Well, I see a few things are incomplete....... including missing decking. So how do I know that the areas where the concrete was being poured didn't have all of the bolt in place at the time of the pour? I find it hard to believe that it could be that cut and dry.
This was a picture of a connection that had not fallen, elsewhere in the building. I hope eventually the photos for the beam get out to public, so you can make your own assumptions. Just think of that beam having form deck, and concrete being placed, and still only having the bolts shown, and you will understand why it fell.
When you see the pics, its that cut and dry. Believe me.
I'm not trying to discredit you or anything. All I'm saying is that your pictures shows a bolt to the column, with the decking yet to be installed, so in this area they are not even ready to pour concrete.
If that is all the bolts they had in the connections during the concrete pour that is the first place I would look for a failure. I would like to think people are smart enough to complete the connections prior to concrete pour..... but then again.
It sounds like Ztengguy has some info. or has seen some pictures that we haven’t seen yet. I don’t doubt that his scenario might be the/a direction to look for the cause of the accident. The things I see in his photo are that someone didn’t fill all the bolt holes in one of the connections at that particular location, and that beam has a white paint mark right at that location, an inspectors warning mark? The other connection at that location was completed and it appears that the bolt-up people got interrupted, didn’t complete the second connection, and moved on. They tend to move on down the line, and unless someone sees it, these things sometimes get forgotten, in the routine of that type of work. And, while no decking is in place yet, the missing bolts won’t be easier to see or get to once decking is in place.
Over the years I’ve seen those types of conditions during inspections or during investigations, after a roof failure or some such. Missing bolts (unfilled bolt holes), thus lack of shear cap’y; wrong sized bolts used in some holes, thus less shear cap’y. and some bolts not acting until the joint started to fail other bolts; or wrong grade of bolts used. These types of things are many times pretty easy to see and find in the rubble. Given the way the rubble lands you can often hone in on where to start looking.
There was in fact only two 3/4" bolts in place in the south end of the 60ft W44x262 girder that was supporting 1800 sq. ft of area. The north end was fully bolted.
Thanks connectegr, the pics in there are the ones I saw, but didnt want to post out of getting someone in trouble. Shame that it was something so simple that could have been fixed in minutes before pouring.
