The next frontier in floor system construction is here

By Ronald Klemencic, P.E., S.E., NAC, NAE, F.SEI, Dist.M.ASCE, and Jerome F. Hajjar, Ph.D., P.E., NAE, F.SEI, Dist.M.ASCE

FastFloor is a visionary leap forward and proof that structural engineering innovation thrives on collaboration.

For decades, engineers and contractors have been pursuing a simple idea with not-so-simple implications: Build faster, safer, and more sustainably by shifting the fabrication of critical systems into the shop. SpeedCore was a vertical-framing breakthrough, a shop-fabricated composite steel plate shear wall that shaves months off high-rise construction schedules.

Floor systems, however, have proven more stubborn. They remain a field-built, multitrade bottleneck that can govern the pace of a project. If you have ever watched a tower pause for a concrete deck placement, finishing, and curing before anything else can move forward, you know the feeling. Vertical construction might be fast, but the floor system often is not. So the question remains: If we can prefabricate the core, why not the floor?

FastFloor is a potential answer taking shape. It is a modular, shop-fabricated, all-steel floor-framing and diaphragm system that eliminates the composite-concrete deck and the time that comes with it. The aim is not incremental improvement but a step change in speed: floors that install quickly as panelized assemblies with simple, optimized connections, aligning with the American Institute of Steel Construction’s broader “Need for Speed” initiative to compress the path from concept to occupancy. AISC’s target is ambitious: Increase the speed of steel building design, fabrication, and erection by 50%. FastFloor fits squarely in that lane.

The concept is deliberately collaborative and nonproprietary. The research team is drawn from Iowa State University, Johns Hopkins University, Northeastern University, Purdue University, Virginia Polytechnic Institute and State University, and West Virginia University, with industry partners and funders that include the Charles Pankow Foundation, the Magnusson Klemencic Associates Foundation, and AISC.

The work is proceeding in phases. Phase 1 established FastFloor’s viability through brainstorming with industry partners, analysis, and early vibration testing, while Phase 2 scaled up with broader prototype analyses as well as vibration and acoustics studies. Phase 3 investigated connection details as well as module strength and stability, and ongoing Phase 4 testing considers fire performance and will establish design recommendations.

The goal is a modular floor that can be erected 30% to 50% faster than conventional concrete-on-metal-deck systems; integrated with a raised-access floor for mechanical, electrical, and plumbing distribution; and designed for performance across strength, deflection, vibration, acoustics, and fire objectives.

A typical FastFloor module includes two W24×68 steel beams spanning 40 ft, spaced at 5 ft on center with a 10 ft wide, 0.5 in. thick plate welded to the top flanges and a shear tab or seated connection at the ends of the beams, suitable for framing into building components such as a lateral resistance system or a spandrel girder. The free edge of the plate rests on the top flange of the neighboring module and is typically bolted to that flange in the field. An alternative includes a 5 ft wide module and a 5 ft filler plate that is bolted to the beams in the field.

Additional alternatives have been and continue to be considered, but the simplicity of two beams and a plate has advantages throughout the production pipeline that have elevated it to the best initial option to explore. A typical office floor plan is shown below.

SpeedCore proved what a shop-built structural backbone could do to speed up construction in the field. At Seattle’s 58-story Rainier Square, the system supported steel erection that topped out in 10 months and moved 43% faster than conventional methods. The core was constructed at roughly four floors per week rather than one floor every three to five days. FastFloor extends the logic horizontally so that the frame and floor rise together at an accelerated pace.

From a research perspective, the challenge was not only practical but also fundamentally scientific: how to address strength, serviceability, connection reliability, and diaphragm behavior comparable to a composite concrete deck floor system while dramatically increasing the speed of construction.

Early trials and tribulations

To be successful, a new floor system must achieve fabrication, shipping, and field installation efficiencies while satisfying all engineering criteria. Early all-steel floor concepts, including a 2016 MKA design inspired by shipbuilding practice, were lightweight and elegant on paper but broke down on cost and complexity in the shop: too many parts and too many unique pieces to rationalize production. If a fabricator cannot fabricate parts efficiently, repeat details, and count on a stable assembly sequence, the economics do not pan out.

Phase 1 of the FastFloor research leaned into that lesson, establishing an approach that simplicity is not a preference; it is the enabling constraint. The research team built a matrix dedicated to addressing the challenge of distinguishing between what is optimal and what is elegant and optimally buildable. This matrix spans the entire life cycle, including:

• Fabrication, transportation, erection, construction sequence, and future deconstruction

• Gravity and diaphragm behavior

• Connection details

• Deflection, vibration, and acoustics

• Extreme events, e.g., seismic, blast, and fire

• Project-level metrics, e.g., weight, speed, sustainability, initial cost, and long-term maintenance

This system view has framed every decision that followed.

