A Place of Sense

Over the last decade, one new seismic design technology has been rapidly adopted in the US.  The Buckling Restrained Braced Frame (BRBF) system is one of those rare innovations that radically improves the ability of structures to resist earthquakes, while at the same time is completely backwards compatible with previous technology.  (See MSC articles from Sabelli & Lopez and Robinson for more information)

The ability of this system to resist earthquakes comes from a dramatically simple idea:  decouple bending and compression.  To show how easy this concept is, let us review how the inventor came up with it.  An engineer, Benne Narasimhamurthy Sridhara from Bangalore, wanted to get more strength out of his braces (see my earlier post on braces for more info).  He created a simple physical model using a small rod and a plastic pipe.  He put the rod inside of the pipe and applied force on each end of the rod.  Instead of the rod buckling out of shape and failing, the pipe held it in place.  Brilliant!

Because the pipe (or sleeve) is not participating in resisting compression, it is “decoupled” from the rod.  This means that the rod is continuously braced and will develop full material capacity.  The implications of this small change are huge.  It allows engineers to specify braces that:

1. Will fit easily into existing designs, allowing retrofits and new construction
2. Will act similarly in tension and compression, eliminating the need for paired braces at every location
3. Help dissipate destructive seismic energy by steel yielding (like a car’s crumple zone)
4. Remain stiff and strong even after the initial event
5. Cost much less than comparable technologies

It’s a really awesome invention (patent info).  The rapid uptake of this technology shows how important it is to the future of seismic resistant buildings.  A recent article from India uncovered a little more of the interesting story behind its creation.  It makes me wonder what structural engineering inventions will be discovered in the coming years. It goes to show that the simplest solutions are sometimes the best, and they are hiding in plain sight.

This technology can be applied in even more interesting applications as engineers grow familiar with its use.  I am anxiously awaiting the first use of this in a bridge application.  Congratulations to Mr. Sridhara for figuring out how to do more with less.

Of special note to anyone who been working with facade connections in steel buildings is two documents from AISC. The first is their “Design Guide 22: Facade Attachments to Steel-Framed Buildings” and the other is a recent article in MSC: “Steel Framing & Building Envelopes”.

The Design Guide 22 is free to AISC members (~$60 otherwise) and is probably one of their best. It has a great amount of information about spandrel beams, connections, facade issues, and even backs it up with some FEA work.

The MSC article “Steel Framing & Building Envelopes” by James A. D’Aloisio, PE, SECB, LEED AP should be considered as an addendum to the design guide, specifically dealing with the issues of thermal bridging and building envelope thermal performance. Basically, if an engineer applies the suggestions from DG22 without considering thermal bridging effects, then the R-value of the wall assembly could be halved (!).

D’Aloisio’s has published some interesting details he is experimenting with. His recommendation is to always use a thermal break, and he shows a Fiberglass-Reinforced Plastic shim plate to isolate steel lintels and hangers from the exterior environment. As he points out, many LEED NC buildings are not meeting their expected performance levels. The reason may be because of conventional details used by the construction industry.

On January 12, a 7.0 seismic event centered close to Haiti’s capital, Port Au Prince, caused massive devastation. The collapsed structures and untreated injuries may cause up to 200,000 deaths.

The past few days have been a nightmare for people on the ground. The EQ knocked out much of the country’s fragile infrastructure. Haiti was a nation that was already in need of major assistance, having experienced 4 full-scale hurricanes last year and decades of political instability. A 7.0 EQ is absolutely a major event, and coming so close on the heels of last years problems is just horrible.

To put it in perspective, California’s Northridge EQ in 1994 was one of the USA’s worst disasters causing $20B worth of damage and it only registered a 6.7 magnitude. Haiti’s EQ caused strong lateral movements, and judging from the USGS map the accelerations were almost as strong as gravity. This is the structural equivalent of taking a building and turning it on its side, again and again.

Very few buildings can survive this type of movement undamaged. Haiti was even worse off because of their building materials. Many of the buildings were built from unreinforced, hand-mixed concrete blends. The images on TV show the results well enough, the TV crews probably don’t even need to look very hard to find examples.

As a structural engineer, it is always difficult to see the problems caused by improper construction and to know that many of the problems could have been avoided. Of course once an earthquake hits, engineers are powerless.

