A New Design for a
New World Trade Center

he fundamental principles of skyscrapers constrain what designs might be employed. Before showing my basic design let's see what they are.

The Principle of Square

In a smaller buildings with ample funding this principle does not constrain much. It is an economic constraint in small structures but a practical constraint as well in extremely tall buildings. Functionally, we move around and fit into right angles better. We memorize maps and patterns better when laid out in grids.

All very tall buildings are severely constrained by this principle. To make the most economic use of available space we simply have to make boxes ... and boxes on top of boxes. You might see a cylindrical building of 50 stories but up in the 100s ... forget it. We need those corners. Round rooms and pie shaped rooms don't make it.

The Petronas Towers are cylinders but they paid a price for it. They wanted something primarily to show off Islamic architecture in the skyscraper style. I regard them as ugly and ... they ought properly to be blown up anyway in retaliation for ........ ah ... fuck 'em all.

The Sears Tower uses available space properly. Where no box is set atop a box, we get some shaping. Imagine stacking different size cylinders in the manner of the Sears "blocks". Lots of wasted space would exist in the interstices.

The Principle of Verticality

The higher you go, the less you can use an Effiel Tower type design ... broad at the base and "curved" on the sides. If a big building was made in this style we would have to endure odd shaped rooms on the exterior (the ones which would have the windows). Interior rooms could still be the cheap and functional cubes but not on the sides. Also, if you "flare out" toward the bottom, you use up your limited real estate which is quite costly in most city centers.

Then there is the elevator problem. These things only go straight up and straight down. They can't follow "slopes" without a great deal of unnecessary expenditure as in the Gateway Arch in St.Louis. I once tried to design a sloped elevator with the idea that it would dead drop in the express mode right out to the parking lot. You would go from 150 stories up to the parking lot in about 10 seconds. A drop on the "Splashdown" at Six Flags Over Texas cured me of that idea (way to many G's for the average person ... me).

Straight up ... straight down ... at a fast but endurable speed.

The Principle of Fire

This is the big horror show in tall buildings. None are made correctly in my estimation. All take the prophillactic approach. That is, they solve the problem of fire with absolute prevention. True, they apply a palliative balm in the form of sprinkler systems but they won't work in huge fires as we have just seen and we all see people jumping from tall buildings in fires anyway (at least on the Spanish channels - the American channels consider that toooooo disturbing for their "impressionable" viewers).

I'll apply the "real" palliative ... one that firemen everywhere would appreciate.

The Principle of Collapse

The only skyscraper to collapse utterly (that I know of) has been the World Trade Center. This is a small problem unless the destruction is deliberate. Collapses from other forces can be foreseen and counter-measures installed, e.g. hurricane, earthquake.

The design of the WTC did exactly what its engineers said it would do ... it withstood the impact of a jetliner without collapsing. Unfortunately, in combination with the fire, there was just too much damage. Preventing total catastrophic collapse costs money. One plans for what seem to be "real" possibilities. Planning for a willful jetliner assault was not in the "likely" category.

WTC Exoskeleton - 6kb The weight of the towers was entirely on the outer support beams. These formed an "exoskeleton". Each vertical beam was about a yard apart and each floor was supported by a 33 inch deep trusses running from one side of the exoskeleton to the other. The elevators were supported by separate vertical beams in the center of the structure. These beams did not carry any of the buildings weight ... just the elevator system.

Addendum 10-20-01:
I've since read elsewhere that the central columns did in fact carry much of the load of the building. I don't know who has got it right. And I've seen an "expert" state that if the building had been hit lower, it might have fallen over like a tree (which is physically impossible for such a heavy mass so lightly reinforced against lateral forces). They can only tip slightly before the bottom disintegrates and the whole thing collapses straight down, vis. to fall over, the side and center line of the building would have to move UP a little and the building would then be standing on its edge ... sure ... in your dreams (literally). Plus there's a little thing about angular momentum and long "sticks" that we don't have to get into but you see a chimney demolition and as it keels over it breaks in half.

One can see why the building held up for so long. When the jet entered the tower, it took out a side and the remaining three sides, in combination with the trusses, held up the floors. If the jets had hit the corners and taken a significant number of external beams, I think the tower would have fallen immediately. It's a good thing these people are so primitive else they wouldn't have gone for the "flush, right angle" shot and more lives would have been lost.

The Principle of Rapid Egress

Well, here is the main bone to pick. People must be able to get out of the building PDQ. It's OK to take a little longer to get in ... but they gotta' get out real fast if necessary.

One thing that ought to be done right away is to automatically begin evacuating large buildings as soon as some major event happens in the vicinity of the building. I don't mean necessarily in the building itself. If the small building next door catches serious fire ... the big building must begin evacuating preemptively. None of this "Go back to your offices, the situation is under control.". Because of the time needed to fully evacuate, those in very large buildings should expect a lot of practice getting out.

But the best means of getting out fast is to take the elevators OUT of the building.

My Design

New Design for WTC - 5kb What I've done is to keep the fundamental design but I've removed the main express elevators to "outrigger" status. These are elevator buildings connected to the main towers by an external concourse at about every fifth floor. Part of the concourse is covered (for weather reasons) and part uncovered so that smokeless egress is possible to the main elevators. In the event of fire you walk up or down a maximum of 5 floors to a concourse and go to the elevator buildings or to the other tower. There are stairwells on the elevator buildings as well as stairwells in the towers themselves. There are many independent ways of egress.

newwtc2.gif - 4kb In the tower, I've placed the hall by the outside wall, sacrificing direct views of the city for safety (hopefully no one need jump from a window since they are in the hall and there is a stairwell at every corner (except the concourse level where there are only three stairwells shown).

If one building should fall, it drops out of the concourse levels without taking them with it. The towers are connected to the elevator buildings against lateral forces but not vertical forces ... as in a "slot". They can't move left or right but if they fall, they just slip down and out of the moorings.

My design needs aesthetic improvement of course but that's not a big problem for today's architects. They can make anything look good. My concern is just with the fundamentals of such structures.

I know that firemen would like to be able to get to the fire ... fast ... without having to climb stairs. I think this is basically the right way to go in general.

What do you say?

Addendum 10/18/01:
I've given up on the idea of having elevator outriggers that would stay up when one building collapses. The forces at the base of such a huge collapsing building are such that no structure nearby could be expected to remain standing. The cost of reinforcing it would be too great. In lieu of this I've gone to a much more rapid egress mode.

See the next installment ... > > >..."The Dead Drop"