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

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

INTRODUCTION:-

• The procedure and anaylsis and design of given building will depend on the type of building, its complexity, the number of stories etc.
• First architectural drawings of the building are studied, structurl systems is finalised sizes of structural members are decided and brought to the knowledge of the concerned architect.
• The procedure for structural design will involve some steps which will depend on the type of building and also its complexity and time availabel fr structural desgn.
• Following data is need before designing the structural design:-

1.  A set of architectural drawings
2.  Soil investigation report
3.  Location of place or city in order to decide wind and sesimic load condition
4.  Data for lifts, water tank on top of the building and roof loadong ad its features.

In this project, participants will get to experience the entire design process from modelling, analysis, design, and preparation of construction drawings. The architectural drawings of a G+3 RCC building is provided. The following information on the building is to be used:

• Location – Guwahati, Assam
• Function – Hostel block in an academic institute

The walls will be made of AAC blocks. Other loadings are to be calculated as per the architectural drawings. 

The buildings rests on type 3 soil. Piles of length 10 meters and 500 mm diameter with a load-carrying capacity of 280 KN is to be used. 

The ground floor level will be at a height of 2 meters above the existing site level to avoid floodwater enter the building.

M25 grade of concrete with Fe500 for longitudinal reinforcement and Fe 415 for shear reinforcement is to be used. 

The following design IS codes will be required for reference:

• IS 875 part 1
• IS 875 part 2
• IS 13920
• IS 1893
• IS 2911 part 2
• IS 456
• SP 34

Students will have to produce the following:

• Etabs model for the two blocks on either side of the expansion gap
• Foundation details illustrating the pile & pile cap reinforcement
• Tie beam details connecting the pile caps
• Column reinforcement
• Framing plan for typical floor
• Beam reinforcements for ground floor

PROCEDURE:-

• Open the ETABS software.
• Click on New Model to create a new file.

• Next fill the model initialization as below;

• Choose the built-in settings option and select the display units and codes.
• New dialogue box will appear named New Model Quick Templates.
• Select Custom Grid spacing and custom story data.

 

• After models initialization, select grid and storey inputs from new model quick templates dialogue box.
• In the dialogue box choose grid spacing and custom story data which is used to provide the input specified above.

• Now edit stories by using the user-defined story input, 26 stories are incorporated (plinth at 1.5m and 25 story with 3m height each).
• Storey 1 has been labelled as a master storey and all above levels are labelled similar to that.

• So, 3 storeys are successfully added in the peoject.
• Create alll the storeys as similar to storey 1.

• Select Material properties under define tab.

• New dialogue box will appear named Define Materials.
• Select Add new Material from the window.

• Now need to add material type as concrete and grade as M25.
• Now we need to check the material property data, as shown below.

 

• Now need to add material type as rebar and grade as HYSD 415.
• Now we need to check the material property data, as shown below.

• Now need to add material type as rebar and grade as HYSD 500.
• Now we need to check the material property data, as shown below.

• Now select Section Properties under Define Tab.
• Select Frame Sections.
• Select Add new properties in Frame Properties.

• Create a new Property as a beam and input values as 450*650.
• Select Modify/Show Rebar in Reinforcement option.
• Select M3 Design only (Beam).
• Select Reabar as HYSD415.

 

• Create a new Property as a beam and input values as 300*500.
• Select Modify/Show Rebar in Reinforcement option.
• Select M3 Design only (Beam).
• Select Reabar as HYSD415.

 

• Create a new Property as a column and input values as 450*650.
• Select Modify/Show Rebar in Reinforcement option.
• Select P-M2-M3 Design (Column).
• Select Reabar as HYSD415.

• Create a new Property as a column and input values as 400*650.
• Select Modify/Show Rebar in Reinforcement option.
• Select P-M2-M3 Design (Column).
• Select Reabar as HYSD415.

 

• Now select Section Properties under Define Tab.
• Select Slab Sections.
• Select Add new properties in Slab Properties.

• Using the membrane properties, slab size 125 mm has been added to the list.
• Membrane property will help to consider only slab weights and Floor weights in analysis of structure while no stiffness component of flange advantage are considered during calculation.

• Using the membrane properties, slab size 200 mm has been added to the list for staircase.
• Membrane property will help to consider only slab weights and Floor weights in analysis of structure while no stiffness component of flange advantage are considered during calculation.

• Now Draw columns of size 450*650mm at the intersection of the horizontal and vertical grids and beams with quick draw Column keeping all the stories on.

• Now draw columns of size 650*400 mm at the intersection of the horizontal and vertical grids and beams with quick draw Column keeping all the stories on.

• Columns are Successfully added to the structure.

• Now Draw the Beams.
• Draw beams of size 450*650mm at the intersection of the horizontal and vertical grids and beams with quick draw beam keeping all the stories on.

• Beams are Successfully added to the structure.

• Now Draw the Slab.
• Draw slab of size 125mm thickness, Draw slabs with quick draw floor/wall keeping all the stories on.

• Slabs are Successfully added to the structure.

• Now we go to base plan and select all the joints.
• Now we select the Restraint from joint option, as shown below.

• Now define the Load patterns.
• Click on the define tab and click on load patterns.
• Define the loads like dead load, live load, brick load, earthquake load in X direction and same loads in Y direction also.
• Mention IS codes of respective loads.

• Next we have to click on assign option and then select  shell loads and select Uniform option.

