Innovation in Seismic Bracing Design

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!

A typical column buckling under applied load

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.

Facade Issues in Steel Buildings

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.

A Tragedy in Haiti

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.

Metastable Equilibrium

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.

Advice for Young Engineers Looking for Work

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.

Conspiracy Theories in the Realm of Structural Engineering

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.

BRIC Construction

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

A Day in the Life of a Structural Engineer

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.

My Engineering Education

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.

Recipe for Tall Buildings in Your City

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.

Role of Structural Engineers in Sustainable Construction

As more and more structural engineers have been considering their role in sustainability, there have been more resources available. The best sources of useful information concerning structural engineering and sustainable development are the May and June editions of Structure Magazine. This printed publication is made available freely to all NCSEA and SEI members, but anyone can access the online articles.

Sustainability articles typically address either the entire design process or specific strategies. This provides a convenient way to separate them into categories. First up, we have the articles that address design in general:

Overall Design Strategies
Once again, Structure Magazine leads the way with an article "Sustainable Buildings and the Structural Engineer." This article delineates all of the issues that sustainable develop should address and then shows how the structural engineer can impact the design. This is a great way to see all of the ideas laid out in one easy to grasp format.

Another article that I found useful is hosted at GoStructural.com (publisher of the trade magazine Structural Engineer). This is actually a collection of articles all on the same topic of sustainability.

Reuse of existing structures
One of the great things about sustainable development is that it recognizes the importance of historic preservation, or retaining existing buildings of any type. You may have heard the expression "The greenest building is one that's already built." This is the title of an article published by the National Trust for Historic Preservation, written by Carl Elefante. It's a great introduction into how these two topics work together, and a great rallying cry for those who feel that LEED credits don't properly address the issue.

Building on this call to reuse rather than tear-down and rebuild, another Structure Magazine article "Missed Opportunities in Structural Sustainablility" quantifies exactly how effective it would be to reuse a building. The bottom line: very effective. Essentially, this article shows that tearing down a building in just about any condition is the least green thing that can be done.

The National Trust for Historic Preservation has issued a whitepaper laying out exactly why reusing buildings is sustainable, extending the definition to include economics, social benefits, and environmental benefits. Another great read for people looking for ways to change policy and public opinion.

Lastly, the NTHP has put up a fun slideshow of pictures of structures submitted by readers that show promise for renovation or adaptive reuse. So here is Reuse it! (a Flickr group). Feel free to add your own.

Minimizing use of materials
An interesting editorial in Structure Magazine on the topic of "Voided Two-Way Flat Plate Slabs". This is a particular strategy of sustainable design called dematerialization. Basically, if you consume fewer resources for a building of similar strength then you are doing good for the environment. Of course, you can't put that sort of strategy into a ratings system (e.g. LEED) because then every engineer will claim they are using less material. The USGBC handled this problem in other trades by creating a baseline case, so the strategy may still work for structural engineering. But few people want to encourage engineers to use less material, so it probably won't be included for that reason.

Maximizing material effectiveness
Another interesting Structure Magazine article addresses materials that act as structure, insulation, and soundproofing. "The Road to Code Acceptance for Autoclaved Aerated Concrete" details how AAC is being (slowly) approved by code provisions, as well as how to use it in your buildings even today by getting a per-project approval from your local jurisdiction.

And finally, news from the Pakistan Straw Bale and Appropriate Building (PAKSBAB). This group has more of a "damn the torpedoes" mentality because there really are no trade groups that would profit from such a low cost building material. So the only way this type of material will ever get used is from prototypes and bona fide living experiments. I wish them the best of luck!

Engineering and Systemic Risks

On a basic level, an engineer's primary job is to manage risk. The problem is that all current methods of engineering risk management deal exclusively with individual projects. Unfortunately, there is no forum for a discussion of systemic risk.

Systemic risk was exposed recently in the financial system. The Great Recession, as I've heard it called. In this case, financiers were engaging in business dealings and signing a separate contract with an insurance provider to pay costs in case of a default – a default credit swap. Taken as individual transactions, each one was well-managed and almost risk-free for the holder of the assets. All of the credit rating agencies were in agreement, these companies had managed their risk very well. But when you look at the whole system, where was the risk going? Was it just disappearing into thin air?

