concrete foundation

huangyhg

concrete foundation
someone i know poured an 8' heigh foundation and now wants to go to nine feet. any suggestions or recomendations on how to properly bond/secure the new 1'concrete section to the existing foundation? any reference material covering this problem?
thanks,
john
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here is what i have seen some guys doing.
you break the existing concrete in the area where you are going to add more concrete. you leave the reinforcement intact. clean up. then you add reinforcement and tie them to the existing. finally you pour new concrete over.
this is probably easier than using chemically bonded rebars.
one opinion from me. good luck.
just to make sure you dont miss this one:
"happycamper" posted a question joining new concrete to old in the concrete engineering forum, and ron,jae, qshake etc great guys did a very good job answering that.
visit there too as you wait for better responses to your specific question
what is the foundation meant for?
are the rebars sticking out? will u have enough development lenghths/laps for fixing reinforcement.
if its yes, than u can roughen the area of concrete that is to receive new concrete by say 25mm to 50mm. clean by sand blasting or wire brush. the surface should be dry and free of standing water. apply sikadur 32 ( sika product ) by brush and place fresh concrete while it is still tacky.
riz
yeah riz
great idea. never used sika 32 before, a nice new adventure.
seems a good solution if you have enough reinforcement sticking out from existing part. i will definitely use that.
i am just curious, what shall we do in case of no reinfocement sticking out, since in most cases, especially in metal structures, you dont have reinforcement projecting out at a finished level.
equally interested.
ijr
well, i agree with the first answer to your post however, it all depends on the spacing of the existing re-bars. if the re-bars provided are not adequate, spacing and size, then the best solution would be to drill the existing wall place a re-bar in the drilled holes with proper length and then form and pour the new concrete section. i would check the height of unballanced fill to make sure it is not exceeding the design of the wall. make sure that the holes in the existing wall are clean and epoxy them after the re-bar placement.
gita