About

Jerome Hajjar, CDM Smith Professor and University Distinguished Professor, has been recognized by the American Society of Civil Engineers as a 2026 Distinguished Member for his fundamental contributions to civil engineering education and to design practice through research in steel and composite structures, including structural stability and earthquake engineering, and for leadership of professional and academic committees and boards of direction that advance the practice of civil engineering. During his tenure as chair of the Department of Civil and Environmental Engineering from 2010 to 2025, the department tripled in size and significantly elevated its global research impact. Hajjar, who also serves as director of the STReSS Laboratory, will be officially honored at the ASCE OPAL Gala in October 2026.

Research topics

• Artificial Intelligence
• Computer Science
• Computer vision
• Mathematics
• Data Mining
• Machine Learning
• Engineering
• Geology
• Remote sensing
• Optics
• Structural engineering
• Geometry

Selected publications

• A Synopsis of Sustainable Structural Systems With Rocking, Self-Centering, and Articulated Energy-Dissipating Fuses

  2026-02-01 · 28 citations

  articleOpen access1st authorCorresponding

  This synopsis examines previous research related to seismic energy-dissipating structural systems for buildings. These systems are grouped into self-centering systems, systems exhibiting rocking behavior and systems with energy-dissipating fuse elements. Bracing systems, precast buildings, steel frames with post-tensioning strands, rocking shear walls and some similar structural systems are investigated for self- centering behavior. Rocking motion reduces seismic loading and ductility demands by generally forcing structural behavior to remain in the elastic range. Energy-dissipating fuses are structural elements that protect the surrounding structure by absorbing energy from an earthquake that would otherwise be absorbed by the primary girders, columns, and braces of the structure, as well as nonstructural elements.

  PublisherOA PDFDOI

• Assessing risks and opportunities for offshore wind energy under evolving tropical cyclone hazards

  Advances in wind engineering. · 2026-03-01

  articleOpen access

  This study presents a simulation-based framework for assessing offshore wind turbine failure risks and potential benefits from conceivable increased power generation during tropical cyclones. Using a future climate model based on projected sea surface temperatures (SSTs) of the Shared Socioeconomic Pathway 3 scenario (SSP3-7.0), the research examines the impact of changing tropical cyclone patterns on offshore wind power generation efficiency, safety, and reliability. Bias correction techniques are applied to global climate models (GCMs) to improve the accuracy of future climate projections, resulting in more robust and representative outcomes. Hazard curves for hurricane wind speeds indicate increased wind demand under the SSP3-7.0 scenario, particularly affecting Northeastern sites. In this study, the projected 50-year return-period wind speeds increase by 8 to 27% by 2060. Under the worst-case scenario in which the turbine loses yaw control and experiences a 65° yaw misalignment with respect to incoming wind, the probability of failure remains below 10% for IEC Typhoon Class (Class T) turbines with a reference wind speed of 57 m/s. Benefit analysis highlights potential increases in power generation at northern locations such as Massachusetts, New York and New Jersey, due to the greater frequency of weak tropical storms reaching northern regions. This study also evaluates hurricane-induced failure risks for offshore wind turbines by integrating site-specific hazard curves with structural fragility analysis. Results indicate that evaluating turbines designed for current climate conditions, particularly those based on IEC Class I (50 m/s survival wind speed) and Class T (57 m/s survival wind speed) specifications, using future hazard curves leads to more than an order-of-magnitude increase in annual failure probability, whereas designs that account for future climate conditions demonstrate substantially lower failure probabilities and improved structural reliability. At the time of manuscript preparation, several manufacturers produce turbines that exceed the IEC standard, with survival wind speeds of up to 80 m/s. The failure risk of these turbines is therefore expected to be lower than that evaluated in this study. • A simulation framework evaluates both risks and power gains from tropical cyclones. • Future SSTs under SSP3-7.0 increase hurricane hazard levels for 11 U.S. offshore wind energy sites. • Mid-Atlantic and northeastern offshore wind sites may require higher turbine survival capacities under future climate conditions. • Northern sites may gain power due to increased frequency of weaker storms. • Designing towers based on current climate conditions reduces tower reliability if future hurricane hazard under SSP3-7.0 pathway is realized.

