Concrete beam has been cut

[lotiman]

My house interior size is 20x30ft but now I'm extending it to 20x36ft. There's a concrete beam on the 30th feet but my contractor cut the beam into half thus at the same time remove the bottom steel rebar. Originally got 2 top and 2 at the bottom but now only left 2 top. The strength of the beam is greatly reduce and will not hold in my opinion but eh contractor said it will. Note: he did nothing to distribute the load from the cut beam. Is there anything can be done to fix it to prevent the beam from deflect?

A structural engineer advise to add a 3x3in steel bar (square in size and blank in the middle) or what ever it call just right at the bottom of the cut beam to prevent deflection. Will it help?

 

[Ron]

Have the contractor put shoring under the beam immediately. Then have a structural engineer evaluate and design a repair. A 3x3 tube steel (HSS) section can be an appropriate repair; however other repair methods might present a better/more workable profile for residential use.

Your contractor should be prepared to pay all costs of repair and design for the repair. He screwed up!

 

[msquared48]

Bigtime... Agree with Ron totally.

You always need bottom steel in a structural concrete beam. Sometimes the steel on top is non-structural, but that depends on the system of support and the loading on the beam.

Mike McCann
MMC Engineering

 

[hokie66]

Why did the contractor cut the beam? For a new doorway? I assume the 3 x 3 HSS is vertical, i.e. a column. If so, you probably need one on both sides of the opening.

 

[JStephen]

Lotiman,
Take Ron's advice, hire somebody local and competent to look at it and go from there. The forums here are intended for engineering discussions, but when it comes to actually making engineering recommendations, you need somebody that is working for you and can look at it in person if necessary, not random strangers on the internet looking at pictures.

 

[BAretired]

The contractor was wrong to cut the beam without first checking with an engineer to see if it was okay. The beam should be supported temporarily and work should be stopped pending a review and recommendation by a local structural engineer.

BA

 

[Archie264]

You've heard from the best, listen to their advice! One other thing: if it's as you describe it may be a serious safety issue. Evacuate the building until a local structural engineer can advise otherwise.