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[cvrm]

Dear Colleagues:

That was another question that interests me...

列低横向诠释ional flexural stiffness (alpha.EI/L^3) and reasonable lateral translational shear stiffness (GAs/L). But, Structural Walls have the opposite characteristics � high lateral translational flexural stiffness (alpha.EI/L^3) and relatively lower translational shear stiffness (GAs/L). This means columns undergo bending actions largely, and Structural Walls shearing actions.

The first question is: how does an engineer determine which action is dominating? A ratio (beta) is defined for each column and beam, of the lateral translational flexural stiffness (alpha.EI/L^3) to lateral translational shear stiffness (GAs/L). If beta of the vertical member is small (close to zero), then bending actions dominate, and if beta is large (more than 5-15), then shearing actions dominate.

The second question is: how does an engineer incorporate this in the computer programs. Different computer programs do it differently. But, the most appropriate program is that which uses (at the back end) expressions for flexural stiffness coefficients including the effect of shear deformations. So, when in doubt as to flexure will dominate in a vertical member or shear, it is best to exercise this option of �including the effect of shear deformations� in the estimation of the member properties. One needs to be careful, when extremely stocky members are being used, for ill conditioned stiffness matrices.

with warm regards...
C. V. R. Murty
..

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[nrk]

Dear Prof.C.V.R.Murty:

As per the book 'Seismic Design, Assessment and Retrofitting of Concrete Buildings: Based on Eurocode 8', by Prof.Michael Fardis, a limit of 4.0 for the aspect ratio (long-to-short dimension) of a rectangular cross-section is conventionally adopted by most design codes, to distinguish walls from columns.