Using a list of simple rules engineers can easily design buildings that, for the most part, will preserve life safety. Designers of critical structures such as police buildings, hospitals, and bridges know in advance that they must make sure the structure will be operational in even the worst of events. The hospitals, bridges, and government buildings in Haiti appear to be worse off than other buildings, even.

So why do events like this happen? Engineers understand earthquakes, but that is only one step in the chain of safe construction. Simply stated, it is a political failure. Building codes are rolled back by politicians, with the excuse that they are too expensive. Contractors pay bribes to inspectors to pass suspect materials and shoddy workmanship. Engineers are asked to turn a blind eye in the name of patriotism. The problem with this “build quickly” theory is that the buildings remain and the legacy of poor construction becomes a ticking time bomb.

I am not trying to lay this problem at the feet of Haitians. I doubt many of them knew they were sitting on a fault line. They probably didn’t understand that reinforcing is required in columns for earthquake resistance. The engineering community needs to make a greater effort to encourage seismic resistant buildings in developing nations.

The engineer’s sole weapon against natural disasters is good design. If engineers aren’t proactive in the political realm or if engineers cede their responsibilities, then they will fail in their duty to protect the public welfare.

Anyone interesting in helping the efforts in Haiti should donate to the American Red Cross disaster relief foundation. Engineers wanting to donate specific skills should go to the ASCE Disaster Assistance page.

One of the key concepts in engineering theory is metastable equilibrium. Systems are designed to resist forces, but a large shock can cause catastrophe.

The classic example of this is a marble resting on the dish. The marble can move in any direction but will come back to rest in the middle of the dish – unless it is pushed hard. Then it is given enough energy to seek a new equilibrium position. Maybe the new equilibrium position is inside a larger dish. Maybe it’s on the floor, rolling straight towards a heating vent.

The principle at work here is minimization of potential energy. Every object at every scale seeks to minimize its energy level. It explains the throwing off of photons from excited electrons in a neon light, it explains the shape of water condensate, it governs the flow of hot gas up a chimney, and, unfortunately, it means that our buildings fall down in high winds.

You can never prevent minimization of potential energy because you can’t stop entropy. However, you can slow it down. You can trick systems into finding a local minima, just like the marble was tricked into the middle of the saucer. This is called metastability. The system is not at its preferred state, but a further investment of energy is needed to push it over the edge. Until that energy is provided the system will remain in its metastable state.

This concept is not only useful in structural engineering, it is broadly applicable. For instance, we can use the principles to discuss why sustainability is important. If we look at the ecological system here in the Midwest, we see that everywhere people are constantly altering small aspects of our environment. None of these actions by itself cause much damage. But if we consider the sum total of all of the actions, we realize that a destabilizing force is being applied.

An ecological system is merely metastable. Most people believe that humans can act as responsible stewards of the environment (e.g. recent tuna conservation debate). The current theories of resource management assume that we can study natural systems and determine where the tipping points are. As long as we don’t push nature over the edge then we can optimize our utility of it.

The problem is that balancing nature on the edge means only a small shock will lead to disaster. History is full of civilizations who have learned too late that nature should not be pushed too far. A recent study pointed out that the Nazca civilization may have been decimated by a combination of over-harvesting Huarango trees before a severe El-Nino event. The old forests are now deserts, having suffered a complete ecological collapse in CE500. The people kept pushing that marble towards the edge, never expecting the strong shock that forced it over.

We are now playing the same game on a global scale. We don’t have to think too hard to find the next shock to the system. Climate change is expected to be capped at a 2degC change, but could go higher if politicians don’t find a way forward in Copenhagen (current rate is 6degC – BBC). This rapid climate change could force our ecological systems over the edge and hurtling out of control.

Not only will these changes devastate our natural resources, especially for those areas fenced in by human development, it will cause our carefully cultivated croplands major problems. Imagine trying to curb world hunger and disease when global crop capacity decreases by 30%.

As an engineer, I am familiar with the effects of upsetting metastability. Our industry is always studying disasters and trying to learn from them. Of course, the disasters leave human tragedy in their wake. Society buries its dead. Survivors return to the scene of the tragedy and face a pile of debris that was once the source of their community. Amid all the calls to rebuild, everyone begins to doubt if what was lost could ever be replaced. We must remember that certain things can never be replaced.

It’s a tough economy out there. Graduate engineers are in a better position than most people when looking for a job, but getting that first job is a hard task for anyone right now. But, even with all of the problems facing young engineers right now, they still have some options if they can’t find their ideal position.

