Concrete Watertight Joints

[Zimba1]

I am working on a government project (Zimbabwe that gives you an idea on the funding). I am extending a boiler house on one of the rural hospitals. I have a channel (2.4m deep x 2.5 wide 13m long) which i m am supposed to duplicate in the new boiler i m supposed to link the channel to an existing one. there in lies my challenge the joint should allow differential movement of two types of concrete. I am familiar wit Sika products that may be used as sealants as well as water tight expansion joint sealers, i m also familiar with other products but all of them are not readily available in Zimbabwe. The concrete walls of the channel are 250mm thick. Is there a way i can link the two walls catering for differential movements (ie to cater for different thermal expansion properties) at the same time maintaining a water tight joints using the traditional concrete and motor methods.

thanks in advance

 

[JAE]

I might be inclined to dowel in and rigidly attach a new length of trough to the existing - then extend the new trough only a short distance - say 1m - then have an expansion joint - that way you can detail a new expansion joint configuration without having to deal with existing conditions.

Even with that, you still have the challenges of Zimbabwe.

 

[Zimba1]

I m thinking if i expose reinforcement for a meter into the existing channel have enough lap to satisfy design requirements cast new concrete and offset the expansion join by a meter as you suggest. My worry is what will happen at the old-new concrete interface. Wont the difference in thermal properties cause too much stress to cause cracks that may lead to .... (embarrassment of the engineer).

Dowelling in Zimbabwe is just something else

 

[JedClampett]

Zimba, whether you dowel in or uncover the existing reinforcing, if the concrete cracks, don't be embarrassed, BLAME THE CONTRACTOR.
This is the same in Zimbabwe or anywhere else.

 

[Zimba1]

JedClampett lol I am the engineer I am the contractor! Amazing Zimbabwe! The client who is Ministry of Health and the Contractor/Engineer Ministry of Public Works. I work for the latter! We have an engineering unit as well as a construction unit so its interesting you design and go and build as well. Its a challening situation in terms of keeping engineering ethics and supervision... who will police the police