Damaged W-Beam Flange

[mmarlow]

Excuse the poor title, I wasn't sure how to phrase it..

Im doing some work at a local college where facility workers noticed concrete haunches were cracking and spauling. Assuming that rusting steel on the inside of the haunch was causing this, I asked them to remove some of the hunch to expose the steel. They got a little carried away and exposed the entire beam. I intend on replacing this beam for obvious reasons. I have a good understanding of the loads on the member, and selected a W6 member for dimensional constraints.

What confuses me is the top flange of the existing beam. It looks as the it has been intentionally damaged to cause it to grab the concrete? The attached image represents what the entire beam looks like. The top flanges are like this the entire length of the beam. My only guess is this was someones attempt at increasing composite action in the 1930's? It would makes sense that this was a composite beam, because its 2" shallower than the beam I sized, and presumably 36ksi steel, while mine is 50. Mine was sized as a single member, I did not design for composite action. Im going to have them shore, add a new beam, and hard pack grout the top of the new beam.

For future reference, has anyone ever seen anything like this before?

Thank you,
Morgan

-MMARLOW EIT

 

[SlideRuleEra]

Morgan - IMHO, your assumption about intentional damage for composite action is as good as any; I have not come across anything like that.

For reference, 36 ksi steel was not introduced until the early 1960's although it is common for older samples to test that high.
Though 1933, structural steel yield value varied from 30 ksi to 33 ksi with allowable working stress of 18 ksi.
Starting in 1934, structural steel yield value was 33 ksi with allowable working stress of 20 ksi.

If you will be working on older steel in the future, consider downloading "AISC Iron & Steel Beams, 1873 to 1952" from my website.

http://www.SlideRuleEra.net

 

[mmarlow]

SRE,

Thank you. I've used your website before (identifying bar joists). It's a great source.

-MMARLOW EIT