The answer, as we found out, was that the risk was just being hidden by complicated instruments. Maybe it is an appropriate time to discuss whether this same process is at work in the field of structural engineering. By minimizing risk to individual projects are we amplifying the risks to the system?

Engineers owe responsibilities to different parties in a complicated web of liability. I think the best clarification of what we are trying to accomplish is stated in the ASCE's Code of Ethics (1997) Fundamental Canon #1:

CANON 1.
Engineers shall hold paramount the safety, health and welfare of the public and shall strive to comply with the principles of sustainable development in the performance of their professional duties.

We act in the best interests of our clients and the public welfare, but it is not always clear what actions we should take to meet these requirements. Our developments do not exist in a vacuum, our designs affect the environment to a great degree. Looking at a quick example in civil engineering, there is plenty of evidence that installing levees down the Mississippi River valley has had some negative consequences:

1. Lack of regular flooding has reduced alluvial floodplain buildup, reducing natural barriers to storm surges
2. Development alongside the river has been encouraged, as the risk is perceived to be much lower than it actually is

As one can see, this is a good example of increasing systemic risk solely because of reducing risk to a bunch of individual projects. When the system breaks down, a huge amount of development is affected.

Likewise, we can see a similar process occurring in structural engineering projects. Engineers are partly responsible for some of the most intense greenhouse gas emissions on the planet. Buildings today use almost 1/2 of all energy consumed in the world. Construction activities contribute to C02 emissions directly and indirectly. Concrete production alone (because of cement) accounts for 5% of annual worldwide carbon emissions.

Engineers are culpable because we do little to reduce the concrete consumption on a project. Concrete is used for shallow foundations, retaining walls, shearwalls, and sometimes just as dead weight. Concrete isn't the only material that will work, but it is the easiest best solution. Some building codes won't even allow an engineer to specify anything else for foundations. We are so intolerant of risk that we require reinforced concrete in a part of the project that typically won't cause a problem even if it failed.

This matters because we are continually raising the quantity of greenhouse gases in our atmosphere. At some point, sea levels will rise, storms will gain strength, wildfires will be more severe, and global conflict will erupt over limited resources. This is the systemic risk that structural engineers face right now. If we are serious about meeting our ethical obligations to protect the public welfare then we need to change our habits, and quickly.

Engineers and the building code industry needs to find out why we are specifying so much concrete and provide guidance on other options. Specifying high levels of fly ash or slag cement is a good start, but since we'll need to be carbon neutral soon then we need to go further. Expensive technologies might help the US, but we must figure out solutions that are scalable and useful in the developing world.

I don't think there is a silver bullet solution for this problem, but I do think it is important for engineers to remember that they have obligations that extend beyond the boundary line of their latest development.

Engineering does indeed matter

I was reading the latest Urbanophile post, and it really struck me as relevant. I came away with a few important conclusions from his post and the resulting comments:

• Engineers should not take their responsibilities to aesthetic qualities lightly,
  
• The design of engineering works is important,
  
• civic leaders must require their engineering departments to meet the highest standards of quality.

2 good weeks

I've been quite busy since my last post. In fact, I found time to:

• build a patio
• repair some leaking pipes
• pull out the motorcycle
  
• general house maintenance

It's been great with the perfect weather we've been having. No complaints whatsoever.

I did come across a new blog about bridge building in the UK. Thought it was good stuff, wanted to share it with everyone. It's also added to my sidebar. I strongly recommend everyone view the insightful posts about criticism in the engineering field.

A BLDG BLOG

Since I've been writing this blog now for about 1 year or so, I figured it was a good time to reflect. My first entry "structural engineering weblog manifesto" was the first step on my new adventure. While my scope of topics has grown somewhat as time passed, I am comfortable with the inclusive nature of the website.

My purpose in writing this blog was to show that structural engineers should be actively involved in the process of design. Engineering is not just another trade involved in construction. Engineers must be intimately involved from day one for optimal results. Strong communication skills and a synergistic relationship with the design team is the only way a project can move from adequate to sublime. Buildings that inspire, that push the boundaries of technology, or that serve as an icon for a community need more than just the best architects, they need the best engineers as well.

