Sep 11  | CTBUH Journal

9/11 Ten Years On

By Peter A. Weismantle FAIA, RIBA

Representatives of Donald Trump arrived at the offices of Skidmore, Owings & Merrill in Chicago on a beautiful late summer morning. They had flown in from New York to kick off the design of a new supertall, mixed-use project located on the Chicago River, just off of Michigan Avenue. The project, Trump International Hotel & Tower, was discussed in terms of superlatives. Not only would it be the grandest project undertaken by the Donald, but it would be the tallest. As a matter of fact, Trump International was to be the tallest building not only in the city of the Sears (now Willis) Tower but, the tallest in the world.

As it happened, the Trump Team’s flight brought them into Chicago early on the morning of September 11, 2001. As events of that morning unfolded, it became obvious that the world had changed. It was not hard to imagine that the era of tall buildings may have ended.

What have been the main debates following the events?
Immediately following the events, there was a lot of soul-searching and wondering what went wrong. Since that time, many lessons learned about what was fundamentally a military/terroristic attack. From that standpoint, we have recognized that the prevention of another similar tragedy involves more than “hardening” the building. Common-sense approaches to security and surveillance are the first steps, and these have been followed by the application of “enhancements” to the physical structure and building systems.

Has there been a change in the perception of tall buildings?
No one in the U.S. who was near a TV on that day will ever look at a tall building without having the images of the events of 9/11 in the back of his or her mind. Having said that, the reasons behind building tall are still as valid as ever. The increasing urbanization of the world, limited land area and high land cost, the desire for views, the prestige, the economic incentive, the value creation of a tall building and the ego behind creating a landmark are especially compelling in the rapidly developing areas of the world. Tall buildings and a dramatic skyline are still the most important self-images that cities around the world want to project.

Has there been a code change or other fundamental change in our industry?
The US model codes, which traditionally assumed that the most critical emergency event would be a fire of a certain magnitude in a single location, have now recognized other scenarios, with specific emphasis on enhancing the evacuation provisions in tall buildings. Many well-intentioned changes to the US model building codes were vigorously debated and several items ultimately adopted, primarily due to the diligence of non-professional, but intimately interested, parties. The requirement to provide an additional exit stair beyond the minimum two or alternate application of evacuation elevator provisions is probably the best known. Other areas that have been addressed by the codes include, but are not limited to, improving fire service access, establishing more stringent standards against local and/or global structural failure, better awareness and monitoring of emergency events, redundancy to certain critical systems and requirements for improved evacuation management.

What are the most important lessons our industry has learned?
Even with the new code provisions, designers of every supertall are now going beyond code and proposing enhancements to certain critical aspects of the building. Most proposals have to do with occupant evacuation, especially by the provision of areas of refuge along the egress path. Many others cover the building fire protection system, emergency power provisions, communications system and alarm system.

Has the event reduced in significance over the past ten years?
As an architect who is keenly interested in tall buildings and practices internationally, I have seen the effects of those events both close to home and in far-flung corners of the world. I would say however that the magnitude and impact of 9/11 has proven to be in roughly inverse proportion to the distance from Manhattan and time since the event. That is not to say that changes effecting projects on the other side to the world have not occurred. Rather, after the emotions of the event subsided, a more researched and rational view has arisen.

Getting back to the story of Trump International Hotel and Tower, after about one year of inactivity the Trump team came back to Chicago to re-start the project. The fundamental factors and market forces behind the project had not changed. The project proceeded, but in a somewhat more modest fashion. Instead of challenging for the title of tallest building in the world, it settled for being the second tallest in Chicago. When completed in 2009, Trump Tower was the sixth tallest in the world.
Even more telling about the time since the events of 9/11 is this: In the less than two years since Trump Tower was opened, three taller buildings, all outside the US, have been completed, pushing Trump down to number ten.