Since longevity is a key measure of sustainable design success, perhaps we can learn from some of the monumental structures that exist today, 5,000 years after their construction.~Tweet
Since longevity is a key measure of sustainable design success, perhaps we can learn from some of the monumental structures that exist today, 5,000 years after their construction.
In November 2010, the Discovery Channel aired two 90-minute documentaries that I made with Atlantic Productions called “Engineering the Impossible.” The idea behind the show was to view some of the construction feats of the Egyptians and Romans through the eyes of an engineer. The viewer would be educated, fascinated, amazed, and intrigued by the skills and ingenuity of the designers and builders of more than 4,500 years ago.
Among the structures I was fortunate to visit in Egypt were Hierakonpolis at Edfu, Karnak, the Valley of the Kings, Alexandria, and the Giza Plateau, and in Rome the Coliseum, the Baths of Caracalla, Baia’s dome and the stadium at Pozzuoli, the Aqueducts, and the Pantheon. These structures represent 5,000 years of history in engineering and architecture, to which I was allowed unprecedented access and expert historical support.
The opportunity given to me to research, study, review, and comment on these incredible pieces of architectural and engineering design made me wonder about their relevance in today’s world. What can we learn from them? In particular, as longevity is a key measure of success in assessing a sustainable design solution, then surely these monumental structures might contain some clues and advice with regard to today’s design opportunities.
Foundations of Longevity
Imagine a client giving you a brief today that specifies the design life of the building you are required to design to be 5,000 years. We might well think that such a brief would be impossible to achieve. Certainly it would be impossible to obtain professional indemnity insurance on that basis; although we probably won’t be around when it might be needed. In Egypt today, buildings constructed 4,500 years ago provide revenue that drives the national economy through tourism and study. That is also true to a large extent in the city of Rome, and in fact Italy in general.
So what we have in both Egypt and Italy are buildings that have not only survived the test of time (perhaps only by chance in some cases) but that provide a vastly different function today from that for which they were originally designed. Call it what you will: flexibility, 20/20 hindsight, or even foresight. While that may be amusing to muse upon, many of these buildings are places of legend, and legends are built on a foundation of dreams rather than just facts.
The survival of these amazing structures has a common factor in that they use materials that are, by definition, durable but also remarkably compatible and consistent in their nature. Each material appears to have been selected based on well-known performance-based properties. Each was typically prepared offsite and assembled on site. My sense is that someone had to be responsible for the total design and construction, and I am convinced that this is an important factor in the overall performance and longevity of each structure. The roles of master builder, architect, and engineer are crucial, and it’s clear to me that conscious choices, not just chance, contribute to the success of these structures. It is as true now as then that the designers’ vision is as vital as the owner’s brief in achieving a successful outcome.
Perhaps the final crucial factor in longevity is maintenance. These structures are robust in every sense of the word; they do not rely on significant human intervention for their survival. They are able to take their knocks and bumps over time as they are fundamentally resistant to the forces of nature applied to them and by implication to abuse by mankind. That fact alone gives them the resilience to withstand the test of time.
Imagine the difference between an RFP for the Great Pyramid and an iconic building today. Let’s try and step back almost 5,000 years and consider a meeting in Egypt around the year 2,600 B.C. between client and designer.
Chiseled on a stone comes the following request for a proposal:
RFP for the design of an iconic building to house the body of the pharaoh
- Brief: To design and construct one iconic building in context with prior solutions on the Giza Plateau but to exceed those solutions in scale such that it will be the tallest man-made structure on Earth for several centuries
- Primary purpose: To house a burial chamber, location of chamber to be kept secret but within the iconic building such that the 10,000 work force keep it secret
- Building life: Eternal with little to no maintenance
- Construction cost: Negotiable within the treasury limitations of the country
- Schedule: To be completed within the lifetime of the pharaoh (detailed period unknown)
Note: Failure to complete on time will result in the project being aborted, and unpaid fees will remain unpaid.
