Why Rc Buildings Failed in the 2011 Van, Turkey, Earthquakes: Construction Versus Design Practices

Abstract

The 2011 Van earthquakes revealed that although earthquake-resistant codes were revised after significant research and after each major earthquake, construction quality had a little progress in the region. A total of 63 RC residential buildings that collapsed or were severely damaged in 2011 Van earthquakes were investigated in detail. It was found that there is an increasing trend in terms of number of stories in Ercis, Turkey. However, not only the taller buildings experienced more damage but also the shorter ones were damaged or collapsed. Column ratio has a decreasing trend but shear wall ratio increases with time. As for the ratio of the total vertical elements to the total floor area, it has a slight decrease with time. Although some design projects provide lower reinforcements, after 1995, the reinforcement ratio was either close to 1% or greater. Reinforcement ratio at the site was found to be lower than the ones specified in the design projects. Most of the buildings had shear walls but they were mostly oriented in the weak axis of the building and the as-built shear capacity of the buildings was found to be 50-60% of their design shear capacity. Concrete compressive strength was approximately 8 MPa. Some buildings were vulnerable even under gravity loading. (C) 2016 American Society of Civil Engineers.