by Jerry Peck - Codeman on Tue Aug 17, 2010 5:41 pm
Hi Lisa,
Those aspects of concrete slabs would be based on the engineer designing the driveway and within any requirements within ACI 318 (ACI is American Concrete Institute), but those design elements would be flexible as one could engineer fewer expansion joints which were wider or more expansion joints which were narrower depending on the sizes of the area between expansion joints. The material would also be the engineers choice as fewer expansion joints would indicate the use of a material which can address greater movement, whereas fewer expansion joints would not require a material which would need to address much movement.
What is an issue with the driveway and the expansion joints? Or is this a new/proposed driveway not yet designed or constructed? Personally, I would lean toward more expansion joints and less movement to keep the expansion joints within the center of there elasticity range, which would mean less 'squeezing upward' or 'stretching downward' of the expansion joint material, allowing for the material to remain closer to the same plane as the concrete on each side of the expansion joint so as to not create a trip and fall hazard due to humps or dips at the expansion joints.
In the end, though, it is up to the designer of record (engineer/architect/design professional) to make those choices.
Jerry Peck - CodeMan
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Construction Litigation Consultant - Retired
Construction and Code Consultant - Semi Retired