Non linear Pushover Analysis and simulation of progressive collapse mechanisms using FE Models for Nativity Church

Abstract

This paper presents some advanced finite element FE analyses conducted on one of the most historic structures in the world. The Church of Nativity located in Bethlehem (Palestine). To ensure the model quality, a 3D FE model was created using two different commercial software, DIANA FEA and SAP2000, one of the expected behaviors for this kind of masonry structure “low modal period” was found. The seismic behavior of the church was studied using pushover analyses, which were conducted using DIANA FEA as well as a dynamic analysis using SAP2000 is carried out using the accelerogram (1940 El Centro earthquake) to simulate a complete progressive collapse process. The first unidirectional mass proportional load pattern was created in both directions, X direction as a longitudinal direction and Y direction as the transversal direction. An incremental iterative procedure was used with monotonically increasing horizontal loads, using constant gravity loads. The results showed that the transversal direction is the most vulnerable and the damage concentrates at the main lateral (longitudinal) walls, mainly at the south and north alignment walls, and also at the vaults and at the connections of the vaults to the apse. A more accurate nonlinear dynamic analysis is recommended in the near future, which takes into account the material nonlinearity for good seismic behavior, anticipation for such an important monument, and heritage.