Nugroho, G., & Aughitri, F. (2026). Effects of Square Body Openings in Castellated Steel Beams on Stiffness and Natural Frequencies. INERSIA Lnformasi Dan Ekspose Hasil Riset Teknik Sipil Dan Arsitektur, 22(1), 40–48. https://doi.org/10.21831/inersia.v22i1.87871