Project 2_Design & Analysis of a Hostel building at Guwahati, Assam

 Aim:

 To carryout modelling, analysis, design and preparation of construction drawings of a G+3 RCC hostel building situated in Guwahati Assam. 

 Procedure:

• Open the ETABS software and then provide the required information to create grids and stories as shown below.

              

              

              

• Next define the material property i.e., concrete as (M25) and rebar as (Fe415 and Fe500).

             

              

              

               

               

• Now, define section properties. i.e size of beams as (400x500), size of columns as (450x650) and thickness of slabs as (150mm) etc.
• Go to Define and then choose section properties then select Slab properties.
• Also, define a slab for staircase as one way slab.

              

              

             

             

              

               

• After defining the materials, place the components.

                    

• First place the frame elements and then slab elements.

                     

• Now define the load cases.
• Go to Define then select load cases and then Provide DL, LL, Eqx, Eqx+, Eqx-, Eqy, Eqy+, Eqy- as loads.

                        

• Assign the following loads: 
  • For live load take the value as 2 `(kN)/m^2` with reference to IS 875:part 2.
  • Brickwall load as 3.5kN/m
  • Floor finishes as 1.5`(kN)/(m^2)`

                      

                     

• • Next assign the joints in their respective positions
  • Then define the mass source and response spectrum function for the building modelled till now.

                       

                      

• Now, define the load combinations.

                        

• After that assign diaphragm to the shell.

                       

•  After that, we have to carry out the analysis and design.

                        

• Also check for story drifts for RSx and RSy.

                     

                    

• Here, both the story drifts are within the limits provided by codal provisions. 
• Next, we have to carry out the concrete frame design and then extract the design results for beams and columns ( for both flexural and shear rebar).

                     

• Beam- longitudinal reinforcement

                              

• Beam-Shear reinforcement

                              

• Here, the design result shows that 3 beams are failing in shear.
• Hence inorder make them safe, we need to increase the size of the beam.
• So, for 2 beams size have been changed to 450x650mm and for other beams size is remained as it is i.e., 450x750mm.
• Beam - Longitudinal reinforcement

                                  

• Beam - shear reinforcement

                                 

• Column - Longitudinal reinforcement

                                

• Column - Shear reinforcement

                                

• Now, the design part is completed.
• Now, we need to export the Base reactions and load conditions in f2k format for footing design using SAFE software.

                                

• Now, import the f2k file into the SAFE software.
• All the reactions and loads have been imported to the software.

                               

• Define the materials for concrete and rebar as shown below.

                               

                               

                              

• Define slab properties.

                             

                              

                             

                             

• Now using draw point option, draw the points for footing for each column.

                           

• Now, go to draw option and draft points on footing for the piles to be projected.

                        

• Next, provide pile, using the above process and also mention material property as pile500.

                  

• Then place the columns along the grid intersections.

                   

• Define beam for tie beams.

                  

                   

• Now, assign springs at the locations, where piles are placed.
• For this, we need to calculate the spring constant: 
  • Spring constant= AE/L=490873 N/mm.
  • Then assign this spring constant.

                   

• Now, define the load combination for serviceability limit and ultimate limits.

                     

• Next, check the design results:
  • Displacement values are within the permissible limits, hence  it is safe.

                         

• • Reaction check :

                        

• Punching shear values are also within the range.

                      

• Design the strip.

                        

• Now, carryout the design again:
  • For strip layer A
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  • For strip layer B

                    

• Hence, the design of required footing is completed.