Time–history analysis of URM walls in out-of-plane flexure

This paper introduces a single degree-of-freedom analytical model which has been used by the authors to investigate the out-of-plane performance of unreinforced masonry walls in vertical one-way bending subject to seismic actions. The objective of the modelling is to reduce costs on physical experimentation by supplementing and extending the limited experimental database on dynamic wall behaviour with analytical data. The procedure necessitates sufficient physical testing of specimens with representative boundary conditions to enable the analytical model to be calibrated against experimental results. A computer program which requires minimal data preparation effort and computational time has been written to conduct time–history analysis on the model. Importantly, key parameters have been incorporated in the program to facilitate calibration of the model. Details in developing representative tri-linear elastic force-displacement relationships and non-linear damping relationships to define the model are described in the paper. The developed model has been verified by comparing the computed acceleration and displacement response time-histories with results obtained from an extensive series of shaking table experiments. Seven of such time-history comparisons are shown in the paper to demonstrate the accuracy of the analytical model.