Dynamic behavior of lightweight concrete solid slabs with EPS beads

ABSTRACT

The use of Lightweight Concrete with EPS Beads (LCBE) in structural slabs emerges as an economically attractive alternative to reduce the self-weight of reinforced concrete structures. However, the modification of the structural mass and the substitution of conventional coarse aggregate by EPS directly impact the dynamic properties of the structure. In this context, the objective of this study is to investigate the influence of replacing Conventional Concrete (CC) with LCBE on the dynamic properties of the structure, considering the significant decrease in mass and stiffness of the material. For the determination of dynamic parameters such as natural frequencies, modal deformations, and damping factors, experiments were conducted on cylindrical specimens and rectangular slabs using stochastic modal analysis methods and dynamic acoustic response tests. The results reveal clarity in modal deformations and a satisfactory approximation between experimental and numerical natural frequencies. Regarding the damping factor, it was observed that for LCBE, this parameter is slightly higher than that of CC, suggesting adequate structural integrity of the slabs. Based on the obtained results, it is concluded that for individual analyses of crack-free LCBE elements, it is recommended to adopt an average value for the damping factor of 0.5%, which proved to be higher than the corresponding average value for crack-free CC tested, of 0.4%. However, for global structural analyses, conventional theoretical values are more appropriate. Although the research provides results on the dynamic behavior of LCBE slabs, the need for additional studies under cracking conditions is emphasized for a more comprehensive understanding of the material in realistic situations.

Keywords:
Dynamic analysis; Concrete with EPS; Modal analysis; Natural frequencies; Damping