Javier Fernando Jiménez-Alonso

Esta guía desarrolla una metodología integral para la aplicación del Análisis Modal Operacional (OMA) en la conservación del patrimonio arquitectónico. El OMA es una técnica no invasiva que permite identificar las propiedades dinámicas de estructuras históricas —frecuencias naturales, modos de vibración y amortiguamiento— a partir de vibraciones ambientales, sin necesidad de excitación artificial. La obra aborda fundamentos teóricos, procedimientos de adquisición y tratamiento de datos, y aplicaciones orientadas al control de intervenciones estructurales y la calibración de modelos numéricos de elementos finitos. Además, incorpora cinco casos de estudio reales: el Teatro Romano de Cádiz, la Capilla de la Jura de Jerez, los Monasterios de San Jerónimo de Sevilla y Granada, y la Capilla del Palacio de Würzburg (Alemania). La guía ofrece un protocolo práctico y replicable para arquitectos, ingenieros e investigadores dedicados al diagnóstico estructural del patrimonio histórico.

Evolutionary game theory allows determining directly the solution of the maximum likelihood finite element model updating problem via the transformation of a bi-objective optimization problem into a game theory problem. The formulation of the updating problem as a game avoids the computation of the Pareto front and the solution of the subsequent decision-making problem, the selection of the best solution among the elements of the Pareto front. For this purpose, each term of the bi-objective function is considered as a player that interacts collaboratively or non-collaboratively with the other player during the game. One of the main advantages of this method is that a different global optimization algorithm can be associated with each player. In this manner, a higher performance in the solution of the updating problem is expected via the linking between each term of the objective function (a player) and the algorithm considered for its minimization. In this study, this advantage is analysed in detail. For this purpose, the finite element model updating process of a real footbridge, the Viana do Castelo footbridge, has been considered as a benchmark. As global optimization algorithms, different nature-inspired computational algorithms have been considered. The updating problem has been solved using two different methods: (i) the linking of a conventional bi-objective optimization method together with a decision-making method; and (ii) an evolutionary game theory method. As a result, a higher performance of the game theory method has been highlighted. Additionally, the influence of the considered optimization algorithm in the updating process has been noted.

Human–Structure Interaction (HSI) can significantly influence the dynamic characteristics of pedestrian footbridges, particularly those distinguished by their lightness and slenderness. This study examines the performance of Tuned Mass Dampers (TMD) and Semi-Active Tuned Mass Dampers (STMD) on pedestrian footbridges when their modal parameters change due to the influence of HSI. For this purpose, a 30 m long simply-supported footbridge with linear mass values ranging from 200[ ]kg/m to 2[ ]000[ ]kg/m and a fundamental frequency varying from 1[ ]Hz to 5[ ]Hz has been considered. In addition, several pedestrian streams with different pedestrian densities have been used to assess the structural dynamic response. The analysis highlights that structural lightness and slenderness are critical factors in determining whether the incorporation of an HSI model is relevant to accurately predict the dynamic performance of the structure. The findings indicate that while TMDs can become ineffective due to shifts in natural frequencies caused by HSI, resulting in a degradation of vibration reduction from 70–75% to 40–45%, STMDs demonstrate a robust capability to adjust and cope with these frequency changes, maintaining a higher average vibration reduction of around 55–60%. Consequently, STMDs emerge as a necessary solution for very slender structures where HSI significantly alters the global frequency response. This study highlights the importance of considering HSI in the design and implementation of damping solutions to ensure optimal functionality and user comfort on lightweight pedestrian bridges.

Ultra-fine blast-furnace slag binders have recently been introduced to repair masonry. The reduced particle diameter of these binders makes them especially suitable for use as grouts, since this characteristic enables these grouts to fill even the smallest voids. The current necessity and effectiveness of Finite Element Analysis in any process concerning construction, repair or reinforcement of building structures remains unquestionable. In this way, the calibration of Finite Element material models for their correct performance has become compulsory. Regarding quasi-brittle materials, such as mortar and grouts, the Microplane model is recommended to reproduce their behaviour. This paper is targeted towards obtaining Microplane model coefficients to exactly reproduce the behaviour of ultrafine blast-furnace slag grout samples. To this end, several compressive tests have been carried on in order to obtain the experimental stress–strain curves that define the behaviour of these samples. Furthermore, reverse engineering by means of an optimisation algorithm successfully attained the possible coefficients to reproduce this material with the Microplane model. The correctness of these coefficients has been verified with a new campaign composed of compressive tests, Double Punch tests, and flexural tests. These tests have been reproduced by Finite Element Analysis, thereby confirming the accuracy of the set of coefficients. Thus, two are the main conclusions obtained: (1) the framework for the modelling of ultra-fine blast-furnace slag grout elements based-on the Microplane model has been proposed, implemented and validated; and (2) a value for the coefficients of the abovementioned model has been proposed.