Write short notes on the following; Derive an expression for depth of Whitney’s stress block (Compression block) What is the effective width of a T beam? What does it represent? The ACI code provides...

Write short notes on the following;

1. 
   Derive an expression for depth of Whitney’s stress block (Compression block)
   


2. 
   What is the effective width of a T beam? What does it represent?
   


3. 
   The ACI code provides the following limiting shear values for members subjected only to shear & flexure:
   ,
   
   &
   . What is the significance of each of these limits?
   


4. 
   Distinguish between tied, spiral and composite columns