It has been a very long time since I last was active on Eng-Tips. So long, in fact, that I have misplaced my old password, and my old e-mail has changed. I had used the handle, "Aton". Thus now "Aton2"
But to my question (I am hoping that other engineers who have had my experience can comment and help me resolve my dilemma):
I have designed a foundation for a client in the high Arctic. [I have had much experience designing and living in permafrost regions, and have designed other buildings and foundation systems in the North successfully. I am not a geotechnical engineer, and have worked with geotechs in the past to obtain optimum foundation systems.] So my question is not a technical one - rather, it is how to manage my client's expectations and inject some reality ...
The situation: My foundation is (was supposed to be) for a minimally-heated storage garage (pre-manufactured steel moment-frame) on relatively flat tundra (composed of post-glacial till and raised beaches). The active layer is approx. 2 m. An airport terminal building is very close to my site, and it has an RC slab, underlain by a system of thermosyphons. It has stood the test of time for at least 20 years.
However, a minimally-heated storage building does not call for the expense of thermosyphons. Originally, I had a long discussion with my client regarding the advantages of thermosyphons, but the expense had been an issue, understandably. Instead, I have designed a series of RC grade beams resting on 1 m thick well-compacted gravel, supporting a 150 mm (6") RC slab. 4" (100 mm) of extruded polystyrene insulation Type VII (for high compressive strength) will be placed under the grade beams, and 4" of Type IV under the RC slab. This is equivalent to (Imperial) R-20. This should take care of any residual heat being conducted down from a low-heat building.
The general approach to building on permafrost is to remove (isolate) the source of heat from conducting into the ground by elevating the building on ad-freeze (or ideally, rock-socketed) steel piles - or, in the case of a small building, to place it on wood cribs or adjustable steel jacks so the air can wash underneath. An insulated RC slab-on-grade supported by such piles would work in my case too, but it is expensive and not called for in a building with a very low heating regime. I have known simple warehouses to be placed directly on the ground on some gravel, but I will not take the chance that the permafrost will not melt and the building subside - even with minimal heat. For "unheated" warehouses, a thick pad of compacted gravel, as I have designed, is normally recommended, as I have designed in the past.
This design is complete and is due to go to the AHJs for permits. HOWEVER, I now have learned that:
1. my client is ignoring his initial written assurance that the building will have minimal heat, and is now planning on creating offices in one portion of the building, going ahead with oil-burning boilers and forced-hot air throughout.
2. Has also asked me to remove the 1 m gravel pad so access is at grade level.
Yikes!
I cannot allow my design as completed to be built (not with my seal on it!).
My intention is to immediately write a letter to my client, (re)explaining the technical problems of heating the permafrost, and the advantages of thermosyphons or ad-freeze piles (rock-socketing is not an option at my site). Either system would require me to engage a qualified geotech at my client's expense. I have also previously laboriously explained to my client that insulation only SLOWS or delays heat flow, but cannot entirely stop it...
My letter would also explain that I cannot affix my seal to a heated building unless the issues are properly dealt with in an appropriate design. The first step would be to engage a geotech to provide me with, as a first step, a desk-top study which hopefully I may be able to use to design a less conservative foundation. Even if my client agrees that he will take full responsibility for any subsidence issues should he opt to go ahead with his intentions. Ethically, I do not want my foundation to fail and some other owner (or, by default the government) have to bear the cost of remediation (huge or impractical) - or demolition - should the building become untenable.
The alternative is that I explain that I must remove myself as the EOR (a situation that my contract provides for).
I do not want to lose my client (who clearly does not comprehend the concerns, and is convinced that such measures as I have recommended are not necessary).
Any thoughts would be much appreciated. I have searched Eng-Tips, but cannot find any posts that seem to address this issue.
But to my question (I am hoping that other engineers who have had my experience can comment and help me resolve my dilemma):
I have designed a foundation for a client in the high Arctic. [I have had much experience designing and living in permafrost regions, and have designed other buildings and foundation systems in the North successfully. I am not a geotechnical engineer, and have worked with geotechs in the past to obtain optimum foundation systems.] So my question is not a technical one - rather, it is how to manage my client's expectations and inject some reality ...
The situation: My foundation is (was supposed to be) for a minimally-heated storage garage (pre-manufactured steel moment-frame) on relatively flat tundra (composed of post-glacial till and raised beaches). The active layer is approx. 2 m. An airport terminal building is very close to my site, and it has an RC slab, underlain by a system of thermosyphons. It has stood the test of time for at least 20 years.
However, a minimally-heated storage building does not call for the expense of thermosyphons. Originally, I had a long discussion with my client regarding the advantages of thermosyphons, but the expense had been an issue, understandably. Instead, I have designed a series of RC grade beams resting on 1 m thick well-compacted gravel, supporting a 150 mm (6") RC slab. 4" (100 mm) of extruded polystyrene insulation Type VII (for high compressive strength) will be placed under the grade beams, and 4" of Type IV under the RC slab. This is equivalent to (Imperial) R-20. This should take care of any residual heat being conducted down from a low-heat building.
The general approach to building on permafrost is to remove (isolate) the source of heat from conducting into the ground by elevating the building on ad-freeze (or ideally, rock-socketed) steel piles - or, in the case of a small building, to place it on wood cribs or adjustable steel jacks so the air can wash underneath. An insulated RC slab-on-grade supported by such piles would work in my case too, but it is expensive and not called for in a building with a very low heating regime. I have known simple warehouses to be placed directly on the ground on some gravel, but I will not take the chance that the permafrost will not melt and the building subside - even with minimal heat. For "unheated" warehouses, a thick pad of compacted gravel, as I have designed, is normally recommended, as I have designed in the past.
This design is complete and is due to go to the AHJs for permits. HOWEVER, I now have learned that:
1. my client is ignoring his initial written assurance that the building will have minimal heat, and is now planning on creating offices in one portion of the building, going ahead with oil-burning boilers and forced-hot air throughout.
2. Has also asked me to remove the 1 m gravel pad so access is at grade level.
Yikes!
I cannot allow my design as completed to be built (not with my seal on it!).
My intention is to immediately write a letter to my client, (re)explaining the technical problems of heating the permafrost, and the advantages of thermosyphons or ad-freeze piles (rock-socketing is not an option at my site). Either system would require me to engage a qualified geotech at my client's expense. I have also previously laboriously explained to my client that insulation only SLOWS or delays heat flow, but cannot entirely stop it...
My letter would also explain that I cannot affix my seal to a heated building unless the issues are properly dealt with in an appropriate design. The first step would be to engage a geotech to provide me with, as a first step, a desk-top study which hopefully I may be able to use to design a less conservative foundation. Even if my client agrees that he will take full responsibility for any subsidence issues should he opt to go ahead with his intentions. Ethically, I do not want my foundation to fail and some other owner (or, by default the government) have to bear the cost of remediation (huge or impractical) - or demolition - should the building become untenable.
The alternative is that I explain that I must remove myself as the EOR (a situation that my contract provides for).
I do not want to lose my client (who clearly does not comprehend the concerns, and is convinced that such measures as I have recommended are not necessary).
Any thoughts would be much appreciated. I have searched Eng-Tips, but cannot find any posts that seem to address this issue.
