The Application of “Capacity Design” in a RC Building Frame Structure

Abstract

Many countries throughout the world have accepted the concept for design of RC buildings based on the “capacity design” methology.This has been proved also by the Eurocode-8 that is largerly based on this method.The main idea of this method is to predetermine places at which the occurrence of nonlinear deformations shall be dictated.This critical parts,the so called plastic hinges,are designed and processed separately to enable those places dissipate the total energy.It is desirable that all the inelastic deformations be due to bending,which with the provided previous and necessary conditions,corresponds to ductile behavior of the structure. This paper presents the application of the “capacity design” in a structure consisting of RC frames in both orthogonal directions.In such structures this method is reduced to elimination of the possibility of formation of plastic hinges in the columns in order to fulfill the basic principle of(weak beams-strong columns) which is included in almost all seismic regulations,this method requires a considerably higher bearing capacity of columns.Such a conservative approach leads to the requirement of larger proportions of columns and a greater amount of longitudinal reinforcement. As an example, the proposed methodology is applied to an actual reinforced concrete building frame structure.Beams,supporting floors,and columns are continuous and meet at nodes,called rigid joints.Such frames can readily carry gravity loads while providing adequate resistance to horizontal forces ,acting in any direction.We will make the elastic and plastic analysis by the program,according Eurocode 8. The analysis will be performed until the response of the building will reach three conditions. After the final model is reached we will propose the next step to design the structural elements.The final design of elements will be given in the % of required reinforced steel.And finally ,we will make the time-history analysis for an actual earthquake.