Truss rail method for punching shear strength of flat-plate slab-column using high-strength lightweight concrete

Large construction companies in Korea are particularly interested in technical solutions for high-rise buildings. In particular they are looking for ways to maximise economy by reducing the dead load and increasing the height of storeys in buildings. To achieve this, a flat-plate system using high-strength lightweight concrete has been proposed. To solve the weakness of the brittle failure of lightweight concrete as well as punching shear of the flat-plate system, this study developed a new shear reinforcement method. According to the shear reinforcement method and pitch intervals of shear reinforcement bar, the new method was assessed according to the first cracking load (P_cr) and displacement (δ_cr), the maximum load (P_max) and maximum displacement (δ_max), ductility index, reserved shear strength, economic feasibility and ease of construction. The test results indicate that with the new method, the specimen showed better shear performance and ductility effect in high-strength lightweight concrete than in normal concrete. Compared to the existing shear reinforcement method, the new method enhanced both shear strength and ductility effect as the pitch interval decreased. The truss rail method was able to reduce the quantity required and the production costs, while also improving construction efficiency.