24 Mar 04 12:12
i'm well acquainted with large bore engine foundations and have done a ir-kvg for that matter. in fact, engine type does not really matter.
been 10 years or so since, but summarizing...
the foundations were replaced with engine/compressor in place. as existing concrete was removed, a steel support structure, with jacking bolts was installed to support engine/compressor. once bad concrete was removed, a reinforcing cage (rebar) was installed. pour new concrete to within 3 inches of existing engine foundation. cap foundation w/ 1" epoxy and embed a galvanized metal drain pan. pour the final 2" of epoxy under each engine footing, with the assurance that the engine's web deflections are w/in tolerance.
there are many variants as to epoxy and/or engine sole plates and alignment jacks. whoops, before i forget, the new engine tie-down bolts consisted of a 2-bolt system in which the upper bolt was a load monitoring bolt and utilized a super-nut. the 2-bolt system length is nearly the entire length of engine foundation as old foundations were cracked & deterioated at existing tie-down bolt length. you want to utilize the entire engine foundation to hold the engine in place.
in terms of reputable company's, the 1st and 3rd you mention have been used for their services. the epoxy mfg you mention is also a reputable supplier and we used their products. my memory is fading, but there is (or was) another company that had the resources to do engine foundations as well. in fact, this outfit did engine foundation replacements w/in a 2-3 week schedule. rather aggressive and he accomplished the job with great success. if requested, i can determine this outfit. i now remember the guy's name, but will not publish it as i do not know whether or not he is still in the business.
as far as concrete, we used a silica fume concrete mix and i cannot remember the slump - thinking 8", but not certain. in some cases, plastersizers were used as the travel time to plant was long (2-hours).
probably a little more than you needed, but i trust this helps.