Seismic response of a historic church considering pounding phenomena

The vulnerability of historic masonry structures and monuments under seismic loading including churches has been confirmed during major recent earthquake events. The current research focuses on pounding effects on masonry structures, a vulnerability factor that even though it is considered to be significant for the response of adjacent reinforced concrete structures is rarely taken into account for masonry structures in current engineering practice. The central church, the so called “Katholikon”, of the Kaisariani Monastery located in Athens, Greece, is selected as a case study of a historic structure that may present pounding phenomena because of its contact with an adjacent ecclesiastic structure, added during the 16th–17th centuries. The Katholikon, one of the finest Byzantine monuments of Greece, is a Byzantine crossed-dome church constructed during two separate structural phases build in contact during the 10th/11th and 16th/17th centuries, respectively. Based on data collected with the aid of an extensive experimental investigation of the monument different modeling approaches and different analysis methods were applied including time history and response spectrum analysis using the finite element method. The results indicate that pounding significantly affects the seismic response, while an individual analysis considering pounding is needed to provide accurate results. Also significant differences are observed between the results obtained from the response spectrum and the time history analysis suggesting that the usually applied response spectrum analysis does not always provide conservative results of the actual behavior.