Structural Steel Building Frame

[cse1]

What are the criteria used to determine when a W beam should be connected between W column flanges or webs and when the W beam should be connected to a top plate of a W column?

 

[eng1nejoe]

normally connecting to the web is best as it keeps eccentricity to a minimum. if beams are being connected in both directions then the more balanced direction should be connected to the flanges. for roof beams it is often most economical to cantilever one beam and support the other between the cantilevered ends. in this case it is best to run the beam over the top of the column.

 

[JAE]

If the roof system is repetitive, we usually prefer setting beams on top of columns (a naturally more positive bearing connection) and use a series of cantilevers to form a continuous-type beam system.

For irregular conditions, we just use single plate connections. The concepts of eccentricity mentioned by eng1nejoe above are valid, too.

 

[edba]

Allow me to share my opinion.

For structural point of view, if you want a rigid connection for rigid frame, its preferably best to connect the beam in the column flanges. For frames that do not required rigid connection (i.e., brace frame), its better to connect it in the column webs.

For top most platform or roof beams as mention by eng1nejoe, it is better to place the beam on top of column plate (cap plate). Continuous beam has an advantage in terms of strength and connection is simple.

Another criteria to consider is in construction. The erection should be doable and simple.

Many thanks.

 

[ishvaaag]

I would say that your question refers mainly to structural design in the more ample sense. In fact as we work this is done either customarily by working within a very known typology of building or if not these issues are better decided when laying the architecture of the building. If one knows what is doing it is not normally necessary to modify the structural connections classes, because well decided at that stage.

Every connection type has interesting and useful properties and so its selection must put at work such fitness for use. The entries above refer to some of them. I only will add that if you want rigidity (which is normally the case for what are main directions to your structure) you will be making rigid connections and to the flanges of the columns' sides. If you can live with the simpler shear connections they are still better made to the flanges of the columns; connections to the webs may be weaker and cause some bolting or welding or dimension problems, so one does not tries first except if necessary. In fact to avoid such connections some situations permit and even advise to use bridge plates to the flanges, even if uncommon.

 

[cse1]

Thank you for all of your inputs!