triangular area)

A2 = [1/2 * 2.5 * 1.529 ]* 2 = 3.82 m2

Bay width of B2 = A2/L or L/4

= 3.82/5 = 0.764 m or 1.25m

UDL transferred from slab-2 to Beam-2 = B.W X Slab-2 load

= 1.25 X 7.25 = 9.0625 KN/m

Beam-1 Self weight = 0.4*0.4*25 = 4 KN/m2

Total UDL on B2 = 4 + 9.0625 + 3.5 = 16.5625 KN/m

Total load on B2 = (16.5625 X 5) = 82.82 KN

Load on each beam B2= 41.41 KN

Total axial load on column C1 = 44.804 + 41.41 = 86.21 KN

Total axial load on C1 column = Number of floor X Load in first floor Column C1

= 15 X 86.21 = 1293.15 KN

Now we have almost got that same result from ETAB sodtware analysis= 1309.87 KN

RESULT :

• Manual calculations for the base reactions in gravity load cases
• Submit ETABS model with the complete model of the tall building (exported .e2k format, do not attach .EDB format directly)
• The model should pass all design and serviceability requirements.
• A comprehensive project report from the ETABS software (as PDF file)