The Foundations of Form: Understanding the Past, Present, and Future of Structural Systems
If architecture is art with constraints, then structure is the canvas. In addition to the forces of gravity, architects must consider factors during the design process like fire safety, openness, privacy, access to daylight, and the ability to circulate, all of which are impacted by structural decision-making.
The foundation of a building, or substructure, is considered a structural system and, more often than not, consists of reinforced concrete. In this article, we’ll examine a building’s superstructure, which includes all the elements that support its loads safely above ground.
THREE MAJOR SYSTEMS
Structural systems typically fall into one of three categories: wood, concrete, or steel. There are hybrid systems that use two or even three of these, and commonly, there is at least some crossover between systems within a building’s structural design. Interestingly, some fascinating non-common systems, like fabric structures, are often used in long-span, open spaces like stadiums and airports. For this discussion, the focus will be solely on unpacking the advantages and disadvantages of the three primary structural systems while omitting hybrid and other specialized systems.
WOOD
Chances are that a house built outside an urban center leverages wood and a basic stud frame.¹ Wood is the most commonly used material for residential construction, especially in North America. It’s flexible, lightweight, and easy to procure. 92% of new homes built in 2021 were constructed out of wood.
The barrier to entry for wood-frame construction is incredibly low compared to other systems, hence its popularity. It’s possible to go to a home improvement store today and purchase all the materials required to construct the entire frame of a house right off the shelves. Wood can be cut with a circular saw and fastened together with a nail gun, both available at the very same store. Most of that lumber can be easily transported with a personal vehicle, ordered for delivery, or loaded onto a truck rented at the same store. Basically, the barrier to entry for wood-frame construction is incredibly low compared to other systems.
From a construction perspective, wood is much more forgiving than concrete or steel. Often, architects or general contractors can design a system without the input of a structural engineer. If you need to increase structural capacity, purchasing larger members or joining two smaller members is simple. And if a piece of lumber is cut incorrectly or damaged, another one can easily replace it.
While wood is a versatile construction material, it faces significant drawbacks. Its susceptibility to environmental factors like moisture can lead to rot or mold, potentially shortening a structure’s lifespan. Wood’s vulnerability to pests further compromises its integrity. Additionally, wood’s combustibility poses a substantial fire risk, necessitating additional fireproofing, especially in larger structures. Architecturally, wood’s limitations become evident in its inability to support taller structures or span long distances, restricting its use in high-rise buildings and large-span projects.
Mass timber,² which is praised for its strength and sustainability, presents challenges in terms of cost and accessibility, currently limiting its practical use in a wide range of construction. Mass timber is a subset of wood framing that glues together the strands of small-growth trees into larger members manufactured to take much heavier loads.
Previously, the use of large timber members was becoming less common due to its negative impact on forestry. One interesting case study is the rebuilding of the Notre Dame Cathedral after its 2019 fire. Large, heavy timber beams were used in its construction centuries ago, and a massive effort is underway to replace these beams, which will require felling thousands of oak trees aged 150 to 200 years. Due to deforestation, these materials are not nearly as readily available as they once were.
Although not enlisted in the Notre Dame project, mass timber is a successful, sustainable alternative in new construction. As it becomes more accessible, it will become a viable alternative to heavy timber and other longer-span structural systems. This system can achieve the strength of heavy timber without the felling of old-growth trees, which is a win-win for both the building industry and environmental advocates.
STEEL
Steel is often associated with larger structures like bridges and towers. The iconic photograph, Lunch atop a Skyscraper, shows a legion of workers precariously sitting on a slender beam, dangling high above midtown Manhattan with Central Park stretching off into the distance. This image is symbolic of the progress and ambition that steel construction enabled. The shape of an i-beam (now mostly replaced with its counterpart, the wide flange beam) is itself seminal. It’s associated with industry, progress, and the growth of cities.
Steel is excellent for tall structures and for creating large open spaces due to its ability to span long distances. Office buildings often rely on steel structural systems due to the flexibility required to appeal to different types of tenants. The programmatic requirements of an office are much different than those of a residential building as tenants change relatively frequently, needs vary, and open space is essential to house desks for employees.
