Saturday, October 22, 2011

Column Design (Part 4)

From Column Design (Part 3), we compute the value of column constant (Cc) and slenderness ratio (KL/r_min) to check whether the column is long or short.
If the column is long, Euler formula will be used for calculation. The Euler formula is defined as,
Another form of this equation can be calculated form substituting r2 = I/A into the above equation. Then we get,
Notice that the buckling load is dependent only on the length (L), cross section (I) and the stiffness of material (E) of the column. The strength of the material is not involved at all. Therefore, in a long column application, there is no benefit to use a high-strength material. A low-strength material having the same modulus of elasticity (E) would perform well.

See the J.B. Johnson formula in the next post.