How to define schemes of PERMANENT and USEFUL loads for equivalent frame model?

28 January 2017

This post describes how to define schemes of permanent and useful loads for equivalent frame model of the reinforced concrete flat-slab structure. In my education video tutorial, I summarise any comments and instructions by showing the optimal, in my opinion, methodology.

What should you pay attention to while defining permanent and useful loads for equivalent frame model?

The equivalent frame model is a specific two-dimensional spatial mapping of the reinforced concrete structure composed of only two elements: flat floor slabs and columns. It should be mentioned that additionally strengthened floor slabs (thickened) are also used in the column neighbourhood area. The method of modelling equivalent frame is described in details in my other post published in this blog. The combination of actions on the equivalent frame should consider the width of load transmission on sections corresponding to the axial spacing between columns in perpendicular direction to the section axis. Taking into account different cross-section values of columns and spandrel beams, it is recommended to enter self-weight values of those elements manually as permanent loads in frame nodes can be overestimated by the software which automatically assumes self-weight value of the structure.

Example of defining schemes of PERMANENT and USEFUL loads for equivalent frame model

The video tutorial available below shows the methodology of defining schemes of permanent and useful loads for the equivalent frame modelling the reinforced concrete flat- slab structure with the regular column grid. Prior to the process of defining load schemes, I conducted a procedure of load combinations using the “Load report” module in Autodesk Robot Structural Analysis 2016 software. The combination of actions was based on instructions and guidelines set out in Eurocode [1].