Citicorp Center engineering crisis

[Swammerdami]

I've always wondered how anyone could dare to build a skyscraper. One wouldn't want to waste many millions of dollars on unnecessary steel, but on the other hand people would be upset if the entire skyscraper toppled in a storm.

How many of you have heard of the  Citicorp Center engineering crisis?

Citigroup Center at 59 stories is now only the 48th tallest building in the USA. But when it was built in 1977 it was the fifth-tallest building in New York City. In part due to a weird constraint -- stilts were set at side centers rather than at corners -- it was an engineering marvel. Among other unusual features, a  Tuned mass damper was placed on the roof. Some of William LeMessurier's (the structural engineer) brilliancies have been copied in recent skyscraper designs.

But after the building was built, was occupied, and loomed over thousands of workers in downtown Manhattan the engineer learned of a change to his designs.

In May 1978, after the building structure was completed, LeMessurier was designing a similar building with wind braces in Pittsburgh, and a potential contractor questioned the expense of using welded rather than bolted joints. LeMessurier asked his office how the welds went at the Citicorp construction and was then told that [to save money] bolts had been substituted for the welded joints he had prescribed.

The bolts were adequate to cope with wind perpendicular to a building face, but it was corner winds relevant because of the unusual stilt locations. And winds were on the way: Hurricane Ella, one of the strongest storms ever to be aimed at New York City. LeMessurier did the calculation. The 4 bolts per joint were not enough: TWELVE were needed. Better yet, just tear out the walls and weld on "band-aids." And do all these repairs in total secret! The 1978 repairs remained secret until 1995.

Fortunately Hurricane Ella veered away from New York at the last moment and Citigroup Center survived. Learn all about it in a Veritasium YouTube.

 

[Loren Pechtel]

Worse. Local case, last I knew still involving major finger-pointing. The rebar unquestionably seriously did not match up with the plans. Fortunately this was caught before there was a catastrophe, but the result was a billion dollar building that was condemned because there was no way to establish how strong it actually was. And, because of it's location, it couldn't even be blown down. 40 stories, they had to chew it up bit by bit.

 

[Tigers!]

We have an equivalent of flawed design, poor construction, lack of communication etc. in Melbourne with the Westgate Bridge collapse in 1970.

(My father took some of the pictures of it in the Yarra River that appeared around the world. He and a friend will actually looking at it in a public viewing area. They turned around to go back to their cars. Heard the rumble and were knocked over by the blast of air. Dad took out his camera for some shots then helped rescue workers.)

 

[steve_bank]

Hartford Civic Center roof collapse. I looked down on it from a nearby building a few days atyer. Shepard bolt heads were found on the floor weeks before the collapse, but nobody did anything. A college basketball game ended a few hours before the collapse.

One of the contributing was that the roof drains froze up and allowed water to accurate on the roof which froze.

Structural Failures - Hartford Coliseum | Structural Engineering Licensure Coalition

Structural engineering for the next 100 years

www.selicensure.org

This roof was noted for being one of the first large-span roofs made possible by computer design and analysis, and was modeled as a space truss using a trusted program. The roof of this three-year-old structure collapsed at 4:15 AM on January 18, 1978 during a freezing rainstorm after a period of snow. Fortunately, there were no injuries sustained as a result of the collapse. The night before, there were over 5,000 people in the coliseum attending an event. Following several investigations of the collapse, it was determined that this was an instance primarily of inadequate structural design.

A triangular lattice steel space grid, supported on four reinforced concrete pylons giving spans of 270 feet and 210 feet, was used to support the roof. Smith and Epstein concluded that the interaction of top chord compression members and their bracing played an important role in the redistribution of load and the eventual collapse. They noted that certain compression members were braced against buckling only in one plane. As loads increased, these members buckled out of plane and redistributed the loads to other members. Over a period of time, more chords buckled and fewer and fewer members carried the load. This situation worsened until the remaining members were unable to withstand the added stress due to the loads present that night, and the final, sudden collapse took place.