Steel is also relatively light for its strength, which means that buildings constructed of steel weigh less relative to the amount of space and height they can provide. The magic of steel is derived from its ability to be incredibly strong in both tension and compression — the sum of these benefits has contributed to contemporary urban density. From a logistical aspect, steel is more challenging to work with than wood. It is incredibly difficult to cut without machinery, and the most efficient way to prepare a steel frame for construction is in a factory or “in the shop” rather than “in the field.” Unlike wood, which can be cut in the field, steel must be documented thoroughly and meticulously prepared for on-site assembly. A conundrum of steel is that it is much heavier than wood by volume but actually relatively light for the weight it can support, as noted above. This means steel erection usually requires a crane, but because of its incredible strength, steel is the material of choice for many new construction projects.
Ultimately, steel is less forgiving than wood and requires more meticulous planning before construction begins. This responsibility falls not only on the contractor and steel fabricator but also on the architect. The architect’s role is critical in coordinating the project during the design phase, ensuring there are no conflicts with other building systems, such as air conditioning ducts or plumbing pipes. Such planning and coordination are vital elements of an integrated design process. Careful consideration during this phase can lead to a more streamlined construction phase.
The process of manufacturing steel is also carbon-intensive. Steel creation requires iron ore composed of iron and oxygen. Iron is separated from oxygen, and carbon is added to it. This is typically done at the same time by burning the iron ore with coke, a type of coal. Some of the carbon from the coke binds with the iron, forming steel, but much of it binds with oxygen during the process, forming carbon dioxide, which gets released into the atmosphere unless captured. This process generates 1.8 tons of carbon for every 1 ton of steel produced.³ Considering the multiple sources of carbon emissions inherent in the steel manufacturing process, this method has significant environmental repercussions, underlining the need for sustainable supplements and alternatives.
CONCRETE
While wood is commonly seen in smaller residential projects, and steel is used for its relative lightness and flexibility, concrete is the most widely used construction material on the planet.
Its incredible compressive strength, which means it can be compacted and withstand tremendous pressure before failing, accounts for its popularity as the material of choice for foundations. Combining concrete’s compressive resistance with steel’s tensile strength reveals an engineering marvel: reinforced concrete.
Concrete construction is logistically challenging yet highly efficient. As with steel, a great deal of engineering, expertise, and coordination is required to build with concrete. However, concrete construction methods are more efficient than steel or wood. Building with concrete still commonly relies on the structural post and beam concept, although in this case, the elements aren’t manufactured offsite and then erected. Instead, builders use formwork to create the negative space where the concrete will be poured, and then the forms will be removed after the concrete has cured.
Concrete’s malleability makes it extremely versatile, unlocking almost infinite possibilities. Before concrete is poured, a steel reinforcement is added to the framework, resulting in a frame that’s entirely cast in place, solid, and strong. Because the framework needs to be built precisely, tremendous logistical planning is required in concrete construction. The proper steel reinforcement design needs to be applied in each condition. Once it’s poured, it’s almost impossible to modify.
Concrete is common in multifamily housing. It cannot achieve the long spans steel can in similar applications and is more often found in buildings that don’t require large, open spaces. An apartment, which is typically a series of smaller rooms adjacent to each other, is served well by concrete and its ability to produce optimally spaced columns. The size of apartments has evolved to support this efficiency. The emergence and understanding of the capabilities of reinforced concrete led to a rapid rise in its use in the second half of the 20th century as the post-war housing boom further accelerated its popularity. Today, it’s the material of choice for rapidly growing economies.
Even with tremendous growth and use, there are also downsides. High embodied carbon⁴ is a significant factor in concrete structural systems. Concrete has the biggest impact on the environment relative to the other structural systems discussed due to its popularity and carbon-intensive manufacturing process. Not only is concrete carbon intensive from a logistics standpoint, requiring a significant amount of energy to mine the raw materials, transport them, and process them, but its creation also releases carbon dioxide directly into the atmosphere. Concrete calls for calcium, which is produced by burning limestone. Limestone contains calcium plus carbon and oxygen, so the burning process separates the carbon and oxygen from the calcium. Similarly to steel, a tremendous amount of fuel is required here.
If steel was the catalyst for the construction boom in New York at the turn of the century, then concrete is the catalyst for China’s incredible contemporary growth. Almost half of the world’s concrete is used in China, and it’s being used in all types of buildings and infrastructural projects as their cities grow at a breakneck pace.
