Triton Posted July 29, 2019 Share Posted July 29, 2019 Upper floor has collapsed after crews just laid down concrete. https://abc13.com/live-7th-floor-of-building-collapses-in-north-houston/5427346/ 1 4 Quote Link to comment Share on other sites More sharing options...
jmitch94 Posted July 29, 2019 Share Posted July 29, 2019 It will be interesting to see what caused this. Quote Link to comment Share on other sites More sharing options...
Luminare Posted July 29, 2019 Share Posted July 29, 2019 50 minutes ago, jmitch94 said: It will be interesting to see what caused this. Project will most likely be on hold indefinitely till they figure this out. Normally the order of investigation goes like this; first test the whole building, then the architect, then the engineers, then the GC, and finally the subs. If the other floors check out, then the check the drawings with the architect. If that checks out then they approach the engineer to check specs on loads and field tests required. If that checks out then they approach the gc to see if he mandated the tests required, and procedures were done correctly regarding moving up floors. If that checks out then they approach the subs to see if they poured and cured everything correctly. Don't know how long it will take, but it is a smaller job, but we will see. 1 1 Quote Link to comment Share on other sites More sharing options...
Triton Posted July 29, 2019 Share Posted July 29, 2019 @Purdueenginerd Any thoughts? 3 Quote Link to comment Share on other sites More sharing options...
Purdueenginerd Posted July 29, 2019 Share Posted July 29, 2019 (edited) 1 hour ago, Triton said: @Purdueenginerd Any thoughts? You just gave me a heart attack. I have a light gage building of similar height and construction that's topping out soonish. Quote Upon initial review of the incident, the inspector believes the shoring was "inadequate," Erin Jones, a spokesperson with Houston Public Works, said. That means whatever temporary support system was in place while workers poured the concrete may not have been working properly and resulted in the collapse. Let me just say, from the imagery I can see -- theres not a lot I can discern. But I will comment on the quote above, which involves shoring. Typically (though not always) steel decking can support a live load (ie, people), but can't support the wet, uncured concrete weight (dead load) without additional shoring. Typically for this style construction, the shoring is designed by a subconsultant that the contractor hires. Once the concrete cures then it effectively "adds" strength, or can self support without the shoring. The shoring is subsequently removed and construction proceeds. Getting into the weeds here, but this is the load tables both the contractor and their subs would have access to http://vulcraft.com/catalogs/412 (PDF warning) and if you go down to the load tables. You'll see every single deck has a table of its capacity... followed by another table of its "Maximum Construction Clear spans". For Example go to page 30, you'll see in some of those configurations, the deck can only span 5-6 feet before needing shoring (during construction). Obviously, I dont have their span tables or deck drawings so I cant comment on if their shoring was sufficient.. however looking at the photos. I dont see shoring on the level below the collapse. Thats not unheard of, but not that common. Generally you want to shore 2-3 levels. I also dont see shoring on the area to the right, though its not clear if that area was to receive concrete decking. Was the contractor dumb enough not to install shoring? -- I'd be genuinely surprised if that was the case... but contractors have surprised me in the past. Maybe more likely is that the shoring got bumped out of place (or improperly installed) which lead to collapse during concrete placement. Edited July 29, 2019 by Purdueenginerd slight clarification. 2 6 Quote Link to comment Share on other sites More sharing options...
Purdueenginerd Posted July 29, 2019 Share Posted July 29, 2019 Additional comment: I went back and looked at a few photos from earlier in construction. I'm not totally convinced shoring is the issue here. Im still at my office, so when I go home, I'll get into my blind speculation. 3 Quote Link to comment Share on other sites More sharing options...
mollusk Posted July 29, 2019 Share Posted July 29, 2019 5 hours ago, Luminare said: Project will most likely be on hold indefinitely till they figure this out. Normally the order of investigation goes like this; first test the whole building, then the architect, then the engineers, then the GC, and finally the subs. My experience is that everybody gets involved in trying to sort out the how and why pretty much immediately. Quote Link to comment Share on other sites More sharing options...
Luminare Posted July 30, 2019 Share Posted July 30, 2019 30 minutes ago, mollusk said: My experience is that everybody gets involved in trying to sort out the how and why pretty much immediately. Agreed. What I described is more along the line of where does blame go first if their were a hierarchy for such things. Quote Link to comment Share on other sites More sharing options...
