Seismic Behavior of Historical Conical Masonry Vaults

Abstract

This paper presents the results of a study of the earthquake resistance and behavior of historical Persian conical vaults. Masonry towers dating back to the 13th century AD, were used as funeraries in the Varamin region of Iran e.g. the Gunbad-I ‘Ala al-Din tomb located in Varamin south of Teheran. Such tomb towers suffered damage during previous earthquakes e.g. Bou’in – Zahra earthquake of 2002. This mausoleum basically consists of a tall cylindrical brick structure with a conical vault roof over an interior spherical dome. A 3-D finite element analysis model of an idealized conical masonry vault (including the interior spherical dome), over an idealized cylindrical shell was developed using the SAP2000 software, and analyzed under the action of gravity plus seismic loading. The conical roof vault height is 11.3 m with a span of 10.6 m. The height of the cylindrical shell wall is 15 m. The ultimate objective of the study is to develop a practical approach to the understanding of the seismic resistance of conical brick vaults on cylindrical shell walls. The major focus of the analysis results is the distribution of reactions at the base of the conical vaults, relative to the cylindrical shell wall, and the cylindrical shell wall relative to the base. The lateral displacement at the peak of the roof conical vault were very small indicting that this structure is very stiff.