Out‐of‐plane seismic behaviour of rocking masonry walls

Abstract

The evaluation of the out-of-plane behaviour of unreinforced walls is one of the most debated topics in the seismic assessment of existing masonry buildings. The discontinuous nature of masonry and its interaction with the remainder of the building make the dynamic modelling of out-of-plane response troublesome. In this paper, the results of a shaking table laboratory campaign on a tuff masonry, natural scale, U-shaped assemblage (façade adjacent to transverse walls) are presented. The tests, excited by scaled natural accelerograms, replicate the behaviour of external walls in existing masonry buildings, from the beginning of rocking motion to overturning. Two approaches have been developed for modelling the out-of-plane seismic behaviour: the discrete element method and an SDOF analytic model. Both approaches are shown to be capable of reproducing the experimental behaviour in terms of maximum rotation and time history dynamic response. Finally, test results and numerical time history simulations have been compared with the Italian seismic code assessment procedures

Numerical Assessment of the Out-of-Plane Response of Masonry Panels Reinforced by Means of FRCM Systems

“…It is worth noting that the model was able to represent the variation of the collapse mechanism from the unreinforced prototype to the reinforced one. In the latter case the numerical damage was concentrated mainly at the central part of the façade (Figure 8) according to the experimental observations [3,4].…”

“…Aiming at showing the capability of the macro-modeling approach, to reproduce the outof-plane response of masonry structures reinforced by means of FRCM, the results of the experimental campaign described in [3,4], were numerically simulated.…”

“…In this paper a macro-modeling approach, already developed for modeling masonry structures [1,2], is used to predict the out-of-plane response of a masonry prototype reinforced by means of FRCM, experimentally investigated through shaking table tests [3,4].…”

Influence of boundary conditions on the out‐of‐plane response of brick masonry walls in buildings with RC slabs

“…The blocks are separated by joint interfaces, along which the blocks can detach or slide without limit on relative displacement or rotation. Because of these features, DEM is particular suitable for analysing the dynamic behaviour of rocking masonry structures; past studies include investigation of the seismic behaviour of single blocks or block assemblages [21,22,25], masonry arches [23,24], masonry facades [25,26], free-standing columns [27,28] and entire historical structures [29,30].…”

“…For rocking motions, the natural rocking period is not constant [34], and therefore, it is impossible to specify a constant level of damping for a given mode. Specifying 0% damping at all frequencies not only can lead to a good approximation of the initial portion of the strong ground motion response [29] but also can lead to unrealistic vibration displacements at no-tension interfaces [25] and overestimation of the response to either continued strong shaking or large separated pulses in the ground motion [25,30]. This overestimation can be limited by specifying a small stiffness-proportional damping level that eliminates the high-frequency rotational vibration of individual blocks [24].…”