Ted's ramblings have been answered by real scientists. A quick overview can be found here.
Nice pictures of static suspension bridges supported by steel cables... irrelevant to the discussion. A cantilevered bridge would be more apropos but even there the structure of the sauropod neck is not very close to a cantilever bridge.
I especially liked this comment by the "real scientist" at your link:
I made some experiments to find out whether the idea was feasible. [...] the mass of the real head and neck would have been 1,340*10 = 13,400 newtons. [...]
First of all, he did no "experiments;" he did some calculations. Secondly, a Newton is a unit of force over distance and time not mass... it acts on a mass. A Newton is the force neccesary to accelerate a 1 Kg mass to 1 meter per second2. Perhaps the real meaning got lost in the ellipses? Did it originally say "The force necesssary to support ..."? That I can agree with.
More from your link:
Even considering the seismosaur, which very much resembles a 1.6 times scaled up diplodocus, and therefore (if isometrically scaled) would have had 1.6 times the load per area in its nuchal ligament,
This seems to be nonsense to me... how does isometrically scaling up the beast by 1.6 times increase the load per area of its nuchal ligament by only 1.6 times??? The mass at the other end of the nuchal ligament is 4.1 times greater... while the ligament is only 2.56 greater in area. There is a factual disconnect here. I have a serious problem with the claim that the Seismosaurus at 1.6 times larger than Diplodocus with essentially similar neck structure will have only 1.6 times more stress on its neck. This is ignoring, again, the Square Cube Law and assuming that scaling of mass is linear. It isn't. Any engineer can tell you that.
Let's go over it again... the cross section of the neck muscles and ligaments, and therefore the strength of the neck muscles and ligaments, increases by the SQUARE of the multiplier... 1.62 or 2.56... while the MASS or WEIGHT of the neck increases by the CUBE of the multiplier... 1.63 or 4.1. The strength of the Seismosaurus' neck would be 2.56 times stronger than the neck of the Diplodocus, but that increase strength would have to support and lift and move a mass that is 4.1 times as heavy.
Let's see what the real scientist does with this his data for the Diplodocus...
...the weight acts 2.2 meters from the joint and the the ligament tension have been needed to balance the weight is 2.2 * 13,400/0.42 = 70,000 newtons (7 tons force). The third force shown in the diagram [seen here] is the force in the joint itself, where one centrum presses on the next.The calculated tension may seem enormous, but the ligament was very thick. If it was as thick as in the diagram, its cross sectional area was 40,000 square millimeters and the stress in it, for a force of 70,000 newtons, would be 1.8 newtons per square millimeter. This is more than the stress in the ligamentum nuchae of a deer with its head down (about 0.6 newtons per square millimeter), and would be enough, or nearly enough, to break ligamentum nuchae.
All that was calculated for the Diplodocus... Why didn't he do it for the Seismosaur??? He just made some ex cathedra assertions about how everything is OK with Seismasaurs and even bigger beasties... without proving it. Since he didn't, let's do it for him, and scale up the data to represent the Seismosaurus...
2.2 meters from the joint becomes 1.6 x 2.2 m = ~3.5 meters from the joint.
Taking his low-ball 1,340 Kg mass for the Diplodocus head and neck (heck, he might be right...) then the 1.6x scaled Seismosaurus' neck and head would weigh in at 5,494 Kg. It would take 54,940 Newtons of force just to support that larger neck and head against a 1G (10M/s2) gravity field. Let's plug that data into the calculation for the force on the nuchal ligament: 3.5 * 54,900N/0.42 = 457,500 Newtons! That's six and a half TIMES more force to support the neck and head with the nuchal ligament that worked OK for the Diplodocus!
The Diplodocus' 40,000 mm2 nuchal ligament is also scaled upward by 1.62 or 2.56. Is it enough to keep the Seismosaurus' head off the ground? Let's see.
40,000 mm2 * 2.56 = 102,400 mm2. If we now divide the force into the area of the Seismosaurus' scaled up ligament, we find that the 1.6 Newton per square millimeter of the diplodocus' nuchal ligament, which was "enough, or nearly enough" to break it, is now almost 4.5 Newtons per square millimeter... well beyond the force needed to break the Seismosaurus' Nuchal Ligament!
I wonder if that is the reason he didn't do the calculations on the Seismosaurus?