Shake table tests on the out-of-plane response of unreinforced masonry wallsThis article is one of a selection of papers published in this Special Issue on Masonry.

Abstract

Given sufficient anchorage to the diaphragms, out-of-plane walls in unreinforced masonry (URM) buildings have been shown to crack above midheight and then rock as two rigid bodies. This study investigates the sensitivity of the rocking response to the type of ground motion and the quality of the wall construction. Shake table tests were conducted on four full-scale multi-wythe walls, all with a height to thickness (h/t) ratio of 12 but of varying construction quality and subjected to three different ground motions. All walls experienced cracking at less than one half of the 2005 National Building Code of Canada (NBCC) level for Vancouver, but exhibited a stable rocking behaviour without collapse beyond a ground motion 1.5 times the 2005 NBCC level.

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

“…The tests were designed to provide idealised boundary conditions at the top of the out-of-plane loaded walls. The idealised boundary conditions at the top reflected in most cases a roller condition [8][9][10][11]13]. Only Dazio [12] modified the pinned condition at the top to model a certain rotational restraint and an eccentric axial force.…”

“…All studies applied the same motion at the top and the bottom support. Three studies [10,11,13] placed springs between wall and support in order to account for deformations of flexible diaphragms, which resulted from the inertia force of the supported wall. It is interesting to note that none of the existing studies applied different motions at the top and the bottom in order to account for acceleration amplification over the height of the building because of in-plane deformation of walls that are orthogonal to the out-of-plane loaded walls.…”

“…The test results underlined the importance of displacement rather than acceleration demand when determining whether a wall loaded out of plane will collapse under seismic loading. Meisl et al [10] performed shake table tests on four clay brick multiwythe rectangular walls and also concluded that the peak displacement demand has a greater influence on out-of-plane collapse than the peak acceleration demand.…”

“…The most recurrent parameters that were investigated by the experimental studies were the effect of wall slenderness [8,9,12,13], axial load [9,11,12] and flexible diaphragms [10,11,13] on the out-ofplane response of URM walls. With the exception of Simsir et al [11], who included in-plane loaded walls and the top slab in the test setup, all the aforementioned tests studied the out-of-plane behaviour analysing the walls as single elements, separated from the rest of the structure.…”

Seismic Vulnerability and Risk Assessment of Historic Masonry Buildings

“…As an alternative, a number of authors have worked on correlating performance indicator and damage indicator on experimentally obtained capacity curves, by way of shaking table tests or push-over tests [41,42]. The major limitation of these tests have been carried out focusing only on the capacity of in-plane walls, while very limited experimental work has been conducted on the characterisation of out-of-plane capacity for URM [43] have considered the out-of-plane failure of URM bearing walls constrained by flexible diaphragm, however the support conditions predefine the failure mode with three horizontal cylindrical hinges, already highlighted by [44], and rather different from on site and laboratory observation collected by [45]. A testing scheme more informed by observation of post-earthquake damage in existing masonry structures is the one devised by [46], however by predefining a state of damage the mechanism is also predefined.…”