Restraint of Thermal Expansion of Beam with Concrete Slab on

[gls4286]

Hi!

We have a question about the thermal expansion of steel beams of a composite floor system during construction. The EOR has detailed both ends of each beam to be welded to bearing plates on reinforced CMU bearing wall. When the building is done, this will all be within an environmentally-controlled space. To date the GC has installed the beams, welded down the ends, installed composite floor deck (welded to beams) and concrete slab.

The building will be exposed to the weather for the next few months and the steel will be subjected to thermal expansion. The basic thermal expansion calc is simple, but then we asked the question about HOW the attached composite slab will affect that expansion. Will the slab restrain the beam from expanding and therefore eliminate (severely reduce?) any lateral forces from transferring to the supporting CMU walls?

We are concerned about damage to the CMU supporting walls, which are to be painted as the finished wall and will be permanently visible within the building.

Any comments are appreciated.

 

[BAretired]

The coefficient of expansion for concrete is about the same as for steel, so the concrete will not restrain thermal movement significantly. Hopefully, the walls are sufficiently flexible that they can take the movement without excessive cracking.

BA