Structural and Thermal Performance of a Novel Form of Cladding Panel: the I-beam Beetle Elytron Plate

To develop a nonbearing prefabricated straw sandwich concrete wallboard (I-beam beetle elytron plate: IBEPsc), the effect of certain structural parameters (e.g., panel thickness T, number of I-cores N and core height h) on the mechanical and thermal insulation performance was investigated by using the finite element method. The results are as follows: 1) The bearing capacity of the IBEPsc is controlled by the maximum principal tensile stress; the optimal structural parameters of the IBEPsc for a self-insulated wall with a large safety margin are presented. 2) The consideration of strips vs. whole plates and the selected upper bearing constraint type have little influence on the mechanical properties. In practical applications, the strips and whole plates can be reasonably selected according to engineering needs, and these components can be connected with the main structure by conventional mortar. 3) According to a qualitative analysis and comparison with common I-shaped thermal insulation walls, the IBEPsc requires the least material and weight while ensuring a sufficient safety margin in terms of mechanical and thermal insulation performance. Hence, biomimic techniques can play a key role in breaking through the limitations of traditional structures. This paper can help direct the application of beetle elytron plates in prefabricated wallboards.

Performance of variously shaped glass-fibre-reinforced polymer bars in concrete columns

An investigation was carried out into the structural performance of concrete columns reinforced with various shapes of glass-fibre-reinforced polymer bars and stainless-steel stirrups under concentric loading at ultimate limit state. Six square-section columns were cast to investigate the effects of different reinforcement types. The results showed failure modes depended on reinforcement material, shape and stirrup spacing. Across all specimens, steel-reinforced columns had higher loading capacity and better ductile performance, followed by L-shape and then round polymer bars. Smaller spiral spacing increased confinement efficiency and ductility and provided sufficient restraint against longitudinal polymer bar buckling. Finite-element models were also calibrated, and the results were in close agreement with experimental measurements. Based on the calibrated models, numerical parameters were studied to understand further the behavior of composite columns reinforced with glass-fibre-reinforced polymer.