The following values have to be calculated for the columns with elastic supports:
Сm — stiffness factors of an elastic clamping equal to the reaction moment arising in a support section at its rotation on a unit angle;
Cn — stiffness factors of an elastic support equal to the reaction force arising in a support section at its unit displacement.
The most common examples of the calculation of the factors Сm and Cn are given in the table below taken from the “Guide to Design of Steel Structures (to SNiP II-23-81*)”.
|
The models of columns in a dialog box |
The design model of the elastic supports |
Formulas for the calculation of the stiffness factors |
|---|---|---|
|
|
|
\[ C_{m} =\frac{3EI_{1} }{l_{1} } \] |
|
|
|
\[ C_{m} =\frac{4EI_{1} }{l_{1} } \] |
|
|
|
\[ C_{m} =\frac{3EI_{1} }{l_{1} } \] |
|
|
|
\[ C_{n} =\frac{3EI_{1} }{l_{1}^{3}} \] |
|
|
|
\[ C_{m} =\frac{3EI_{1} }{l_{1}^{3}} \] |
|
|
|
\[ C_{m} =\frac{4EI_{1} }{l_{1} } \] |
|
|
|
\[ C_{m} =\frac{3EI_{1} }{l_{1} l_{2} }(l_{1} +l_{2} ) \] |
|
|
|
\[ C_{m} =\frac{3EI_{1} }{l_{1} l_{2} }(l_{1} +l_{2} ) \] |