I have also learned to appreciate my role as a blogger. The typical stereotype of an engineer is someone who shuns public attention and concentrates on technical subjects even when humanistic problems are to blame. I am no different. It is a horribly frightening experience to put one's opinions on the internet and start discussions about sensitive topics. Even when someone tells me that they enjoyed a post or article it feels wrong. But I know it is absolutely necessary that we speak up for ourselves as individuals. Instead of shunning public attention, I have instead shunned anonymity. Since my profession is one of accountability, I feel it would be unethical to anonymously voice my opinions.

Our professional organizations do a great job speaking for our profession, but that is only one side of life. I encourage engineers (and indeed anyone who has something to say) to start a website. Maybe join up with a few like-minded individuals, either as a student group at an engineering school, or fans of architecture within a city. If that is still too far for the first step, then start small with a journal or notebook where you write down ideas for later use.

Engineers have the ability to change the built environment so that public welfare is dramatically improved. Civil engineers are the builders of civilizations. But we are also a part of that civilization. We need to show our social awareness in addition to our technical skills.

Risk is Never Eliminated

I have faced a little bit of criticism over my claims that investing money in the New Orleans levee system maybe wouldn't have worked. Well, now the National Academy of Engineering seems to be insinuating that levees won't work, no matter what we do.

There had been "undue optimism" about the ability of the protection systems to withstand the impact of a storm on the scale of Katrina.

"the risks of inundation and flooding never can be fully eliminated by protective structures, no matter how large or sturdy those structures may be".

So, no matter how much money we contribute to levees or any structure, there is always the potential risk that a natural event will exceed our design. We can only minimize risk to the extent it is economically feasible and set up systems to mitigate the effects when disasters occur. I don't think ASCE or any engineer should be promising that investing in our infrastructure will result in perfect designs or elimination of risk.

Skyscrapers topping out early, some just tapping out

Here's a heartwarming story about a construction defect that was discovered halfway through completion. Reinforcing for the concrete columns wasn't installed correctly (don't know exactly what that means, but could be pretty expensive to fix). The novel solution: just stop building...



But, in these times of economic woe, it seems like everyone is scaling back their plans. Not just the unlucky builders who hire incompetent contractors. Even the famous Chicago Spire is now just a smoking hole in the ground. The fun thing is that so many of these "super-tall structures" or "towers of babel" are associated with equally large egos. Schadenfreude to the max.

2009 Indiana Building Green Symposium

This year's Building Green Symposium at the IMA (March 12-13) was a great success. I attended the full Friday session, and definitely felt positive about the future of sustainable design as well as inspired to get something done.

The introduction by Mayor Greg Ballard obviously focused on Indy's efforts towards becoming "the most livable big city" in the US. The Office of Sustainability, recently announced by the Mayor, got some more press. He discussed the recent deal that will result in a group of new LEED Certified buildings. This is great progress. It's far short of a commitment to build every new public structure as LEED Gold Accredited (we can dream, right?), but it's a start. It's clear that the gears are turning in the City-County building, but an entrenched bureaucratic system is difficult to change overnight. I believe that a lot of city planners are now understanding that green design involves a holistic approach that increases up-front costs but has the chance to decrease long-term costs.

Actually, that may be the best way to summarize this event. Over and over again, each presenter stressed the fact that a well-planned design that considers life-cycle costs and productivity can reduce costs. And not just a small amount, a huge amount. Greenhouse gas emissions are lowered, people are happier and healthier, commercial activity and tax revenue increases... the benefits go on and on. Green design is the opportunity that we have to reinvent our built environment to serve communities and the people who live in them. Green design is the best way to advance our nation's economy and keep our current standard of life.

Ed Mazria was the keynote address. An architect with a long list of carbon neutral projects, he also authored the Architecture 2030 goal which seeks to eliminate greenhouse gas emissions as quickly as possible. He brought a lot of data to show what our CO2 problem is, what it will be with no action taken (global disaster, basically), and what it can be if the construction industry fully embraces green design. Basically the message is business-as-usual can't continue, so prepare to adapt once again.