There are a few employers of graduate engineers that are always hiring, including:

• Work for a related industry or employer
• Graduate School
• Military Service
• Development and charitable organizations
• Go live at home and help the family

Other Work
The first option makes an explicit assumption that not everyone will get their #1 choice for a job. This is not really a problem, though. There are still plenty of jobs available in the market, but some graduates will have to expand their concept of engineering.

Many firms that do not receive national press, have poor presence on the internet, and do not recruit at schools actually do very important engineering work. They are more difficult to find, but they can provide a new graduate with their important first job.

Another strategy is to apply for jobs in a related industry or employer. There are many companies that make products, components, or sell services directly to engineering firms. These companies prefer hiring engineers because they understand clients better. Just remember, becoming an engineer is a long process and engineering experience can come in many different forms in the first few years of employment.

Graduate School
Personally, I graduated during a recessionary period after the Dot.Com market fiasco. This was also a time when fewer entry positions were open. I was totally unprepared for this event and didn’t even know what part of the country I wanted to live in after graduation, and I certainly didn’t know where to apply for jobs.

Eventually I decided that graduate school was a good option for me. This decision must me made early in the final year of school, or else it is unlikely that all of the paperwork and testing can be completed on time. Graduate fellowship positions are extremely competitive when the job market is at a low, but sometimes it is worth the additional debt to continue classes anyways. The tuition costs can be paid off later with a stronger resume and a better job.

Military Service
Military service is also an option. I know several friends and classmates who chose to join the military after graduation instead of looking for a job. It’s a hard decision for anyone to make because of the risks and consequences, but engineers can be a valuable asset in the military.

Experience in the military is a great way for graduate engineers to differentiate themselves when applying for a job. Here in the US, most employers are cognizant that honorably discharged soldiers make some of the best employees and get great training from Uncle Sam. On the other hand, military service is incredibly hard even during times of peace, so the decision should not be made lightly.

Development Organizations
Another option beyond military service is finding a position with peacemaking and development organizations. The Peace Corp, Americorp, Teach America, and similar programs can provide a great way to give back to the global community with engineering skills. These programs also carry risk and consequences, so they must be carefully considered before any decision is made.

Moving Back Home
One final option for many graduates is to return home and live with their family. This is a very common action in times of economic hardship. Single family homes typically have an elastic capacity to absorb grown children, pets, married couples and their children. All of the empty apartments, rental houses, and foreclosed homes are good evidence of this happening. The last time this happened on such a large scale was the Great Depression, which forced many families back together.

Moving back home was also part of my strategy for graduate school. I was fortunate enough to grow up down the road from a state engineering school that accepted me for grad school. Not everyone will fit into that circumstance, but many people have families, relatives, or close family friends near engineering colleges.

Most people are often more than willing to have a long-term guest in their house to help out friends and family. The lower costs can make a big difference, as my stipend would have put me well below the poverty line but my free rent gave me the opportunity to eat things other than Ramen.

The Big Picture
Whatever choices graduate engineers make, there are a few key points to remember. The first is that most graduates should find jobs that will support their application to become a Professional Engineer (PE). This means that the job should be managed by an already licensed PE or should be academic in nature. The NCEES licensure page has additional information. Graduate engineers should *never* assume that their job is applicable unless specifically noted.

Also, the first few years after graduation are a time of continuing education. Indeed, this is true for the entire career of most engineers. Engineers must make every attempt to continue learning, studying, and asking questions. As noted in the beginning, not every engineer will find their #1 job waiting for them upon graduation. This is not the time to despair and abandon one’s goals. Instead, work hard to develop into the type of engineer that will qualify for one’s ideal job.

Whatever the future may bring, graduate engineers must take the initiative to learn from coworkers, stay active in the community, join professional groups, read books, play softball and sports whenever possible, and maybe even tackle some collaborative design challenges with other engineers and architects.

As a structural engineer, I get a lot of questions regarding the collapse of the World Trade Center buildings. People want to know if there is any validity to the claims of demolition by explosives. As with anything in life, there are no certainties, but I find the claims of conspiracy to be very unlikely. Consult the NIST website on WTC collapse (and final report here) if you want to see the official accepted course of events based on thousands of hours of research and analysis by disinterested scientists and engineers. For other opinions, consult Structure Magazine‘s archives and search for WTC articles (like WTC 7 and WTC 5).

