SEISMIC BEHAVIOR OF LIGHTLY REINFORCED CONCRETE BEAM-COLUMN JOINTS AT FIRST FLOOR

Abstract

An extensive experimental test has been conducted in the order to investigate the performance of interior reinforced concrete beam-column connections subjected to lateral earthquake loading. In the past, however, most experimental programs were paid attention to individual beam-column connection specimens particularly in cruciform configuration. Those typical tested programs have been made on the assumption that the inflection points were located at middle length of columns and beams. In real behavior of structure, especially in the first floor building, the inflection point may not stay at mid of column height because the relative stiffness between beam-column connection and fixed foundation is difference. Disparity of actual behavior and classical assumption affect the behavior for both beam-column connection and column. This paper presents an experimental study of intermediate lightly RC frame subassemblies. Four specimens were cast and divided into two series. These two series have the same dimension and reinforcing details except that the columns in second series were extended twice times from the beam-column connection and fixed to foundation base. The specimens in second series intended to represent the 1^st floor of interior building frames. The different behavior of specimens in these series was described experimentally. Based on observed behavior, it can be understood that the inflection point in column at bottom story of building frame plays the important role for behavior of both beam-column and column. In addition, the study results can also be used as informative data for further researches.