Analysis and Design of G+3 Residential building with flat slab using STAAD PRO V8i

1. ANALYSIS AND DESIGN OF
RESIDENTIAL BUILDING
WITH FLAT SLAB USING
STAAD PRO
BY
CH MANOHAR BABU.

2. INTRODUCTION:
• With the increase in population and development of civilization, the demand for
HOUSING is increasing at a peak rate.
• Adapting the construction of Multi-storied Building not only matches with
demand but also decreases the price of single house.
• The aim of our project is to design a G+3 building with flat slabs instead of
conventional slab.
• It is designed by using M25 grade concrete and Fe415 steel.
• The dead load, live load and roof load are applied for the design of beams and
columns,.
• Analysis & Design of the building with flat slab is done by using STAAD PRO
software.

3. SCOPE OF STUDY :
• Flat slabs system of construction is one in which the beams used in the conventional
methods of constructions are done away with.
• In general normal frame construction utilizes columns, slabs &Beams.
• However it may be possible to undertake construction without providing beams, In such a
case the frame system would consist of slab and column without beams.
• These types of slabs are called flat slab, since their behavior resembles the bending of flat
plates.
• The slab directly rests on the column and load from the slab is directly transferred to the
columns and then to the foundation.
• To support heavy loads the thickness of slab near the support with the column is increased
and these are called drops, or columns are generally provided with enlarged heads called
column heads or capitals.

4. FLAT SLAB AND ITS COMPONENTS
TYPES OF FLAT SLABS:
There are three different kind of flat slabs
Flat slab without drop and column head.
Flat slab with column head and no drop.
Flat slab with column head and drop.
COMPONENTS OF FLAT SLABS:
DROP PANELS:
To resist the punching shear which is predominant at the contact of slab and column Support,
the drop dimension should not be less than one -third of panel length in that Direction.
COLUMN HEADS:
Certain amount of negative moment is transferred from the slab to the column at the support.
To resist this negative moment the area at the support needs to be increased by providing column
capital/heads.

5. ADVANTAGES
• The ease of the construction of formwork.
• The ease of placement of flexural reinforcement.
• The ease of casting concrete
• The free placing of walls in ground plan.
• It reduces the weight of the super structure
• The reduction of building height in multi-storey structures by saving one
storey height in every six storey’s thanks to the elimination of the beam
height. These structural systems seem to attract global interest due to their
advantage

6. DISADVANTAGES
There are two main failure modes of flat slabs:
a. Flexural Failure
b. Punching Shear
Failure Slabs are designed to fail by flexural failure, the failure mode is
ductile therefore giving relatively large deflections under excessive loading
and also cracks will appear on the bottom surface before failure occurs.
These signs allow the problem to be addressed before failure occurs.
Punching shear failure by comparison is a brittle failure mode when shear
reinforcement is not added, meaning failure will occur before significant
deflections take place, in addition to this any cracks that will develop before
failure will propagate from the top surface. Since this surface is typically
covered, it is unlikely that there will be sufficient warning available before
failure occurs.

7. MODELLING AND ANALYSIS
• Open STAAD PRO software and select new project and select space and
add plates and click geometry and run structure wizard.
• Select Bay frame in frame models
• Merge the model from structure wizard to STAAD PRO V8i.
• Select cut section command and click select to view option and ok.
• Cut the slab portion and keep it in 3D view and front view.
• Select all node points and to create drop panels, click copy and paste.

8. • Give x direction distance 0.5m and click ok and copy the same direction
on x -0.5m and click ok.
• Delete all unnecessary node points.
• Copy respective node points in z direction 0.5m and -0.5m by selecting
all points node except on nodes on beam portion.
• Create node points for corner section in z direction distance 0.5m and
• -0.5m and all unnecessary node points.
• To add drop panels, keep it in 3D view and select add four node plate
and select node points.
• After creating drop panels, we need to move the drop panels in
downward direction to the width of the slab.
• Select all drop panels using plate cursor and click on move option to
y direction -0.15m.
• Select four node plate to create main Continuous slab and delete beam
section by click on select option and click on beams parallel to z.

9. • Copy ground floor to all remaining floors , select translation repeat option.
• Select all plate using plate cursor and repeat same above translation
repeat process.
• 3D rendering view

10. PROPERTIES
• Select general option to create slab and column thickness and click
define option and give rectangular section dimensions 0.5m*0.5m
and Click thickness 0.15m and assign it to view.
• 3D rendering view for the flat
• Slab building is consisting of
• Drop panel of 0.5m width and
• column 0.5m*0.5m and plate
• Thickness 150mm.

11. LOAD END DEFINITIONS
• Select general and load end definition and load end details.
• Add dead load and its self weight and assign it to view.
• Add live load and give pressure -4 KN/m2 and give y direction distance
minimum 3m and maximum 12m and assign it to view.
• Add roof load and pressure -2 KN/m2 and give y direction distance minimum 3m
and maximum 12m assign it to view.
SUPPORTS
• Select general and choose supports and create and fixed and add.
• Assign it to view.

12. ANALYSIS
• Select Analysis/print option and click on add.
• Click on commands and analysis and perform analysis and run analysis.
• After no errors and go to post processing mode and apply all load cases.
• Deflection for respective building

13. • Select beam and select Fy.
• Shear force for respective flat slab building.
• SHEAR FORCE DIAGRAM

14. • BENDING MOMENT DIAGRAM
• Select Mz option.

15. • MAXIMUM ABSOLUTE PRESSURE
• Select plate and select maximum absolute pressure in stress type and
click on apply and click on OK.

16. DEFLECCTIONS
• Select animation and click on deflection and click on apply and ok.
• Select DEAD LOAD and its deflection is
• Select remaining loads for deflections.

17. BENDING MOMENT DIAGRAM
• Select beams option.

18. MAXIMUM ABSOLUTE PRESSURE FOR DEAD LOAD CASE
• Select plate and go to maximum absolute pressure and apply and ok.

19. DESIGN
• Select modelling and click on design and select concrete design and
code as IS 456.
• Select parameters and initially we need to deselect all the selected
parameters, we need to pick
• Compressive strength of concrete
• Yield strength of shear reinforcement steel
• Yield strength of shear reinforcement and
• Click on ok.
• Select define parameters and give values for
• Click FC and Compressive strength 27579.2 KN/m2 and assign it to view.
• Click FYMAIN and yield strength for main reinforcement steel is
41368 KN/m2 and assign it to view.
• Click FYSEC and yield strength for shear reinforcement 413688 KN/m2
and assign it to view.

20. COMMANDS
• Select commands option
• Add design column, design slab/element and take off and assign it to
view.
• Select analyis/print and add and close.
• Select analysis and run analysis.
• After no errors, go to post processing mode and done.
• Click on beam and deselect the bending moment diagram.

21. RESULT
• BEAM 210

22. CONCRETE DESIGN

23. SHEAR BENDING

24. DEFLECTION

25. OUT PUT