2,000,000# and 10 seconds sounds like a launch of the recent rockets. I only saw a couple of firings.
On the ground in FLA you will likely have a good amount of moisture in the concrete. Our tests were on a rush 24/7/365, so the concrete never dried out and that is the reason for water cooled flame deflectors. We kept the flames away from the concrete because it never had a chance to dry out and Fondue Fire was used generously around the stands.
I was a structural engineer straight out of school. Since I had taken surveying(required class) in a 5 year CE curriculum, I used it my second day of work to observe the actual connection of the engine to the thrust measuring system on the rocket test stand. The new type engine was days old and scheduled to be fired 4 days. I used the transit, drew up a sketch, my supervisor looked at it for a couple of minutes and sent it off to be fabricated, installed and used a couple days later. - We referred to it as "cowboy engineering". Because we had about 12 test stands 10 miles from the office, we frequently instrumented the joints and mid-span gauges and accelerometers) on a 150' high steel test stand (with about 15,000 gallons of liquid hydrogen and liquid oxygen for determining the typical behavior as the tanks emptied quickly during a test. We did not design the original stands, but modified them as the rocket engines were modified and upgraded. Virtually everything was stainless steel (beams, columns and even grating and stairways) because of the cryogenics and corrosive properties of the fuels and oxidizers. The stands were built on the side of a mountain slope, so the rock and soil had to be protected from the temperature and erosion of the blast.
Good first job. The company paid night graduate courses at USC for 3 or 4 nights a weekly for 2 years including 50 miles daily of mileage, dinner and books. The continuing education was required to get more than the usual 10% or 15% annual increase.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.