  PublisherDOI

• Comparative life cycle assessment for two structural framing plan alternatives in a composite hybrid steel—cross laminated timber (CLT) building

  Environmental Research Infrastructure and Sustainability · 2026-01-12 · 1 citations

  articleOpen accessSenior author

  Abstract The construction industry is increasingly focused on reducing embodied carbon emissions to address climate change. Steel—cross laminated timber (CLT) composite hybrid structures, where CLT floors and steel framings work in composite action to resist gravity forces, offers benefits such as carbon storage, recyclability, reduced use of carbon-intensive materials, and improved project schedule and quality control. This composite hybrid system can accelerate progress toward net-zero embodied carbon by integrating carbon-storing materials within the existing AEC (Architecture, Engineering, and Construction) ecosystem for commercial and high-rise buildings, where timber use is limited. This study analyzes two structural patterns within the composite hybrid system and uses life cycle assessment (LCA) to identify trade-offs in embodied carbon. A 12-story office prototype is designed using two framing spans of 12.5 feet (3.8 m, Basic Hybrid ) and 25 feet (7.6 m, Stretch ), resulting in a change in the wood-to-steel ratio. In the Stretch design, the structure’s mass increases by 20% due to thicker CLT panels for the longer span, despite reduced steel framing, resulting in a 5% heavier foundation. The LCA considers upfront emissions from the product and transportation stages (A1–A4). Excluding biogenic carbon, the Stretch design has 3% higher embodied carbon than Basic Hybrid ; however, including biogenic carbon storage shows an 83% greater carbon benefit for Stretch . A dynamic assessment of biogenic carbon storage reveals that the building must be in service for 23 years for forest regrowth to offset initial forestry emissions, while the 7-ply system achieves net-zero carbon for the whole building in 67 years, compared to 80 years for the 5-ply system.

  PublisherDOI

• Carbon reduction strategies with steel-CLT hybrid structures

  2025-06-30

  book-chapterOpen access

  Biogenic materials are a promising path for building decarbonization. However, carbon storage in short-lived components may only postpone the crisis when releasing the carbon back into the atmosphere. Design strategies for longevity, whether by designing buildings to be reused, or to be deconstructed and materials reused, are just as important. This research explored solutions to the short- and long-term problem through the design of hybrid steel-timber structures. The design leveraged the spatial efficiency, reusability, and market dominance of steel in US commercial buildings to accelerate the path to decarbonization. The cross-laminated timber (CLT) designed for deconstruction and reuse replaced the concrete slab to store carbon for the long term. This paper describes design strategies, from structural patterns to enclosure and distribution of services, and shares results from the Life Cycle Assessment about their relative contribution to carbon reductions from the equivalent baseline steel-concrete building to achieve net zero embodied carbon.

  PublisherOA PDFDOI

• Modal Testing and Finite Element Model Updating of a Fast-Floor Specimen: A Modular All-Steel Floor System

  2025-01-01

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Cyclic Behavior of Steel Headed Stud Anchors in Concrete-Filled Steel Deck

  SSRN Electronic Journal · 2025-01-01

  preprintOpen access
  PublisherDOI

• Prototypes in collaboration: Practice-based research and research-based practice

  2025-06-30

  book-chapterOpen access

  Building decarbonization is a fertile space for collaboration between architects and engineers from academia and practice. Reflecting on the process of prototyping deconstructable steel-timber hybrids for net zero carbon, from components to whole buildings, shows research questions emerging from experimental projects in practice, and how design research explores feasible paths towards more broad application. This collaboration in prototyping is not about an idiosyncratic project nor a prescriptive solution. Instead, digital prototyping of whole-building scenarios defines the widest range of performance requirements in different contexts, explores alternative paths to regulatory compliance, informs physical testing prototypes at smaller scales, and measures Life Cycle impacts, to anticipate challenges and opportunities faster than real buildings. This paper examines the shared motivations of academics and practitioners to engage in collaborative research and explains how the process can result in more useful outputs that reduce uncertainty in the design and construction industry to accelerate its transformation.