Just as with the moon landing conspiracy and the Obama is an alien conspiracy theory, providing evidence to debunk the myths does nothing to dispel the rumors. People believe what they want to believe, despite having the ability to reason for themselves. Thus, I don’t think any logical argument or presentation of evidence will change anyone’s minds, so I am not going to present one here. For a good, logical refute of the arguments, see Rolling Stone’s “The Low Post.”

However, I do want to discuss the ethical implications of these beliefs among the structural engineering and architectural community. If someone has not yet decided what happened on any of these occasions, just be aware that spreading conspiracy theories will have a negative impact on one’s career. Basically people will think they are crazy or stupid, neither of which are positive characteristics for an engineer.

An important ethical implication that must also be considered is that the many engineers that have been closely involved with the original design and investigations are essentially being accused of mass murder. Or covering up for mass murderers. These engineers have absolutely nothing other than the highest respect for human life, throwing them into the same category as history’s greatest villains will not win any points.

In fact, a recent debacle at the White House showed that indicating support for these ideas can create professional problems many years down the road. The Green Jobs adviser for the Obama Administration was forced out because of support for 9/11 conspiracy theory. This is a good lesson for all of us to learn. Extraordinary claims require extraordinary evidence.

The fast growing economies of Brazil, Russia, India, and China (BRIC) need complex infrastructure solutions and they need them fast. There is a great opportunity for engineers who know how to meet those needs. Considering that these countries are the next dominant world powers based on current global development trends, we had better begin brushing up on our Portuguese, Russian, Mandarin/Cantonese, and Hindi.

A lot of engineers in the US feel threatened by overseas competition. I don’t. I feel that our ethical obligations to “build their professional reputation on the merit of their services and shall not compete unfairly with others” mean that we shouldn’t put up unfair barriers to outside competition. I encourage honest competition, if we can lower prices and maintain safe structures then everyone benefits. Competition for important jobs always inspires creativity.

Let’s not try to hold back our engineering friends from the BRIC countries, I say we welcome them and start working together to solve humanity’s great problems. But seriously, I expect great things to come out of these countries in the next few decades. Russia and Brazil are scheduled to host upcoming Olympic games, China just hosted one itself, and India has been widely acknowledged as one of the new world powers.

These countries are still working through some difficult issues like guarantees of democracy, freedom of the press, and human rights issues, but their own ascension to the world geopolitical stage is not unlike the US or similar countries. It took the US many many years before we met our goals of a society based on equal rights (still an ongoing process). It’s important to look at where these countries will be in 30 years, not necessarily where they are right now.

A caveat remains, however. As the people living there acquire more wealth and seek the luxuries that the US and Europe currently enjoy, then the efforts at preventing climate change could be thrown into disarray. It is important that we get this right, because the BRIC countries represent 40% of the human population! The way to do this correctly is for the US and developed countries to start making serious policies regarding climate change. The time is right for developed countries to save the world, and it is our responsibility because we have been the cause of most of its problems through our centuries of industrial experimentation.

BRIC presents us an opportunity to start a meaningful dialogue about the future of the human condition. It is not just an opportunity to open their markets and sell them gasoline cars, it is an opportunity to raise the quality of life of every person on the planet in a meaningful, and sustainable, way. We have the capability to meet the needs of all people while still preserving a viable future for our later generations.

The BRIC economies have shown off the human ability for innovation. From the bus transit system of Curitiba, Brazil to the speeding bullet trains of China, these countries have no fear of modernizing their transportation systems. Of course, the traditional neighborhoods in these countries are some of the most efficient and low-impact styles of living, so we need to encourage BRIC to retain them. Let’s not export our worst product – suburban sprawl. What we need are ways of accommodating the wants and desires of the middle class with the realities of a world under threat of climate change.

In this sense, the Western countries can continue to develop green designs that will deliver safety under environmental hazards, comfortable climate controls, and continued transit solutions. Working together, BRIC and the US/Europe can accomplish more than working alone. In support of these goals, I am including translation tools for this website. I may speak only one language, but I think if we listen carefully we find ways to understand each other.

(UM LUGAR DO SENTIDO) Portuguese

(भावना की जगह) Hindi

(MECTO SENSE) Russian

(地方的感觉) Chinese

What is a Structural Engineer?
An engineer is a person who applies principles of math and science to solve problems. A structural engineer focuses on built objects that resist loads. Structural engineers typically work in building construction industry, but highway departments, space agencies, airframers, and the petroleum industry also employ structural engineers.

