Displacement Distribution Index as а Tool for Identification of Vertical Irregularity of Structures

Abstract

Vertical regularity plays an important role in the behavior of structures exposed to seismic action. The structure can be classified as regular if it meets certain prescribed requirements, which are usually explicitly defined in the seismic design codes. In this paper, the vertical irregularity of structures has been identified through the ratio between the maximum inter-story drift and maximum roof drift. In order to quantify this relationship, regardless of the number of stories, the parameter named as index for distribution of the displacements along the height (DDH) has been defined. Evaluation of the proposed index has been done through an extensive incremental dynamic analysis of six masonry infilled reinforced concrete frames with open first story. Obtained results shows that this index can be used as an indicator for the detection of structural potential to go into the unfavorable failure mechanism.