THE CURRENT STATE
A cyclical pattern of innovation and regulation drives the history of building typologies and, therefore, the evolution and use of various building systems. Before building codes, humans built whatever and however they wanted, which led to numerous issues. Building codes were established to help prevent tragedies and allow for the safe expansion of cities. As innovation occurs, codes are typically revised to catch up, but this often means that the adoption of newer technologies is delayed until these revisions are made.
To examine the current state of structural systems, start with regulations, as jurisdictional laws govern the type of construction that developers, architects, and contractors can use within cities. In the U.S., many jurisdictions adopt the International Building Code (IBC) as a foundational text for setting construction standards, modifying it to suit their specific needs with additional requirements or alterations. The IBC is a large text and is updated every few years. However, it often takes several revision cycles to address and integrate new technologies thoroughly.
Outside the U.S., the regulatory framework for construction typically falls under a single national authority. For example, the United Kingdom consolidated its building regulations under The Building Act of 1984, while China’s construction landscape is overseen by its Ministry of Housing and Urban-Rural Development.⁵ It’s critical to distinguish between building codes and zoning laws. At their core, building codes aim to protect the lives of building occupants, requiring designs that prevent fire from spreading in dense areas and ensure safe exit routes in emergencies. To mitigate the risk of a building’s collapse, structural designs must endure long enough for emergency response teams to act.
However, codes are careful to take into account real-world economics and logistics while still striving for safety. A single-family suburban home in the middle of a larger plot of land does not have to be as fire-resistant as one that shares a common wall with a neighbor, like a rowhouse or a brownstone. In the event that the suburban home catches fire, the inhabitants would be intimately familiar with its layout and know how to escape. If the entire house burns down, it would be tragic for the owners, but fortunately, it would likely not cause any significant damage to neighboring homes. Such a house can be constructed using combustible materials.
In contrast, a rowhouse poses a greater risk of fire spreading to adjacent buildings. Because of that, they must be built out of non-combustible materials, at least on the exterior walls adjacent to their neighbors. Extending this principle to larger, denser, and more crowded structures where occupants may be less familiar with the layout or less mobile, like hospitals, requires significantly increased levels of fire resistance.
Many dense cities have had devastating blazes — there were the Great Fires of London in 1212 and 1666, the Chicago Fire of 1871, and multiple examples in New York in 1776, 1835, and 1845. Constantinople had one in 1660 that destroyed two-thirds of the city. Given this, it’s clear why regulations exist and how many building codes were written in response to these tragic events.
Cities worldwide share evolving attitudes toward the use of different materials in constructing structural systems. In fact, New York City, like many other major cities, has established fire districts⁶ that prohibit combustible materials entirely. These regulations, however, are slowly relaxing as engineers and researchers find new methods of safely constructing large buildings out of mass timber.
Exploring existing regulatory frameworks to understand how innovation drives the expansion of allowable methods is important. The IBC has established five construction types⁷ — Types I through V — which are ranked from the most restrictive to the least in terms of fire resistance. While these construction types come with layers of complexity, a basic guideline states that the more restrictive the construction type, the higher the associated costs. Despite their higher price tag and increased constraints, these restrictive construction types permit the development of larger, taller, and denser buildings. Early decision-making and road mapping of any project should include determining what building type to use, and designers, city officials, and planners can work together to determine the optimal construction types for responsible growth.
INNOVATIVE METHODOLOGIES
Regulations shape the evolution of structural systems. However, innovation in design and construction is equally vital. Many pivotal technological advancements have significantly expanded structural capacities to fuel urban growth.
First, we have the leaps in Materials Sciences and Manufacturing, revolutionizing the very building blocks of our structures. Second, there have been significant improvements in Connection Fabrication and Installation Techniques, enhancing the strength and efficiency of construction. Lastly, the Integration of Computer-Aided Design (CAD) and Finite Element Analysis brings unprecedented precision to structural design.
There are two primary strategies for examining the responsible deployment of structural systems. Architects and engineers can work to find the most efficient system layouts to minimize the actual material used, thereby decreasing the embodied carbon within a building’s structural system. Planning regulations can be used to target and incentivize the optimal structural system for a specific region and condition, weighing multiple factors beyond just project code compliance.
