High Temperature Design

[goestructural]

I am currently working on a design for a micropile foundation system in a glass plant where there have been temperature probes in the ground that show 700F (371C). The plant was originally built on a mat foundation bearing on approximately 3' (1m) of high plasticity clay underlain by shale. The high temperatures have cause thermal consolidation of the clay and shale, thus causing settlement of the structure and all manner of bad things to happen (glass spills, ect.). I have a few concerns that I am having trouble finding answers to:

1. I would assume that there is some reduction in the allowable stress on the casing and grout due to the high temperature.
2. Operations have been shut down for some time (over a year) so I am sure that the temperature in the ground has cooled. What will happen to the bond between grout and rock once the plant is fired back up? The shale could continue to shrink while the grout expands, but probably not at the same rate.
3. Our scope of work includes the design of the caps and grade beam, but I can't seem to find information on the design of reinforced concrete in high temperature environments.

If anyone could steer me in the right direction it would be appreciated.

Thanks

 

[jheidt2543]

Well, regarding the response of the concrete and grout, I would try ACI and PCI technical departments. They may have access to research available on some aspects of your problem.

Sorry, I can't help on the clay/shale question.

 

[miecz]

Check the Nuclear Power industry.