Improving the lateral load resistance of vernacular masonry walls subject to flooding

Low-rise vernacular masonry buildings are vulnerable to damage from extreme flooding. This paper presents findings from a study based in Sri Lanka assessing the structural resilience of non-engineered single-storey houses constructed with either fired clay brickwork or cement block masonry walls. A structural survey of flood-damaged houses enabled characterisation of masonry materials, and development of proposals to improve the lateral load capacity of masonry walls. The structural survey revealed that a combination of low-quality masonry units and variable thickness of mortar beds may have contributed to flexural failure due to the hydrostatic pressures during flood events. An experimental programme investigated the impact of differing masonry units and mortar thickness on masonry properties under dry and saturated conditions. A simple retrofit method has been developed, using reinforced renders, that enhances sectional flexural capacity by over 11 times, offering greater resilience to lateral flood loads. The impact of this research study will have direct welfare benefits for Sri Lankan people living in flood-risk areas, reducing the risk of structural collapse and enabling people to remain safely in their homes during flood events.