Optimization of structural systems is a practice as old as engineering itself, and the emergence of finite element analysis has accelerated the possibilities of structural design. Previously, these tools were incredibly complex and restricted to those with specialized expertise in the field. That limitation is changing due to the advancement of computer applications geared toward all types of design practitioners. Those with specialized expertise can push the limits of these applications and take their strategies to the next level, creating robust yet optimized designs.
There’s a confluence of innovation occurring that has the opportunity to lead to a revolution in structural systems. This can be broken down into two different sides, or workstreams, that have the potential to create incredibly efficient and optimal structural configurations when merged together. The first deals with design, and the second with construction. Both of these processes have been around for decades, but they are becoming more and more accessible as costs decrease and expertise increases.
DESIGN SIDE: COMPUTATION, OPTIMIZATION, AND FORM FINDING
The ability of architects and engineers to leverage computational design⁸ for producing optimal structural systems is increasing daily with the integration of open-source applications into the design process. A generation of designers who are well-versed in software development are also rising into the workforce, blending and technical skills. It’s easier than ever for an ambitious engineer to develop a system for efficiently analyzing a specific type of structure and releasing that process to the public. Merging disciplines such as computer science, data science, engineering, and architecture is powering a new wave of cross-disciplinary innovation crucial for addressing today’s most complex problems.
The principles of intelligent design have long been established, as evidenced by the mathematical thinking that made the ability of Roman arches to span long distances efficiently so groundbreaking. For generations, forward-thinking designers have pushed the boundaries of physics to design beautiful yet functional specialty structures. Felix Candela leveraged the shell for impossibly thin concrete structures. Antoni Gaudi used his knowledge of natural systems and craftsmanship to develop techniques for the design of his form-finding structures. Today, Santiago Calatrava is designing ambitious projects internationally and pushing the boundaries of structural design.
These approaches, however, have been primarily used on specialty structures, and their mass market adoption has been slow or non-existent. These innovative design systems are evident in projects like churches, airports, transit hubs, and stadiums but are rarely deployed on buildings that impact daily life. Initially, it was thought that the efficiency of these systems would diminish at a smaller scale. Several firms and individuals, though, are actively researching and experimenting with ways to adapt these strategies for smaller mass-market projects in an economical way.
One such group is the Block Research Group (BRG) at ETH Zürich, led by Prof. Dr. Philippe Block and Dr. Tom Van Mele. BRG combines academia and practice to design and test masonry structures through methodologies like computational design, analysis, form finding, discrete assembly design, and prototyping.
A particular focus of their research, for which they seek mass market adoption, is the rib-stiffened funicular floor system. This approach combines a few areas of expertise and aims to replace current inefficient floor slab design and construction. By leveraging the structural design approach of a funicular vault, this system is able to reduce concrete usage by 70% and reinforced steel usage by 90%, resulting in a drastic reduction in embodied carbon. The BRG also proposes this system as a pre-fabricated module, eliminating the need for highly specialized formwork and on-site casting to achieve this complex design.
David Benjamin and his studio, The Living, is another example of collaborative research and practice. They are formally an Autodesk Studio, which adds another layer of innovation to this arrangement. Autodesk is a software company, and its partnership with The Living presents a unique model for innovation as it opens up an opportunity for a feedback loop between research and commercial software. The ideal scenario is that the smaller, agile, cutting-edge research group can produce and present innovative ways of working, and the publicly traded company with massive resources can implement these forward-thinking methodologies into their mass-market platforms.
Like the BRG, The Living has invested much time and energy into developing optimized systems. Their Bionic Partition project, in collaboration with Airbus, leverages optimized structural systems and 3D printing to build incredibly strong and light structural frames for airplane partitions. The result is a 50% reduction in the weight of these partitions. When extrapolated to dozens of partitions on thousands of planes, this structural optimization can lead to carbon emission reductions of upwards of one million tons per year due to the fuel saved via weight reduction.
These are just two concrete examples of this type of optimized design approach. The takeaway is not that these specific applications will save the world, though. Will both of these techniques see mass-market adoption and genuinely make an impact? Hopefully, but it’s not guaranteed. This type of research and approach is necessary to rethink what we can do with traditional structural systems and inspire the next generation to build on these techniques. The most ambitious design in the world can look good on paper, but that won’t make a difference until it is constructed. That’s where digital fabrication comes into play.
