Calculation of Deformations of Flexural Three-Layer Reinforced Concrete Elements with A Middle Layer of Arbolite

This study presents a deformation-based calculation approach for three-layer reinforced concrete (RC) elements with an arbolite insulating core. Given the insufficient theoretical foundation in current design standards and the scarcity of experimental data, a comprehensive experimental investigation was undertaken. Two series of full-scale specimens were tested to evaluate flexural behavior, particularly focusing on the influence of vertical and inclined shear reinforcement. Results demonstrate that deflections prior to cracking correlate well with theoretical predictions when both bending and shear deformations are considered. This paper proposes refined equations and section models for accurate deflection prediction in such composite systems.