Seismic Mitigation Framework for Non-engineered Masonry Buildings in Developing Countries: Application to Malawi in the East African Rift

Assessing seismic performance and identifying effective mitigation plans to improve resilience of non-engineered housing construction in developing countries pose a major challenge. Although reliable methods to evaluate current seismic risk levels and retrofitting interventions to engineered structures are available, they are not directly applicable to informal buildings because construction materials and connections between the walls and floors are very weak, resulting in premature failures of the structures. This leads to significant bias and uncertainty in the seismic building performance assessment and risk mitigation, which are difficult to identify. The present chapter proposes a seismic mitigation framework, consisting of four-steps, to increase the seismic resilience of non-engineered masonry buildings in developing countries through retrofitting solutions. The first and second steps identify non-engineered building typologies using global and local datasets. Thirdly, to assess structural performance, existing methods to derive fragility curves are presented to identify applicable methods to different situations in terms of data availability, highlighting the trade-off between rigour of investigations and accuracy of evaluations. The final step offers a mitigation approach based on low-cost engineering strategies for improving seismic resilience. The proposed framework is demonstrated on informal houses in Malawi, located within the East African Rift zone.