The first breakout session I attended was about the new federal building in San Francisco. This one was probably the most inspirational for me as a structural engineer. An architect from Morphosis discussed the design and construction and highlighted the green design accomplishments. This is the first naturally ventillated building on the West Coast since air conditioning was invented. This one fact allowed the designers to throw out all the mechanical equipment typically used for an office tower, saving a huge amount of floor space and overhead space (not too mention cutting energy use to 1/2 of a normal office). Exposed concrete shear walls and gravity systems help regulate the temperature, and the operable windows allow the occupants to set their own level of thermal comfort.


My favorite feature, however, was the skip-step elevator system. This meant the main elevator only stopped at a lobby every third floor, and a staircase was used to go up or down a floor for most occupants (the secondary elevator next to this one stopped at every floor). This allowed the designers to create these fabulous three story tall elevator lobbies with grand staircases that linked three floors into a smaller community, sharing resources like conference rooms and vending machines and encouraging interaction between the different federal agencies.

Leith Sharp was the next presenter. She discussed her appointment at Harvard's Green Campus Initiative (now the Office for Sustainability) and her experiences dealing with change in a huge organization.

I kind of bummed around for the next few hours eating lunch, attending presentations, and visiting vendors. I finally settled into a great presentation on "green streets" by Kevin Perry. Here's a great write-up on some of his efforts.


This was probably my favorite of the day, as it really got to the point about remaking our built environment at a very inexpensive cost but high benefit. I strongly encourage anyone considering stormwater treatment, streetscaping, or similar activities to check out his recent publication on sustainable streets.

Structural Engineer awarded a MacArthur Fellowship

John Ochsendorf, a structural engineering professor at MIT, has been awarded a prestigious MacArthur Fellowship - $500,000 over 5 years with no strings attached. Sounds like a good deal, right? I'm not entirely sure, but I believe he is the first structural engineer to be a MacArthur Fellow. Structural engineers don't get much press unless something really bad happens, so I think this is a great way to show that there are many opportunities in the field of Structural Engineering. Oschendorf is described on the MacArthur site as "a structural engineer restoring cathedrals and other structures of the distant past and identifying ancient technologies for use in contemporary constructions."

The purpose of the fellowship program is to encourage people who have the opportunity to make a big difference in the world to follow through with their work, and to provide them with capital so they can concentrate on doing just that. The wikipedia link to an op-ed article by a former fellow is a humorous and enlightening introduction into the brave new world of a genius.

The bio on his school page and the press releases show he is interested in using ancient structural engineering designs to solve modern problems. His first projects involved researching Incan suspension bridges and seismic resistance of Gothic architecture. I think he is involved in a fascinating field, and I look forward to seeing what happens with his research.

On a related note, I found out one of my colleagues was unfamiliar with the Roman Pantheon (building). It's a great structure, so I'm hoping everyone takes a few moments to learn more about it. I bring it up because it's a good example of how modern structural engineers would be unable to recreate the past or even prove how this structure works. The pantheon has very unique characteristics that engineers even today would consider as brilliant.


If you asked an engineer today how far four inches of unreinforced concrete could span, they would run away screaming to avoid liability. Our modern building code doesn't allow unreinforced concrete in most situations. Is the pantheon unsafe? Maybe, but this unsafe structure has stood for almost two millenia while most modern structures barely hit their expected 30 year lifespan. I think the work that our friend Prof. Oschendorf is doing can lead us to a new way to think about historic and ancient structures.

Bracing is Beautiful!

Heads up for all the building designers out there... Bracing is Beautiful!


There are very few building systems as cheap and efficient as braced frames. Allowing your engineers to put just a few braces in the building will make them a very happy person. You'll see a lower cost per sq. ft of building, use less material, and make a green statement. Moment frames open up the floor areas, but you sacrifice a lot of room for the deeper beams, bigger columns, and tricky connections.

The most important reason to consider bracing is that people love seeing structure expressed in their buildings. It worked for the Hancock Center in Chicago, and it can work for you! There are buildings and architectural styles that it won't work for, but you can hide the braces pretty easily.

There are many flavors of bracing. Concentric, eccentric, chevron, knee, buckling restrained braces, multi-story bracing, etc. Just put those terms into an image search and you'll see a world of options waiting for you.


