INVESTIGATION OF THE FLEXURAL STRENGTH OF COLD-FORMED STEEL C-SECTIONS USING COMPUTATIONAL AND EXPERIMENTAL METHOD
Keywords:Cold-formed Steel, C-section, Four-Point Bend Test, ANSYS, NSCP
Cold-formed steel (CFS) as a structural material has gained popularity because of its high strength-to-weight ratio. In the Philippines, the demand to use it as the structural member has increased recently. However, verification of its actual strength is not extensively studied in the country. To conform to the design standards of the local code, the National Structural Code of the Philippines (NSCP), CFS as a structural member are required to be ductile. However, it was discovered that CFS with higher strength but with brittle behavior is also being commercially distributed in the country. The objective of this study is to investigate the flexural strength of CFS made of these steel materials with the use of the computational and experimental method. The computational method covers the calculation of the theoretical flexural strength based on the NSCP provisions while the experimental method covers the actual flexural strength based on the four-point bend test. A total of 24 specimens of back-to-back C-sections of different thicknesses and lengths were tested. Additional finite element method (FEM) calculation was also conducted using ANSYS. The main failure modes were distortionalbuckling (DB) and lateral-torsional buckling (LTB). For the ductile CFS, DB and LTB were observed in 86.1% and 13.9% of specimen population, respectively. While for the brittle CFS, DB and LTB were observed in 75.0% and 25.0%, respectively. Moreover, it was found that the computational strengths were lower than the experimental strengths. The FEM analysis results were close to the experimental results thus validating the experimental results.