topic Re: Structural Engineer Sees Similarity to 1981 Building Collapse in Community Chat

Structural Engineer Sees Similarity to 1981 Building Collapse

golding76 — Sat, 26 Jun 2021 18:16:18 GMT

[For those who are interested, the information below is reposted from Spectrum News.] Structural engineer sees similarity in deadly South Florida, 1981 Cocoa Beach collapses

By Pete Reinwald Orlando

UPDATED 5:45 PM ET Jun. 25, 2021 PUBLISHED 1:34 PM ET Jun. 25, 2021

ORLANDO, Fla. — Joel Figueroa-Vallines, an Orlando-based forensic structural engineer, says that based on photos he has seen, the South Florida building collapse that has made the nation gasp in shock this week appears to be a product of so-called flat-slab construction.

What You Need To Know

An Orlando engineer sees construction similarities between the South Florida collapse and a deadly one in 1981

The Surfside building, like the one in Cocoa Beach, appears to be a product of flat-slab construction, he said

Flat-slab construction eliminates beams, which can help buildings support their own weight, the engineer said

That would make it similar to a building in Cocoa Beach that drew similar national attention in 1981, he said.

Both buildings collapsed or partially collapsed, with deadly consequences.

“As far as whether that contributed any to the (South Florida) collapse, we don't know at this point,” Figueroa-Vallines, founder of SEP Engineers, told Spectrum News on Friday. “But what we do know is that a flat-slab system, should there be... a cause that would, in theory, impact those slabs... those structures typically have less redundancy.”

Put another way, he said, flat-slab construction reduces the number of ways, specifically beam support, in which buildings can carry their own weight.

In 1981, the five-story Harbour Cay Condominium building in Cocoa Beach collapsed as workers poured concrete for the roof slab. Eleven workers died.

Early Thursday, about half of the 12-story Champlain Towers South building in Surfside inexplicably collapsed, killing at least four people. By Friday afternoon, almost 160 people were still unaccounted for.

Figueroa-Vallines noted that both structures went down in a so-called pancake or domino effect.

“All that means is that the floors punched through the columns, because essentially there are no beams there,” he said.

He said the 1981 Cocoa Beach collapse inspired a law that required structural engineers and inspectors, including himself, to undergo a qualification program to “enhance the quality control and inspection during construction of 'threshold buildings.'

”Such structures include those over three stories or 50 feet or built for more than 500 people.

He called the law “a proactive way of enhancing quality control to minimize some of those contributing factors” that led to the Cocoa Beach collapse.

Builders find flat-slab construction easier and quicker because the floors connect directly to the building’s columns and walls, and they don’t include beams, Figueroa-Vallines said.

That works well for residential buildings because it creates “nice, clean ceilings” and “very low floor height, so you can actually get more floors constructed with less height,” he said.

Figueroa-Vallines called flat-slab construction an “excellent system” when properly engineered and constructed. The construction type continues “to a degree,” he said.

Of the Surfside building, he said: “I don't have any specific drawings... but from looking at some of those pictures, I could not see any beams framing those slabs. It doesn't mean they're not there, but chances are, based on the floor-to-floor height, that building was probably a flat-slab building.”

In the Cocoa Beach case, the University of North Carolina-Charlotte noted the uncovering of “numerous design errors,” including slab width that fell under code.

In the partial collapse this week, news reports have cited human error and corrosion of structural steel among possible reasons and have noted sinking ground at the site of the building.

But Figueroa-Vallines emphasized to Spectrum News that he was hesitant to speculate on the cause.

“It's a cause-and-effect thing,” he said. “So when something collapses, the collapse is the effect. The cause of it is yet to be determined. And there could be many contributing factors why there would be only a partial collapse.”

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

golding76 — Sat, 26 Jun 2021 18:24:12 GMT

Flat slab is a reinforced concrete slab supported directly by concrete columns without the use of beams. Flat slab is defined as one sided or two-sided support system with sheer load of the slab being concentrated on the supporting columns and a square slab called 'drop panels'.

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

Porcelain — Sat, 26 Jun 2021 18:56:00 GMT

Well it is Florida. Buyer beware. You can't automatically assume anything is being repaired or inspected.

I guess people need to hire independent structural engineers to inspect any building they're interested in before signing a lease or or buying a high rise condo. If you can't afford that due diligence, you'll be living there at your own risk.

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

fthunt — Sat, 26 Jun 2021 19:06:54 GMT

Foundation Ground: Sand - always shifting

Elements: Salt Water - Windy- Hot Temperatures pounding buildings

Building Height and Weight of concrete

Buildings go up in a wink of an eye - Lots of very expensive units now useless and zero in value.

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

Mistreatedbycs — Sat, 26 Jun 2021 21:33:51 GMT

so before you buy a condo should you be checking for prior inspection reports, are those reports even available?

if there is similar construction in the Surfside neighborshoods, wouldn't you be suspicious of other buildings?

Why would half go down and not the entire building? Looks like the other side is OK...true?

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

decaf — Sun, 27 Jun 2021 00:49:14 GMT

@Mistreatedbycs wrote:
so before you buy a condo should you be checking for prior inspection reports, are those reports even available?

if there is similar construction in the Surfside neighborshoods, wouldn't you be suspicious of other buildings?

