Mumbai University > Civil Engineering > Sem 5 > Structural Analysis – II

Marks: 10 Marks

Year: DEC – 2015 , MAY – 2016

1) Carry Over Factor [ C. O. F. ]

If a moment My is applied at end I of the member a specified amount of moment , Mji is genetated at the further restrained end. The carry over factor ( C.O.F. ) is defined as , the factor by which the moment at sim ply supported end I, Mji , is multiplied to get the moment carried over to the other end , that is Mji or Cij is the carry over factor. $$Mji = Cji * Mij$$

2) Distributed Factor ( D.F. )

Consider a joint in a structure where two or more members meet. If an external moment M is applied to such a joibt undergoes a rotation , since all the members meeting at this joint undergoes the same rotation Θ. The applied moment M is distributed to each of the ends of the members according to their relative stiffness values. The factor by which the applied moment is multiplied to obtain the end moment of any member is known as the distribution factor ( D.F. ) .

3) Shape Factor [ S ]

The shape factor is defined as , the ratio of the plastic moment of section to the yied moment of section.

S= Mp / Me = plastic modulus of section / elastic section modulus

= Zp / Ze .

It is th geometrical prpprty of section & depends on shape of the c/s.

Shpe factor is always greater than unity.

Since , Mp > Me

S rectangle = 1.5 , S circle =1.7 , S rolled I section = 1.15 , S diamond = 2.

4) Load Factor [ ʎ ]

Load Factor [ ʎ ] is defined as the collapse load to the working load.

ʎ = Wp / W = Mp / Mw = Fy * Zp / F * Ze

Zp / Ze = S = shape factor

ʎ = ( Fy / F ) * S

but , Fy / F = Fy / 0.66 * Fy = factor of safety

where , Fy = working stress = 0.66 Fy

ʎ = FOS * S

Load factor = FOS * Shape factor

5) Plastic Hinge & Mechanism :

When yielding of section is takes place over entire depth . Section behaves similar to mechanical hinge called Plastic Hinge.

But , at this plastic hinge , moment is constant.

It is denoted by , Mp .