Expansion Joint

[ben3929]

A two story office building will be constructed inside existing industrial building. The existing building has movement joints (expansion joints)on concrete floor. The new two story building (135'X45') will be built crossed over existing concrete slab expansion joints. New building will not be attached to existing building structure. Steel frame with steel stud wall will be used for the construction of the new two story building. would it be any problem if the new building constructed over the expansion joint?

 

[msquared48]

How much allowance has been provided in the existing expansion joint? 1", 2" 3"?

If the amount is less than an inch, I would consider ignoring it depending on the lateral system and its layout used in your new building.

However, I would provide an expansion joint in your new building if it was over an inch - gut call here only.

Mike McCann, PE, SE (WA)

 

[MotorCity]

Most of the time, expansion joints are provided in the steel framing but not in the foundation. This is because the largest expansion typically occurs at the top and gradually reduces to zero at the base.

In your case, an expansion joint in the slab leads me to believe that there may be significant temperature variation and the slab is expected to expand/contract. Or the other option....whoever put an expansion joint in the slab did not understand what they were doing.

If the inside of your building is at a constant (or near constant) temperature, and there are no other loads that would result in the slab moving, I would construct your new building over it. If that is not the case, you should have an expansion joint in your new building to match that of the existing building.

 

[ben3929]

The allowance provided on the roof is 2" and less than 1" on the floor. existing building size is 1/2 mile by 1/2 mile. the slab supports heavy equipment and vehicles.

 

[haynewp]

There are anti-fracture fabric membranes that are used for tile over moving concrete joints. I would consider using that before just ignoring it.

 

[hokie66]

If the slab you are talking about is a slab on ground, I doubt they are expansion joints. Probably normal control joints, for shrinkage crack control.