If you are concerned about exposed steel members (fire resistance, corrosion, vandalism) then you may want to coordinate with a specialist during your initial design. If appearance is a concern, then I strongly recommend you consider some of the newer imported components available. For smaller loads, a pin-connected rod from StaLok will work, whereas for a Cast Connex bracing component can handle even large bracing forces seen in high seismic areas.


We all want to do our part to help the owners get the building they want - at a reasonable cost with great performance. I think recommending a bracing system is a great way for engineers to add value to the project, without the high initial cost of shearwalls or moment frames.

The high costs of ignoring seismic design

Hopefully you guys remember the EQ in china (7.9M) from a few months earlier. The Chinese gov't has now posted some expected costs for rebuilding efforts. Total expected costs are $147B, which is an almost unimaginably large cost. For comparison sake, the Northridge EQ (6.7M) in California cost a total of $12.5B and was one of the costliest disasters in US History.

One of the larger costs will undoubtedly be the rebuilding of 3400 schools and strengthening a further 2600 schools. How did so many schools collapse? It's hard to pinpoint blame in a situation like this. Was it the engineers fault - a faulty design? Or maybe construction crews built it wrong? Or maybe the building inspectors who signed off on the building? Or perhaps the national government for not providing financial support or motivation to meet the applicable building code?

It should be noted that China has a modern building code, and that any of their new modern skyscrapers will probably compare pretty well to US skyscrapers. But the lower profile of rural schools and other buildings probably made them easy targets for low quality construction in return for bribes to local officials. While I haven't personally investigated any of those sites, it seems a likely probability because students were so disproportionately affected by the earthquake.

Certainly, any developing nation has a hard choice to make between investing money and resources in EQ resistant buildings vs. building cheap and quick and hoping the big event never comes. Poor choices create a legacy of risk that future generations must live with. We all have a different personal tolerance for risk, let yours be known.

A case in point - one of the heroes of the EQ in China was a school principal in the area, Ye Zhiping, who led efforts to strengthen his school against seismic events. All 2323 students in the school were saved. The total cost for the work was about $60k, or about $25/student. I'd say that was a pretty large return on the investment.

Seismic upgrade cost calculator

For owners/engineers/architects looking to estimate how much it would cost to do an actual seismic renovation or upgrade to an existing building, see this online calculator.

You have a few options to get an answer, but I recommend using the detailed option and form entry. When I go through the exercise using my own building, I get ~$82 per sq. ft. which works out to a total cost of $500k for a complete seismic retrofit. I promise to get around to that as soon as I can...

Note that the choices you make can have large consequences on the overall cost. When I choose a lower the lowest goal of "risk reduction" and limit other anticipated work then the cost drops to half of the original $82/sq.ft.

The methodology is based on a database of retrofit projects. It knows how much those projects ended up costing, so it can compare the variables chosen for your project against the database and come up with an accurate market driven answer. Pretty nifty. Now you can tell your clients that you have a pretty good idea how much the work will cost. Of course, you might want to really investigate the options and help menus before you submit any numbers from it. And don't forget to convert the answer to today's values, because the cost it gives you is in terms of 2002 dollar values.

CTBUH World Congress videos online

Everyone who is an architect, engineer, contractor, or just likes tall buildings ought to know that CTBUH has just put the 2008 World Congress (held in Dubai) videos online.

I also want to extend my congratulations to CTBUH for hosting a successful World Congress and sharing all the information freely. You may have ruined every Friday night for the next few months by putting these videos up, but I'm very appreciative.

Resource Management in Engineering

Call it sustainable, eco-friendly, environmentally conscious, or green design... it's really about managing resources. It is the future of all construction trades, and it means a great deal to our clients. So what is green design, how would it apply to engineers, and why is it important?


Green design basically means that you will purposefully choose options that will reduce consumption in the long term. When you consider the full life cycle of the structure, there is a lot of energy that goes into the building during construction, and a small input of energy throughout it's useful design life. A significant amount of energy can be also be spent during demolition, or the building can be "deconstructed" and recycled. See LEED guidelines published by the US Green Building Council for good tips.


