A tuned mass damper inerter (TMDI) is a new class of passive control device based on the inclusion of an inerter mechanism into a conventional tuned mass damper (TMD). The inerter device provides inertial resisting forces to the controlled system, through relatively small masses, converting it in a mechanism with the potential to enhance the performance of passive energy dissipating systems. This work presents a study of an optimal TMDI design through an exhaustive search process. TMDI device design using the cited parameter selection methodology consists in the determination of the damper critical damping ratio,ζ_TMDI, and frequency ratio,υ_TMDI, which result in the minimum structural response of a multidegree of freedom structural system, considering predefined values for mass ratio (µ) and inertance ratio (β). The used optimization process examines all possible damping device design parameter combinations to select the set of values that results in the best device performance to reduce response parameters in a structure. Four different optimization processes are performed by independently minimizing four performance indices:J₁associated to the reduction of the structure’s maximum peak displacement,J₂calculates the minimal RMS value for the structure’s peak displacement,J₃seeks by the minimal peak interstorey drift, andJ_Pdetermines the lowest value for a linear weighted combination of the abovementioned three indices. A numerical example is developed with the purpose of validating the proposed optimization procedure and to evaluate the benefits of using TMDI as controlling devices for structures under seismic excitation, by carrying out a comparative analysis to contrast the performance of the optimization alternatives developed, running up to 1968192 cases. The obtained results show that devices designed based on exhaustive search optimization produce peak displacement reductions of up to 35% and peak structure displacementRMSreductions of up to 30%.

This paper introduces a novel methodology for the optimum design of linear tuned mass dampers (TMDs) to improve the seismic safety of structures through a novel Whale Optimization Algorithm (WOA). The algorithm is aimed to reduce the maximum horizontal peak displacement of the structure, and the root mean square (RMS) response of displacements as well. Furthermore, four additional objective functions, derived from multiple weighted linear combinations of the two previously mentioned parameters, are also studied in order to obtain the most efficient TMD design configuration. The differential evolution method (DEM), whose effectiveness has been previously demonstrated for TMD applications, and an exhaustive search (ES) process, with precision to two decimal positions, are used to compare and validate the results computed through WOA. Then, the proposed methodology is applied to a 32-story case-study derived from an actual building, and multiple ground acceleration time histories are considered to assess its seismic performance in the linear-elastic range. The numerical results show that the proposed methodology based on WOA is effective in finding the optimal TMD design configuration under earthquake loads. Finally, practical design recommendations are provided for TMDs, and the robustness of the optimization is demonstrated.

Infrastructure development is a common feature of emerging countries. As a result, the design and construction of complex structures susceptible to damage is becoming increasingly common. Over the years, multiple advances in Structural Health Monitoring (SHM) haven allowed researchers and engineers to detect, locate, and quantify structural damage in critical components of civil engineering structures. Frequency-based methods have demonstrated their reliability in multiple numerical and experimental applications. This study presents a brief chronological literature review of methodologies based on frequency analysis that have been used in the detection ofstructural damage over the last forty years. It is worth noting that the paper focuses on computer-aided techniques such as artificial neuronal networks (ANN), genetic algorithms (GAs), and metaheuristics that have been employed to solve the inverse damage detection problem.

Debido al alto índice de crecimiento demográfico y la poca disponibilidad de tierra que enfrentan las grandes ciudades, la disposición de residuos sólidos se ha convertido en una problemática constante para las administraciones; adicionalmente, se suma el aumento de las lluvias por largos periodos lo que combinado con prácticas deficientes en la captación de aguas de escorrentía en los rellenos sanitarios, ocasiona una mayor producción de lixiviados en los sitios de disposición. Para estudiar el efecto que pueden generar los lixiviados de residuos sólidos en los suelos tropicales, se caracterizaron geotécnicamente dos muestras de suelo residual del mismo origen, una expuesta al efecto de lixiviados de residuos sólidos por más de 15 años y otra en condiciones naturales (no contaminada), con el objeto de estimar el efecto que genera la presencia del contaminante en las propiedades geotécnicas de dicho suelo residual. La investigación se realizó mediante una campaña de ensayos de laboratorio para caracterizar las propiedades físicas, químicas, estructurales, mecánicas y mineralógicas de los suelos. Los resultados permitieron establecer que la exposición de la muestra contaminada a los lixiviados genera cambios significativos en sus propiedades físicas, químicas, estructurales, hidro-mecánicas y mineralógicas. En consecuencia, se presenta una degradación del comportamiento geotécnico de los suelos expuestos a contaminantes, lo que debe servir como base para generar conciencia en las autoridades ambientales y que se impongan normativas más rígidas ante la disposición inadecuada de lixiviados y en general cualquier tipo de contaminante lanzado directamente al sub-suelo.