Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Reinforcing Existing Beam

[Subject Prev][Subject Next][Thread Prev][Thread Next]
How is the existing beam connected and how is it supported?  Do you require
adding additional supports?  I'll bet it will have to be unloaded or jacked
up.  Any other solution would depend on exist connections and support
-----Original Message-----
From: Rehan.Nawab(--nospam--at) <Rehan.Nawab(--nospam--at)>
To: seaint(--nospam--at) <seaint(--nospam--at)>; Rehan.Nawab(--nospam--at)
<Rehan.Nawab(--nospam--at)>; structx(--nospam--at) <structx(--nospam--at)>
Date: Saturday, March 13, 1999 10:34 AM
Subject: Reinforcing Existing Beam

>          Folks,
>          I am in a situation, where I have to reinforce an existing
>          beam (18B40) while it is still carrying load.  The client
>          requirement does not allow for welding cover plates.
>          Therefore, I am opting to add a new WF beam to the existing
>          beam using 3/4" A325 bolts.  This existing beam has full
>          lateral support, i.e. Fb = 24 ksi.  This existing beam under
>          existing loads is stressed to 18 ksi.  This only allows for
>          approximately 6 ksi (18+6=24 ksi)  after adding the new
>          beam.  Since, the new loads are heavy, this requires a very
>          large composite section modulus to keep the stress around 6
>          ksi.  In, this case W33x201 attached to 18B40.
>          Is this approach overly conservative?  Is there any other
>          way you would analyze the problem?  Existing beam is up-high
>          and I don't think, I can have the beam jacked-up to unload
>          the existing stress in the beam.
>          Existing Moment = 100 ft-kip
>          Combined Existing and New Moment = 385 ft-kip
>          Composite Section Design Moment = 285 ft-kip
>          Composite Section Modulus = 611 in3
>          Any ideas?  Thanks in advance.
>          Rehan Nawab, P.E.
>          P.S. I posted this question yesterday, but it appears it got
>          missed some how.