Mostaganem, in Algeria, has experienced several seismic activities in recent years. It was classified in a zone of high to medium seismic activity according to the actual Algerian earthquake regulation. This ensures the safety of new constructions, however, the code done not include a technical reference for the seismic analysis and protection of existing constructions, in Algeria. The aim of this research is to constitute seismic scenarios of the masonry buildings used for educational purpose; therefore, the realization of seismic scenarios consists in crossing the data resulting from the seismic hazard (intensities) with those resulting from the analysis of the vulnerability. The analyses of the urban system will make it possible to interpret the scenarios in terms of functional damage. Seismic vulnerability of existing buildings was assessed under the RISK-UE method, which was selected to be suitable and applied to Algerian buildings for its convenience and simplicity. As a sample, 29 educational establishments (among of 199 masonry buildings for different use: primary school, middle school, secondary school, universities.) located in the historic city center of Mostaganem were assessed to identify the seismic vulnerability index, to allow to simulate seismic scenarios. The seismic vulnerability index is varied between 0.6 and 1.10 according to the diagnoses of each building carried out in the study area, The data from the vulnerability analysis are combined according to the RISK-UE approach (beta law) with the latter estimate by seismic hazard (seismic intensity), This correlation led to the birth of eight seismic scenarios expressing the results in terms of functional damage. As a result, moderate to heavy damage is expected for vulnerable constructions, significant economic losses are also expected for IEMS-98 >8 intensities. These seismic scenarios were considered and incorporated through a geographic information system (GIS) Guide decision makers estimated the severity and magnitude of the seismic risk for the remaining educational buildings in Mostaganem; or in other cities of the country to implement preventive measures and naturally reduce the risk of disaster by reducing vulnerability. Recommendations can be proposed to the Algerian authorities to simulate and facilitate efforts to take concrete preventive measures to strengthen existing educational buildings in order to reduce the negative effects of future earthquakes.

Existing seismic vulnerability has become a topical of actuality, concerning both new and old buildings. Several techniques have been used to allow structures to better resist seismic events. In recent years, these have been so-called intelligent materials such as shape memory alloys (SMAs) due to their superelasticity and their ease in returning to their initial state after deformation, which can reach 10%. In the present article, nickel–titanium SMA is considered in a minaret of an old church transformed into a mosque to control the seismic response in terms of displacements, stresses and accelerations. The assessment of the seismic behavior was performed based on a modal and then transient analysis with Ansys software. The main objective was to determine the effectiveness of the addition of shape memory alloys by varying their number.

The direct modeling of masonry infill walls on many buildings, based on damage recorded by various past earthquakes, has become increasingly necessary in order to identify the seismic behavior of these elements, which constitute an important part of reinforced concrete buildings. In this paper, several 3D models were analyzed by the nonlinear static (pushover) method, when ignoring, and when considering, masonry infill walls. The finite element software SAP analyzed the proposed models. These models represent low and mid-rise reinforced concrete buildings infilled with double-leaf hollow bricks. The properties of materials used in Algeria, either in the frame elements or the infill elements, were used. The results obtained were compared according to two parameters, the natural time period of the building and the pushover curve, by varying the values of the dead load and the concrete compressive strength. The results were discussed according to the suggested parameters. The results showed that indirect modeling of such walls, either by taking assumptions embedded in the seismic behavior factor or by means of the macro-modal, can lead to a poor appreciation of the seismic behavior of such buildings. Consequently, direct modeling of walls by the infill of the real void showed acceptable results to some extent. This contributes greatly towards understanding the seismic behavior of this type of building.

The traditional optimization methods are effective when dealing with small-scale problems. However, for large-scale problems, these methods fail to obtain optimal solutions, and after a long operation, several solutions are obtained. New methods, known as metaheuristics, have provided new implementations to be used in many applications. They have enabled the resolution of many complex industrial and technical problems. They have the merits of avoiding local optima and finding optimal solutions, due to their ease of understanding, flexibility, adaptation simplicity, and ability to get out of local optima traps. This article aims to model a 2D metal frame gantry with two spans and two levels already optimized by ROBOT Millennium software in order to show the effect of structural optimization in the pre-design phase and of obtaining its non-linear behavior by the pushover method. Three optimal dimensional configurations of this gantry were taken into account and the best was chosen, one which satisfied an adequate behavior in the non-linear domain while respecting the CM66 and Eurocode3 regulations.