evaluating quality seismic damage index for urban residential buildings

by identifying the damage index of a structure, in addition to a correct understanding from real behavior of the structure, the required criterion for strengthening would be given. researchers have given many relations for determination of damage index but such relations have been based upon laboratory methods which challenge their usage in a broad term. in this paper two new methods are given for calculation of damage index. surveying the first crack limit and total structure failure is based upon the formation of plastic joints in the first column and basic floor columns. to give a qualitative simple and functional damage index, the functional method was given in the form of a qualitative method with statistical analysis and collection of different views. using this method is very simple and meantime offers suitable accuracy. with a numerical study on three models it was made clear that the difference of new method with amended method of papadopolos in approximate 3%. this shows that given qualitative method is suitable to be used in a broad terms.