I saw a particularly good one once. A 30 cubic yard wall, scheduled for 7:30 am. Should have easily been finished by noon, but it was a really tight schedule day for us (and the contractor, this will become critical), so my boss had me scheduled for another job at 2 pm. They got 25 or so yards in, and, yep, someone forgot a few snap ties right at the bottom of the form. BLOWOUT! Penis ensued.
The wall had to be finished that day, so they had to clean up the mess, reform it, and pour it again. We were required to inspect the steel and such before the front of the form was put on (I’d done that once, the previous day, already), so I had to stay for the whole cleanup, reinspect and document that the steel hadn’t been affected, wait while they replaced the front of the form, and stick around to inspect the concrete again. We didn’t finish that job until about 10 or 11 that night. The VP of my division had to go do my 2 pm job. Fortunately for me, I only lived (according to Google Maps) 0.7 miles from that job.
And every bit of this portion was built on caissons that I was at the bottom of. Holes 3 feet wide, and 40 feet deep. And I was at the bottom of those holes. One of the most frightening things I’ve ever done. And the damn building is still standing. I did my job right.
I’m getting my information second-hand, but this is what I hear about how it goes - architects should all be lined up against a wall and shot (or maybe required to put in a rotation during their training actually building the buildings they’re designing so they have a better understanding of why the builders can’t do what the architect has designed). The architect designs something that is impossible to build; the contractor puts in a change request to make it work; the architect ignores the change request for a month or two; the contractor has the client breathing down his neck because part of the winning bid was a time schedule that needs to be met or high penalties will need to be paid, not to mention that all the sub-trades have to be scheduled in a certain order. Meanwhile, the contractor figures out a work-around and puts in in place, hoping that they will get signed off at some point so all their work doesn’t need to be ripped out.
I remember two decades ago learning from the “Japanese management method” was all the rage. (How’s that working for you now, Akahito?) One point was that the new engineer was with the company for life, another obsolete tradition. As a result, they could afford to spend some serious time on education. The engineer would work 6 months or a year each on accounting, in quality control, on the shop floor in production, then in shipping… after a few years, when he was ready to start designing, he would better understand the full life cycle of challenges of the items he was designing. You would not get those fabulous Detroit designs, where in one of their earlier small cars, you had to remove the steering column to replace the fourth spark plug.
The problem is book learning is no substitute for practical experience or vice versa, and the skill of being able to learn sometimes needs to be acquired too.
This might be regional but I have never seen different colored hard hats in my 30 years practicing as an Architect. Always white. Occasionally a cowboy hardhat which was cool, and a couple of General Contractors I worked with had pink hats for those foolish enough to forget their hard hats at home. Interesting they never forgot their hard hat after wearing a pink hard hat all day. But other than that, I don’t ever recall seeing any other colors except white.
As long as we’re story telling, I’m an estimator for a landscape company. We were asked a while back to budget a rooftop garden going on top of the 4th and 15th floors of a downtown building. About a year later, we’re asked to come in for a scope meeting. We say “Umm… those were budget plans, got anything newer?” and we get sent a much more recent set of landscape documents with a couple days to put together a new proposal.
The new landscape documents show 24" of soil media in the rooftop planters (this is a garden area; these will have shrubs and trees in them to walk around). The previous set had 12-18" of media. We bid the new set and go in to the scope meeting. At the meeting, one of the project supervisors says “Those aren’t 24 inch high walls, those are 24-36 inch high walls”. We check against the architectural plans and, yep, the walls are much higher than shown on our documents. Some further discussion and it comes out that the GC sold the job based on the budget plans and then someone there approved the new plan set… apparently without getting new pricing. So now the rooftop landscaping was around 100% over budget.
So that sucks, huh? Oh, the supervisor makes another observation: there’s no way the structure will hold a 36" depth of wet soil media. We say no problem, we’d be happy to design it using foam in most of the planter and just 12-24" of soil on top depending on what’s getting planted. This will also lower the overall cost, foam being (literally) cheaper than dirt. We do so and send it back… but they want to award it based on the latest plan set with the full depth of soil. They can’t build it that way but we’d have a contract to build it that way until they can convince the various levels of architects (building, landscape) to accept the new detail.
I lost track of where I was going with this (damn phone calls) but just another illustration of how the ball gets dropped and multiple trades need to look out for problems. You had miscommunication between the architects in designing it, problems with the general contractor is buying it, problems with accepting revisions, etc. you have (as described above) a plan that is impossible to build as drawn. They’re at about $400,000 right now for a phase they budgeted maybe $175,000 for. Should be a fun phone call between the general contractor and the owner. You might think that sort of number would get swallowed up in the multi-million overall cost but when each trade division has its own guy overseeing it, they notice an extra $225k pretty easily.
Thank you all for the entertaining and informative replies. It sounds like a large construction site only appears to be chaos to my untrained eyes. However, it is really a giant pile of much smaller tasks, each getting completed on its own. So, the guy paving our new parking lot doesn’t need to know anything about hanging the light fixtures in the new gym. However, the paving guy may want to know to hold off on his paving until after all the heavy, concrete-crunching cranes get done with their work. So, there is a site supervisor who makes sure that every trade knows when it is okay to do his/her thing.
The Hyatt in Kansas City is a well-known disaster of a building in active use when it failed. What about other similar failures that were discovered before disaster ensued? For example, freeway interchanges fascinate me. Living near Houston, Austin, and San Antonio, I have seen many interchanges in various levels of construction. It amazes me that these long, curving, slender bridges can be built from opposite ends and meet properly in the middle. Have there been instances where a flyover is being installed and, when the two ends meet, it is discovered that they are offset by a few feet and cannot be mated? How do they fix it?
Surveyors with modern laser equipment can keep a centerline pretty darned accurate. For overpasses, it’s not all that challenging because you can just drop a plumb bob to see if you’re where you should be, at least horizontally (not that that’s actually how they do it). And if you’re only an inch off, you can sort of split the difference with the final form.
More amazing to me are the tunnels dug from both ends. As I recall, the Chunnel met with only a few centimeters difference. But in the 1860s Chicago dug a tunnel two miles long out under Lake Michigan, to bring in fresh water from far offshore. The workers started at both ends and obviously had no way to see into or out of the tunnel, and the lasers were quite primitive kerosene-powered affairs. Yet when the two drifts met, the centers were only four inches apart.