• Here we apply 2 `(KN)/m^2` live load for the staircase portion, verandah and liftcore area.

• Next we need to select the distributed load from the frame loads.

• Then after the new tab will appear, in that case we select load pattern as Brickwall and we take uniform load as 3.5 `(KN)/m` an then apply.

• Now go to Mars Source from define tab.
• Modify the mars source and tick mark the required loads.
• Add load patterns and assign the model.
• Insert the dead load as multiplier to 1, live load as multiplier to 0.25 and wall load as multiplier to 1.

 

• Mars source is been added successfully.

• Now go to Load cases in define Tab.

• Now create the Diaphragm by going to the assign tab then shell and select diaphragm.

 

• Now go to Load combinations in define Tab.

• Select add default design combos.
• Select concrete frame Design.

• Next we need to check the Model.

• After the model is checked, it will show us No warning.

 

• Analyse the model using analyse option then click on check model the modelled structure is verified without errors and warnings.

• After Run analysis, We select Show deformed Shape Option.
• We select Earthquake load in that.
• Next we see the deformed shape of structure with Earthquake loads.

• Next we have to start the beam design by selecting 'start design/check' option, as shown below.

• After the completion of beam design, we need to select the 'Display Design information', as shown below.

• After selecting the 'Display Design info' option the new tab appears, in that we select the longitudinal reinforcement in the design output and click on the ok button, as shown below.

 

• Next the longitudinal reinforcement details will appear, as shown below.

• Now we need to draw the reinforcement diagram of 7-span continuous along Grid-1 and also need to provide the reinforcement details.
• The maximum Ast for the Bottom support is 637 mm2 and bottom middle is 637 mm2.
• The maximum Ast for the Top support is 1038 mm2 and bottom middle is 637 mm2.
• now we provide 6-12 diameter at the top and bottom, as shown in below Figure .
• Now we provide 3-16 diameter top support for the continuous beam as shown below.

• Now from the Elevation view, we can see details of column Reinfoecement.

• Here we take column 1-L for Reinforcement.
• Maximum Reinfoecement foe column is 4632 mm^2.
• Now we provided 16 bars with 16 mm dia. 
• We have provided size of stirrups as 10mm.

 

SAFE MODELLING OF BASE FLOOR :-

• Next we have to export the base floor loads and loads from above to SAFE 2020.

• Next we have to open the safe 2016 and import the f2k file.

• Then the file has been opened in safe 2020.

 

• We select the show loads from the display option,as shown below.

• After selecting the show load options, and the new tab will be visible, in that we select to dead_above as load pattern.

• Now we select Live_above as load pattern.

• Next we selected materials from the define option to assign the material.

• After selecting the materials the new tab appears, then we add new materials by selecting the add new materials options.
• Now we need to add material type as concrete and grade as M25.
• We enter weight per unit volume as 25 KN/m^3.
• WE enter modulus of elasticity as 25000 N/mm^2.

• Now we need to add material type as rebar and grade as HYSD 500.
• We enter weight per unit volume as 77`(KN)/m^3.`
• WE enter modulus of elasticity as 200000 `(N)/(mm^2`

• Now we need to add material type as rebar and grade as HYSD 415.
• We enter weight per unit volume as 77 KN/m^3.
• WE enter modulus of elasticity as 200000 N/mm^2.

• So, materials are assigned.

• Now select Section Properties under Define Tab.
• Select Slab Sections.
• Select Add new properties in Slab Properties.

• After Selecting the new property, name the slab property as Pile_cap.
• We put the slab thickness as 800mm ans material as M25.

• After Selecting the new property, name the slab property as Pile_500.
• We put the slab thickness as 800mm ans material as M25.

• We have to add another slab propery as Column_stiff.
• We put the slab thickness as 800mm ans material as M25.

• Slab properties are assigned Successfully.

• Now we are transfering this model to the 2016 version because of smooth Results.

 

• Pile caps are assigned as shown below.
• The piles are assigned with 500 mm diameter.
• The columns are assigned with the size of (450 mm x 650 mm) and  (650 mm X 450 mm).

• Next we need to assign the soil properties.
• We select the soil properties from support data.
• Select the soil property as thickness of 150 mm.

• We select the points to assign the springs for the piles.
• Now we select the springs from the support data from assign option.
• Next point spring properties tab will be visible.
• Next we select the modifiy/show property, then the new tab appears. We take for 490.87 in translational z.

   

• Point springs are assigned successfully.

• We have to assign the point load from the column.
• Now we select the point loads from the load data from assigned option.

• Next the point load tab will be visible, in that we add the gravity load at  Z-direction as 1071.53 KN.
• Next we enter the size of punching shear as (650X450 mm).

• Point loads are assigned to the column successfully.

• Next we right click on the pile cap the new tab appears.
• In that we need to check the rebar material whether the fe500 is assigned or not, if not we change to every Fe500.
• We need to check all the pile caps.

• Now we need to Run the Analysis.
• The deformed shape will be visible after completion of Run Analysis.

• From the display option we select show reactions forces.
• After selecting the reaction forces option the new day will be visible, in that we put the load cases as Dead.
• Next click on the apply button.

• Next from the display option we select the punching shear design.

• Next, we select shoe slab design.

• Now we see that slab strip design results, We can provide the reinforcement at the top and bottom.

 

Result :-

• The G+3 hostel building has been designed and analyzed in ETabs.
• Foundations are designed and analyzed in SAFE.