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RE: Alternate Cold Joint Location

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All are excellent questions.


My responses to some:


Ralph Hueston Kratz and Thomas Hunt are concerned about vertical movement.

The slab is going on a base of crushed rock; 3/8” gravel placed in very small lifts. I’m not saying there won’t be any chance of movement, but if there is a potential for that, the slab dowels should provide enough resistance, IMO. The use is a fast food restaurant, so the loading shouldn’t be severe.


Joe Venuti is concerned about moisture traveling upward.


There is a vapor retarder specified. Hopefully, it will get installed properly and run down the face of the footing. The floor finish is either vinyl or ceramic tile. Funny, I have a concern about the horizontal joint for the same reason; the moisture traveling from the outside across the joint and under the slab but above the vapor retarder.


Bob Garner is concerned that the contractor might be trying to screw the owner with this change.


The problem is that the contractor did not bid on placing his concrete over a pea gravel base. This base was required by the onsite geotechnical engineer. I haven’t seen it, but it sounds more like a road base than a pad for a one story commercial slab-on-grade building. If the base was more conventional, formwork would not have been as precarious. Therefore, the contractor says that this proposal is to reduce the cost to the owner. He asked me about it before he bid, not after.


No one mentioned the elegance of my CAD program.






T. William (Bill) Allen, S.E.


Consulting Structural Engineers
V (949) 248-8588 F(949) 209-2509

-----Original Message-----
From: Bill Allen [mailto:T.W.Allen(--nospam--at)]
Sent: Tuesday, May 22, 2007 2:36 PM
To: seaint(--nospam--at)
Subject: Alternate Cold Joint Location


Dear colleagues,


A contractor has requested an alternate cold joint location. In the sketch found in the link below:


Alternate A is the method shown on the approved plans.


Alternate B is what the contractor wants to do.


The dowels match the slab bars.


Should I have a concern about the request?




T. William (Bill) Allen, S.E.


Consulting Structural Engineers
V (949) 248-8588 F(949) 209-2509