Crane structure bracing & compression strut 2

[GD_P]

Hello community,

I am designing crane supporting structure, please find the attached image of elevation view with oneside columns supporting gantry. The crane capacity is 10T & Span is 8.7m.; other dimensions as indicated in the attachment.
My questions are:
1) Can I use only single braced bay for transferring lateral forces from gantry to foundation, induced due to crane movement & seismic load? I think as long as they are designed (tension & comp both) for applicable forces, single bay is okay. or is it mandatory to have bracing in min 2 bays?
2) If there is only 1 braced bay, and crane is operating at point A as indicated in the attachment, how to design the gantry which also act as strut for this case? Offcourse it has to be designed for the compressive force from crane movement in addition to procedure for gantry girder design (strength & serviceability). Although columnn bases are fixed type but all lateral load is considered to be transferred through bracings, for such a case what additional requirements need to be checked? May be slenderness limit or non dimensional slenderness limits or anything else.....
Your opinion please.




GD_P

 

[JAE]

1. You should only use either one braced bay or set two side-by-side in the center of the runway length. Don't put braces at either end as they will fight each other should there be foundation settlements, thermal changes, etc.

2. Multiple questions here. You seem to understand that the craneway beam must be designed for combined vertical and axial loads. Good. We typically don't assume fixed bases but rather assume them as pinned...especially if we have X braces. Other things to be checked - very numerous - beam deflections (crane limits), end connections, fatigue, axial-moment conditions for the columns, beam-column connection to avoid fatigue, etc.



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[oldrunner]

You also have to design for torsion coming from the gantry itself to the top of the runway rail above the supporting runway beams.