Effects of adding illegal storeys to structural systems

Abstract

Earthquakes in Turkey are frequently occurring disasters, causing much loss of life and property. It is tragic indeed that earthquakes should share the agenda with amnesty laws for illegal buildings. Illegal buildings are those constructed without authorization, legal bureaucratic sanction and, in most cases, without normal engineering control and checks. Buildings may become illegal for a variety of reasons. The very prospect of a waiver bill for illegal buildings spurs further illegal construction. The status of illegal buildings may legally change in time. What is an illegal building today may well be legal tomorrow under these circumstances. The present study deals with two different kinds of building: one is the framed building and the other has shear-wall frame. The capacity ratios, storey drifts and natural periods for the legally approved buildings and the effects of illegal or legal additional floors on these values are compared. It is determined that these buildings with illegal storeys should be strengthened and retrofitted by providing cast in-situ reinforced concrete shear walls.