Innovative Methods for Retrofitting Timber Structures for Seismic Safety: The Case of Tekirdag

Historical buildings are part of urban identity and cultural heritage. Türkiye has a rich stock of timber buildings, many of which were constructed using hybrid systems combining timber framing and masonry. In Türkiye, preserving timber buildings with heritage value for future generations requires enhancing their seismic resilience. This study investigates the structural condition and seismic performance of two traditional timber-framed residential buildings in Tekirdag and evaluates an intervention approach for improving their global seismic response while preserving their architectural characteristics. Field investigations documented existing structural systems and damages. The selected buildings, representing different physical conditions, were modelled and analysed in accordance with the Turkish Building Earthquake Code (TBEC-2018). The seismic response of the structures was evaluated primarily through their natural vibration periods and maximum roof displacements. Based on the identified deficiencies, steel diagonal bracing was proposed at each floor level to enhance lateral stiffness and in-plane floor action. The proposed retrofitting approach reduced the natural vibration periods and roof displacements by an average of 20% and 36%, respectively, indicating a significant improvement in seismic performance. The findings demonstrate that this approach can provide an effective retrofitting strategy for traditional timber buildings while maintaining their architectural functions and heritage values.