Roles of timber tie-rods to reduce seismic vulnerability of historical buildings in Egypt

Historical un-reinforced masonry (URM) buildings in Egypt from the medieval period generally comprise timber tie-rods that link the arches of arcades at the top of the column heads and along the arcade plane (in-plane). Usually, additional tie-rods are found perpendicular to the arcades (out-of-plane). Timber ties can also be used between facing tall URM bearing walls to minimise their buckling vulnerability. They play a considerable role in resisting seismic forces and minimising the deficiencies of URM buildings. A limited experimental investigation and a wide analytical campaign were conducted on two model buildings with the prevailing dimensions and materials of historical medieval buildings in Cairo by employing finite-element three-dimensional modelling. The focus of the work was the roles timber tie-rods play in the seismic stability of parallel-arcaded and cross-arcaded URM historical buildings. A proposal for enhancement of the seismic resistance of parallel-arcaded systems using a steel bracing system is provided.