I was able to translate the browser, the beam collapse in a Swedish mall in November of last year. Unfortunately this beam failure did result in a fatality on site.
'A narrow beam of life gave way and concrete slabs fell on a road. The beam had a thickness of 25 mm, but the measure was in the design firm to 7 millimeters.'
'A 34-year-old engineer was responsible designer. On Friday, three days during the trial, she told the hearing that the document with 7-millimeter measure, sent to beam manufacturer, was an advance copy.
Since the drawing was not dated, she considered that the beam manufacturer should have discovered that it was not a manufacturing drawing.
In drawing out the thickness of the beam life to seven millimeters. The measure would actually have been 25 millimeters. Now could the responsible engineer in prison.
- The drawing is incomplete otherwise, there is no livavstyvningar at one end. The production should have reacted to that the beam saw disproportionate out, she said.
The interview focused largely on e-mails exchanged between the companies prior to the current drawing are, as well as on the two versions of its own checklist that the designer has done.
In one version is checked for self-monitoring the error code, but in the second version is the beam is not checked.
The designer claimed that she had accidentally bent on control in the wrong line, and had accidentally saved the wrong version of the project's quality binder.'
Judging by the failure of the beam, would you say that it was a web buckling failure? 7mm web thickness is not very thick for a 1320mm deep beam with 40mm thick flanges. The 6mm fillet weld to the flange plate also seems disproportional.
The web thickness translates to about 1/4", and the depth to about 52".
I agree the thickness compared to the depth looks real suspicious without web stiffeners. I would expect the web thickness to be more in the range of 3/8 to 1/2", depending on stiffeners.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
1) Obviously, there was no web stiffener over the support, with apparent collapse of the web
2) Insufficient connection between the shallow beam and the deep beam or otherwise provide continuity for lateral restraint of the top flange. (Although, based on the post-failure shape, it doesn't look like the top flange displaced laterally.)
The photo should be required viewing for every new engineer.
I think it also displays the necessity to thoroughly review steelwork shop drawings and to have your work thoroughly reviewed by another engineer in the office before it is issued for construction. Particularly when designing fabricated plate girders.
How did it get past fabrication? I would think most fabricators would have picked up the phone when this was set up in the shop? Inexperienced fabricator? I realize it is not the fabricators job or responsibility, however, lets face it they are one of the last lines of defense. I would think even an experienced iron worker might speak up on something that looks so poorly proportioned. Makes me think of a replacement simple span highway bridge going up by my house. New beams are about half as deep as original 1950's construction with paper thin webs. It is quite the contrast to see the new span erected and still have the original northbound span in place! Major reason for reconstruction is corrosion! We have become much more liberal with LRFD it seems in the US.
