Mad Mike
Geotechnical
- Sep 26, 2016
- 220
Hi All.
I'm involved in a job which has gone horribly pear-shaped. It entailed the construction of a high earth-fill embankment which would support a major warehouse with very flat floors. The Engineer's design specification for the bulk fill was 95% Mod. AASHTO minimum. I gave predicted settlements based on a sandy fill engineered to 95%, following which we set up a survey monitoring programme.
Due to bureaucratic issues, the warehouse structure was erected very early in the monitoring programme. It then transpired that the fill embankment settlements were greater than anticipated. Independent geotechnical consultants were called in, who found that the fill material was under-engineered, with a number of tests through the upper 3m of the substantial fill embankment recording field densities as low as 85% Mod. AASHTO and averaging less than 90%.
Given that the warehouse frame, roof and mezzanines are all in place there is limited headroom in a number of areas. All existing foundations are shallow pads. The information was handed to a local (South African) geotechnical engineer, with whom I looked at a number of ground improvement concepts, the most feasible of which were compaction grouting and rigid inclusions.
We're now in the process of putting the work out to tender, to all of our major geotechnical contractors. It will be design and construct, and we're not dictating any specific method. The cost of the work is expected to be enormous, in excess of ZAR 100 million, and so before our local design is approved for construction, it must be peer-reviewed. Unfortunately all of our senior South African experts are attached to the Contractors, who employ them in-house.
I'm now trying to obtain contact details for international experts, who must have extensive experience in the whole "piled fill embankment", whether rigid inclusions, compaction grouting, or any other conceivable solution, to include in the review team.
The interested party would be contacted once I have received the design proposal from our local engineers. If appointed for the review, I expect you would come down to South Africa for a briefing, walk over the site and then carry out the design review back home. The design performance will be bound by some performance criterium, provisionally at this stage that settlement of the improved embankment cannot exceed 25mm over the 25yr service period, and that no more than 40% of this settlement should be exceeded in the first three years post-installation.
Are any of you chaps interested in this work or if not, are you able to provide contact details for a reliable expert who might be willing?
Best,
Mike
I'm involved in a job which has gone horribly pear-shaped. It entailed the construction of a high earth-fill embankment which would support a major warehouse with very flat floors. The Engineer's design specification for the bulk fill was 95% Mod. AASHTO minimum. I gave predicted settlements based on a sandy fill engineered to 95%, following which we set up a survey monitoring programme.
Due to bureaucratic issues, the warehouse structure was erected very early in the monitoring programme. It then transpired that the fill embankment settlements were greater than anticipated. Independent geotechnical consultants were called in, who found that the fill material was under-engineered, with a number of tests through the upper 3m of the substantial fill embankment recording field densities as low as 85% Mod. AASHTO and averaging less than 90%.
Given that the warehouse frame, roof and mezzanines are all in place there is limited headroom in a number of areas. All existing foundations are shallow pads. The information was handed to a local (South African) geotechnical engineer, with whom I looked at a number of ground improvement concepts, the most feasible of which were compaction grouting and rigid inclusions.
We're now in the process of putting the work out to tender, to all of our major geotechnical contractors. It will be design and construct, and we're not dictating any specific method. The cost of the work is expected to be enormous, in excess of ZAR 100 million, and so before our local design is approved for construction, it must be peer-reviewed. Unfortunately all of our senior South African experts are attached to the Contractors, who employ them in-house.
I'm now trying to obtain contact details for international experts, who must have extensive experience in the whole "piled fill embankment", whether rigid inclusions, compaction grouting, or any other conceivable solution, to include in the review team.
The interested party would be contacted once I have received the design proposal from our local engineers. If appointed for the review, I expect you would come down to South Africa for a briefing, walk over the site and then carry out the design review back home. The design performance will be bound by some performance criterium, provisionally at this stage that settlement of the improved embankment cannot exceed 25mm over the 25yr service period, and that no more than 40% of this settlement should be exceeded in the first three years post-installation.
Are any of you chaps interested in this work or if not, are you able to provide contact details for a reliable expert who might be willing?
Best,
Mike
