L’Aquila Italy Earthquake, Day 4
Day 4: Report from Ricardo Hernandez
We took a trip to observe the damage and building performance in the infamous village of Onna, where 40 of the 300 habitants were killed. It was a sobering place to do the observation. The small village had primarily two to three story structures. Most of the “downtown” buildings were constructed of “mud” unreinforced stone walls, consisting of stones layed together with a very poor mixture of mud. The “mud” mortar was easily scraped by rubbing my finger over it.
The first house, however, that we observed was a house that was outside of the “downtown” area. The house is owned by a couple, both doctors, who had built the house. The owners paid careful attention to the quality of construction of their house and survived the earthquake with abousolutely not structural cracks in any of the exterior or interior walls. This was in stark contrast to building additions constructed of reinforced concrete over “mud” unreinforced stone walls which took the life of so many.
Other interesting photos include a “in-construction” concrete moment frame building that experienced bar buckling of the longitudinal column reinforcing due to lack of ties at the top/bottom ends of the beam.
Lesson Learned: It was a city waiting to be shaken…no amount of “retrofit” could have saved the “mud” mortar, leaving the village with a high vulnerability.