This publication comprises the articles selected from the 5th EPI International Conference on Science and Engineering (EICSE, September 28-29, 2021, virtual) and is devoted to the investigation of some latest issues in structural mechanics. Vibration research of plate structures, analysis of critical load on quadrilateral and circular hollow pipes under pure bending and pure torsion and also laboratory testing and numerical analysis on reinforced concrete frames with prefabricated cellular lightweight concrete are the main covered topics. The presented research results will be interesting to mechanical engineers in structural engineering.