Week 6 Challenge
- Summarize your study for the bending moment, shear force and deflection diagrams for the elements of the model
Answer:
The Elements present in this Model include
Simply Supported Beams
Fixed Beams
Columns Fixed at one End and Free at the other end = Fixed-Free Columns
Columns Fixed at Both ends =Fixed-Fixed Columns
Footings
Slabs
Bracings
Supports
The Main Strategy behind to Resist the Internal Forces which are generated after the application of the loading is provide the Reactions against those members using the appropriate Sectional members.
Bending Moment Diagram
Design Moment or Moment of Resistance > Bending Moment generated by Internal Forces
Only this condition satisfies the Beam or Column any other elemnt to have stability.
1.Beams
The Bending Moment Diagram for the Simply supported Beam = Maximum at the Centre and Zero at the Ends
The Bending Moment For Fixed Beams = Maximum at the Ends and have Point of Contraflexures.
For Cantilever Beams
The Bending Moment is maximum at the Support
The other end which is free has Zero Bending Moment
2.Columns
For Column we have Bending Moment maximum at the ends and Minimum at the Centre
For the Corner columns we have the Bending in Major Direction
For Other Columns we have Bi-axial Bending that is at the both Major and Minor axes.
3.Slabs
For slabs we Design for Bending Moment is resisted by the Main Reinforcement,Distributed Reinforcement
Main Reinforcement is provided along the shorter span
Distributed reinforcement is provided along the Longer Span
4.Footings
To resist the moment for the Footing we check for the effctive depth which should be provided at the Face of the Column
The Footing is treated as a Cantilever and Designed as a cantilever Slab
5.Bracings
The elements Like Bracings or Trusses doesn't have Bending Moment.
The Bending Moment diagram helps us to find the Limiting Bending Moment that is to be generated by the section.
It means that the Bending Moment should not exceed the Limiting Value.
If the Member Fails then another appropriate member which can resist the Bending is added.
Shear Force diagram
Design shear capacity or Shear Resistance > Shear force
This condition satisfies the Beam or Column any other elemnt to have stability.
1.Beams and Columns
Shear Force generated by Beam and Columns is resisted by Stirrups along with Main reinforcement
2.Slabs
For the Slabs to resist shear we design for the Cranked bars or Bent up Bars at critical positions for Shear.
3.Footings
Shear Force for the Footing is designed for
One Way shear and Two way shear
These Shear Forces determine the Thickness of the Footing
4.Bracings
Bracings and Trusses doesn't consider Shear Force
The Shear Force diagram helps us to find the Limiting Shear Force that is to be generated by the section.
It means that the Shear Force should not exceed the Limiting Value.
If the Member Fails then another appropriate member which can resist the Shear Force is added.
Displacement Diagram
Axial Forces are considered as Compression and Tension in the Elements
Axial Forces are considered for Isolated Footings,Columns,Bracings and Trusses.
Based on the Axial Load ratio we design for the elements like Columns and Footings.
For Bracings we consider the Stability based on the DISPLACEMENT
The DISPLACEMENT of the member is caused due to Bending or Buckling or Shear in combination with the Tension and compression in the respective members.
The Deflection diagram helps us to find the Limit of the deflection of the Structure and Rearrange the Member or Resize the member accordingly.
2.Based on the analysis design the members and outline the thought process in selecting the member sizes along with the foundation design
Answer:
1.The Analysis of the Structure is done.
2.Find the Element or the Member which is Failed
3.Find the reason for Failure of the Member
4.If the Member Fails by Bending then choose the Member which is able to resist the Bending.
5.The Member which has more Section Modulus that member is best selected for Resisting Bending.
6.At the same time check for the Shear Failure and other Failures doesn't occur for the Replaced Member.
7.Similarly if the Member Fails by Shear
8.Replace the Member by having good Shear Capacity.
9.This may be defined as Low shear = 0.6 Vd
10.Also check for the Deflection if the Member doesn't satisfy the Limiting Deflecion then Replace the Member with the suited member as per IS 800-2007 Table 6.
Foundation Design:
The Foundation Member Design is selected in a way that it should satisfy three conditions:
They are:
Bending
One way shear
Two way shear
The depth of the Member is predicted using the one of the above three Internal Forces which has the worst case for Failure.
The Bearing Capacity of the Member decides the SIZE of the Footing Member.