A Hispano-Portuguese research team has developed a method to analyze and reduce the vulnerability of school buildings to seismic damage. The work focuses on primary school buildings constructed in Huelva and the Algarve during the 1970s.
Experts from the universities of Sevilla and Algarve (Portugal) have created a system to evaluate and reinforce schools against earthquakes. Through a set of indicators, the method offers the best solution to make these buildings more resistant, considering principles of efficiency, cost, and architectural impact. The formula can be extrapolated to other types of buildings such as homes, high schools, or hospitals.
Using computer software, these experts analyze the behavior of buildings according to seismic regulations. This provides data to understand the structural response and the level of damage the building would suffer during an earthquake. From there, the method evaluates how the school’s performance would improve with different structural reinforcement systems. This information is then assessed alongside cost and architectural impact indicators to determine the best alternative.
“Many centers could be candidates for structural reinforcement, so part of the work involved filtering which construction solutions best fit our technology, are more economical, and respect the building’s design to keep it functional,” says Antonio Morales, co-author of the study and head of the PERSISTAH project at the University of Sevilla, funded by the INTERREG-POCTEP program, within which this research is framed.
The study focuses on schools built in Huelva and the Algarve. “Most of these schools were built during the 1970s. Therefore, seismic requirements were not strict and, in most cases, buildings were only designed considering gravitational loads,” explains María Victoria Requena García de la Cruz, lead author and researcher at the University of Sevilla.
The method has been successfully applied to a school in Huelva, and the results, along with the different phases of the system developed by the expert group, have been published in the journal PLOS ONE.
Area of high seismic activity
The regions of Huelva and the Algarve are characterized by significant earthquake activity, similar to other areas in Andalusia identified on the seismic hazard map of Spain. This is due to their proximity to the Gibraltar-Azores fault, where the Eurasian and African tectonic plates meet.
Exposure to tremors can be worsened depending on the type of soil on which a building stands. “In the case of Huelva, being near the coast and marshland, the presence of soft soils acts as a multiplier of seismic effects,” notes Requena.
Additionally, primary schools in both regions share common seismic vulnerabilities. The oldest buildings (from the 1960s) use a load-bearing wall system, with a high percentage of openings in the walls and poor-quality materials. The rest rely on shorter-than-usual pillars and reinforced concrete beams. Their ground floors are weaker due to lack of enclosure and do not rest directly on the ground but on an insulating layer, known as a “crawl space” slab (forjado sanitario).
Bibliographic reference:
Requena-García-Cruz MV, Morales-Esteban A, Durand-Neyra P, Estêväo J. ‘An index-based method for evaluating seismic retrofitting techniques. Application to a reinforced concrete primary school in Huelva’ PLOS ONE. DOI: 10.1371/journal.pone.0215120.
Access to the complete article here.