Could've collapsed for any number of reasons, from design to construction to parts employed. They will investigate and determine the cause; lawsuits will follow and insurance carriers will start writing checks.brewster wrote:Anyone who has ever hired an architect and contractor knows what happened here. The clowns on the crew ignored the specs. I'm sure this was a brilliant design, it's hard to fuck up this bad with today's engineering design technology. Workers on the other hand, are much harder to control.
I had a partially circular stair built. The company's engineer did a brilliant construction design from my CAD sketch. Then the work arrived. The 6 treads that came assembled from the mill shop were out of square by 1/2" over 36". I bounced it. Later when they were installing the spindles, custom made on a pattern lathe, they had fucked up the parting so the bottom block on the short ones was 1/4" longer than the long ones. So in this case the engineer was great, the installers were great, the millwork guys were drunks. The GC on the job, not the stair guys, also fucked up reading the architect's drawing, framing the opening in a way that would have failed inspection.
I could go on and on with contractor stories of ignoring drawing specs, using the wrong materials, or stupid crap like mixing grout too loose because it makes it easier to spread. People assigned to do jobs they didn't even know how it was supposed to look when it was done, never mind be able to do it. And this is simple residential work, no affirmative action, or other bullshit. This bridge collapse was probably the 20th time this contractor and his crew did shitty work, it just finally caught up to them.
How many of us remember the Hyatt Regency walkway collapse back in the 1980s that killed > 100 people?
https://en.wikipedia.org/wiki/Hyatt_Reg ... estigationThe two walkways were suspended from a set of 1.25 in (32 mm) diameter[19] steel tie rods, with the second floor walkway hanging directly under the fourth floor walkway. The fourth floor walkway platform was supported on three cross-beams suspended by steel rods retained by nuts. The cross-beams were box girders made from C-channel strips welded together lengthwise, with a hollow space between them. The original design by Jack D. Gillum and Associates specified three pairs of rods running from the second floor to the ceiling. Investigators determined eventually that this design supported only 60% of the minimum load required by Kansas City building codes.[20]
Havens Steel Company, the contractor responsible for manufacturing the rods, objected to the original plan, since it required the whole of the rod below the fourth floor to be screw threaded in order to screw on the nuts to hold the fourth floor walkway in place. Indeed, these threads would probably have been damaged and rendered unusable as the structure for the fourth floor was hoisted into position with the rods in place. Havens therefore proposed an alternative plan in which two separate -- and offset -- sets of tie rods would be used: one connecting the fourth floor walkway to the ceiling, and the other connecting the second floor walkway to the fourth floor walkway.[21]
This design change proved fatal. In the original design, the beams of the fourth floor walkway had to support only the weight of the fourth floor walkway, with the weight of the second floor walkway supported completely by the rods. In the revised design, however, the fourth floor beams were required to support both the fourth floor walkway and the second floor walkway hanging from it.
The serious flaws of the revised design were compounded by the fact that both designs placed the bolts directly through a welded joint connecting two C-channels, the weakest structural point in the box beams. Photographs of the wreckage show excessive deformations of the cross-section.[22] During the failure, the box beams split along the weld and the nut supporting them slipped through the resulting gap between the two C-channels which had been welded together.
Investigators concluded that the basic problem was a lack of proper communication between Jack D. Gillum and Associates and Havens Steel. In particular, the drawings prepared by Jack D. Gillum and Associates were only preliminary sketches but were interpreted by Havens as finalized drawings. Jack D. Gillum and Associates failed to review the initial design thoroughly, and accepted Havens' proposed plan without performing basic calculations that would have revealed its serious intrinsic flaws — in particular, the doubling of the load on the fourth-floor beams.[20] It was later revealed that when Havens called Jack D. Gillum and Associates to propose the new design, the engineer they spoke with simply approved the changes over the phone, without viewing any sketches or performing calculations.
Life: it's complicated.
