Depth reduction in existing beam
Depth reduction in existing beam
(OP)
I have 40 in deep existing steel beam 40 feet long span. For sure beam is overly designed. I need to cut out 20" deep
and 5' long piece of beam to provide clearance. At the new short section I can add plates to mock reduced size W beam. But any other thing I need to know in design which can affect especially due to abrupt change in section.
and 5' long piece of beam to provide clearance. At the new short section I can add plates to mock reduced size W beam. But any other thing I need to know in design which can affect especially due to abrupt change in section.






RE: Depth reduction in existing beam
RE: Depth reduction in existing beam
There are twelve sections in the webinar but I believe the pertinent discussion occurs in the first and second one.
RE: Depth reduction in existing beam
Mike McCann
McCann Engineering
RE: Depth reduction in existing beam
How long I should extend the new flanges?
RE: Depth reduction in existing beam
The AISC Manual of Steel Construction discusses how far to extend cover plates beyond where they are needed--your new flange is not exactly a cover plate, but I think these rules would apply.
DaveAtkins
RE: Depth reduction in existing beam
they should overlap far enough that the load can shear into the new flange ... practically, i'd see this being done by angles eteneding over the new flange and projecting back into the original beam ... calcs will tell you how far this needs to be
RE: Depth reduction in existing beam
Mike McCann
McCann Engineering
RE: Depth reduction in existing beam
RE: Depth reduction in existing beam
Even if the reduced section can take the load, in effect, reduced stiffness is almost creating a pin connection, which would change the way the frame reacts to loads (wind, earthquake,...) moving stresses from one part of the structure to another part, which might not have been designed for it.
RE: Depth reduction in existing beam
RE: Depth reduction in existing beam
Mike Halloran
Pembroke Pines, FL, USA
RE: Depth reduction in existing beam