DESIGN OF BEAM-COLUMN, Equivalent Load Method 1

[nedians]

Salam,
I want to know for designing beam-column we have to use equivalent load method...in that method why we convert the load into axial load and design the member as Axial Loaded member..why ?
Is there any other method of designing the beam-column and is this equivalent load method gives good results or not?

 

[par060]

sure ..if you have the loads that the beam column is experiancing then you can use the interaction equations to check if the member has enough capasity

 

[nedians]

iam not asking whether i can use this formula or not...iam asking why in this method of design we convert the load into axial load and then design it as a compressive member and is there any other method of design avaible instead of equivalent load method

 

[phuduhudu]

As I understand it you are talking about a method which converts all loads (including beam loads) into axial loads? I have never heard of such a method. The only one I know of is the interaction method that par060 talks about in which the equivalent uniform moment and the axial load are divided by the buckling resistance moment and the buckling compressive strength respectively. These are then added together and should come to less than one for compliance. Give us more info if you need more help.
Carl Bauer

http://www.bauerconsultbotswana.com

 

[nedians]

Iam asking about the same interaction formula, i just want to know why we change it into axial load ( whats the basic theory ) why not into bending moment .
OK. lets say that you have a beam column and the loads coming on it in the form of axial and bending moments, no section properties are given.
how will you design it .

 

[Taro]

The equivalent load method is a procedure for estimating a trial column size. Bending moments are transformed into "equivalent" compressive forces so that the member size can be easily picked from tables for concentric column designs. This time-saving method has been developed by Yura and others and is described in the AISC Steel Construction Manual. Note that this method is not for final design. It only helps you pick a trial size that you then check for the actual compression and bending moments using the interaction equations mentioned by others. With the advent of computers for structural analysis and design, it is probably just as efficient to just guess a trial size and iterate until you get a section that works.