  PublisherOA PDFDOI

• Promoting Circularity of Building Materials through Novel Structural Systems for Adaptive, Deconstructable Hybrid Steel-CLT Designs

  2025-01-01

  articleOpen access

  Concrete and its steel reinforcement account for up to 50% of the embodied carbon emissions in typical high-rise commercial buildings. Replacing concrete floors with cross-laminated timber can lead to dramatic reductions in embodied carbon, and these reductions can be extended further if steel and CLT elements can be recovered, potentially recertified, and reused in another structural application. Vibrations and noise travel more easily through lightweight timber diaphragm floors compared to concrete slabs. These vibrations are typically reduced by pouring 1-2” of concrete on top of mass-timber floors, which impair the adaptability of the floor-diaphragm systems for deconstruction and reuse. The challenge is to design a system of connections and floor assemblies that provides the requisite structural performance, adherence to Type IV-B building codes for vibration, acoustics, and fire, while still enabling deconstruction and circularity of the structural materials. This submission will present an innovative design strategy for deconstructable, carbon storing buildings that can enable large-scale uptake of CLT into steel-framed commercial projects. Attendees will learn about the engineering and architectural challenges in designing hybrid steel-CLT buildings without typical concrete toppings, and how the proposed design uses novel connections that allow for rapid deconstruction that reduces costs associated with building material reuse. We will also cover the functional structural performance achieved by utilizing high-strength bolted connectors in steel-CLT hybrid structures, supplemented by experimental tests results, and how these results can be used to support major changes to code requirements that would enable deconstructability of an important class of buildings where it is currently rarely done. Finally, the presentation will guide attendees through the environmental benefits of this approach through application of life cycle assessment, but using a dynamic accounting framework that reveals that CLT must stay in use for more than 60 years in order for the prototype building to achieve net zero embodied carbon, either in the original building or reused in a new structure.

  PublisherOA PDFDOI

• A unified three-dimensional nonlinear mixed formulation with analytical interpolation functions for slender column analysis

  Engineering Structures · 2024-12-17 · 1 citations

  article
  PublisherDOI

• Physics-Guided Machine Learning for Structural Metamodeling and Fragility Analysis

  Lecture notes in civil engineering · 2024-01-01 · 1 citations

  book-chapterSenior author
  PublisherDOI

Recent grants

• Collaborative Research: Reconfiguring Steel Structures: Energy Dissipation and Buckling Mitigation Through the Use of Steel Foams

  NSF · $60k · 2010–2013

• Physics-Reinforced Deep Learning for Structural Metamodeling

  NSF · $599k · 2020–2024

• NRI: Large: Collaborative Research: Fast and Accurate Infrastructure Modeling and Inspection with Low-Flying Robots

  NSF · $328k · 2013–2018

• Deconstructable Systems for Sustainable Design of Steel and Composite Structures

  NSF · $264k · 2012–2017

• Collaborative Research: Transforming Building Structural Resilience through Innovation in Steel Diaphragms

  NSF · $232k · 2016–2021

Frequent coauthors

• Sanjay R. Arwade

  University of Massachusetts Amherst

  56 shared

• Andrew T. Myers

  ORCID

  53 shared

• Robert J. Dexter

  38 shared

• Wystan Carswell

  37 shared

• Sean C. Cotton

  Thornton Tomasetti (United States)

  35 shared

• Roberto T. Leon

  34 shared

• Tōru Takeuchi

  Osaka University of Pharmaceutical Sciences

  32 shared

• Ryota MATSUI

  31 shared

Labs

• STReSS LaboratoryPI

Awards & honors

• American Society of Civil Engineers Distinguished Member (20…
• William H. Wisely American Civil Engineer Award (2025)
• BSCES College Educator Award (2025)
• Structural Stability Research Council (SSRC) Distinguished M…
• AISC Special Achievement Award (2024)