If any of you here ever watch the "Mayday" series which shows many types of NTSB investigations (mainly aircraft accidents but also railway, highway, bridges etc.) they always look into the human factors which may lead to an accident or make an accident worse. They will undoubtedly look into why...
To TehMightyEngineer (sorry don't know how to do quotes)
To the contrary the article clearly indicates that the FDOT was represented at the morning meeting, it does not indicate if the pictures were shown at the meeting or if only a discussion was held and the FDOT rep. was in a secretarial role...
If you go to the following Miami Herald web page photos of many large cracks not revealed before can be seen. https://www.miamiherald.com/news/local/community/miami-dade/article216388430.html These photos were apparently taken on March 13 or March 14 at least one day before the collapse. This if...
hokie66 "appster, I think the result of the investigation will assign blame clearly enough." Actually they very seldom point out one cause or name anyone specifically because usually a number of things add up to why it happened and they usually make recommendations to prevent the same thing from...
If we are going to run computer models lets at least get the loads/ft correct, so in the spirit of joint effort why not use calculated numbers. Biggest room for error here is scaling the length of web members
Taking the area of the canopy it is 16.29 ft2 so at 150 lb/ft3 this is 2.44 k/ft. or...
The NTSB will not assign blame as it is not their job; neither I believe is it the objective of this forum to assign blame but to try and uncover facts. We are trying do this with a lot of questions that may never be fully answered simply because some of the evidence may never be revealed to the...
In gwideman's post of 28 Mar 18 07:00 with the looped video it appears that the crane is backing up during the sequence; not sure if this is due to zooming but the car is moving forward.
Also to sailkee119 I thank you for the information on the deck and canopy tendons. Appears then that the...
saikee119 Re strand vs PT rods
No I was referring to the strands immediately either side of 12 in the deck, not in member 12 itself. The concept drawing section of the bridge shows 6 x 19 strands either side of 12 and smaller or fewer strands outboard. The smaller bundles seem to be inboard and...
Hold on a minute here Prof. Simon. :
I calculated the stress in 11 on the pier with its axial load and assuming two PT bars at 250K tension each. Under dead load only the axial stress in 11 with a reaction of 887 kips after removing DL of 12 and half of canopy between 11 and 12 = 1508 k/ 22 X...
Looking at the photos in gwideman's post of 15:04 two things that I have noticed.
1) The PT strands each side of 12 appear to be smaller than originally planned, in the concept the smaller tendons were outboard of the 6-19 tendons, they appear here to be inboard, not sure number of tendons in...
UKJIm
I was referring to the white snake going almost full length of the blister. Can only hope that the NTSB keeps a few larger pieces such as what is left of this cap and what is left of 11 and 12 to examine more closely.
Meerkat 007
"This confuse me. For my untrained eye looks like a PT bar but from where to where ?"
I believe that it is tendon duct or utility duct from the canopy but could be wrong.
Do we actually know what prestress was applied to the canopy and to the bottom deck. Have the number of strands total but 1) were all of them tensioned and 2) where they all tensioned to the maximum allowed, I assume the they would be but cannot find verification anywhere.
By the way I have...
The drawing that I have of the overall structure is stamped, dated 12/9/16 and signed by the Engineer. Not sure about US dating convention but it is either Dec. 9 of 2016 or Sept. 12 of 2016. The span is shown as 175' on this drawing; was the 11' added later than this. Here in Canada we would...
Quote SheerForceEng
"Do we know when the PT cables in the bottom deck/chord were stressed? Were these cables stressed after the entire truss was poured or was the bottom deck poured, then stressed, then the diagonal/verticals poured and so on?
If the cables in the bottom deck were stressed...