I imagine the meeting to discuss the proposal would involve three parties: an architect, an engineer, and a builder. Perhaps this is therefore the world’s first integrated project delivery project. That’s lesson No. 1: A great design requires an understanding of the factors that drive the solution between the owner, designer, and builder working in a partnership toward a common goal.
Each party would begin by setting out the constraints. The architect would outline the planning issues, the scale needed to meet the brief, and some history of the previous projects on the plateau. At this point it’s likely that the height was set as a minimum value to be iconic and the form was set by the context of pre-existing structures on the Giza Plateau, so a very large pyramid was the agreed-upon solution.
The engineer would immediately remind the group about the Bent Pyramid, saying that ground conditions would likely govern the maximum height that could be achieved and also letting the team know that the angle of the sides was a limiting factor, and that the accuracy of cutting and placing the stone would govern the performance and maintenance aspects of the solutions chosen. Taller structures add increased stresses on the stones, so the height, angle of the sides, and stresses equal to the previous pyramids would determine the volume of stone needed.
Finally, the builder would point out the time needed to source and transport the materials, erect the pyramid, and assemble, house, and feed the work force needed. These factors would govern the schedule and the cost.
Perhaps at this point all three parties would inquire about the health of the pharaoh and the age at which his parents died as a check on whether the project looked feasible, especially given the payment clause in the RFP.
Maybe these requirements clashed with each other and the height was lowered, the sides steepened, and the work force increased. But surely through negotiation, the time, cost, and quality requirements were balanced as they always must be in any successful project, as these points matter every bit as much as the points of the proposed pyramid.
Based on this agreement, certain decisions have been made, and maybe they list out as follows:
- Speed matters, so the site needs to be a place of assembly, with stone cut offsite and placed on site.
- Groundworks to choose and level the site needed to start immediately in an enabling works contract so that while quarrying is happening the work starts in preparation.
- The height is agreed to and is based on the number of men who could be assembled as well as the speed at which the blocks could be raised and placed.
- The stone should be consistent to ensure quality and compatibility.
- The size of the base and angle of side slope should ensure less ground pressure than the Bent Pyramid and no more than nearby successes.
- Work would need to be continuous and on several fronts to ensure adherence to schedule, meaning shift working and overtime for the work force.
- A plan B is needed such that if pharaoh becomes ill, the job can be modified. The burial chamber is on the critical path, and putting it in the lower third might be a sensible idea for the schedule.
In agreeing to these terms, the pharaoh accepted that time and quality come before cost; therefore, the project’s priorities were set and aligned to the brief.
Simple though this process is, it’s one we don’t pay enough attention to today. Failure to align expectations from the outset will result in disappointment from owners, as time, cost, and quality must always balance for a project to be a success. Each of these constraints is a leg supporting a three-legged stool, and they all work in harmony (or not, as the case may be). Build poorly, and the structure likely won’t last; build fast and quality may suffer; build cheaply and the project may be fast but the structure won’t be quality.
Fast forward 4,000 years or more to the ecological age in which we exist today.
Today’s problems still revolve around time, cost, and quality. When we do not align these, a tension develops. For example, a sustainable solution is one in which whole-life costs drive the design decisions, but if the space is to be sold or leased to a third party, then perhaps first-cost drives outcomes and so the sustainable aspirations may not be as effectively met as they could be. The result is a solution with lower first-cost but higher operational and maintenance costs. Even then, how are maintenance costs determined over the whole life? In fact, how often is the life of the building clearly defined and aligned with the many materials and assemblies from which it is constructed? Not often, but in the future that will change.
We may think today’s solutions are more complex than 4,000 years ago, but is that really so? I would suggest that an eternal building or even one that would last 4,000 years or more would be considered outside our experience today. If we were asked to build it without any plant or equipment, we might just consider that impossible. The concept of “Engineering the Impossible” comes from just such a premise — that what was being done then is something we might consider beyond us today.
What can we learn from our predecessors? I learned a few things that will inform my approach in the future.
The first thing that was clear to me was that physics matters. The idea of keeping the center of gravity low and through the center of the foundation, of equalizing pressures on the foundation, and of keeping structural load paths clear and direct is evident in abundance in ancient Egypt and Rome.
