Out-of-plane cyclic tests of pre-damaged hollow clay masonry school facades retrofitted with bamboo-reinforced mortar

Reducing seismic risk in schools is critical to safeguarding education and ensuring community resilience. In Colombia, schools often serve as emergency shelters, yet many rural facilities rely on unreinforced masonry (URM) structures that are highly vulnerable to earthquakes. This study evaluates the seismic performance of URM school buildings in rural Antioquia and examines two low-cost retrofitting schemes using bamboo slats, chicken wire mesh, and mortar. The experimental program included diagonal compression tests on nine small wall panels and full-scale cyclic tests on two masonry façades with flanges at both ends (C-shaped). One façade was tested in the non-retrofitted condition and subsequently retrofitted with the enhanced scheme (bamboo + wire mesh + mortar), while the second was retrofitted with the simplified scheme (bamboo only). Both in-plane and out-of-plane loading protocols were applied. Results showed that the enhanced retrofit increased out-ofplane overturning capacity by 3.8 times, drift capacity by 2.7 times, and energy dissipation by more than six times compared to the non-retrofitted wall. The simplified scheme, while less effective in strength, still prevented brittle failure and improved drift and energy dissipation capacities. These findings demonstrate that bamboobased retrofits can substantially enhance the safety of rural school buildings, offering a sustainable and lowcost alternative for seismic risk reduction in developing regions.