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Yes. Another example would be one of those mainrenance sheds in the midwest that is a dome sitting o the ground. The chord is the distance across the base, but not necessarially equal to the diameter defined by the radius.

Your methodology for the measurement of a radius would be a good way to get the CHORD, the distance where the ceiling meets the walls. By taking the same laser measurement from the floor to the highest point on the roof and subtracting the height of the wall will give you the chord height. Again accuracy is critical for finding an accurate area of the sphere.

All I want is for someone, anyone to describe, in detail, the method, bullet points, they would use and the tools involved in getting an accurate measure of the skin of the dome on the New Orleans Super Dome and the number of squares of roofing needed for a complete reroof. The method has to be practical and doable, not some wild fantasy or just a theory as to how it "might" be done.

Whoa, my only thought in these postings was to provide calculation methods, that i know work, for a question posed. I have absolutly no intention of scoping the roof of the Superdome, nor claim the ability to do so.

Hurricane Katrina damaged the roof on the New Orleans Super Dome and an adjuster handled the claim. A contractor made the repairs. The next time a Hurricane hits New Orleans the Dome will be damaged again and maybe the roof will be totaled.

Best to have some notion of the equipment needed and the method long before they are actually needed. Maybe someone who reads this forum will come forward and describe how to accomplish the feat.

Posted By rickhans on 21 Aug 2010 01:15 AM
When you talk about a dome, does it have a straight surface like an upside down ice cream cone?  If so, and if I remember my geometry, the surface area is the circumference of the base times the length of the slope to the tip divided by 2.   If you are referring to a spherical shape dome, I don't think there is one specific formula without knowing the actual design, especially if the vertical plane has a varying radius.

Posted By Medulus on 20 Aug 2010 12:40 PM

We all use basic geometry in our profession.  For instance we know that the area of a gable roof slope is the base times the height or that a triangle is the base times the height divided by two.  Here are a couple that are less common.  What formula would you use and how would you determine the square footage of the following?

 

You visit a farm after a windstorm.  The domed metal silo is damaged.  How would you calculate the square footage of metal needed to replace the exterior metal?  How would you calculate the dome?  (I've had claims with this scenario.)  BTW, calling a contractor and asking for a quote is NOT the correct answer.

 

You are asked, after a hurricane, to handle a claim involving a domed sports stadium.  You find that the rubber membrane of the domed roof is compromised and the roof membrane will need replacement.  How do you calculate the square footage of the dome?  (I've also had a claim like this, except that it could be repaired rather than fully replaced.)

Posted By ChuckDeaton on 22 Aug 2010 10:58 PM
Hurricane Katrina damaged the roof on the New Orleans Super Dome and an adjuster handled the claim. A contractor made the repairs. The next time a Hurricane hits New Orleans the Dome will be damaged again and maybe the roof will be totaled.

Best to have some notion of the equipment needed and the method long before they are actually needed. Maybe someone who reads this forum will come forward and describe how to accomplish the feat.

Hi Chuck , they replaced the entire roof on the superdome, They had a documentary about replacing the roof and that with some new polymer, the roof will not fail as it did from Katrina (so they say)

Robbie, you hit on the practical problem encountered, "and you can measure the radius R so you can work it out!". Describe the tools and methods you would expect to use to measure the outside diameter of the deck of the Super Dome.

Posted By ChuckDeaton on 23 Aug 2010 09:25 AM
Robbie, you hit on the practical problem encountered, "and you can measure the radius R so you can work it out!". Describe the tools and methods you would expect to use to measure the outside diameter of the deck of the Super Dome.

Posted By ddreisbach on 24 Aug 2010 04:11 PM

If I needed to know the roof area of a domed stadium, the first place to look would be the original construction documents.  Why measure something that's already been measured?

 

If drawings aren't available, I've measured some very large rectangular buildings by measuring the size of one bay and multiplying by the number of bays.  You just have to watch for the occasional short bay.  How that might apply to a domed roof depends on how the roof is constructed. 

 

Previous replies suggest treating the roof as a portion of a sphere.  That should be a good approximation even if the roof isn't actually spherical.  As noted, the most difficult part of that method is determining the radius of the sphere. 

 

If you ran a tape (a very long tape) from the eave to the peak and assumed the roof is a circle with that as the radius, you'd have a fair approximation with some overage depending on how flat the roof is.  The flatter the roof the closer it would be.  Now, if you also had the eave length you could cut the roof up into wedges (triangles), calculate the area of each triangle and add them up.  The more triangles the closer the approximation, so I'd have hundreds of triangles. 

Since it's been seven years since I measured and calculated the Hampton Coliseum dome in Hampton, VA, I don't remember all the details of how I calculated it. I do remember obtaining the radius from the interior floor and then calculating the circumference of a hemisphere. How I obtained the proportion of a sphere represented by the dome I do not remember. It involved some internet searching. And the dome was relatively flat. A silo roof is more likely to be an actual hemisphere. Then there were all these jutting peaks (double triangles) around the outside of the rim of the dome. Had I known of Google Earth at the time, the easiest way to get the radius would have been to use the measuring tool in google earth to get the diameter and divide by two.
Another interesting roof to measure on the same claim for the city of Hampton was the roof of the Langley Air Force Base Museum. This roof was composed of hundreds of intersecting steel of heavy guage aluminum triangles in the form of a stylized dome. All the triangles were equilateral and fit together at angles such that they formed multiple peaks. Even a fraction of an inch miscalculation in measuring the triangle would be multiplied hundreds of times over when applied to the entire roof. No damage to the steel roof so ultimately I did not have to accurately calculate it. Counting the triangles would have been the most difficult part.
You can google earth or google map these two building at 1000 Coliseum Drive and 413 West Mercury Boulevard, both in Hampton, VA. I feel that I was priveleged, as part of my profession, to have the opportunity to walk both of these roofs.

BTW, Chuck,

I measure the radius of the supedome at approximately 359 feet using google earth.

There are bound to be plans and specifications of the Superdome, and other similar structures, sitting in an architect's office, or a general contractors office somewhere, which would give the adjuster/contractor the necessary measurements, specifications, material types, fastener types, etc, that would allow the building/roof to be re-built to the original specs. I would find those plans and go from there.

Posted By Joe on 28 Aug 2010 11:49 PM
There are bound to be plans and specifications of the Superdome, and other similar structures, sitting in an architect's office, or a general contractors office somewhere, which would give the adjuster/contractor the necessary measurements, specifications, material types, fastener types, etc, that would allow the building/roof to be re-built to the original specs. I would find those plans and go from there.

The under lying question is, if your money is on the line, what level of expertise would you want handling the big money claims. Would you want an adjuster that relied solely on the blueprints and/or the roofers documents or would you expect that your representative, the adjuster, would make independent measurements, images and calculations of the roof area, just as though it was a much smaller residential roof.

Best to work out procedures, a method, in theory, in advance, than to decide, on the fly, how to proceed.

Chuck,

On a very large commercial structure, I believe the smart guy would use the blueprints and engineering drawings. The adjuster is more prone to make a mistake than the actual plans of the structure.

Just my thoughts

See, that is why we love the United States so much. You can be "smart" and copy somebody else's work and I wouldn't be caught dead copying. There is no question that I am going to climb the roof, make lots of images, measure and calculate and then compare to the blueprints and drawings. We might have to reconcile our differences, but I am going to have a professional, independent opinion. That is what I get paid for.