Steel–concrete composite systems are an efficient alternative to mid- and high-rise building structures because of their high strength-to-weight ratio when compared to traditional concrete or steel constructive systems. Nevertheless, composite structural systems are susceptible to damage due to, for example, deficient construction processes, errors in design and detailing, steel corrosion, and the drying shrinkage of concrete. As a consequence, the overall strength of the structure may be significantly decreased. In view of the relevance of this subject, the present paper addresses the damage detection problem in a steel–concrete composite structure with an impact-hammer-based modal testing procedure. The mathematical formulation adopted in this work allows for the identification of regions where stiffness varies with respect to an initial virgin state without the need for theoretical models of the undamaged structure (such as finite element models). Since mode shape curvatures change due to the loss of stiffness at the presence of cracks, a change in curvature was adopted as a criterion to quantify stiffness reduction. A stiffness variability index based on two-dimensional mode shape curvatures is generated for several points on the structure, resulting in a damage distribution pattern. Our numerical predictions were compared with experimentally measured data in a full-scale steel–concrete composite beam subjected to bending and were successfully validated. The present damage detection strategy provides further insight into the failure mechanisms of steel–concrete composite structures, and promotes the future development of safer and more reliable infrastructures.

Climate deterioration and environmental pollution has been widely studied by a wide scientific community. The effects of the ecosystem deterioration impacts directly to human activities. In this scenario, the building industry has increased the pressure on proposing new materials to replace the cementicious component and natural resources (water, sand, gravel, and limestone) on mortar and concrete to reverse this trend. To this end, organic residues can offer opportunities as an available alternative for construction applications. Therefore, this paper aims to broaden the scope of research in this field by investigating the potential use of organic residues as cementicious building material based on bibliometric-statistical analysis using scientific information. A preliminary bibliometric analysis using VOSviewer was carried out to define the keywords co-ocurrence from Scopus database. Type of organic material, constructive use, and its properties (physicochemical, mechanical, and thermal) were extracted from scientific publications. Then, a systematic analysis criteria was defined to limit the scope of the study. Finally, statistical variance analysis and multiple correlation for identifying constructive application were applied. From the co-ocurrence analysis of keywords, we determined that 54% of the selected scientific publications were closely related to the scope of this study. State-of-the-art study established that related researches grew exponentially at a rate of about $30\%$/year. Moreover, scientific publications reported the use of a wide variety of organic residues, such as wheat, paper, hemp, rice, wood, molluscs, olive, coconut, among others. Mainly, agricultural residues ($82\%$) with building applications related to structural concrete, mortar, bricks, and blocks, had been evaluated. Physicochemical properties from organic residues (extractives content, lignin content, and density) were correlated to mechanical (compressive, flexural and tensile strength) and thermal properties (thermal conductivity). The identification of the physicochemical properties of the organic residues allow us to predict the mechanical and thermal behavior of the material with residues. In summary, agricultural residues are the most promising organic building material due to their abundance and lignin content, exhibiting better mechanic and thermal properties than any other organic residues.

The prediction of structural damage through vibrational analysis is a critical task in the field of composite structures. Structural defects and damage can negatively influence the load-carrying capacity of the beam. Therefore, detecting structural damage early is essential to preventing catastrophic failures. This study addresses the challenge of predicting damage in composite concrete–steel beams using a vibration-based finite element approach. To tackle this complex task, a finite element model to a quasi-static analysis emulating a four-point pure bending experimental test was performed. Notably, the numerical model equations were carefully modified using the Newton–Raphson method to account for the stiffness degradation resulting from material strains. These modified equations were subsequently employed in a modal analysis to compute modal shapes and natural frequencies corresponding to the stressed state. The difference between initial and damaged modal shape curvatures served as the foundation for predicting a damage index. The approach effectively captured stiffness degradation in the model, leading to observable changes in modal responses, including a reduction in natural frequencies and variations in modal shapes. This enabled the accurate prediction of damage instances during construction, service, or accidental load scenarios, thereby enhancing the structural and operational safety of composite system designs. This research contributes to the advancement of vibration-based methods for damage detection, emphasizing the complexities in characterizing damage in composite structural geometries. Further exploration and refinement of this approach are essential for the precise classification of damage types.