Your example is not that far off, I know of a building where the subcontractor’s subcontractor substituted a less elastic steel and it caused bolts to fail with the potential to drop a few 100m out of the sky and land on the public below. I don’t know the details but the subcontractor could probably only have picked up the defect by hiring a metallurgist to spot check the bolts to verify that it was the right steel they had been supplied with and I’m guessing that wasn’t done.

More generally, what often happens with big projects like this is the design team is not connected with the contractors that build the job. The reason why this happens is because early in the design stage when you speak to a main contractor you don’t get to talk to the actual subcontractors that will build the thing, you are essentially speaking to the salesmen that will eventually get their buying guys to hire subcontractors to do the actual work. If they are brought on early then Contractors typically find ways to use proprietary lock in and cost ratcheting techniques to increase the cost of a build once they have secured the job so to avoid this a fairly common setup for a building of this size is for a design team to prepare drawings and a performance specification to a level of detail that gets you regulatory compliance, but not a full nuts and bolts design with buildability assessed. This is not just the architectural design but also the structures, M&E, security, landscape etc. So, for example, the electrical design might be a block diagram and the loads, but the bus bars might not be sized and the suppliers for all the switchgear wont be selected. At pinch points there may be a more detailed reference design.

At this point there will be a design build contract made between the contractor and the client based on the partially complete design. This design gets handed over to the contractor to complete and the contractor’s engineers take over and complete the details. Sometimes some of the original design team gets novated from the client to the contractor, quite often only the architects but you have to be really sharp in your negotiations if you do this because once they have you hooked there will be huge time and cost pressure to complete the designs for less fees and to find ways to save money.

A rule of thumb I use is that on a A1 sheet’s worth of information takes about 1 person week to complete when you include all the research. Often with consultations with other specialists this work will be stretched over a couple of months. On a big project there will be 10s of thousands of drawings in play. This can’t be rushed if you don’t want any mistakes, but it almost always is and if you are an engineer or an architect working for the contractor at this point there is huge pressure to cut corners. Non-famous architects and engineers are actually not very well paid compared to other professionals and we tend to work very long unpaid hours with workers rights laws regularly flouted, e.g. firing pregnant women etc.

Another issue is that there is corruption in the buying department of the main contractor as well, they have gold watches and get taken on days out to go and ‘bet on horse racing’ by the subcontractors.

So the contractor’s incentive to cut costs and corruption cause a lot of last minute design changes to use a ‘preferred supplier’ or to reduce complexity or use cheaper materials. When coupled with the time pressure, things go wrong.

Everyone will say, ‘oh you architects should design everything properly down to the last detail, there should be PLM models like the aircraft industry’ but the fact is every building is a prototype, a building this large has a much higher margin of safety but it is as complicated as an airliner and airliners cost a lot more money to develop than buildings. No-one is willing to pay for the time input, they would rather let the contractor bodge it on site, often contractors will end up using the reference designs and filling the details themselves on site, e.g. using drawings never intended to be construction information.

Another one is ‘well then you should use more standardisation’ from personal experience in trying to make my own business more profitable, you can try to standardise construction details but there are a lot of high level client influenced design decisions that ripple right through a building down to the 1:2 construction details so this only works up to a point. I’ve managed to break my details down into reusable components, but I’ve not managed to literally reuse the same drawings for multiple projects.

As we’ve seen with the 737 Max debacle the airline industry is not immune from these kind of mistakes, I think ultimately the problem is probably more with project management and construction contracting culture than it is with ‘the Architects are hand wavy artists’ (we’re mostly not)