Out-of-plane shaking table tests on URM single leaf and cavity walls

Engineering structures, 125

REFERENCE

Graziotti F., Tomassetti U., Penna A., Magenes G. (2016). Out-of-plane shaking table tests on URM single leaf and cavity walls. In Engineering Structures 125, 455–470. DOI: 10.1016/j.engstruct.2016.07.011

Scope and methodology

• Understanding the seismic behaviour of cavity walls: failure mechanisms and how it is affected by boundary conditions and degree of connection between the two leaves.

• Full-scale cavity wall panels were formed of inner calcium silicate brick wall and outer clay brick wall, rapresentative of the Dutch URM buildings.

• The energy dissipation involved in the mechanism has been investigated in terms of coefficient of restitution and damping ratio.

FINDINGS

• All the test walls collapsed in one-way vertical bending/rocking behaviour, exhibiting the classical top, bottom and mid-height hinges.

• All the tested cavity walls showed lower capacities than single-leaf wall loaded with the same axial force.

• Damage due to failure of the bed joints caused by steel ties compression has been detected in all the cavity wall specimens. The experimental work confirmed that the specimen capacity is strongly influenced by the vertical stress acting on the walls, also for cavity walls.

• The number of ties connecting the two walls does affect the cavity wall response.

• Regarding the F- D relationship, it was noted that the capacity of the cavity components can be modelled starting from the sum of RB mechanisms of the two walls considered independently.

• For the energy dissipation model concerning the equivalent viscous damping ratio, values from 5 to 10% have been observed for the single-leaf specimen and much larger ones for cavity wall components (up to 30%).