Something not smelling right here IMHO. Get rid of the evidence if you ask me about doing a bridge extension. If they have problems with this part of the Three Trails how many more problems are awaiting to pop up or fall down so to speak. Hey KDOT........wanna do a nice review of MODOT's engineering and design of this project? I don't trust MODOT at all as they are in a CYA mode right now.
I can't see KDOT coming in and doing an independent engineering review on this--they have to work with MoDOT on KC Scout and metro Kansas City freeway planning in general. That doesn't mean there aren't people in the State Bridge Office in Topeka watching MoDOT stew in its own juices.
It is hard to say how all of this is likely to play out in terms of attribution of responsibility, but overall I would say the likelihood of "forgive and forget" is high, because the worst consequences of this wall failure are motorist inconvenience and added cost--this is not like the Hyatt Regency balcony collapse, where dozens of people died and there was a systematic effort to assign responsibility which resulted in several professional engineers losing their licenses to practice in Missouri.
The construction plans for the retaining wall were developed by HNTB, which is a Kansas City-based PEF with offices all over the country. HNTB: "What if we move our HQ out of Kansas City?" Moreover, the wall plans have only three sheets, and the shop drawings, which were developed by the Reinforced Earth Company out of Vienna, Virginia, have 17 sheets. The two sets of drawings are in broad agreement as to the basic design parameters for the wall, i.e. select backfill immediately behind the precast wall panels, and "random backfill" deeper inside the embankment. Retaining wall design is actually fairly specialized and it looks like crucial elements of the design may have been devolved to the contractor, possibly with Reinforced Earth Company acting as a subcontractor for engineering design of the wall.
As a generalization, the liability of a party to a contract for bad effects resulting from good-faith performance of the actions agreed to under the contract is constrained by whether the party could reasonably have predicted the bad effects. The basic principle involved is that you cannot be held responsible for things outside your knowledge or control. By contracting out wall design, MoDOT has in theory transferred the risks associated with wall failure to the contractors, but
this transfer of risk will not in reality have occurred if the contractors can show that (1) MoDOT knew, or could reasonably have been expected to know, of circumstances which would lead to the failure of the wall as designed; (2) that this knowledge was not passed on to the contractors; and (3) that they could not reasonably have been expected to find it out for themselves.
My suspicion is that the wall has failed for reasons which were not known to MoDOT, HNTB, Reinforced Earth Company, or the prime construction contractor prior to the start of construction. If this matter is litigated and the courts find this to be the case, then MoDOT will pay to resolve this because it has the underlying responsibility. I actually doubt MoDOT will litigate this because I don't see how they could be confident that they would win in court, and even if they were, they would still have to consider ulterior costs such as loss of capacity within the highway construction industry within Missouri. So--"forgive and forget."
But this is all speculation at this point because we don't have the full set of documentation that would have been involved in the design of this wall. For starters, calculations would have had to be performed to determine things like soil pressure and length of reinforcing rod needed. These would have been carried out by certain individuals and would have been based on certain assumptions about ground conditions at the wall site. This information, in turn, would tell us who knew what when the wall was being designed. This information would not need to be publicized in order to replace the wall with a bridge extension, but you can bet that it would form part of the record in any court case between MoDOT and the other parties involved in building the wall.
The really smart thing for MoDOT to do in this situation, IMO, would be to commission the state transportation research center (is that based in Columbia?) to carry out an independent review and find out why the wall failed. It would be a shame to lose the chance to learn from a mistake.