Floors number influence on the instability parameter of reinforced wall- or core-braced buildings

Resumo

This work aims to investigate the floors number inlfuence on the instability parameter limit alfa1 of buildings braced by reinforced concrete walls and/or cores. Initially, it is showed how the Beck and Konig discrete and continuous models are utilized in order to define when a second order analysis is needed. The treatment given to this subject by the Brazilian code for concrete structures design (NBR 6118) is also presented. It follows a detailed analytical study that led to the derivation of equations for the limit alfa1 as functions of the floors number; a series of examples is presented to check their accuracy. Results are analyzed, showing the precision degree achieved and topics for continuity of the research in this field are indicated.