Coincident Axial Loading

[AAK11]

Hi, I'm having trouble getting my head around coincident axial loading, Can someone explain to me how it works and the method of calculation? It is with regards to shoring braces.

Any help would be much appreciated.

Thanks in advance

 

[BeFEA]

Hi AAK11. I don't know the answer to your question, but for me and others to respond, I think you should at least state the code you are referring to. I have not heard the term "coincident axial loading".

 

[AAK11]

Hi BeFEA, Apologise I should of included that info in my first post.

The Calcs have been conducted in accordance with BS5950:2000. I basically have a 4 sided frame system made out of SHS with an integral hydraulic cylinder acting as a brace in an excavation. I'm looking through the specs in the technical file and it informs me that the load effects considered are the UDL taken from the geo analysis and also the Coincident axial load where applicable on a 4 sided frame.

The brace members are treated as flexural members and the compression is assumed to be fully restrained for calculation lateral torsional buckling.

I'm struggling to see how they have calculated the coincident axial force.

Not sure if that helps.

Kind Regards

 

[canwesteng]

I don't know what coincident axial loading means. I'm assuming because you mention shoring you are referring to a member with an axial load at each ends - but every member resisting axial loads has an axial load at each end in order for equilibrium to be preserved. A member resisting soil surcharge on both ends is no more stressed than one resisting soil surcharge on one end with the other end reacting at a support.

 

[jayrod12]

I think it's saying the waler (horizontal beam) needs to be designed for the uniform UDL along it's length, and for the Axial load applied to it from the perpendicular beams at each end. So it each waler must be designed as a beam column.

 

[AAK11]

Thanks for the response guys, i understand that there will be axial loads applied to the members and that the limiting factor will be the capacity of the inegral hydraulic ram rather than that of the box section itself seeing as its 140x140x8 with a NcRd of 1420kN and the ram has a SWL of 150kN. I think jayrod12 makes sense by saying that the coincident axial load is from the perpendicular. If this is the case what would be the best way to calculate it?

Also if i wanted to calculated the maximum deflection in the beam coukdni use the formula 5L^2/384EI?

Thanks again for your help