Evaluation of force‐based and displacement‐based out‐of‐plane seismic assessment methods for unreinforced masonry walls through refined model simulations

Abstract

Summary The performance of force‐based and displacement‐based seismic assessment methods for the life‐safety limit state check of out‐of‐plane loaded unreinforced masonry walls is evaluated on the basis of refined numerical simulations. For this purpose, a discrete element model of a vertically spanning wall is built and validated against experimental results from static and dynamic test conditions. The model is then analysed for a large range of wall configurations. For each configuration, a static pushover analysis and a series of incremental dynamic analyses are run, the latter permitting to determine the capacity of the wall under dynamic loading. The accuracy of the assessment methods in predicting the acceleration at which the walls collapse is evaluated. It is found that the displacement‐based method is more accurate, robust, and safe than the force‐based method. The comparison also shows that for walls characterised by a relatively high ratio of axial load to Euler's critical load, both assessment methods lead to an overestimation of the wall capacity. As a remedy, a modification to the methods based on a recently developed mechanical model is put forward and tested. For the force‐based method, it is additionally suggested to set for walls with relatively high overburden ratios the behaviour factor equal to 1. To ensure reproducibility of this study, all input and output files of the numerical simulations are made publicly available.

Nonlinear Static and Dynamic Analysis of Rocking Masonry Corners Using Rigid Macro-Block Modeling

“…The capacity thresholds are represented by the three LS0, LS1 and LS2 limit states expressed by Eq. (14), which are the same for the two presented models. It is worth highlighting that the LS1 limit state is close to the¯rst threshold horizontal displacement (phase 1 to phase 2) for both directions, corresponding to the complete unthreading of the roof.…”

“…In order to compare the results of the two proposed modeling approaches, the values of the parameters 0 and d à 0 in Eq. (14) are derived by the application of the static model and considered valid for the dynamic one, as developed in the following sections for the case under study. The only slight di®erence is in the PFA C , which for the static model takes into account the rate of the total mass e à described in Sec.…”

Seismic fragility assessment of nonstructural components in unreinforced clay brick masonry buildings

“…The development of the peak strength in two‐way spanning walls involves significant inelastic deformation (Griffith and Vaculik ), which may be utilised to reduce the elastic demand on the component, eg, by using a response (R) modification factor. Godio and Beyer () used a factor of 2 for out‐of‐plane loaded one‐way vertically spanning walls. The seismic loading code in Australia (AS 1170.4; AS (Australian Standards) ) specifies a factor of either 1 (for rigid components) or 2.5 (for ductile components).…”

“…Ceran and Erberik () and Godio and Beyer () investigated the seismic fragility of out‐of‐plane loaded walls assuming one‐way vertically spanning elements. Walsh et al () completed a related study based on a preliminary street survey of URM buildings jointly undertaken by the University of Auckland (UoA) and Auckland Council (AC).…”

Discrete Element Modeling of the Seismic Behavior of Masonry Construction

“…Presently, it is possible to address much more complex structures, composed of a large number of blocks, and assess their seismic capacity by means of either pushover methods [4] or dynamic analysis [5]. DE models using these alternative analysis techniques, based on static or dynamic representations of the seismic action, have been applied in the simulation of lab experiments of masonry walls under out-of-plane loading [6,7]. The failure modes observed in lab tests involving in-plane cyclic loading of masonry panels have also been effectively reproduced by these models [8].…”