Another lesson learned was to avoid jumping from component modularity to volumetric modularity. FastFloor is not a room-in-a-box; it is a structural module. The sweet spot is panelization using highly repeatable connections that let field crews set, lock, and move. That is why the current development focuses on panelized steel beam + plate modules paired with a raised-access floor for MEP distribution, replacing the conventional steel deck and in situ concrete placements with shop-controlled quality and site speed.

Collaboration accelerates adoption

Complex innovations survive only if they are stress-tested. FastFloor’s innovation model is intentionally open source in spirit and included funders, industry practitioners, and academics in the meetings from day one, meeting regularly, iterating on details, and refusing speculative economics.

The Pankow Foundation, AISC, and the MKA Foundation established the vision and underwrote the work. The principal investigators — W. Samuel Easterling, Ph.D., P.E., F.SEI, Dist.M.ASCE (Iowa State), Benjamin W. Schafer, Ph.D., P.E., F.SEI, M.ASCE (Johns Hopkins), Amit Varma, Ph.D., P.E., M.ASCE (Purdue), Matthew R. Eatherton, P.E., M.ASCE (Virginia Tech), Onur Avci, Ph.D., P.E., F.ASCE (WVU), and Jerome F. Hajjar, Ph.D., P.E., NAE, F.SEI, Dist.M.ASCE (Northeastern), who is coauthor of this article — established the engineering research program.

Fabricators, erectors, and contractors weighed in on what would work in the shop and on-site. The collaboration showed its value at the Phase 1 closeout, when design engineers, material producers, fabricators, acoustic consultants, raised-access floor suppliers, coatings manufacturers, and major contractors met with the research team to consider initial results and help plan the remaining phases.

The research program was structured to address the toughest challenges first: module simplicity and efficiency, vibration performance, and acoustic performance. As the research proceeded and continued to show promising results, the team engaged in a much broader range of work to validate the system when subjected to extreme events. The team fostered a collaborative environment that incorporated input and assistance from practitioners at MKA, the research experts at AISC, and the professionals on FastFloor’s Industrial Advisory Panel, including project sponsors, while underpinning the work with independent academic neutrality. This combination has provided broad support and credibility that will foster confidence in this system for future owners and building officials.

What the research results show

The research program is comprehensive and ongoing, but several pillars are clear:

• Structural performance and diaphragm action. A new floor system must efficiently carry gravity loads and act as a diaphragm for lateral load transfer. The research program explicitly targets gravity strength and ductility, diaphragm performance, and the connections that make both reliable. Phases 2 and 3 included full-scale prototype analyses and testing to verify behavior and refine design procedures.

• Vibration serviceability. Lightweight floor systems are often controlled by vibration serviceability design. The team has reported analytical results and laboratory testing that benchmarks FastFloor modules against serviceability criteria, using tools like AISC Design Guide 11 (Vibrations of Steel-Framed Structural Systems Due to Human Activity) and finite-element simulations. The findings indicate a more complex modal response than conventional construction, but the results are clearly within acceptable ranges for typical building uses. Testing in Phases 2 and 3 confirmed promising results on a full-scale test specimen. See page 62 for an example of a full-scale structure representing a 30 ft by 40 ft bay being tested for vibrations in the laboratory at WVU.

• Acoustics. Removing the composite concrete floor affects airborne and impact sound transmission. Phase 2 included acoustic testing at WVU. Industry partners on the advisory panel include acoustic specialists who worked with the research team to validate that FastFloor performance will meet typical building occupant expectations.

• Fire and extreme events. Fire performance remains a key workstream. The program’s matrix explicitly includes fire within “extreme events,” and parallel AISC efforts on related steel systems provide context for appropriate fire protection scenarios. The objective is to identify protection strategies compatible with shop fabrication and rapid erection while meeting code and performance expectations. Phase 4 includes full-scale fire performance testing.

• Sustainability and embodied carbon. Conventional concrete-topped steel deck floors carry a material and carbon burden that is well documented. By eliminating the placing of the concrete and removing its contribution to overall building mass, FastFloor aims to reduce weight and embodied carbon at the system level while shortening the construction time and decreasing corresponding contributions to embodied carbon. The research team cites sustainability and life-cycle assessment as explicit metrics alongside schedule and cost. As the steel industry continues to introduce processes that lower carbon emissions, the sustainability benefits of FastFloor will continue to improve.

