Structural behaviour of slab panel system with embedded cold-formed steel skeletal frame

Abstract

Precast lightweight slab panel system offers several advantages in construction industry, such as lightness, high strength-to-weight ratio, ease of transportation, saving of materials, and offers rapid construction. The design for the conventional reinforced concrete slab has been well established in current code of practice. There is, conversely, little scientific and technical information available for structural-grade lightweight foamed concrete (LFC) and lightweight slab panel design involving LFC incorporates with cold-formed steel (CFS) sections. This study aims to develop the design procedures for lightweight slab design, to find the optimal mix design for structural-grade LFC, to develop lightweight slab system that utilizing lightweight foamed concrete and cold-formed steel sections, to investigate the strength behaviour and to validate strength of the developed slab system via analytical and experimental investigation. Theoretical prediction on ultimate resistance and design procedure based on stress block method was deliberated. Trial mixes for structural-grade of LFC material are performed in accordance with Eurocode and ASTM to obtain the optimum mix design, with its mechanical properties are investigated. In addition, 16 full-scale slab specimens, incorporating different concrete mixes, reinforcement and CFS sections are prepared and tested to investigate the structural behaviour, such as ultimate load resistance, load-deflection profile, load-strain distributions and the failure modes. Theoretical validation for the experimental results was carried out. A design procedure for the lightweight slab panels is proposed for its possibility to be used. From the material study on LFC, an optimal mix design with cement-sand ratio of 3:1 and water-cement ratio of 0.49 was identified. Throughout the experimental investigation on full-scale slab, it was observed that all slab panels achieved the design resistance in accordance to Eurocode. Comparison is made between normal weight and lightweight slab panels revealed that the flexural resistance of lightweight slab panel is lower than that of normal weight slab panel. Nevertheless lightweight slab panel can save weight up to 47.1% relatively. The lightweight slab panels with single horizontal (SH) configuration showed the best performance. In addition, the results also exhibited that the flexural resistance of the slab panels increased as the effective steel area of cold-formed steel section increased. The convincing results concluded that the lightweight slab panel system incorporating lightweight foamed concrete (LFC) and cold-formed steel (CFS) skeletal frame is feasible to be used in construction industry.