CONSTRUCTION SIDE: DIGITAL FABRICATION
One of the most significant challenges to constructing the optimized systems mentioned above is the complexity required to build them. Increasingly efficient designs seem like an obvious solution. Wouldn’t less material equal lower costs? More complex shapes are rarely used due to the additional labor, time, and expertise; therefore, the cost required to construct them far outweighs any cost savings captured by using less material. Post and beam construction is the standard because it’s straightforward. Usually, all of the elements are arranged at 90-degree angles, and the structural shapes are mostly rectangles. The construction industry has opted for less efficiency in favor of speed and simplicity.
Digital fabrication, in conjunction with computational design, is revolutionizing how things get built. With tools like CNC mills, 3D printers, and robotic arms becoming more affordable and user-friendly, 3D model designs can be directly converted into physical structures. This marks a significant shift from the traditional manual process of translating designs into construction, a method reliant on drawings and often limited by time and cost due to complexity. Previously, the need to simplify shapes was crucial, as the complexity of a design directly impacted the feasibility and cost of construction. Now, new tools have changed everything. As long as the design specified fits within operational constraints, there’s no difference between making a simple rectangle or a complex funicular arch. This technological advancement is leading towards a future where if a structure can be built digitally, it can almost as quickly be realized physically, often with the push of a button.
Secondly, digital fabrication’s ability to print or mill objects can leverage techniques and processes more often seen in product and automobile manufacturing than in architecture. This marks a shift from a more field-based construction process to a more factory-based one, which means more efficiency and savings.
Within a factory setting, the ability to operate round-the-clock, especially with less reliance on manual labor, can lead to increased production and greater economies of scale. Factories also mitigate delays caused by external factors like bad weather. It also enables the simultaneous handling of multiple projects, which is crucial because the cost of designing and establishing a system for a single project can be prohibitively expensive. To justify the investment, it’s much more desirable to have the cost distributed across several projects because the more projects are undertaken, the lower the per-building design cost. Eventually, this leads to a point where the design cost for each building or element is significantly reduced, making the overall business case more viable.
While the virtues of factory versus field building are clear, there’s still more to consider. Icon is pioneering an approach that extends the concept of bringing factory efficiency to the field — blending the best of both worlds. They’re investing in robotic construction methodologies, mainly 3D printing, to rethink how high-quality homes are built. Imagine a scenario where, instead of the traditional methods of constructing or shaping the structural walls of a new home, one could simply print them right on the construction site. Icon is producing results that are not only efficient but also remarkably elegant. Their preliminary approach is focused on addressing the single-family home market, and their technology currently works well at that scale. In fact, global projections from the IEA indicate that the amount of total residential floor area required to support increased demand between 2022 and 2050 will reach 310 billion square meters globally, or 3.3 trillion square feet. Single-family homes will play a large part in meeting that benchmark.
As noted previously, increasing concrete use raises environmental concerns. However, Icon is investigating how its technology measures up from a carbon impact standpoint. According to a whitepaper released by the MIT Concrete Sustainability Hub in March 2024, 3D-printed homes can reduce operational and life-cycle carbon compared to traditional stud-frame construction across multiple climate types. There are a few ways this is achieved.
First, Icon’s system reduces carbon impact by using low-carbon concrete mixes in its 3D-printed homes. By using optimized aggregate grading, they reduce the cement and powder content. In addition, the raw material is all sourced within 80 miles of the batch plant to help reduce transportation-related carbon.
Icon’s second carbon reduction method involves more efficient designs for exterior wall assemblies. Traditional stud framing requires multiple layers of materials to achieve structural support, insulation requirements, waterproofing, and finish surfaces. Concrete can do the work of most, if not all, of these other elements. Plus, because concrete is unbiased in terms of shape, the form can be customized to achieve different configurations and thicknesses to account for structural and performance needs.
The third method leverages concrete’s operational advantages. The localized construction process minimizes transportation needs and labor requirements while accelerating building timelines. Further, related to the point above regarding efficient wall assemblies, it reduces the number of trades required. Finally, concrete is typically a more resilient material than wood, both in terms of long-term durability and resistance to natural disaster events. So, while the analysis in the MIT whitepaper normalizes the duration of both projects to a 75-year lifespan, there’s an argument to be made that concrete can provide an even higher reduction in lifecycle carbon due to the fact that the replacement rate for both building elements and entire structures would be lower.
