In the world of structural engineering, steel girders are the unsung heroes, supporting everything from towering skyscrapers to sprawling energy infrastructure. But what happens when these girders have a sudden change in depth, creating a step that can lead to catastrophic buckling? This is the question that Amin Almasri, a researcher from Jordan University of Science and Technology, set out to answer in his recent study published in the journal *Fracture and Structural Integrity* (translated from Arabic as “Integrity and Fracture”).
Almasri’s work focuses on a phenomenon that, until now, has been largely overlooked: the local web buckling of stepped steel I-section girders. Unlike tapered girders, which have been extensively studied, stepped girders—those with an abrupt change in depth—have been largely ignored. “This is a significant gap in our knowledge,” Almasri explains. “Stepped girders are used in various applications, including energy sector projects, and understanding their behavior is crucial for safety and cost-effectiveness.”
The study begins by verifying linear buckling analysis against experimental results and established design codes like AISC-360 and Eurocode 3. But the real story unfolds in the case study of a stepped steel girder failure during construction. Through this investigation, Almasri uncovers a sobering truth: stepping the girder section can cause local web buckling at alarmingly low loads, sometimes as low as 27% of the original buckling capacity.
The implications for the energy sector are substantial. Steel girders are integral to the construction of power plants, oil refineries, and other energy infrastructure. A failure in these structures can lead to costly delays, safety hazards, and environmental risks. “Our findings highlight the need for careful consideration when designing stepped girders for high-moment locations,” Almasri notes. “But there are solutions. Moving the step to the tension flange or to lower moment locations can mitigate the problem.”
The study also explores the use of stiffeners to reinforce the girder. Almasri found that adding a long enough horizontal stiffener can almost fully restore the web buckling capacity, while a vertical stiffener only restores about half. Using both vertical and horizontal stiffeners nearly doubles the buckling capacity at the step. “This is a game-changer,” Almasri says. “It gives engineers a practical way to enhance the stability of stepped girders without compromising on design flexibility.”
As the energy sector continues to evolve, the demand for innovative and reliable structural solutions will only grow. Almasri’s research provides a vital foundation for future developments, offering insights that could shape the design and construction of energy infrastructure for years to come. “This is just the beginning,” Almasri concludes. “There’s still much to learn, but our work is a step in the right direction.”
In a field where safety and efficiency are paramount, Almasri’s study serves as a reminder that even the smallest details can have a profound impact. As the energy sector looks to the future, the lessons learned from this research will be invaluable in ensuring the integrity and longevity of our critical infrastructure.