Why would half go down and not the entire building? Looks like the other side is OK...true?

@Mistreatedbycs I'll try to give you some educated guesses or information I've heard from local network news here.

With properties selling within the first 24 hours in S Fl you wouldn't have time to visit the building department at city hall, request the records and research all prior inspection reports. S Fl is known to be very lax about inspections to begin with. Homes and condos are being sold sight unseen to out of town and international mostly cash buyers, they're scooping them up, just going by the real estate photos online. It's an unprecedented market.

This Champlain South Condo bldg has a sister building right down the street. Same builder, built the same year, same design and building materials. The Surfside city officials cannot guarantee that building is safe. They're strongly recommending that residents move out, until a thorough inspection is done. The city is now also implementing plans to inspect all oceanfront condo buildings over five stories high and 40 years old.

Approximately half the building went down, the side that directly faced the ocean. The side that faces the stree,t Collins Ave, is intact. I'd suspect it has something to do with being exposed to the salt air for 40 years. Salt air is highly corrosive, known to weaken and deteriorate many, if not most, building materials. Plus building codes were not very strict in S Fl when it was built in 1981.

Hopefully they'll be enough evidence remaining so structural engineers will be able to determine what caused this disaster. Right now, they say all they can do is guess.

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

ValuSkr — Sun, 27 Jun 2021 01:08:33 GMT

This demonstrates the importance of having a home inspection, done by a qualified engineer, before buying a property - even a condo - even a high-rise condo.

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

golding76 — Sun, 27 Jun 2021 01:47:23 GMT

ValuSkr (and others),

Because I recently had a woeful tale that cost me some big money, the plumbing company that assisted me related the story of another customer they were helping the same week. Their sad story is a cautionary tale.

Because properties move so briskly in this area of Northern Virginia, the people who do home inspections are incredibly behind in doing their evaluations. In our area, people not only offer cash for a home but often offer thousands of dollars more than the asking price just to nab the property. They've also forgone getting the home inspected and bought it on blind faith. Apparently, this has become commonplace. The plumbers told me that a couple who bought a "mansion" (as the plumbers described the property) did not have it inspected and discovered not long after their move-in that something was very wrong with the plumbing. Everything backed up in the basement. The plumbing had been installed "backwards" (or some such) and worked successfully for about 20 years -- until a few weeks after the new owners moved in.

They had to have about $30,000 worth of plumbing/sewer work done. Their insurance did not pick up one cent of it.

What an expensive lesson learned. Better to let the property go if you cannot get it professionally inspected before the purchase.

(I hope I made it clear that they skip the inspection in order to have their offer accepted first.)

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

suzyQ3 — Sun, 27 Jun 2021 01:47:22 GMT

@ValuSkr wrote:
This demonstrates the importance of having a home inspection, done by a qualified engineer, before buying a property - even a condo - even a high-rise condo.

@ValuSkr, while true, I'm not so sure that they would have spotted whatever factors went into this massive destruction.

BTW, during this overheated real estate market, some potential buyer are giving up the right to have an inspection in order to increase their change of getting the house. VERY BAD IDEA, NO MATTER WHAT.

We once backed out of a deal after the inspector told us that there was erosion that could cause the property to end up down the cliff toward the ocean. We figured that's one ride we didn't want to take.

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

golding76 — Sun, 27 Jun 2021 01:48:29 GMT

suzyQ3,

You and I addressed the same topic simultaneously.

Weird.

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

suzyQ3 — Sun, 27 Jun 2021 01:49:07 GMT

@golding76jinx, you owe me a Coke!

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

suzyQ3 — Sun, 27 Jun 2021 01:49:35 GMT

And we just did it again.

Re: Structural Engineer Sees Similarity to 1981 Building Collapse

decaf — Sun, 27 Jun 2021 03:16:48 GMT

@golding76 wrote:
ValuSkr (and others),

Because I recently had a woeful tale that cost me some big money, the plumbing company that assisted me related the story of another customer they were helping the same week. Their sad story is a cautionary tale.

Because properties move so briskly in this area of Northern Virginia, the people who do home inspections are incredibly behind in doing their evaluations. In our area, people not only offer cash for a home but often offer thousands of dollars more than the asking price just to nab the property. They've also forgone getting the home inspected and bought it on blind faith. Apparently, this has become commonplace. The plumbers told me that a couple who bought a "mansion" (as the plumbers described the property) did not have it inspected and discovered not long after their move-in that something was very wrong with the plumbing. Everything backed up in the basement. The plumbing had been installed "backwards" (or some such) and worked successfully for about 20 years -- until a few weeks after the new owners moved in.

They had to have about $30,000 worth of plumbing/sewer work done. Their insurance did not pick up one cent of it.

What an expensive lesson learned. Better to let the property go if you cannot get it professionally inspected before the purchase.

(I hope I made it clear that they skip the inspection in order to have their offer accepted first.)

@golding76 On a local real estate TV show here in S fl last week, a realtor was giving tips on how to make your offer stand out in this crazy RE market. His #1 suggestion was to forego asking for a home inspection!
That's an advantage for sellers and real estate agents, just an horrible tip to give a buyer.