Assessment of Seismic Behavior of Monumental Minarets in Egypt

Abstract

The research work presented in this thesis deals with the structural behavior of old masonry structures with special emphasis on the behavior of masonry minarets under the effect of earthquake loads. Application is made on the historical stone masonry minaret of the mosque of “Fatma Elshaqra” at Darb el Ahmar, a crowded area in old Cairo, which showed deterioration and cracking in addition to obvious inclination of its upper part after the major earthquake in 1992. The restoration project carried out is described, including and site investigation and documentation of deterioration and damage signs. A review was given for the styles and construction of existing historical minarets in Egypt. Also overview of locally and internationally published literature related to structural analysis of masonry towers and minarets and their seismic performance is presented. In the thesis, numerical modeling and structural analysis were performed for the minaret, where several three-dimensional finite element models were created for the minaret including all architectural details and representing the material properties. Linear and nonlinear analysis under the existing loads are made for the minaret using commercially available finite element software SAP2000 and ANSYS v.19. Seismic analysis of the minaret structure is performed to assess the expected deformation and stress levels in case of earthquake events. Seismic analysis is made using response spectrum techniques and also dynamic time history analysis under three strong earthquake records, scaled to the seismic zone parameters of Egypt. The results are presented and discussed. The results of seismic analysis showed that the observed deterioration signs to be the direct results of previous earthquakes acting on the monuments throated for the monumental ughout its history. The steps followed to execute the restoration and strengthening actions for the monumental minaret of Fatma Elshaqra mosque in old Cairo are illustrated and described. Following, numerical modeling and seismic analysis are made for the