EIT Research: A recent catastrophic earthquake in North Africa that claimed thousands of lives has caused civil and environmental engineering experts to emphasize the need for quake-proof buildings. Read on to discover their recommendations, as well as key insights from recent seismic studies.
The Morocco Earthquake: A Wake-Up Call for Building Resilience
In the late hours of 8 September 2023, a powerful earthquake struck beneath the formidable Atlas Mountains, near Marrakech, Morocco. With a magnitude of 6.8, this seismic event resulted in the tragic loss of at least 2,901 lives and left more than 5,500 injured.
The earthquake also served as a stark reminder of the vulnerability of older, traditional structures in seismic zones.
Morocco’s infrastructure, especially in rural and historical areas, often relies on construction methods that were not designed to withstand earthquakes. Many buildings, particularly those made from mud bricks and unreinforced masonry, are ill-equipped to handle the intense forces of a major seismic event.
This underscores the importance of integrating earthquake-resistant engineering practices into building design—especially in regions with a history of seismic activity.
In her latest research paper “A Comparison Analysis of Buildings as per Norwegian and Ethiopia ES-EN1998-1 Seismic Code”, Dr. Ana Evangelista, Course Coordinator and Lecturer for Civil and Structural Engineering at the Engineering Institute of Technology (EIT), emphasizes the critical role of advanced seismic design techniques.
She noted that “earthquakes are unpredictable and can wreak havoc on infrastructure, so engineering methods must evolve to mitigate these risks.” Her research, which compares building behavior under seismic forces in both Norway and Ethiopia, highlights how essential dynamic analysis is for designing resilient structures.
Understanding the Causes of Building Collapse During Earthquakes
Experts agree that the high casualty rate from the Morocco earthquake was partly due to two major factors: the timing of the quake and the lack of disaster-resilient infrastructure. Many victims were caught off-guard while sleeping, and older buildings—constructed without modern seismic considerations—collapsed under the quake’s force.
Dr. Evangelista’s study also found that traditional seismic codes, which often rely on static analysis methods, may not be sufficient for high-rise buildings. Her research demonstrates that, in earthquake-prone areas, dynamic analysis should be the preferred approach.
“For high-rise and multi-story buildings, dynamic procedures like the Response Spectrum (RS) method should be used instead of static methods like the Equivalent Lateral Force (ELF) approach,” she explained.
The ELF method, commonly used in some regions like Norway, tends to underestimate the structural response in tall buildings, especially when compared to dynamic methods. According to Dr. Evangelista’s findings, the ELF technique produces higher displacement and base shear, which can lead to significant damage if not addressed.
Designing Earthquake-Resistant Buildings: Key Strategies
With the ongoing need for safer, more resilient structures, engineers have identified several key strategies for designing earthquake-resistant buildings. They are as follows:
Solid Foundations: Flexible foundations, such as pads or reinforced concrete slabs on sand cushions, help maintain stability during an earthquake.
Seismic Dampers: These shock-absorbers, initially developed by NASA, absorb seismic energy, reducing the movement of a building during a quake. Materials like graphene-coated rubber pads are now being used to enhance their effectiveness.
Effective Drainage: Proper drainage systems prevent water from pooling around buildings, which can weaken their foundation. Earthquake-specific drainage systems also help prevent liquefaction in sandy soils.
Structural Reinforcement: Engineers employ shear walls, braced frames, and diaphragms to redirect lateral forces, reinforcing the building’s structural integrity.
Ductile Materials: Materials like structural steel and eco-friendly ductile cementitious composites absorb large amounts of energy without failing, helping to prevent catastrophic building collapse.
Advancing Earthquake Resilience: Lessons from Global Research
Dr. Evangelista’s comparison of building designs in high seismic zones, such as Norway and Ethiopia, provides valuable insights into how different seismic codes influence structural resilience.
Her study used the EUROCODE 8-2004 recommendations for static and dynamic analysis of multistory buildings and concluded that buildings designed with dynamic considerations—such as the Response Spectrum (RS) method—offer significantly improved earthquake resistance.
“The ELF method simply doesn’t account for the complexities of high-rise buildings during seismic events. For such structures, dynamic approaches are essential to prevent excessive displacement and to maintain stability,” She noted.
The World Economic Forum has echoed similar sentiments, proposing “base isolation” systems to enhance earthquake resilience. This technology separates buildings from their foundations using springs or runners, ensuring that the building remains detached from the ground during a quake. Japan and Chile have successfully implemented this technology, though it is often prohibitively expensive for many countries.
In Morocco, where many older buildings still dominate the landscape, such high-tech solutions may not be immediately feasible. However, cost-effective innovations, such as the use of bamboo and 3D-printed concrete homes, are gaining traction in other earthquake-prone regions like Nepal and South Africa.
These materials offer sustainable, affordable alternatives to traditional construction, allowing for the design of resilient buildings that are less reliant on costly reinforcement.
Engineering for the Future
The tragic earthquake in Morocco has underscored the need for stronger, more resilient buildings worldwide.
Engineers, like EIT’s Dr. Evangelista, are continuing to refine seismic design practices to ensure that buildings—especially those in high-risk areas—are better equipped to withstand future earthquakes.
Whether through the application of dynamic analysis methods, the integration of new materials, or the use of base isolation technologies, the goal remains the same: to save lives and prevent destruction during seismic events.
The continued evolution of earthquake-resistant design, informed by global research and practical innovation, will be crucial in minimizing the devastating impact of future earthquakes.
References
Engineering Experts Share 5 Ways to Construct Earthquake-resistant Buildings
A Comparison Analysis of Buildings as per Norwegian and Ethiopia ES-EN1998-1 Seismic Code
5 Keys to Designing Earthquake-Resistant Buildings
