Study on the Bending Performance of Steel Frame-LFT Glass Fiber Reinforced Tempered Surface Layer Composite Formwork

Abstract

To address the unsuitability of traditional construction formwork for the complex conditions of pipeline corridor projects, and after considering factors such as cost and quality, LFT (Long Fiber Thermoplastic) tempered boards were selected as the face material. These were combined with steel frames of higher structural strength to create a steel frame-LFT glass fiber reinforced tempered surface layer composite formwork. This study includes both experimental testing and numerical simulations of the pipeline corridor system, analyzing the effects of various parameters on performance. The experiment focused on the influence of two variables—support spacing and the number of support points—on the formwork's load-bearing performance, comparing it with traditional steel formwork. The results showed that the failure mode was characterized by unstable bending, with the panel bending and the steel frame bulging, and some specimens showing cracks at mid-span. As the support spacing increased, the ultimate load-bearing capacity and stiffness of the steel frame-LFT glass fiber reinforced surface composite formwork decreased. Fewer support points led to a more significant reduction in both load-bearing capacity and stiffness. Compared to traditional steel formwork, the steel frame-LFT glass fiber reinforced surface composite formwork demonstrated similar load-bearing capacity and stiffness, while being lighter in weight and having a higher turnover rate. The steel frame-LFT glass fiber reinforced surface composite formwork exhibited excellent performance in terms of load-bearing capacity and initial stiffness, meeting the strength requirements for construction formwork. It can replace traditional steel formwork in practical applications, particularly in environments with shorter support distances. Based on the combined results of the experiments and numerical simulations, the optimal support spacing and number of support points were identified. These findings offer valuable insights for the design and application of such formwork systems in future engineering projects.