This adherence to such basic principles means that construction can be safe, simple, and fast and was a consistent and abiding legacy of the great builders of yesterday.
Another principle vital for longevity is chemistry. This refers not just to the chemistry between client, design, and builder but also the simple idea that inert materials used together means that the structure exists more in harmony than in opposition to its environment. By definition, the structures I saw in Egypt and Rome were those that lasted the test of time. But my review of the Pharos in Alexandria, which now sits in pieces on the sea bed, was an example of the designer and builder not considering the environment well enough. To build tall, slender, and irregular using metal cramps embedded in open stone joints on a site with saline wind and waves was to trust maintenance to provide longevity. When the work of sealing, patching, and replacing stopped, then so began the steady but inevitable decline of one of the wonders of the world. The surviving buildings are relatively homogenous; where maintenance is required it is designed into the solution such as with the Aqueducts that feed Rome, where consideration for cleaning out waterborne particulate was a fundamental design consideration.
Perhaps the most surprising (and yet so obvious in hindsight) aspect of these buildings is that, where possible, materials were prepared prefabricated. Stone was cut before delivery and assembled on site rather than being cut in place. This meant two things:
- Everyone had a single job. When we practice something every day we get to be very good at it.
- Site was a place of fitting and not a place of making, which aids speed and improves quality.
One of the most quoted and embarrassing statistics in construction today is that productivity improvements over the past 60 years in many areas are poor to zero. On the Giza Plateau, the progression of scale and quality over several hundred years shows how the Egyptians improved productivity out of all recognition — from the Stepped to the Great Pyramid, a full-scale construction schedule we can still study today.
What if we measure these incredible solutions by their carbon footprint? Just how would these great buildings stand up by comparison to today’s iconic solutions?
Although the exact answer would involve an extensive study in itself, perhaps some empirical assessment can point toward the conclusion.
If we define the carbon footprint of each to comprise the embodied energy to create the structure, the energy used to build it, and the operational energy in use, then we get the total energy over the life up to the point of demolition. Annualizing this would give the pyramids a huge advantage over any modern building just because of their longevity, but that raises the question about designing buildings for a longer life and certainly directs us to the question of repurposing existing buildings.
The issue of longevity is an interesting one. How much more does it cost to design a loose-fit, flexible building than one lacking flexibility? The answer is little to zero, or maybe it could cost less.
How much more does it cost to build in flexibility, adaptability, or buildings capable of change? The answer is that it costs very little in percentage terms but does require a mindset that lowest first cost is not the decision-making criteria.
Payback over a longer life is the return on investment that allows the flexibility in a design to be realized. In a building that is not owned or occupied by the promoter, this can be a challenge. Legislation or green tagging buildings based on lifetime carbon caps would force a change in approach, but until then tenant power, shareholder power, and doing the right thing are the drivers of change.
You could say that all this is just post-rationalization of great buildings to make it seem as though there was more foresight than really existed, but don’t we all judge our entire built environment by its endurance? Whether we are amazed by the skills it took to cut stone, the speed at which the Empire State Building was erected, or the beauty of Sagrada Familia, it is endurance that permits us the opportunity to be amazed by those who have gone before us.
My take away from my opportunity to examine up close some of the world’s greatest structures is that they share a common greatness: Their mere existence enhances our world, connects us to our history, and shows us that we are creators of our own future with all the responsibility that comes with it.
One day we will be judged by our legacy. Perhaps we don’t consider that enough. If we did, then maybe we would make some different decisions, ones our children’s children could look back on with pride.
Steve Burrows is the leader of Arup’s Property Business in the Americas. He is based in San Francisco and he leads a number of major multidisciplinary projects around the world. He has more than 25 years of experience and has been involved in a wide range of projects, including serving as project director for the Bird’s Nest Stadium in Beijing. Burrows is a registered professional engineer, and in 2009, he was awarded a CBE by Queen Elizabeth II for services to civil engineering overseas.