Out-of-plane Proof Testing of Masonry Infill Walls

Structures, 15

REFERENCE

Dizhur D., Walsh K., Giongo I., Derakhshan H, Ingham J. (2018). Out-of-plane Proof Testing of Masonry Infill Walls. In Structures 15, 244-258. DOI: 10.1016/j.istruc.2018.07.003

Scope and methodology

• In-field out-of-plane testing of clay-brick unreinforced masonry (URM) infill walls set within reinforced concrete frames.

• 19 air-bag tests performed in six existing buildings.

• Effects of existing in-plane damage on the out-of-plane (OOP) capacity of a URM infill wall was investigated.

• Material strength related to brick compression, mortar compression, masonry bed joint shear, and cavity tie pull-out, as well as other properties, were determined.

FINDINGS

• Tested walls are capable of resisting seismic demands in regions with moderate to high seismicity (e.g., Wellington, New Zealand) despite some simplified predictive methods suggesting lower strengths for some walls.

• Restraint at the walls’ vertical edges (horizontal boundaries), resulting in two-way OOP flexure, substantially improve the OOP load-carrying capacity.

• Topside fixed restraint and presumed ‘arching’ action from the building frame can significantly increase the OOP capacity of URM wall.

• In-plane damage was found to reduce the OOP capacity of URM infill walls by up to 40%.

• On-site proof testing was shown to be a cost-effective and straightforward way to establish actual lateral capacities of walls in cases where boundary conditions cannot be clearly established, and the models predict low lateral capacities.