Expert: Veto Varma - 4/16/2007

Question
We have a 1 1/2 story house with a basement under the single story section.  A foundation company installed an "I" beam supported by 3 steal 4" x 4" posts with helical pier screws, that go through the concrete foundation in our basement, to provide more support to the portion of the house above the basement.

The 3 posts were not evenly spaced so the end of the "I" beam - under a load bearing wall above - is cantilevered and not supported by a post.  

When they first installed the beam and did the "lift" the doors above the basement were square, but within a week they were not.  Representatives of the company came back and added steal shims from the center of the I beam to the "free" end (going from 0" to 1 1/2" in shims).  The  end of the I beam is now twisting. (So, if you look at the end of the beam it is now an "italicized" I).

The engineer was not present during the "adjustment" and when the workers saw the beam was twisting they stopped work and called the engineer.  He is now scheduled to come to see what has happened.

My questions -
 1- Was the original design flawed?  
 2- Does the I beam need to be supported at both ends?
 3- Has the twist in the I beam ruined it?

Thanks in advance for any assistance.  The company came well recommended - but I now have lost my confidence in their opinions.

CKB  

Answer
Hello Cindi,

I can not comment on the design of I section beam as I do not know the section size of it. But as you describe the twisting I think it is the problem of installing the Beam. The top end and bottom end of the beam has to be well connected to the structure. I suggest simple steps for you. You can go to this beam and have a look and you will find if it was properly installed or not.

a. Check at the support location of the beam i,e. where it is sitting on the post. The beam must be resting on a plate and bolted together, if not welded. Check if this connection is loose or misplaced or at all there or not.

b. Check the top flange of the beam how it is connected to the floor. Is it just there or is it nailed to the floor in some way.

C. I assume it is a beam of 8 inch depth. Check if this beam is supported on all columns in the same way and aligned properly or not.

Once you do this you will know what is happening there. Usually beam size is alright but the installation is poor causing all sorts of problem. I also can not comment on other engineers design.

The beam can be cantilevered and it an take the load but it has to be designed for it. Check the overhang portion of the beam and how long it is. If it is a beam of 8 inch depth or more and overhang is not more than 4 feet I assume design is all right. If it is not the case consult with an engineer.

My guess is that the twist in the beam is caused by improper lateral support of the beam. and If the twist is significant and throughout the beam or more then 50% of the span it should be replaced. Consult with the engineer on this, who can see it physically in the house.

Hope this helps.

Regards
Veto