In the realm of structural engineering, understanding how buildings and infrastructure respond to seismic events is paramount, especially for industries like energy that rely on robust, uninterrupted operations. A groundbreaking study led by S. Bagheri, a researcher at the Faculty of Civil Engineering, University of Tabriz, delves into the intricate dynamics of structures subjected to pulse-type ground motions, a common characteristic of near-fault earthquakes. The research, published in the journal ‘مهندسی عمران شریف’ (Civil Engineering Sharif), offers insights that could revolutionize how we design and fortify critical infrastructure, particularly in the energy sector.
Bagheri and his team focused on single-degree-of-freedom (SDOF) systems, which are fundamental models used to understand the behavior of more complex structures. They employed the analytical pulse model proposed by Mavroeidis and Papageorgiou, known for its precise physical parameters, to simulate near-fault ground motions. “The key here is to understand how different parameters—like the number of pulses, the pulse phase angle, and the structural properties—affect the frequency response functions of these systems,” Bagheri explains. “This knowledge is crucial for designing structures that can withstand the unique challenges posed by near-fault earthquakes.”
The study revealed that the frequency response functions of total acceleration and relative displacement in linear elastic SDOF structures show a notable similarity. However, when yielding occurs in bilinear SDOF structures, the characteristics of these responses diverge significantly. “In a linear elastic structure, the maximum frequency responses of displacement and total acceleration always increase with the number of pulses,” Bagheri notes. “But in an elastic-perfectly plastic structure or a bilinear structure with a small post-yield stiffness ratio, the maximum frequency response of total acceleration remains almost constant regardless of the number of input pulses when yielding occurs.”
This finding has profound implications for the energy sector, where the integrity of structures like oil rigs, power plants, and pipelines is non-negotiable. Understanding how these structures respond to near-fault ground motions can lead to more resilient designs, reducing the risk of catastrophic failures and ensuring continuous operation. “The energy sector can benefit immensely from this research,” Bagheri says. “By incorporating these insights into design standards, we can build structures that are not only safer but also more cost-effective in the long run.”
The research also highlights the importance of considering the nonlinear behavior of structures. For instance, the number of pulses that cause the maximum frequency response differs at different levels of nonlinear behavior. This nuanced understanding can guide engineers in creating more accurate models and simulations, leading to better-prepared structures.
As the energy sector continues to evolve, with a growing emphasis on renewable sources and sustainable practices, the need for resilient infrastructure becomes even more critical. Bagheri’s work provides a solid foundation for future developments in this field, paving the way for innovations that can withstand the harshest conditions. By translating complex scientific findings into practical applications, this research has the potential to shape the future of structural engineering, ensuring that our infrastructure remains robust and reliable in the face of natural disasters.
