Tuesday, 19 May 2015

FAQ:

In case of haunched frames, the in-plane bending moments are not the same on the corners, under symmetric load.


Important to know, that for the haunched part of the member, new sections are created during the automatic finite element generation, which consist of the original section and the haunch with appropriate web height. These new sections are placed eccentrically on the reference line of the member (except the symmetrical haunch type).
Modified sections on the haunched stage

The eccentricity causes additional effects in the analysis results, due to the eccentric position of the section forces. For instance, at the beam-to-column connection point of a frame  with haunched beams and/or columns the equilibrium of the in-plane bending moments exists only if the additional moments from the eccentric axial forces are taken into account.


The reason is that the Normal force in the beam has an eccentricity compared to the gravity center of the beam-with-haunch cross section. This eccentricity of the normal force causes a change in the My in-plane bending moment results on the beam.

Value of the in-plane bending moment caused by the eccentric normal force is calculated as follows:



*Haunches can be applied on beams or columns under the structural members tab, by clicking on the
button. Three types of haunches can be applied, lower, upper, and symmetric. Good to know, that on the Haunch on bar dialog (picture below), using the black arrow icon, properties of the selected member (beam or column) can be copied, and it will be setted for the Haunch parameters.



Thursday, 7 May 2015

Tips & Tricks:

Placing of multiple point supports:

Building up a complex model can take quite a lot of time. Since a properly builded model is essential to the analysis and for the design of the stucture, it is rewarding if the easy round of duties can be solved quickly, and the more important matters can get more attention.

During the modelling phase, Multiple support placing can speed up the process of placing the supports. Columns are a good example. It is not necessary to place each support one-by-one by clicking the end of all of the columns. With the black arrow icon on the Point support dialog, desired support type will be placed on all of the selected column ends. With this little function, all supports can be placed in about 2 simple mouse clicks.