The earthquakes in Turkey and Syria killed over 45,000 people and decimated large areas. The shockingly high number of fatalities raises the question of whether infrastructure issues are to blame. Roberto Leon, a professor of civil and environmental engineering at Virginia Tech, said there are several reasons for the large number of collapses, leading to mass casualties:
- Poor enforcement of existing codes (modern codes instituted after the 1999 Izmit earthquake)
- Grandfathering of older, deficient structures and not requiring their retrofit (structures built before 1999)
- Poor construction practices (i.e., structures not built to plans) – intentionally or not
- Very large ground motions, probably above the maximum credible earthquake used for design
- Location of buildings (soft soils vs. rock)
- Sequence of two very large earthquakes back-to-back at relatively close locations
- Engineers’ inability to identify “killer” buildings through simple screening procedures
“Most of the casualties in Turkey and Syria occurred in four to twelve story residential structures, which is often the type of housing in high demand in developing countries as rural residents migrate to cities in search of better jobs and services,” said Leon. “There is an enormous inventory of poorly designed and constructed buildings around the globe.”
Leon explained that the replacement of these buildings is beyond what most economies can sustain and said that we will likely continue to see catastrophes like what happened in Turkey and Syria.
In the United States, Leon said that hopefully no disaster of this magnitude will happen. “At risk could be cities located along the New Madrid fault – Memphis to St. Louis along the Mississippi River – which could see a large number of collapses of unreinforced masonry structures if an earthquake were to happen, Three very large earthquakes occurred there in 1811-1812” said Leon.
Leon said the west coast could see the collapse of numerous “killer” buildings if the San Andreas, Hayward-Calaveras and Juan de Fuca faults break and there’s a 30% probability this will happen in the next 50 years.
“Killer” buildings are buildings that because of their age, type of construction, lack of seismic detailing, etc., will not perform to their intended level,” explained Leon. “A recent statistical analysis for the Los Angeles basin indicated that there were about 300 such buildings that would collapse should the maximum credible earthquake occur.”
About Leon
Roberto Leon is a David H. Burrows Professor and Associate Department Head in the College of Engineering. His program area is structural engineering and materials. Leon’s areas of interest include behavior and design of steel and composite connections, seismic design of frames with partially restrained connections, seismic behavior of bridges, serviceability of composite floors, and high performance materials.
Schedule an interview
To schedule an interview, contact Margaret Ashburn in the media relations office at mkashburn@vt.edu or 540-529-0814.