An engineer typically acquires a college degree showing that he or she has mastered the basic knowledge requirements. (see earlier post on engineering education) At this point, the graduate engineer enters the industry as an engineer-in-training or engineering intern and must work as an apprentice to another fully qualified engineer. After several years of gathering experience and passing a professional exam, the engineer is allowed to practice engineering as a licensed professional.

An engineer is obligated to continue learning throughout their career. An engineer’s academic degree does not qualify them as an engineer, it only verifies their willingness and ability to learn. The skills that help an engineer succeed in the real world are learned after their first degree is earned.

What Does a Structural Engineer Do?
The primary responsibility of a structural engineer is to ensure equilibrium between a load and resistance. Engineers quantify loads and resistances using principles of physics or from collected experience (tabulated and published in building codes). Failure occurs when loads overcome resistance. Because knowledge about loads and resistance is never perfect, structural engineers must include additional strength in their designs to account for this uncertainty.

Preventing failure of structural systems is the main goal for a structural engineer, but there are many other constraints that also must be considered such as:

• safety / reliability
• serviceability (limit deflection and drift)
• cost
• constructability
• communicability of design
• interaction of structure with other systems
• aesthetics

Balancing all of the criteria requires knowledge, design talent, a toolbox full of analysis tools, and a lot of experience. While most engineers will arrive at similar conclusions when faced with the same problem, each will have their own unique path and put their own “fingerprint” on the project. Every engineer will view the problem through their own set of experiences and perceived responsibilities.

Our final product is a set of plans communicating our design

How Are Structural Engineers Different From Architects?
Simply stated, structural engineers are not architects. While much of the basic knowledge requirements are similar, the role that each professional plays during a project is very different. The architect is the “master-builder” who is responsible for the overall project. Architects are the single point of contact for the client or property owner. They are responsible for assembling a design team that will design the building. Architects often employ outside consultants or specialists, but sometimes architectural firms will have engineers on staff.

The architect devises the shape, size, use, and requirements of the building. In other words, the architect presents the “problem” to the engineer. This is where technical education helps an architect, because it is very helpful to present a problem that has a solution. If the architect is designing something unconventional, it is helpful to involve an engineer early in the process so that the design need not drastically change for the sake of structural issues.

Some professionals are both architects and engineers, taking on both roles. Santiago Calatrava is a good example. His designs are notable for being structurally and visually integrated. His technical background is a great advantage in his work, as he uses structural constraints as a source of inspiration.

One of the greatest differences between an engineer and an architect is how much time they spend on design versus analysis. An engineer takes years of college courses and spends a great amount of time learning analytical methods. In contrast, an architect student will focus on learning design. Little time in spent on quantifying loads and structural systems. Architects and engineers both spend considerable time in each others’ worlds, but usually they do not feel comfortable enough to do the others’ job. Some states allow engineers to sign architectural drawings (and vise versa), but this is not a general rule.

Computers are the engine of modern analysis and design

What Does a Typical Day of Work Involve for a Structural Engineer?
I spend most of my time at work doing structural analysis and design. This is just like they teach in school. The first step is to fully describe the problem, including all known information and preferably including a graphical representation. Careful notes must be kept because as a professional engineer there is a chance of litigation or sometimes you get sick and someone else needs to step in to finish a project. In any case, documentation and organization are very important skills to develop.

project calculations, code references, office papers, and client contact information

Analysis and design, design and analysis. It’s an iterative process. It is made more iterative because projects are always changing. Sometimes part of the project will be getting built while some of it has not even been designed yet. Managing this web of uncertainty requires a goal of adequacy, not perfection. Striving for excellence is different than striving for perfection.

My office does not specialize in any particular type of structure, so projects can range from pipeline crossings and roadway bridges to large office buildings. We design structural systems in concrete, steel, wood, masonry, or whatever material our clients request.

A typical day in the office is not much different for a structural engineer as it is for any office worker. The majority of the day might be spent on “real” work, that is work that involves design & analysis calculations, but the realities of operating a business mean that much of the time engineers are busy with other tasks. That includes organizational inefficiencies just like you see in Dilbert or The Office. But it also includes an inter-office camaraderie that is fun, and in the end the most difficult tasks do provide a sense of accomplishment.

