Expansion Joint Between Edge Beam and Lift Core Wall 4

[MattyG123]

Hi Guys!

Am new here. Ive got this drawing and wanted to find out the reason behind having an expansion joint between a lift core wall and an edge-beam/slab on ground? I know it might not be much info. What would the purpose of this, as opposed to having an isolation joint around the lift core walls??

Any help would be much appreciated

Thanks

Matty G

 

[Tomfh]

I don’t know the designer’s rationale, but I can tell you that dowel arrangement results in slab cracking.

 

[hokie66]

I think it is in expectation that the compacted backfill around the liftwell will settle a bit. But Tomfh is correct, the wall will restrain the slab, potentially inducing some cracking perpendicular to the joint.

 

[blihpandgeorge]

i agree with hokie666 that it is probably because of likely settlement against the wall where compaction tends to be of lesser quality. It is also not uncommon to put some bottom bars to allow the slab to span onto the dowels / support. If normal dowels are used the slab may crack as there is dowels in 2 orthogonal directions. if the dowel sleeves were amended to be rectangular then this would improve the detail. Alternatively a corbel could be used, but these are expensive to construct due to formwork hassles.

 

[r13]

The dowel is expected to further minimize the potential of settlement of the slab at interface. Properly designed, the concrete is free to move as it expands, or shrinks, and fitting the name "expansion joint". But I agree, the dowel is un-necessary for this case, and may causing more problems as noted by the others.

 

[MattyG123]

Thanks for you input guys much appreciated - I spoke with the designer and he told me what all you guys said - just to help stop the slab moving vertically (minimize the potential of the slab settling).