Engineering Total Lateral Stiffness from Stiffness Matrix

[Tygra]

Homework Statement

How to use a stiffness method matrix to find total stiffness

Relevant Equations

See in post

Hi all,

I am working on the following Moment Resisting Frame:

The frame has the following structural properties:

E = 2.1E+08   % Modulus of elasticity;
I = 0.000117  % Second moment of area
L = 5;   % Frame width
h = 3;  % Frame height

I want to compute the total static stiffness of the frame. I have calculated the stiffness matrix for this frame using the direct stiffness method, but that does not give you the total stiffness.

Here is the stiffness matrix K

K =    [24*E*I/h^3 6*E*I/h^2 6*E*I/h^2;
       6*E*I/h^2 (4*E*I/h + 4*E*I/L) 2*E*I/L;
       6*E*I/h^2 2*E*I/L (4*E*I/h + 4*E*I/L)]

I am following this book (Dynamics of Structures) that shows you how to do it, but I don't quite get it.

Could someone help me please?

Many thanks,

Tygra