Lev Zetlin Associates (LZA) discovered that the roof began failing as soon as it was completed due to design deficiencies. A photograph taken during construction showed obvious bowing in two of the members in the top layer. The four major design errors above allowed the weight of the accumulated snow to collapse the roof (ENR, April 6, 1978). The load on the day of collapse was 66-73 psf, while the arena should have had a design capacity of at least 140 psf (ENR, June 22, 1978). These deficiencies caused the following undesirable results:

List of structural failures

List of building and structure collapses - Wikipedia

en.wikipedia.org

 

[Jimmy Higgins]

Factors of safety exist for a reason. Unknowns in future loadings, issues of aging, and the unknowns of the contractor building it.

Hartford Civic Center roof collapse. I looked down on it from a nearby building a few days atyer. Shepard bolt heads were found on the floor weeks before the collapse, but nobody did anything. A college basketball game ended a few hours before the collapse.

One of the contributing was that the roof drains froze up and allowed water to accurate on the roof which froze.

During construction things weren't going well. It was designed very tightly and the connections weren't lining up as they were supposed to. It was effectively failing out of the box.

Had the contractor stepped back during construction and making specific note on the deflections, there could have been a revisit to the calcs, but instead, if I remember correctly, the contractor decided to force things, which led to eccentric joint connections, which of course, just made things even worse. The roof was doomed.

 

[Loren Pechtel]

Factors of safety exist for a reason. Unknowns in future loadings, issues of aging, and the unknowns of the contractor building it.

Hartford Civic Center roof collapse. I looked down on it from a nearby building a few days atyer. Shepard bolt heads were found on the floor weeks before the collapse, but nobody did anything. A college basketball game ended a few hours before the collapse.

One of the contributing was that the roof drains froze up and allowed water to accurate on the roof which froze.

During construction things weren't going well. It was designed very tightly and the connections weren't lining up as they were supposed to. It was effectively failing out of the box.

Had the contractor stepped back during construction and making specific note on the deflections, there could have been a revisit to the calcs, but instead, if I remember correctly, the contractor decided to force things, which led to eccentric joint connections, which of course, just made things even worse. The roof was doomed.

Yeah, that's the sort of thing that led to the building here being torn down here. Things didn't fit, the workers were doing a lot of forcing and bending of the rebar. On a skyscraper. That was within spitting distance of other skyscrapers. (Multiple hotel towers in the same complex.)

 

[steve_bank]

Also it came out in Hartford that a high school teacher had been hired as a building inspector on the Civic Center project.

When they built the Hancock Tower—and it started falling apart

The tower’s history isn’t as perfect as the reflection in its glass windows today.

www.boston.com

And then the windows, which weighed 500 pounds each, started popping out of the building during high winds while it was still under construction. The opening of building was delayed from 1971 to 1976, and the cost went from $75 million to $175 million, according to The Globe.

Then it was discovered that the tower swayed to a dangerous degree. The tower required “interior reinforcing to prevent walls and partitions from cracking in high winds,’’ according to a Globe article from March 1975.

The 'death ray hotel' burning Las Vegas visitors came up with a simple fix

The Vdara hotel in Las Vegas has a serious design flaw: It's highly reflective glass creates a "death ray" on the pool area.

www.businessinsider.com

The Vdara Hotel in Las Vegas is known for its curved design, which can act like a magnifying glass and focus sunlight on the ground, particularly on the pool deck. This phenomenon, dubbed the "death ray," has been reported to cause intense heat and burns. The hotel has taken steps to mitigate the issue, including installing large umbrella

 

[Bronzeage]

"Why Buildings Fall Down: Why Structures Fail" by Matthys Levy, Mario Salvadori, Kevin Woest is a great read.​

In my city we built a new downtown Library which had the upper 5 stories cantilever out over the main entrance to create a sheltered out door space. When the building interior was being finished, someone noticed cracks in the walls because the cantilever was sagging. After construction jacks, really big jacks were installed, the interior walls were stripped out to inspect the steel frame. The welds had failed, but it turned out the welds were as specified in the specs and properly performed. The structural engineer had either under estimated the total weight to the structure, or over estimated the strength of the frame members used and the overall design was inadequate. Remedial work cost $2million and added 2 years to construction, which seems rather small, all things considered.