Some of the other important things that happen in the office involve networking or marketing services to potential clients, maintaining professional licensure, and professional development. It’s all part of the business, and most of it is enjoyable if you have the right support from your organization.

Trying to find your vocation in a crowded world is a difficult task. I feel very comfortable as an engineer, and I am glad I found something that fits so well. Unfortunately, I don’t think many children understand what an engineer does, only what we help create. Explaining risk and consequences in the construction industry is advanced learning, well beyond stacking wooden blocks.

It takes a lot of work and schooling to become an engineer. You don’t get to engineer anything until the very end of the educational process. A person cannot just start taking engineering courses in elementary school. It’s a long process, and you must pay your dues.

Realistically speaking, the classes that “prepared” me for life as a professional engineer were my least favorite. Differential Equations, E&M Physics, computer programming, linear algebra, etc. These were courses I tolerated, but they held absolutely no appeal to me. I was not attracted to engineering because of the abstract mathematical principles involved. Far from it, I hated the homework that my professors handed out, assuming it was some arcane form of hazing.

Looking back, I can see how important those courses were in my development. I might still be an engineer without them, but an incomplete engineer with no chance of achieving any level of mastery. Now that I can honestly call myself a professional engineer, however, I readily call on these tools that I worked so hard to acquire. They are much more important than the fancy structural analysis programs that produce formatted reports and colorful graphs. The reason is simply that advanced mathematical knowledge gives one a better understanding of the physical world, and without that understanding one will never be able to innovate.

Many young engineers concentrate on learning skills they consider to be important in the industry. Finite elements, sustainable design, and historic preservation have been especially popular in the past few decades. Just as in previous decades it might have been statistical reduction, soap-film analogies, or proprietary truss designs. Remember to concentrate on the basics, remember to do your homework in mechanics class. You will never be forced to admit you have spent your life learning a skill the world no longer needs.

Sometimes I am asked what importance a Master of Science degree has for a young engineer. The answer is not clear. Just as with any aspect of life, you get out of it what you put in. If you are interested in a 1-year classroom focused degree (Master of Engineering or Master of Science Non-Thesis) and you go into it seeking a continuation of your undergraduate classes, then that is not a problem. You will be well rewarded and will see no loss of time required to get your PE license in most jurisdictions. Soon enough, graduate school experience will be required to even apply for a PE license.

On the other hand, a true Master of Science degree requires a substantial amount of time to devote to a thesis. A thesis is nothing more than your opinion on a difficult to solve problem. It is a great opportunity to wet your feet in the process of creating engineering knowledge. A PhD program is more like a headfirst dive off the top board (speaking merely as a spectator), so a little practice with an MS is probably a good thing.

If you are confused about where to apply for a PhD program (and somewhat for an MS), do not make your decision lightly. School reputation is important in some respects, but nowhere near as important as your ability to find a thesis/dissertation advisor who:

• has funding available for new students
• has a proven track record of graduating his advisees
• works closely with your topics of interest

You will be spending a lot more time with your advisor than anyone else in the school, so that is your most important consideration. Whatever situation you end up in, remember that it is now your own responsibility to ensure your work is completed and you move towards graduation. Graduate school can make you lose your bearings quite easily, so you must maintain a professional attitude and keep your eyes on the prize.

The skyline of downtown Indianapolis

Tall buildings are a source of civic pride. They represent technical ability and economic power. Modern cities are defined by their skyline. Young engineers dream of adding their own touch to the cityscape. Tall building construction occurs in phases, and the most recent phase has probably died with the deepening recession. It may be 5 years or 5 decades before the next tall building trend. Tall building designers are a specialized group and are typically well positioned ahead of the start of the next trend. Unfortunately, this means that most engineers will have more experience with a skyline matrix than any actual famous tall buildings.

Construction of the newest Indianapolis hotel tower

For some reason people blame architects and engineers for the lack of tall buildings in their city. Certainly, architects and engineers have become more comfortable with taller buildings as time has passed, and taller heights are easier to achieve. New structural systems, new materials, and new ways to prevent swaying action has led to consistently taller buildings over time.

Throughout the twentieth century US engineers and architects led the way, but now the world is outperforming the US in terms of tall building construction. In fact, the number of foreign tall buildings built in the past decade is staggering. US construction continues along a slow trend but the rest of the world significantly outpaced the US in speed and total numbers of skyscrapers.

