Research Article: An index-based method for evaluating seismic retrofitting techniques. Application to a reinforced concrete primary school in Huelva

Date Published: April 10, 2019

Publisher: Public Library of Science

Author(s): María-Victoria Requena-García-Cruz, Antonio Morales-Esteban, Percy Durand-Neyra, João M. C. Estêvão, Francisco Martínez-Álvarez.


A project named PERSISTAH (Projetos de Escolas Resilientes aos SISmos no Território do Algarve e de Huelva, in Portuguese) is being developed. It aims to cooperatively assess and improve the seismic vulnerability of primary schools in the Algarve (Portugal) and Huelva (Spain). A large number of schools have to be analysed. In order to determine which seismic retrofitting technique is optimal, an index-based method is presented in this paper. It considers three parameters: first, the efficiency of the seismic retrofitting technique in relation to the structural improvement obtained; second, the cost of the implementation of the retrofitting technique; and third, the architectural impact. It should be mentioned that a specific measurement for each solution according to its geometry has been performed. Also, coefficients to consider the singularities of each analysis and the importance of the parameters (number of buildings, typology, available funds, etc.) in the study are considered. The most representative primary school of Huelva has been chosen to test the index-based method. The most suitable retrofitting techniques for this type of buildings have been tested. The retrofitting technique which most increased the seismic performance has been the addition of X and V bracings within the building’s bays. Furthermore, the analyses have revealed that adding the retrofitting elements in the most vulnerable direction of the building provides a high efficiency. The results have also shown that implementing techniques of lower architectural impact gives acceptable results. The analysis of the mean damage level index has shown that the building would experiment a severe damage. All the retrofitting techniques applied have reduced it, at least, up to moderate damage. Finally, it should be noted that the position of the retrofitting elements is also paramount for providing an optimal retrofitting.

Partial Text

A European research project named PERSISTAH (Projetos de Escolas Resilientes aos SISmos no Território do Algarve e de Huelva, in Portuguese) is under development [1]. It aims to cooperatively assess and improve the seismic vulnerability of the primary schools located in the region of the Algarve (Portugal) and Huelva (Spain). The region is characterised by large earthquakes (Mw≥6) of long-return periods [2]. This is due to the convergence between the Eurasian and African tectonic plates, and to the proximity of the acquainted Gibraltar-Azores fault [3].

In this section, the fundamentals that support the methodology proposed in this paper are exposed. First, the seismic Retrofitting Index is presented (RI). Then, the parameters in which this index is based on are shown as well as the method of obtaining them. Next, the selected building’s configuration is presented. Finally, the seismic retrofitting techniques evaluated in this paper are discussed, including the modelling procedure and characteristics.

In this section, the most relevant results obtained from the models analysed are shown. First, the capacity curves for each situation are displayed. In this work, a total amount of 160 capacity curves has been obtained. The comparison percentages have been established according to the shear force of each capacity curve for the displacement of the original performance point. This is 0.06 m and 0.09 m in the X and Y direction, respectively. Then, the indexes obtained for each retrofitting technique have been established.

In this section, the results from the pushover analyses are analysed and compared. Then, the values obtained for the efficiency, cost and architectural impact obtained for each solution are analysed as well as the results obtained for the RI.

The region of Huelva is relevant due to its seismic hazard. A study of the area’s school buildings has revealed that they have one of the most seismically vulnerable building typologies. Therefore, a solution is necessary to improve their seismic behaviour in case of an earthquake. In this paper, a new index-based method for assessing different seismic retrofitting techniques has been presented and applied to a representative school in Huelva. This is based on the efficiency, cost and architectural impact of each solution in order to comply with the Hyogo and Sendai agreements. It can be reproduced to assess and compare any building’s typology and any retrofitting technique. The results have shown that this method is robust and has successfully achieved the goal proposed.