Equivalent Frame vs Finite Element - Panel/Column/Mid Strip widths

[SlenderBeam]

The basic principle of the Equivalent Frame Method (EFM) is that the floor plate is divided into panels along each column line. Each panel is then divided into column and middle strips, the total moment over the panel being distributed by a factor into each strip.

FE Packages now provide tools to allow the engineer to cut sections to determine the elastic moments at certain cross-sections, as well as readily determine the integrated moment over a strip width.

In concrete FE design, is it safe to use the same typical panel widths as described by codes, seeing as the 'actual' load/action distribution is quite different from that assumed by the current codes, which are typically based on regular framed structures?

I would think that code guidance on such issues is required urgently, considering the increased use of FE in concrete design.

 

[rapt]

SlenderBeam,

The column/middle strip logic for equivalent frame design was based on studies of FEM results. There is no reason why they cannot be used.

You just have to use some engineering judjement where support locations are very irregular.