• Field Notes 18.09.2013 2 Comments

    The Council on Tall Buildings and Urban Habitat recently added a new category for the skyscraper heights they recognize as the world’s tallest: “vanity height.” It seems with the rash of buildings claiming to be the tallest, the Council wanted to distinguish between buildings that have the highest occupied floors and the ones that get their height advantage by adding antennas or other unusable space, hence the term “vanity height.” Has there ever been a more appropriate title?

    The Burj Khalifa, at 828 meters (2,717 feet), is slated to be surpassed as the world’s tallest building next April.  Ground has just been broken on the Sky City Tower in Changsha, China, that will be 10 meters (34 feet) taller than the Burj.

    Did anybody catch the duration of construction for that one? Promise, no typos follow: July 2013 through April 2014. In less than 10 months, they want to construct an 838-meter tall tower. Do you find that hard to believe?

    By comparison, the Empire State Building (EBS), built in the 1930s, was 381-meters (1,250 feet) tall; an antenna added in 1950 extended that by 62 meters (203 feet), for a total height of 443 meters (1,453 feet). The EBS was erected at a rate of 4.5 floors a week. On most towers, erecting a floor a week today is pretty typical. Now do it 4.5 times as fast. Unbelievable! Excavation started in January 1930, actual construction started on March 17, 1930, and the ribbon-cutting happened on May 1, 1931, 15 months later. It’s mind-boggling such a building can be erected that fast.

    And, this before computer drafting, scheduling or even electronic calculators were available to help plan and execute the schedule. The architect only needed two months to draw the plans. They used a previous design as the basis of the EBS, which gave them a little bit of an advantage, but come on, only two months?

    There must have been a lot of preconstruction meetings to talk about planning, sequencing, and execution. While the construction only took 15 months, the planning effort must have been equally as long, right? Take out your daddy’s hand tools, Grandpop’s slide rule, your great grand-daddy’s drafting board and construct such a building today ‘cause that’s how it was done. I’d like to know how much was actually fabricated prior to the start of construction. Just on the structural steel alone, they had to be two-three months or more out in front of the field crews.

    I guess it’s all these “modern conveniences” that allow such a project as the China tower to even pass from conception to an actual project, with everyone chomping on the bit to get going. I wonder how long the original schedule was and how it was decided to shorten it to 10 months.

    As an aside, can you imagine what would have happened (in the case of the EBS) or will happen (in the ChinaTower) if one of the subs falls behind in their work?

    It wouldn’t surprise me to learn that the curtainwall is already fabricated and a floor can be erected in one day that we used to think of being done in a week. Fabricating 60-80 frames a day ramped up to say 150-200 a day, or more.

    With the pressure to be on time, the penalty (and hopefully the reward) clauses for being late (or ahead of schedule) must be enough to overcome the risk. Based on what little is known from my vantage point, is there any way fabrication didn’t at least start a year ago, or more?

    There can’t be anything except prefabricated, site-assembled work, like unitized curtainwall, for all the building systems, including structural, mechanical and electrical; even plumbing modules could help conceivably shorten durations. Ship to the site, set it in place and connect it all together. Can’t wait for welding, can’t wait for concrete to cure. Is there a better/cheaper and, most notably, faster way of construction?

    Or are there so many crews planned to be on site at any one time to handle a site built installation? The necessary equipment to move manpower around the tower must be staggering. I heard that moving crews on the Burj Khalifa could take up to an hour near the end of construction, to move from the ground to getting to an assigned work station, and that, to facilitate that, work starting times were staggered so that everybody wasn’t showing up at the same time. That kind of attention to detail, to moving people and materials around the site, must be so well thought-out and planned for in advance. It can’t be possible to meet such a schedule and not have thought out every little thing, can it?

    Stay tuned, we’re in for a heck of a ride if the developers here ever get this wild of a hair to bring these methods to the States. The paradigm shifts are enough to go looking for the aspirin bottle just thinking about it. Or will everyone be saying, “No problems, just opportunities and challenges?” That would have to be the mindset, right?

  • Is the “world’s most expensive billboard” coming down?

    A few years back, we learned the Harmon Tower in the northeast corner of Las Vegas’ CityCenter might be torn down due to alleged construction defects. The 26-story building is considered susceptible to collapse in an earthquake and has remained unoccupied. Although the only “revenue” coming out of the building is from the large ads mounted to its Las Vegas Boulevard façade for upcoming CityCenter events, the debate has been long and complex. Last week saw a new development, bringing it one step closer to the end. By no means is it over yet.

    A Las Vegas judge granted the developer permission to proceed with the demolition of the tower last week. Experts stated there is a 50 percent chance an earthquake large enough to destroy the building will strike within 30 years. The LA Times article reporting on the case doesn’t mention who is paying for the demolition.

    The fallout (pun intended) from this one will be quite some time in the making. And, I’m curious to see how the building’s demolition will affect the outcome. If it’s imploded (“a previous plan was submitted” to the county), will the resulting debris provide any indication about which party was responsible for the defects? Or will the answers become clearer if the building is taken apart piece-by-piece, like construction in reverse?

    It’ll be interesting to see who is eventually cited as shouldering the most blame. Or will everyone have to sign a confidentiality agreement once a settlement is reached, much like Boston’s John Hancock Building in the late ’70s, where none of the associated parties were allowed to talk?  Since it’s Vegas: Bet the house. The only winners here are going to be the lawyers. Somebody will have to pay, and it won’t be the attorneys.

    Secondly, has anybody work on a curved curtainwall lately?  There’s been another concave curtain wall “death ray” report, this time from London. Someone’s Jaguar melted in the mist of the reflected light. How’s that for a quick stop on the way home from work? You run inside for a brief moment and come back to find your car a  puddle.Imagine that call to the insurance company: “All I did was park my car here, and when I came back…”

    And while some of these occurrences appear to be from concave walls, that’s not always the case.

    I love the geometry of complex buildings and curtainwalls, but if the surface is going to reflect sun, let’s make sure we check out just where that reflected light is going. Surely there’s software out there to help figure this out. Any animation software will allow a light source to be located, and resultant shadows can be shown in the rendering. But is anyone asking about reflectivity studies? Can’t the reflective property of the glass be sufficiently modeled to then show any concentrations of light on neighboring facades? If anybody has a software engineer for a brother-in-law, please have them contact me. I have two great app ideas, this one and another I’ll keep to myself for now…

    Billboards, demolition and curtainwalls aside, it’s been a week since word got out about Lyle Hill.  Lyle, please know there are a lot of people pulling for you. We can’t wait to see your next article and anticipate the punch line, knowing a smile, chuckle or belly laugh will shortly follow.

USGlass Magazine

USGlass Magazine