Title: Energy Absorption and Other Structural Parameters of Two-Layer Reinforced Concrete Beams
Authors: John Ayibatunimibofa TrustGod
Volume: 10
Issue: 1
Pages: 68-73
Publication Date: 2026/01/28
Abstract:
This study investigates the energy absorption and structural performance of single-layer and two-layer reinforced concrete beams with varying concrete grades. Seven simply supported beams were tested under four-point bending to evaluate the effects of layer configuration and material distribution on load-deflection response, energy absorption, stiffness, ductility, cracking behavior, and ultimate strength. Energy absorption was quantified using the area under the load-deflection curve, calculated via the trapezoidal rule. Results show that placing higher-strength concrete in the compression zone significantly enhances energy absorption, bending capacity, and failure load, while lower-strength concrete in the tension zone improves strain redistribution and crack bridging. Two-layer beams demonstrated superior post-cracking stiffness and ductility compared to single-layer beams, highlighting the benefits of strategic layer placement. First-crack and yield load measurements indicate that layering delays crack initiation and improves deformation capacity. Load-deflection curves exhibit typical multi-stage behavior, with initial elastic, cracked elastic, and post-yield softening stages, where higher stiffness is associated with increased peak load and ductility. Overall, the findings demonstrate that optimized two-layer configurations can outperform single-layer beams in terms of energy absorption, toughness, and deformation capacity while maintaining adequate load-carrying performance. These insights provide guidance for the design of more efficient, resilient, and sustainable reinforced concrete beams by enabling targeted use of higher-grade concrete in critical zones and lower-grade or alternative concretes in less stressed regions.