Country and hazard overview CASE STUDY Rapid visual assessment for retrofitting Country: El Salvador Organisation: UNESCO, University of El Salvador, University of Udine, Italy Hazards: Earthquakes Keywords: VISUS, rapid visual assessment, information communication technology, government, retrofit, triage, training Summary: Before school retrofitting or SECTION III: PLANNING reconstruction programs can begin, weak buildings need to be identified and prioritised, and retrofit or replacement designs calculated. Rapid visual assessment is typically the first step in this process. In El Salvador, UNESCO and two universities piloted a tablet-based rapid visual assessment tool. The project assessed 100 school buildings in 10 days and built the capacity of government officials, profe ssionals and engineering and architecture students along the way. For many, the pilot was their introduction to building assessments and the fundamental principles of seismic-resistant design. GUATEMALA Ahuachapan Santa Ana Sonsonate HONDURAS Chalatenango San Salvador Nueva San Salvador Sensuntepeque EL SALVADOR San Miguel Usulutan PACIFIC OCEAN 59 El Salvador is both populous and seismically active. In 2001, two earthquakes struck, causing landslides and damaging 1,700 schools – more than one in three in the country. Ten years later, many school buildings remain in disrepair, in sites that leave them vulnerable to earthquakes and other natural hazards, or they do not comply with seismic building codes. School buildings in El Salvador are mostly one story of confined or reinforced masonry. Although some buildings were traditionally constructed from adobe (mud brick), it has not been used for schools after many children and a teacher died during an earthquake in 2001. When existing school facilities have not been built to withstand hazards, they need to be identified and strengthened. In contexts like El Salvador, where resources are insufficient for a full detailed assessment of every school, a rapid visual assessment can quickly collect proxy data from a brief site visit. From these assessments, the MoE can develop school retrofitting programs based on a triage action plan that prioritises the weakest buildings and those with the most students first. Detailed assessments can then determine whether school facilities should be retrofitted or replaced. Using rapid visual assessment Rapid visual assessment approaches have been developed in many countries. These assessments do not empirically determine the structural integrity of a building. Instead they rely on proxy data to determine fragility. Originally, the proxy data was collected by engineers after earthquakes or other hazards. Noting the intensity of the hazard, they recorded the damage to buildings and organised the results by the building typology and other defining characteristics. Over time, enough data was collected to be able to predict damage based on a visual assessment of a building’s characteristics and the expected strength of the hazard. Rapid visual assessment only provides a general prediction of damage. After the rapid visual assessment is conducted, engineers still need to perform in-depth assessments to develop appropriate retrofit designs, but only for those identified during the rapid assessment for an in-depth analysis. This strategy reduces the cost of doing in-depth assessments for every school.