Popular Post Purdueenginerd Posted July 30, 2019 Popular Post Share Posted July 30, 2019 Fair Warning: I dont know what happened, but the reason I dont necessarily think its shoring is because of the joist spacing. The joist spacing, shown above is about 18-24". Which would be more than enough to prevent steel deck failure associated with a lack of shoring. The roof joists are spanning about 30-40' (based off google earth) which isnt too unusual. During construction, the joists could be weaker for lateral torsional buckling, if their bottom and top flange are insufficiently braced. Other baseless speculation: If a joist was poorly connected, improperly connected, or designed poorly, it could facilitate a cascading failure. Lets imagine for a moment joist spacing is 24". And we have 4" of concrete. 4"/12"*1ft*150pcf. =50 lbs/ft^2 ( or PSF) of weight. The construction live load should and could be 50 PSF. Keep note of the construction live load, thats important. The total load theoretically would 100 PSF (plus self weight). On a single joist it would 100 PSF * 2 feet (or 24") = 200 lbs/ft(or PLF). Which means the load bearing wall at each joist is supporting 200 PLF* 30ft/2 =3000 lbs. Now, Imagine one of the joists and its respective connections to the load bearing wall failed. The next joist over, immediately picks up the load. So now the single 100 PSF * 3ft =300 lbs/ft. - a 50 percent increase in load on the next two joists over. Why did I bring up the Construction Live load? Because the roof is traditionally designed for a live load of 20 psf. -- This isnt a code discrepancy, Its just something a lot of contractors dont know about. So its plausible, that contractor may have inadvertently overloaded a connection, a single or multiple joists or some combination thereof. This could have precipitated the cascade. Structural steel Column Failure: Not Likely. Load bearing wall failure: Also not likely, but I have noticed that the studs are not currently braced for weak axis bending. Weak axis bending and strong axis bending are structural topics I wont get into unless you guys really want me to haha. Again, this isnt likely unless they used a much lighter gage steel at higher elevations (not unheard of). 5 5 Quote Link to comment Share on other sites More sharing options...
Luminare Posted July 30, 2019 Share Posted July 30, 2019 12 hours ago, Purdueenginerd said: Fair Warning: I dont know what happened, but the reason I dont necessarily think its shoring is because of the joist spacing. The joist spacing, shown above is about 18-24". Which would be more than enough to prevent steel deck failure associated with a lack of shoring. The roof joists are spanning about 30-40' (based off google earth) which isnt too unusual. During construction, the joists could be weaker for lateral torsional buckling, if their bottom and top flange are insufficiently braced. Other baseless speculation: If a joist was poorly connected, improperly connected, or designed poorly, it could facilitate a cascading failure. Lets imagine for a moment joist spacing is 24". And we have 4" of concrete. 4"/12"*1ft*150pcf. =50 lbs/ft^2 ( or PSF) of weight. The construction live load should and could be 50 PSF. Keep note of the construction live load, thats important. The total load theoretically would 100 PSF (plus self weight). On a single joist it would 100 PSF * 2 feet (or 24") = 200 lbs/ft(or PLF). Which means the load bearing wall at each joist is supporting 200 PLF* 30ft/2 =3000 lbs. Now, Imagine one of the joists and its respective connections to the load bearing wall failed. The next joist over, immediately picks up the load. So now the single 100 PSF * 3ft =300 lbs/ft. - a 50 percent increase in load on the next two joists over. Why did I bring up the Construction Live load? Because the roof is traditionally designed for a live load of 20 psf. -- This isnt a code discrepancy, Its just something a lot of contractors dont know about. So its plausible, that contractor may have inadvertently overloaded a connection, a single or multiple joists or some combination thereof. This could have precipitated the cascade. Structural steel Column Failure: Not Likely. Load bearing wall failure: Also not likely, but I have noticed that the studs are not currently braced for weak axis bending. Weak axis bending and strong axis bending are structural topics I wont get into unless you guys really want me to haha. Again, this isnt likely unless they used a much lighter gage steel at higher elevations (not unheard of). Now this is analysis we need more of! I talk about design stuff on various threads a bunch. Would not mind taking a step back to hear some about engineering. Though the equations immediately fly over my head, its great education nonetheless. This is also a building system I'm not familiar with yet. I know they use this system a lot for multifamily as well, but my only experience with steel has been web joists + steel columns. Not a forest of mtl stud acting as shear walls, and mtl stud being configured to act as beams. Quote Link to comment Share on other sites More sharing options...
Purdueenginerd Posted July 30, 2019 Share Posted July 30, 2019 1 hour ago, Luminare said: Now this is analysis we need more of! I talk about design stuff on various threads a bunch. Would not mind taking a step back to hear some about engineering. Though the equations immediately fly over my head, its great education nonetheless. This is also a building system I'm not familiar with yet. I know they use this system a lot for multifamily as well, but my only experience with steel has been web joists + steel columns. Not a forest of mtl stud acting as shear walls, and mtl stud being configured to act as beams. Im not a super big fan of light gage. Its superior to wood framing and more uniform. But Owners sometimes dont realize there are load bearing walls in the structure. From an architectural standpoint the floor plans more or less have to be uniform. Which is great for a hotel/apartments. Its get problematic and expensive when the floor plans change from floor to floor. 1 Quote Link to comment Share on other sites More sharing options...
