6ft thick foundation 1

[dewins]

is there a code violation if concrete casting will be done with vertical construction joint? is it structurally sound not to pour monolithically?

also, what are the measures to apply in achieving quality concrete and if permitted, construction joints?

 

[hokie66]

Thick foundation slabs can certainly be jointed. But you need to know much more than that, and "achieving quality concrete" is a big subject in itself.

 

[dewins]

thanks, hokie. we are looking for sound engineering practices for this. any suggestions for possible alternative or reference that can be applied for construction jointing detail?

 

[JStephen]

It needs to be designed for that, not just an after-the-fact decision to make it in two pours. Check shear at the interface, for one thing.

 

[SlideRuleEra]

See the Portland Cement Association publication (free) "Engineering Mass Concrete Structures" at this link:

http://www.cement.org/buildings/pdh_se_mass.pdf

With proper planning, a six foot thick slab is not unusually difficult. Even in hot climates, concrete temperature and other mass concrete issues can be properly controlled by careful selection of mix design, using chilled water / flaked ice in the mix, placement at cooler time of the day (night), timely concrete delivery, etc.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[msquared48]

Vertical construction joints for mass concrete are done all the time in Dam construction.

Mike McCann
MMC Engineering

 

[dewins]

appreciate the thoughts, slideruleera. more power!

 

[dewins]

guys, do you know of some vertical construction joint detail that can be applied for this 6ft thick mass concrete?

 

[hokie66]

That depends on the load that has to be transmitted across the joint. As good practice dictates locating construction joints where the shear is minimal, just providing a clean, slightly roughened face is probably all that is required. Continue all reinforcement through the joint and follow appropriate practice for mass concreting as SRE has suggested, and you should be fine. If the joint has to be located where there is significant shear, I would provide some deep shear keys.

 

[TDIengineer]

Also, not sure if this relates to your design or not. But if your foundation is a grade beam of sorts, you might want to follow the provisions for Deep Beam and provide the necessary side steel reinforcement if is that deep.