Experimental Dynamic Behaviors and Empirical Frequency Formulas for Historical Timber Mosques

The structural assessment of historic timber mosques is a challenging process with many uncertainties such as strength and stiffness of structural members, joints and boundary conditions. The analytical models of timber mosques must be calibrated using experimental dynamic characteristics for reliable structural evaluation and accurate interventions. This paper aims to determine the experimental dynamic characteristics such as frequency, mode shapes and damping ratios as well as developing empirical frequency formulas for historical timber mosques. Seven historical timber mosques having different geometrical dimensions in the East Karadeniz Region in Turkey are selected for this purpose. Experimental dynamic characteristics of the selected mosques are determined by using Ambient Vibration Testing and the Enhanced Frequency Domain Decomposition (EFDD) method. The experimental dynamic behaviors of the selected mosques are initially compared using the obtained natural frequencies, mode shapes and damping ratios. Then, empirical natural frequency formulas for the first three modes based on mosque geometrical dimensions have been developed by regression analysis. The proposed frequency formulas were observed to be very consistent with the results measured.