@dik
Thats not a bad idea. Not my property but I can stop by. I was using blu-beam was tracing the lettering. My rudimentary googling wasnt finding anything useful. Might be a local fabricator thats long gone.
Pre-cast piers was my assumption as well.
I'm doing a charity project in the city of houston will be doing some minor structural engineering to save these 1930's era homes. Buildings are in really bad shape. I mostly do renovations and repair design for commercial and industrial buildings but I came upon something I had not seen. The...
I think you bring up a good point here. There's not really a code rationale for a structural engineer to 'strengthen' the shear capacity of an existing slab/column interface unless the design loads were being changed or the existing capacity was insufficient for the applied loads. Based on the...
Compression failure of concrete is typically "explosive". Not like fireball, but the dispersion of energy will send dust and concrete projectiles in all sorts of directions.
I think its hard to equate relative movement on the particles once the building starts to move. Is the camera anchored to something and also moving? The vectors the dust takes will have gravity affecting it and whatever force knocked it loose initially. Whether those were localized shear...
For what its worth, I've seen a 12" Dia concrete column taken out by a forklift (higher mass, but lower speed than a typical car). Photo from during the repairs. I'm skeptical of the car crash hypothesis in this instance, but there can be some plausibility to that.
I get shop drawings for rebar for just about every new construction project I work on. Houston, TX, for what its worth. I would not anticipate this to differ much in the 70s or 80s.
Minor clarification of the drawings might be needed, the steel was called out as #4@13. But the notes state that bars shown on the framing plan are top bars, in addition, unless noted otherwise. The top steel, which would be more pertinent to the bending moment for the cantilever was typically...
This a distinction between ultimate load and service load in the concrete and steel codes. I didnt make the rules, but the thought process for fall arrest systems are that they are only used once: When someone has an uncontrolled fall off of the building and their harness system catches them...
Emphasis mine. This is point were trying to make. 1250 lb load test from an anchor is not a lot of load/weight.
To add to this, the 1250 load test loads are typically performed in a manner that cancels out or creates the reactions locally. Insufficient to create catastrophic failures unless...
As someone who has designed and observed post installed fall arrest systems on buildings as old as 120 years old and a observed the load test. No. Typically the load test is performed by testing, by tying two anchors together, then jacking them with a load meter until yes, 25 percent of the load...
I dont understand the fascination with the fall arrest system(s) being installed, even if they were incorrectly installed. There are much bigger problems if a 4 bolt/2 bolt connection into a concrete structure propagates a building failure. These fall arrest systems were not loaded during the...
Planters are often lined (here in houston, tx) and fail like every 1-2 decades or so- which then facilitates replacement or removal of the planters. At least in renovation/repair projects Ive been involved in.
To be clear, ajk1, corrosion of the rebar is structural distress.
Your top bar deterioration example may have been in a location of low negative moment or you were observing temperature steel. Rebar corrosion of flexural steel and/or shear steel will result in a reduced cross sectional area of...
Two hypthesises (is it Hypothesi?) I've seen here, I dont think I quite agree with.
1. The Cooling tower at the roof level was changed out. Normally these things are about 20-30 kips for a building this size and distributed over 2-4 columns. For a concrete building this size, and with typical...
Yeah, I'll chime in that I mostly do forensic structural engineering and repair design in my career -- I'll add to SocklessJ and JRs87 statement, that anecdotally Condo boards and HOA's are often the least versed clients (present company not withstanding) and often the most cost conscious we/I...
NYT Article indicates that column cracking was epoxy injected, but cracks reformed directly adjacent. That to me is a pretty clear indicated that the root cause of the cracking still existed. If there was embedded and ongoing corrosion of the rebar for the columns that wasnt addressed in 2018...
@Spartan5 I'm actually concerned about the columns supporting the remaining mid-rise. Their unbraced length has doubled due to the ground floor slab falling down. Thats can be a significant drop in axial and bending capacity for a column.
Anecdotal thoughts:
A few years back I worked on a mid-rise condo of the same era and roughly the same height. It had a very scary punching shear failure that was slow enough for residents to notice, report it that day, and for contractors to show up and install shoring posts immediately...