Again, the ability to leverage computational strategies for 3D printing allows for a more direct translation of design to construction. Above all, using these more optimized systems yields a massive reduction in waste and material usage (upwards of 70%) while also striving for ways to reduce embodied carbon. These elegant expressions of structure are also a design ideal as old as architecture itself. Architects should embrace emerging technologies that express the innovative new methodologies used to produce them while also providing high-performance results.
MANUFACTURING SIDE: LOW-CARBON PRODUCTION
A pragmatic, responsible approach to the future of structural deployment in cities must include innovative design and construction methodologies and a rethinking of materials and manufacturing processes. A January 2024 whitepaper released by BloombergNEF and the Climate Technology Coalition argues for implementing new manufacturing processes and incentive programs to facilitate the growth of low-carbon steel.
Specifically, they highlight the benefits of using hydrogen in the steelmaking process, which can decarbonize over 40% of global steel production by 2050, impacting an industry that currently accounts for 7% of global carbon emissions. In order to reach net zero, the steel industry must move away from using coal and natural gas and focus more effort on implementing hydrogen, electrification, carbon capture, and recycling.
The steel industry is worth $1.6 trillion, with the construction sector representing over half of that value. Thus, strategic decarbonization has the opportunity to be incredibly impactful and profitable. Like most emerging technologies, though, there are cost premiums and limitations associated with the production of low-carbon steel.
Policy-makers can incentivize the use of this type of steel, and some initiatives are already underway to help offset cost or supply issues. The US Federal Buy Clean Initiative encourages the use of green steel on government projects. The EU’s carbon market “creates a case for hydrogen-based steel to be cost competitive by the early 2030s.” Also, collaboration among steel buyers and steel producers can increase demand for green steel. Finally, public procurement accounts for 25% of global steel demand. Hence, as governments increase mandates on the use of green technology in public projects, the demand for such products will also increase. Early movers on green steel will be positioned for success as the industry trends more and more in that direction.
CONCLUSION
The three structural systems examined here are fundamental to contemporary architectural advancements, driving the growth of urban environments. Yet, as explored, the environmental impact of using these cornerstones of architecture is becoming more pronounced. This raises a crucial question: How can society design and construct spaces that not only meet high-quality standards but are also environmentally sustainable?
While some advocate for a complete shift away from traditional materials like concrete and steel, such an extreme change is neither realistic nor the most effective. A more pragmatic approach would include these materials judiciously and responsibly as necessary while integrating eco-friendly alternatives wherever feasible. This balanced method aligns with the realistic constraints of construction practices. As various case studies have demonstrated, there are indeed efficient and responsible ways to utilize concrete.
Three key considerations support this approach: First, the necessity of high-density urban development, as seen in New York City. This approach efficiently accommodates a growing global population in limited spaces, reducing per capita carbon footprints through shared resources and public transportation. High-density areas like NYC necessitate strong materials like concrete and steel to support vibrant communities and access to services. This highlights the need to balance traditional and eco-friendly resources in urban planning/city construction.
Second, our population is growing rapidly. The United Nations Department of Economic and Social Affairs (DESA) has projected that the world’s population will reach 9.7 billion by 2050, up from 7.9 billion in 2022. This means that an additional 1.8 billion people will need to be housed and fed in the next 28 years. An equivalent of one New York City (approximately 8 million people) must be constructed monthly to accommodate this growth. This is a daunting statistic, especially considering that much of the world’s population growth is expected to occur in developing countries, such as Africa, where resources are already scarce. Addressing this challenge demands fast and innovative solutions for affordable housing. It’s imprudent to severely limit the use of certain materials in a world where so many do not have access to quality housing. We can achieve a responsible balance by deploying a mixture of sustainable strategies and efficient use of non-sustainable ones while gradually working to phase out non-sustainable methods.
Third, the entrenched nature of these construction materials in industry practices suggests that any significant change is unlikely to occur swiftly. Therefore, a realistic and balanced approach, focusing on responsible and context-sensitive use of both traditional and eco-friendly materials, emerges as the most viable path forward in contemporary construction and urban planning.