Structural engineers usually have a hard time with the green design metrics. Concrete is cheap, you can throw in recycled content like fly ash, and it lasts basically forever. Structural steel is almost 90% recycled content, and can be optimized so that only a small amount of material is used for a structure. Wood grows on trees - it removes CO2 from the atmosphere and is pretty darn good stuff. As long as you aren't using dead pandas as building materials, green design is pretty much a slam dunk for us engineers, right?


Well, not quite. Optimizing the structural system won't amount to much in the end. If you are really concerned about green design, the most important contribution you can make is to help the other design team members meet their goals. Have you done everything possible to help the HVAC designer? Have you eliminated the need for maintenance of the facade? Have you specified low VOC content in your steel paint/primer? Have you maximized your column spacing based on discussions with the architect, and therefore removed 1/3 of your column footings? Have you begun using LRFD and listing all your reactions on the design documents? Have you notated all your design data on the construction documents so that future engineers can renovate and update your building's structure without having to re-invent the wheel?

If you are working on a project where green design is a priority, I would suggest you go beyond the LEED guidelines and reach out to the other design team members. Communication is the key to this. Make sure everyone knows you are there to support their work, and that whatever they feel will best contribute to the green-ness of the building is what you want. Maybe request an extra coordination meeting with the architect, or ask that the HVAC and interior design/lighting, etc. work be substantially complete before a structural system is chosen. This would upset the normal design flow, but it would put the green design priorities in the right order.

So why is green design important? It comes down to environmental impact and economics. For a long time (the last 100,000 years or so) the human impact on our environment was not really well understood. The true cost of altering our own environment was hidden. Now the cost is being priced into everything we will buy and every bit of energy required to operate a building. Simply put, conventional design is going to get too expensive. That's the bottom line.

The other reasons for green design may or may not appeal to you, but are certainly important to me. I believe that engineers have an ethical obligation to protect the welfare of the public. If my structure causes excess CO2 to be produced, thus indirectly causing famine elsewhere in the world due to climate change, I can't say I've done my best to protect the public. If you are uncomfortable with the topic of climate change, here is a good primer.


There are simple ways you can reduce the initial "embodied energy" of your structure, but there is so much more you can do to help out the green design of your structure. Not coincidentally, these options will usually reduce the bottom line of the project, thus saving your client money. We are always pressed for time in a design environment, and often the client is enforcing difficult completion deadlines. It's hard to optimize the structure for cost, safety, and green design and still meet industry minimum profit margins. However, I'm sure that if you set it as a priority, you can accomplish it.

Structural Engineering Weblog Manifesto

This weblog was started because structural engineers were not taking advantage of the opportunity to communicate with each other. While there are any number of architectural blogs, even sites that rank them by popularity, there are no blogs concerning structural engineering. Therefore, this blog is committed to the structural engineering community and to everyone who is interested in structural engineering.

This website is inspired by the idea that people want to know how buildings are constructed and why they don't fall down in a strong wind or earthquake. My hope is that anyone can visit the site and connect to the topics in some way. However, I'll probably put a lot of industry-specific information here so let me know if any of it is unclear and I'll repost with clarifications if possible.

Everything you read in this blog will be filtered through my eyes. So, let's talk about me for a bit. I'm a structural engineer working in Indianapolis. I got my BS from CMU and my MS from TAMU, and I have a PE in Indiana. I work on many types of buildings and structures - industrial, commercial, and residential. I try to stay involved with the engineering community, so drop me a line if anything catches your eye and you want to share it. I'm also very interested in everything my architect friends have to say, so you will probably see a lot of that. I also enjoy discussing technology not related to construction.

Structural engineering is a subtle art and a great structural engineer is sometimes hard to recognize. Unfortunately, this has led many people, politicians, and architects to suspect that engineers are merely technicians, putting numbers into arcane mathematical formulas and then rounding up an order of magnitude just to be safe. Rest assured that there are great engineering firms out there, and great structural engineering is anything but a lost art.

This site doesn't believe that one-size fits all or that pounding a square peg through a round hole is an economical solution. This blog aims to separate great engineering from the mundane, and we welcome all comments and advice. If you know of any great projects or want to share a special topic with the rest of the world, feel free to leave a note for us and we'll check it out. Thanks and welcome to our place!