• Speed and constructability. Shop-built panels reduce field labor and weather risk; simple, optimized connections reduce fit-up time; and pairing with a shop-built core (SpeedCore) aligns sequences so that the frame and floor advance together. The construction of Rainier Square using SpeedCore showed how schedule savings cascade through site operations and related costs, as well as construction financing. FastFloor is designed to produce a similar result for the horizontal plane. Discussions with steel erectors during Phase 1 established erection plans reducing on-site decisions and preserving the cycle-time gains.

As stated above, the researchers at WVU, with support from Iowa State, conducted full-scale vibration and acoustic tests and analyses of the FastFloor system. Researchers at Johns Hopkins and Virginia Tech provided further computational studies of vibration performance as well as investigations of local buckling, diaphragm, and connection strength. The teams at Northeastern and Virginia Tech are investigating the behavior of the FastFloor system for gravity loading, while researchers at Purdue are evaluating the fire performance of FastFloor.

Why it matters

Owners and contractors want a floor system that behaves predictably, with inspection regimes that are clear and logical for authorities having jurisdiction to follow. The FastFloor model is built for that outcome. It is a system grounded in the steel industry’s capacities and aligned with occupant performance targets that make schedule conversations highly reliable.

Regarding costs, speed reduces on-site operational costs during construction and interest expense related to construction loans. Earlier occupancy means earlier cash flow — money in the owner’s pocket. Taken together, these positive financial impacts are substantial.

How adoption works in practice

Adoption is always a chicken-and-egg challenge. The industry wants proven systems, and systems only get proven on real projects. FastFloor’s nonproprietary model and the breadth of its partners are designed to break that loop. The near-term pathway looks like this:

• Design guidance and exemplars. As research milestones are met, design examples and detailing guidance flow through the research team and AISC to provide engineers, fabricators, and erectors with a credible starting point, just as happened with SpeedCore.

• Pilot projects with aligned stakeholders. Early adopters with schedule pressure, supportive building officials, and supply chains comfortable with panelization pick targeted buildings where the payoff is obvious: repetitive floor plates, tight sites, or places where weather and labor constraints make field concrete placements more challenging. With producers, fabricators, raised-access floor suppliers, coatings partners, and contractors already aligned on erection plans and shop-implemented details during Phase 1, early projects inherit fewer unknowns and a faster path to “yes.”

• Iterative refinement. Lessons from the first set of pilots feed back into connection details, panel geometries, acoustic treatments, coatings, and considerations for possible changes to national design specifications to standardize what works and drop what does not. Because the system is not locked to a single vendor, improvements can be implemented quickly.

Building the future

The research window is measured in months, not decades. As additional test series are completed in Phase 4, design procedures and detailing conventions will follow the same path they did for SpeedCore, from papers and reports into the hands of engineers who will integrate them into practice.

For developers and contractors, the ask is simple: Be early and be specific. Choose projects where schedule compression is a first-order driver and where a shop-built floor can eliminate the possible delays that field concrete placements may impose. Involve your fabricator early, line up the raised-access floor supplier, and coordinate with your reviewer so that the conversation is more about performance than the novelty of the system.

While the research team always emphasizes safety, serviceability, and constructability first and foremost, it also focuses on sustainability and economy as critical drivers for society. Construction costs impact everyone. Focusing on systems that bring integrity through rigorous testing and analysis, while offering the opportunity to decrease construction costs and lower embodied carbon in the built environment, is critical for the industry moving forward.

Closing thoughts

Innovation in structural engineering need not be slow. It is nimble when the stakes are clear and the team is aligned. FastFloor is proof that vision paired with collaboration can rewrite the sequence we have considered to be the standard for generations. AISC set a speed goal. The vertical support and lateral bracing of the structural frame delivered a measurable win with SpeedCore. Now the floor system is catching up, with the same recipe of shop quality, field speed, and academic integrity that owners and reviewers can trust.

The FastFloor project has provided an opportunity to bring together research and industry professionals to develop an innovative system that integrates safety, serviceability, constructability, sustainability, and economy. This has been a world-class team effort, and it shows what is possible in improving design and construction with economical, safe, and sustainable building methods. 

Ron Klemencic, P.E., S.E., NAC, NAE, F.SEI, Dist.M.ASCE, is chair and CEO of Magnusson Klemencic Associates. Jerome F. Hajjar, Ph.D., P.E., NAE, F.SEI, Dist.M.ASCE, is CDM Smith Professor and University Distinguished Professor at Northeastern University.

This article first appeared in the September/October 2026 issue of Civil Engineering as “The Next Frontier.”

The FastFloor co-funding organizations are American Institute of Steel Construction, Atlas Tube, Charles Pankow Foundation, Cives Steel Co., Gerdau, Herrick Corp., Metals Fabrication Co., MKA Foundation, Nucor, Schuff Steel, and Steel Dynamics.