I can honestly say it is not our fault that the US is not building skyscrapers as fast. The design expertise for most of these tall buildings has come from US designers, so there is no doubt that the US is still leading the way in technical design. But there is still a feeling that the US is losing some sort of race to assert itself in the international economy.

In reality architects and engineers in the US have no influence over developers and their decisions to build new skyscrapers. No, the demise of US domination over tall buildings has been due to continued suburbanization. The American Dream has killed our cities.

Local market forces determine the height and size of buildings much more than any conscious design decisions. Iconic towers are even more rare than simple tall buildings, because there is a premium on design and construction for a truly unique building no matter what size it is. Developers are not willing to risk such a huge investment unless there is a clear chance for profit. For an in-depth study on this issue, consult The Economics of Super-Tall Towers (full text PDF available) published by CTBUH.

Basically, there are two considerations for developers:

• How much additional square footage is profitable in the current market?
• How big is my plot of land?

To get the height of their new building, they take the total square footage they want to end up with and divide it by the size of their plot.

Smaller plots are difficult for two reasons. The building must be taller for the same square footage, and the slenderness ratio makes the structural system more expensive. Developers are very happy with smaller buildings. They are less expensive, the elevators take up a much smaller percentage of the floor plate area, and they are not terrorist targets (easy to insure).

Companies are reluctant to sponsor construction of a new building these days. Especially with an on-going recession and plenty of leasable space available at inexpensive rates, very few are willing to risk the wrath of shareholders for the headaches of owning an iconic building.

All of this means that there must be a great, compelling reason to build tall. Here in Indianapolis, people desperately want the skyline to fill out. However, there are so many empty parking lots that developers will require a lot more demand before they are willing to take a risk on the premium costs of tall buildings.

Taking Indianapolis as an example, building more tall buildings may not be in our best interest. First, let us assume there is sufficient demand for more leasable floor space. For a tall building in a downtown so centered around car commuting, each tower must have a large parking garage next to it (or under it). In addition to the space lost to the garage (and any existing buildings that are cleared to build it), the road system must be expanded to accommodate the new commuters. Instead of densifying the downtown area it is now spreading out, losing nearby businesses in order to accommodate transportation of workers.

Basically, tall buildings are most appropriate in a dense, urban environment. If the downtown relies on car commuters, it cannot achieve the density necessary for successful tall buildings. Ignoring this caveat, certain communities have achieved tall building construction in a suburban area, but the buildings are out of context and at their base are nothing more than an attempt to draw attention and proclaim relevance as something they are not.

Anadarko Tower in The Woodlands, Texas

This type of environment is an entirely new invention. Drivers leave from their garage at home and drive directly to their garage at work. The need for roads and garages spaces the buildings apart so far that no infill development occurs. It is not an urban environment, it is a suburban environment with a sense of inadequacy. And I suppose if that is what people want, they can have it. But it is just as authentic as the EIFS clad southwest style grocery store sitting behind the hundred acre parking lot.

In order for a skyscraper to contribute to a dense urban environment and really make a difference in the local economy, a few items have to happen:

1. all existing buildings must be leased at profitable rates (Indianapolis is not there yet)
2. all existing surface lots must be converted to income producing leasable spaces, typically of a low rise density (Indy is at least one decade from this step)
3. a public transportation system must be in place that can collect and distribute people from around the city to a single point (Indy is probably three decades from this)

If these requirements are not met, then asking for more tall buildings is just asking for a failed development. You can’t even give away a tall building downtown right now. There is just no demand to fill it.

So, if you are a fan of urban spaces and want to see more investment in your skyline, here is a simple recipe:

Live downtown
Don’t just take up space, take up space in the central core. Without a strong demand for leasable space, no additional supply will be built.

Work downtown
Look for work options downtown. Petition your office decision makers to locate in the central core. Once again, this increases demand and makes it an easy decision for the city and developers to move forward on their plans.

Use public transit options
Without public transit, cars will need to be parked and moved around. This dramatically reduces density, and makes tall buildings less viable. Pedestrian options are reduced as well.

Support local business
The businesses most likely to lease space in that shiny new building are local ones.

Support infrastructure initiatives
Expect to pay higher taxes. The extra costs associated with the urban core are manifold, including security for tourists and commuters, reconfiguring water & electric services, and caring for indigents. Don’t be upset about it, because this is the cost of society. For when someone isn’t paying their share, the rest of us must pay it for them.