Technical improvements for construction efficiency and major structural systems have been explored. However, realizing these advancements hinges widely on policy support. Policymakers can play a pivotal role by adopting a three-tier approach that includes recommending structural systems based on specific factors like building density, promoting sustainable materials such as mass timber through incentives like grants and tax breaks, and encouraging the efficient use of traditional materials in necessary cases to minimize waste.
Additionally, the COVID-19 pandemic has highlighted the importance of adapting these strategies within the context of current global challenges. The pandemic’s impact on supply chains and labor practices has underscored the need for resilience and flexibility in construction practices. This new reality makes it crucial for regulatory bodies to stay abreast of rapid technological changes and to understand how different structural systems can be deployed effectively while addressing contemporary challenges such as supply chain reliability and ethical labor practices.
Advanced environmental systems complement these structural systems, ensuring that buildings are not only structurally sound but also provide habitable and comfortable spaces. While these structural systems undoubtedly represent pillars of modern innovation, their environmental impact demands careful consideration. Navigating the complexities of rapid technological advancements, supply chain resilience, labor practices, and regulatory frameworks is essential for devising new and innovative solutions.
The harmonious integration of structural systems within buildings and urban landscapes stands as a cornerstone of sustainable urban growth. These systems profoundly influence both embodied and operational carbon emissions, shaping the environmental footprint of cities. Materials like steel, concrete, and mass timber serve as the pillars upon which we construct taller and larger edifices, and their efficient manufacturing and distribution play a pivotal role in supporting global city expansion. The future of sustainable urban growth hinges on responsibly harnessing the power of structural systems. By embracing sustainable practices to minimize environmental impact while safeguarding the liveability and vibrancy of cities, a future can be paved where the built environment thrives in harmony with the planet.
[1] Stud framing, also known as stick framing, is a centuries-old technique. Usually consisting of members with a 2x designation (2x4, 2x6, 2x8, etc.), it is popular for its ease of procurement and assembly. It also allows for convenience in adding electrical, plumbing, and heating/cooling systems.
[2] Mass timber has existed in various forms for decades but is becoming popular under this umbrella term. Some of these forms include laminated veneer lumber, multi-panel plywood, and cross-laminated timber. It has tremendous potential as a structural solution in various applications and merges wood’s flexibility with increased structural capacity and fire resistance. It is also considered a more sustainable solution than its structural counterparts. One of its main challenges is a lack of familiarity and availability. Because steel and concrete have existed for centuries, they are ingrained in the construction process, with generations of know-how behind them. Manufacturing capacity is also lagging. Both of these factors drive up costs. With time, mass timber will become more and more of a standard solution.
[3] Gates, Bill. How to Avoid a Climate Disaster. Random House US, 2022. p.
103
[4] For quite some time, a building’s environmental performance was evaluated on its energy use, which equates closely to operational carbon. It ignores the amount of energy required to construct the building. However, embodied carbon attempts to measure ALL carbon costs required to construct a building. For example, a 2x4 has insulative properties that can be used to determine how efficiently it transfers heat. However, 2x4 also has embodied carbon associated with it — how much carbon was expended for it to be processed, transported, installed, and many other factors. A more “sustainable” material that needs to be shipped across the globe may have a greater carbon footprint than one that appears less sustainable but is manufactured locally.
[5] Gates, Bill. How to Avoid a Climate Disaster. Random House US, 2022. p. 104
[6] A fire district is a neighborhood where certain combustible materials are prohibited, even if other aspects of the code allow them. The fire district designation takes precedence. In New York City, all of Manhattan, Brooklyn, and the Bronx are part of the fire district, with portions of Queens and Staten Island included as well.
[7] The five construction types are fire resistive, non-combustible, ordinary, heavy timber, and wood-frame. The more fire-resistant the construction type, the larger and taller the building can be. Designers and builders can achieve these different types with a variety of solutions, but typically, materials like concrete and masonry are used to increase fire resistance. More flexibility is being permitted with mass timber design and engineering evolution.
[8] Computational design refers to the use of computer algorithms and software tools to solve complex design problems, create models, and generate patterns or layouts that might be difficult or time-consuming to produce manually. It is commonly used in fields like architecture, engineering, and digital arts. Essentially, it involves programming computers to assist in or automate aspects of the design process, helping designers explore a broader range of options more quickly and with greater precision than traditional methods. It can also quickly analyze design ideas for structural and environmental performance, allowing for highly optimized designs.
