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

Question:

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

Aim:

Principal Outcomes:

• Manual base reaction calculations (in an Excel or Word document) for gravity load scenarios
  Provide the tall building's full model in ETABS format (exported in.e2k format; do not attach).natively in EDB format)
• All design and serviceability requirements should be met by the model
• .An extensive project report (in PDF format) generated by the ETABS program.

Procedure:

Step by step screen shots of the procedure pictures attached below:

Launch a new model in ETABS and select the metric SI unit in accordance with Indian Standard.

After making changes to the tale and grid system data, click OK.

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 B1 from both ends:

Region 2 (Trapezoidal region)
A1 is equal to 1/2 * (1.529 + 4.587) * 2.5, or 7.645 m^2.
B2's bay width = A1/L or L/4 = 1.66 m or 1.14 m = 7.645/4.587

Slab-1 to Beam-2 UDL transferred = B.W X Slab-2 load
12.035 KN/m = 1.66 X 7.25

Beam-1 Self weight equals 4 KN/m2 (0.4 * 0.4 * 25).

Complete UDL on B1 is equal to 4 + 12.035 + 3.5, or 19.535 KN/m.

89.607 KN is the total load on B1 (19.535 X 4.857).

The load for B1 is 44.804 KN on both ends.

Load B2 from both ends:
Area 2 (the triangle region)
A2 is equal to [1/2 * 2.5 * 1.529] * 2 = 3.82 m^2.

B2's bay width = A2/L or L/4
0.764 m or 1.25 m = 3.82/5

Beam-2 to Slab-2 UDL transferred = B.W X Slab-2 load
9.0625 KN/m = 1.25 X 7.25

Beam-1 Self weight equals 4 KN/m2 (0.4 * 0.4 * 25).
17.5625 KN/m (total UDL on B2) = 4 + 9.0625 + 3.5

82.82 KN is the total load on B2 (16.5625 X 5).
Each beam's load, B2, is 41.41 KN.

Column C1's total axial load is equal to 44.804 + 41.41 = 86.21 KN.

Total axial load on Column C1 is equal to Floor X Load on Column C1, the first floor.
86.21 X 15 = 1293.15 KN

Currently, the ETAB software study yielded about the same result, 1309.87 KN.

Results:

Base reaction calculations by hand in gravity load scenarios
Provide the tall building's full model in ETABS format (exported in.e2k format; do not attach).natively in EDB format)

All design and serviceability requirements should be met by the model.
An extensive project report (in PDF format) generated by the ETABS program