EFFECTS OF POUNDING IN LOW AND MID-RISE BUILDINGS

The seismic performance levels of adjacent buildings with inadequate separated distance can be affected significantly as a result of collision with strong ground motion. This structural irregularity, known as pounding, can cause many damage or collapse in structures with different dynamic characteristics. Important portion of low and mid-rise buildings in our country has inadequate separations having lateral collision potential during earthquakes. The proper evaluation of seismic performance of such buildings is an extremely important issue. This study aims to investigate the effects of pounding on seismic behavior of adjacent low and mid-rise reinforced concrete buildings using nonlinear time history analysis. The low and mid-rise reinforced concrete buildings are reflected using average structural and geometrical properties of existing building stock of 4- and 7-story buildings designed per 1975 and 1998 Turkish Earthquake Codes (TEC). Beam and column elements are modelled as nonlinear frame elements with lumped plasticity by defining plastic hinges at both ends of beams and columns. The link elements are used to connect the adjacent 4- and 7-story buildings. The separation distance between adjacent buildings is selected as 0 and 20 mm, and 400 mm. The “0” and “20” mm gaps reflect inadequate separation between adjacent buildings while the “400” mm gap is used for the reference building without collision. A set of earthquake records is used for dynamic analysis. The outcome of dynamic analysis shows that the pounding seriously affects seismic performance of existing buildings. Displacement demands exceed Turkish Earthquake Code limits in most of the earthquake records. The impact of the collision and sudden changes in demands causes serious changes in interstory drift ratios. It is also clear that the proper seismic performance evaluation of adjacent buildings is not possible without consideration of pounding effect