Out-of-plane flexural behaviour tests and numerical analysis of LEM-infilled CFS walls

Abstract

With carbon neutrality gradually becoming the global focus, employing the energy-saving wall in structure has become the development trend of energy-efficient buildings. This paper focuses on a novel type of cold-formed steel (CFS) wall in which lightweight expanded polystyrene (EPS) mortars (LEM) are filled in the space of CFS framing. The CFS framing and LEM are formed into a whole to resist the bending moment demands. To explore the flexural response of the LEM-infilled CFS wall, six specimens were designed and tested. These specimens included two specimens without wall sheathing and four specimens sheathed with various panel types. The specimens were subjected to gradually increased uniformly distributed loads. Failure patterns, load–deflection relationships, capacities and strain distribution of typical points were also analyzed. Test results illustrated that the flexural bearing capacities of the specimens were 9.69–13.14 times their self-weight. Specimens with sheathings exhibited better flexural response, and specimens with cement-based LEM exhibited higher flexural stiffness and capacities than that of specimens with gypsum-based LEM. Subsequently, finite element (FE) models of LEM-infilled CFS walls were developed and validated by the test data. Effects of steel yield strength, steel thickness, LEM compressive strength and wall panel type on the flexural behaviours of LEM-infilled CFS walls were explored by parametric studies. The transformed cross-section method was employed to calculate the mid-span deflection and the results were validated by test and FE analytical results. The analysis in this research could provide reasonable references for design and application.