Ross Posted July 30, 2019 Share Posted July 30, 2019 36 minutes ago, Purdueenginerd said: Im not a super big fan of light gage. Its superior to wood framing and more uniform. But Owners sometimes dont realize there are load bearing walls in the structure. From an architectural standpoint the floor plans more or less have to be uniform. Which is great for a hotel/apartments. Its get problematic and expensive when the floor plans change from floor to floor. I saw a lot of construction in the Middle East (had one temporary apartment that was next door to a high rise under construction and saw the construction about 50 feet away out the window), and they used concrete pillars for load bearing, then put in steel studs for room separation. That seems to be a lot more flexible, and stronger. Is there a major cost differential doing that as opposed to suing metal studs as load bearing elements? Houses there are built the same way, at least for the structure. Interior walls of those houses are generally concrete block. Quote Link to comment Share on other sites More sharing options...
Urbannizer Posted October 29, 2019 Share Posted October 29, 2019 Still on hold after the collapse? 1 Quote Link to comment Share on other sites More sharing options...
Triton Posted October 29, 2019 Share Posted October 29, 2019 2 hours ago, Urbannizer said: Still on hold after the collapse? Yup, drive by it everyday. The only crews that have come out were to clear up the debris that was hanging over the edge of the building. Not much activity since then. 4 Quote Link to comment Share on other sites More sharing options...
Purdueenginerd Posted November 17, 2019 Share Posted November 17, 2019 I tried looking up some more updated press on this one. https://setexasrecord.com/stories/513240744-construction-worker-alleges-negligence-caused-fall-through-floor-at-holiday-inn-site Only thing new this indicates is that this confirms they were in the middle of a concrete placement when the collapse occurred. 4 Quote Link to comment Share on other sites More sharing options...
Ross Posted November 17, 2019 Share Posted November 17, 2019 Plaintiffs appear to have obtained a temporary restraining order to prevent any alteration to the structure. Defendants are complaining that it's not necessary, and costs them $500 per day in interest. One of the defendants has also argued that the suit is barred by the worker's compensation act. This should be interesting. Case numbers 201952375- 7 and 201955986- 7 on the Harris County District Clerk's site. 6 Quote Link to comment Share on other sites More sharing options...
Triton Posted December 12, 2019 Share Posted December 12, 2019 Construction has started back up on the other side that was not affected by the collapse. I'll try to get a picture in. 8 Quote Link to comment Share on other sites More sharing options...
Popular Post Triton Posted December 28, 2019 Popular Post Share Posted December 28, 2019 On 12/12/2019 at 12:21 PM, Triton said: Construction has started back up on the other side that was not affected by the collapse. I'll try to get a picture in. The side with the crane is the side that collapsed. As you can see, they've repaired the metal and added the external layer. 14 Quote Link to comment Share on other sites More sharing options...
southerncrj Posted December 29, 2019 Share Posted December 29, 2019 This is very good news. I noticed it a couple of days ago, but was not completely sure whether work had resumed or I was deceiving myself. I was afraid this building site was bound to remain in limbo for years. 3 Quote Link to comment Share on other sites More sharing options...
southerncrj Posted May 23, 2020 Share Posted May 23, 2020 (edited) Happened to drive-by today (was not able to snap a photo). There is new scaffolding up on the S. side of the building, and they seemed to have started applying a layer of paint. Edited May 23, 2020 by southerncrj 3 Quote Link to comment Share on other sites More sharing options...
Triton Posted August 15, 2022 Share Posted August 15, 2022 Wow, surprised we never updated this. It's fully open and the parking lot has always had a good deal of cars so it seems to be a success! 1 Quote Link to comment Share on other sites More sharing options...
southerncrj Posted August 18, 2023 Share Posted August 18, 2023 Not sure how to interpret the news, but the hotel has been listed for sale: https://www.loopnet.com/Listing/3401-N-Main-St-Houston-TX/28962433/ Hope it's not the result of occupancy being below expectations. It has been open for just over a year. 1 Quote Link to comment Share on other sites More sharing options...
Houston19514 Posted August 18, 2023 Share Posted August 18, 2023 1 hour ago, southerncrj said: Not sure how to interpret the news, but the hotel has been listed for sale: https://www.loopnet.com/Listing/3401-N-Main-St-Houston-TX/28962433/ Hope it's not the result of occupancy being below expectations. It has been open for just over a year. It's almost impossible to know without more information. It could just as easily be the the result of occupancy being above expectations. Quote Link to comment Share on other sites More sharing options...
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