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1st Int. Transborder Conf. of the Timor Island: Timor %u2013 Science without borderDili, 7-8 May 2025172Keywords: Weighted Simpson index; optimal point; reciprocal weights; proportions.Experimental Study On The Pull-Out Strength of Tek Screws In Cold-Formed Steel Roof Connections Under Wind Load ConditionsLeonel S. G. Madeira, Hugo Ximenes and Toshihiko AsoDepartment of Civil Engineering, Universidade Nacional Timor Lorosa%u2019e, Timor-LesteDepartment of Civil and Environmental Engineering, Yamaguchi University, JapanCorresponding authors: leonel.madeira@untl.edu.tl; hugo.ximenes@untl.edu.tl; aso@yamaguchi-u.ac.jpAbstractIn recent years, damage to lightweight steel roof systems in Timor-Leste caused by strong wind events has raised concerns about the pull-out capacity of tek screws used in cold-formed steel connections. This study presents a combined experimental and analytical investigation into the behavior of tek screw connections with different thread configurations. Two test series were conducted using 12%u00d724-25 mm and 14%u00d710-25 mm self-drilling screws. Results show that threads per inch (TPI) significantly influence pullout strength. Notably, connections with two 14%u00d710-25 screws achieved an ultimate pullout force of 4.5 kN, while four 12%u00d724-25 screws reached only 4.6 kN. A new simplified formula is proposed that incorporates TPI and failure zone perimeter as governing parameters. Failure occurred at the steel plate rather than the screw, highlighting the importance of thread configuration, perimeter, and thickness. The findings contribute to more resilient design practices in roof system construction.Keywords: Cold-formed steel, screw connection, TPI, pull-out strength, roof structure, climate change in Timor-Leste.