To　study　the　load　resisting　mechanisms　of　unbonded　prestressed　concrete　(UPC)　structures　with　different　tendon　profiles　(straight　or　parabolic　profile)　subjected　to　a　middle　column　removal　scenario,　two　1　/　2　scaled　UPC　specimens　and　one　reinforced　concrete　(RC)　specimen　were　tested　by　pushdown　loading　regime.　Test　results　indicate　that　the　load　resistance　of　the　UPC　specimens　with　straight　or　parabolic　tendons　is　95%　and　189%　higher　than　that　of　the　RC　specimen,　respectively.　However,　the　presence　of　tendons　results　in　higher　horizontal　tensile　reaction　forces,　which　in　turn　cause　more　severe　damage　to　the　side　columns　of　the　UPC　specimens　than　that　of　the　RC　specimen.　The　failure　of　the　UPC　specimen　with　parabolic　tendon　and　the　RC　specimen　is　controlled　by　the　fracture　of　the　beam　rebar　whereas　the　failure　of　the　UPC　specimen　with　straight　tendon　is　controlled　by　fracture　of　the　tendon.　Moreover,　high-fidelity　finite　element　(FE)　models　are　built　using　LS-DYNA.　After　validation,　the　FE　models　are　employed　to　conduct　a　parametric　study.　The　parametric　study　results　indicate　that,　for　the　same　tendon　ratio,　the　load　resistance　of　the　UPC　specimen　with　straight　tendon　is　20%　-58%　higher　than　that　of　the　UPC　specimen　with　the　parabolic　tendon.　The　development　of　catenary　action　in　the　straight　tendon　occurs　throughout　the　whole　loading　history,　while　the　development　of　catenary　action　in　the　parabolic　tendon　begins　when　the　displacement　exceeds　one　beam　depth.　©　2023　Science　Press.　All　rights　reserved.